2.4GHzPCB天线
2.4GHz 天线设计
λ/4 printed monopole antenna for 2.45GHz1.PrefaceTaking the demand for small size, easy fabrication and low cost into account in the development of low-power radio devices for short-range 2.4GHz applications, a quarter wavelength monopole antenna implemented on the same printed circuit board as the radio module is a good solution. A printed quarter wavelength monopole antenna is very easy to design and can be tuned simply by slight changes in length.This article presents basic guidelines on how to design such an antenna for use together with the 2.4GHz transceiver and transmitter devices from Nordic Semiconductor.The described antenna should be fabricated on standard 1.6mm, low cost FR4 printed circuit board (PCB).2.Basic properties of a quarterwave monopole antennaA quarterwave monopole is a ground plane dependent antenna that must be fed single-ended. The antenna must have a ground plane to be efficient, and ideally the ground plane should spread out at least a quarter wavelength, or more, around the feed-point of the antenna. The size of the ground plane influences the gain, resonance frequency and impedance of the antenna.The length of the monopole PCB trace mainly determines the resonant frequency of the antenna, but because of the very wide gain bandwidth of a quarterwave monopole, the antenna length is not too critical. But like any other antenna types, the gain of a quarterwave monopole will vary if parameters in the surroundings, such as case/box materials, distance to the ground plane, size of the ground plane, width and thickness of the PCB trace are varied. If any of these parameters are changed, a retuning of the monopole PCB trace length may be necessary for optimum performance in each application.3.Determining the length of the printed monopole antennaThe antenna is fabricated on a standard 1.6mm FR4 substrate material with a typical dielectric constant εr of 4.4 at 2.45GHz.The width of the monopole trace is W = 1.5mm. The wavelength in free air is λ0 = 122mm. It may be approximated that the guided wavelength λg on the FR4 substrate is about λg ˜ 0.75 · λ0 = 0.75 · 122mm ˜ 92mmThe approximate, physical length of a printed quarterwave monopole antenna is then L = 92mm / 4 = 23mmprovided that the size of the available ground plane is close to the ideal as discussed above and that the antenna trace is uniformly surrounded by the FR4 substrate.When implementing the monopole as a trace on the PCB, the length of the trace should be extended somewhat to allow for some fine-tuning of the antenna to resonance at 2.45GHz. If the size of available ground plane is approaching the ideal size and the antenna trace is uniformly surrounded by the FR4 substrate, then the length of the trace should be extended by about 20%. For an example, see Figure 1a.If the ground plane size is considerably smaller than the ideal size and/or much of the antenna trace is routed close to the edge of the PCB, then the length of the antenna trace should be extended by about 30%. For an example, see Figure 1b.bining the printed quarterwave monopole with the nRF24xxdevice RF-layoutThe quarterwave monopole must be fed single-ended, hence a differential to single-ended matching network must be used between the nRF24xx antenna interface ANT1/ANT2 and the monopole feed-point. A suggestion on a differential to single-ended matching network can be found in the nRF24xx datasheet.Figure 1 shows two examples on how a printed quarterwave monopole can be combined with the nRF2401 RF-layout on the same PCB. Figure 1a shows the optimum placement of the antenna trace. With this placement, the antenna is allowed to radiate freely in all directions. The monopole has maximum radiation in the plane normal to the antenna axis, and minimum radiation along the axis. To be omni-directional, the monopole antenna should be placed vertically.Figure 1b shows a more compact layout of the antenna trace. This layout may have lower antenna gain in the direction of maximum radiation than for the layout shown in Figure 1a, but it will exhibit a more uniform radiation in the horizontal plane if vertical placement is not possible.When bending the antenna trace like in Figure 1b, be sure to keep the distance (d) between the open end of the antenna trace and the ground plane as large as possible, preferably 10mm or more. Reducing this distance will reduce the gain of the antenna.There shall be no ground plane on the PCB layer(s) beneath the antenna trace. No ground plane, PCB traces or components should be placed close to the antenna trace.a) b)Figure 1. Examples of nRF2401 RF-layout combined with a printed λ/4 monopole antenna.Tuning of the antenna is done simply by cutting the length of the PCB antenna trace until resonance at 2.45GHz is obtained. The antenna must be tuned with the PCB placed inside the case/box (if any) and hand-held/body-worn (if this is a hand-held/body-worn application).For applications where range performance is not critical the antenna can be tuned by measuring radiated power from the antenna with a spectrum analyzer. For more accurate tuning a vector network analyzer must be used for impedance and SWR (Standing Wave Ratio) measurements.As shown Figure 1 the PCB antenna trace should be made 20%-30% longer than the estimated theoretical length in order to make tuning possible on prototypes. For the production version of the PCB, the optimum antenna length found on the prototype should be used.LIABILITY DISCLAIMERNordic Semiconductor ASA reserves the right to make changes without further notice to the product to improve reliability, function or design. Nordic Semiconductor does not assume any liability arising out of the application or use of any product or circuits described herein. LIFE SUPPORT APPLICATIONSThese products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. Nordic Semiconductor ASA customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Nordic Semiconductor ASA for any damages resulting from such improper use or sale.White paper. Revision Date: 2005-01-21.All rights reserved ®. Reproduction in whole or in part is prohibited without the prior written permission of the copyright holder.YOUR NOTESNordic Semiconductor - World Wide DistributorFor Your nearest dealer, please see http://www.nordicsemi.noMain Office:Vestre Rosten 81, N-7075 Tiller, NorwayPhone: +47 72 89 89 00, Fax: +47 72 89 89 89Visit the Nordic Semiconductor ASA website at http://www.nordicsemi.no。
2.4g板载天线工作原理 -回复
2.4g板载天线工作原理-回复2.4G板载天线工作原理引言：随着无线通信技术的不断发展和普及，2.4G无线信号已经成为日常生活中最常见的无线信号之一。
在许多电子设备中，如智能手机、电脑、无线路由器等，都配备了2.4G板载天线。
本文将详细介绍2.4G板载天线的工作原理，从电磁波的产生到信号的传输，一步一步解释板载天线是如何实现无线通信的。
第一部分：电磁波的产生在理解2.4G板载天线的工作原理之前，首先需要了解电磁波的产生过程。
电磁波是由振荡的电荷产生的，并由电磁场组成。
当电子在导体中产生振荡时，会产生电场和磁场，即电磁波。
在2.4GHz的频段，天线通过快速振荡的电荷在导体中产生2.4GHz的电磁波信号。
第二部分：板载天线的结构2.4G板载天线通常由导体材料制成，如铜箔或铜丝。
这些导体散布在电子设备的主板上，并通过电路连接到无线模块。
板载天线可以有多种不同的形状和构造，包括贴片天线、螺旋天线和PCB天线。
这些天线的设计和排列方式会影响天线的性能和发射信号的范围。
第三部分：信号的接收和发射在接收方面，2.4G板载天线接收到外部的无线信号，并将其转换为电信号。
通过相应的电路处理和放大后，这些电信号可以被设备的其他部分识别和使用。
在发射方面，设备需要将要发送的信号转换为电信号，并通过电路传输到天线。
板载天线会将电信号转换为相应的电磁波信号，进而将信号发送到空中。
第四部分：天线性能与设计优化天线的性能和设计对无线通信的质量起着至关重要的作用。
一些主要的性能指标包括天线增益、方向性、辐射效率和频率响应等。
天线增益是指天线在某个方向上辐射或接收信号的能力。
增益越高，天线的传输范围和接收灵敏度越大。
方向性是指天线在不同方向上接收或辐射信号的能力。
一些天线设计可以实现更加定向的辐射，可以将信号更准确地发送或接收到特定的位置。
辐射效率是指天线将电信号转换为电磁波信号的能力。
辐射效率越高，天线发射或接收的信号质量越好。
2.4g板载天线工作原理
2.4g板载天线工作原理2.4GHz板载天线工作原理随着无线通信技术的发展，2.4GHz频段的应用越来越广泛，而板载天线作为一种常见的天线形式，被广泛应用于无线设备中。
本文将介绍2.4GHz板载天线的工作原理。
一、背景介绍随着物联网、无线通信等技术的迅猛发展，无线设备的需求也越来越大。
尤其是在2.4GHz频段，无线网络、蓝牙、无线传感器等应用广泛。
而板载天线作为一种集成度高、适用于小型设备的天线形式，成为了2.4GHz频段应用中常见的选择。
二、板载天线的结构组成板载天线是指将天线直接集成在电路板上的天线形式。
通常由天线元件、馈线以及与电路板相连的匹配电路等组成。
其中，天线元件一般采用PCB打印工艺制作，可以是线性天线、贴片天线等形式。
三、天线元件的特性与选择天线元件的特性直接影响着天线的性能。
在2.4GHz频段中，一般选择具有较好性能的天线元件，如PCB打印的贴片天线。
这种天线元件体积较小，频段适应性好，并且具有较高的辐射效率和天线增益。
四、馈线与匹配电路在设计板载天线时，合适的馈线和匹配电路能够提高天线的性能。
馈线的长度和宽度应根据设计需求和电路板的尺寸来确定，以确保天线能够正常工作，并且有良好的阻抗匹配。
匹配电路一般采用电感和电容来实现，以进一步提高天线的阻抗匹配。
通过合理设计匹配电路的参数，可以改善天线的反射损耗和传输效率。
五、板载天线的辐射原理板载天线的工作原理基于安培环路定理和法拉第电磁感应定律。
当电流通过天线元件时，会在周围产生一个电磁场。
通过馈线和匹配电路的设计，将电磁能量转化为电磁波，并向空间辐射。
六、优化设计与性能提升在设计2.4GHz板载天线时，需要考虑到天线的辐射效率、工作带宽、方向性等因素。
通过优化天线元件的几何结构、馈线的设计以及匹配电路的参数选择，可以提高天线的性能。
七、应用领域及发展趋势2.4GHz板载天线广泛应用于各种无线设备中，如智能穿戴设备、智能家居、车联网等。
2.4G天线设计完整指南设计(原理、设计、布局、性能、调试)
本文章使用简单的术语介绍了天线的设计情况，并推荐了两款经过测试的低成本PCB天线。
这些PCB天线能够与PRoC?和PSoC?系列中的低功耗蓝牙(BLE)解决方案配合使用。
为了使性能最佳，PRoC BLE和PSoC4 BLE2.4GHz射频必须与其天线正确匹配。
本应用笔记中最后部分介绍了如何在最终产品中调试天线。
1、简介天线是无线系统中的关键组件，它负责发送和接收来自空中的电磁辐射。
为低成本、消费广的应用设计天线，并将其集成到手提产品中是大多数原装设备制造商(OEM)正在面对的挑战。
终端客户从某个RF产品(如电量有限的硬币型电池)获得的无线射程主要取决于天线的设计、塑料外壳以及良好的PCB布局。
对于芯片和电源相同但布局和天线设计实践不同的系统，它们的RF(射频)范围变化超过50%也是正常的。
本应用笔记介绍了最佳实践、布局指南以及天线调试程序，并给出了使用给定电量所获取的最宽波段。
图1.典型的近距离无线系统设计优良的天线可以扩大无线产品的工作范围。
从无线模块发送的能量越大，在已给的数据包错误率(PER)以及接收器灵敏度固定的条件下，传输的距离也越大。
另外，天线还有其他不太明显的优点，例如：在某个给定的范围内，设计优良的天线能够发射更多的能量，从而可以提高错误容限化(由干扰或噪声引起的)。
同样，接收端良好的调试天线和Balun(平衡器)可以在极小的辐射条件下工作。
最佳天线可以降低PER，并提高通信质量。
PER越低，发生重新传输的次数也越少，从而可以节省电池电量。
2、天线原理天线一般指的是裸露在空间内的导体。
该导体的长度与信号波长成特定比例或整数倍时，它可作为天线使用。
因为提供给天线的电能被发射到空间内，所以该条件被称为“谐振”。
图2. 偶极天线基础如图2所示，导体的波长为λ/2，其中λ为电信号的波长。
信号发生器通过一根传输线(也称为天线馈电)在天线的中心点为其供电。
按照这个长度，将在整个导线上形成电压和电流驻波，如图2所示。
2.4g天线效率范围
2.4g天线效率范围
2.4GHz 天线的效率通常取决于多个因素，包括天线设计、制造质量、安装环境等。
一般来说，2.4GHz是用于Wi-Fi、蓝牙等通信标准的频段，而天线的效率对通信性能至关重要。
以下是一些关于2.4GHz 天线效率的一般性信息：
1.内置设备天线：一些设备（如无线路由器、蓝牙设备）内置了
小型PCB（Printed Circuit Board）天线。
这类天线的效率通常
在50%到70%之间，但具体取决于设计和制造质量。
2.外置天线：外置天线的效率可以更高，通常在70%到90%之间。
这种类型的天线常用于无线路由器、Wi-Fi适配器、蓝牙设备等。
3.定向天线：一些特定应用需要定向天线，例如用于点对点通信
的定向天线或用于无线网络的方向性天线。
这些天线的效率可
以更高，达到90%以上。
4.安装环境：天线效率还受到安装环境的影响。
例如，天线在受
阻碍或有多径效应的环境中可能表现不佳，导致效率下降。
5.设计技术：使用不同的天线设计技术（例如贴片天线、螺旋天
线、定向天线等）也会影响天线的效率。
要准确评估特定天线的效率，通常需要进行天线测试或查阅制造商提供的技术规格。
在实际应用中，保持天线的正确安装和定期检查可以确保天线效率的最佳性能。
AN91445_2.4G板载天线设计
The /2-length antenna shown in Figure 2 is called a dipole antenna. However, most antennas in printed circuit boards achieve the same performance by having a /4-length conductor in a particular way. See Figure 3. By having a ground at some distance below the conductor, an image is created of the same length (/4). When combined, these legs work like a dipole antenna. This type of antenna is called the quarter-wave (/4) monopole antenna. Most antennas on the PCB are implemented as quarter-wave antennas on a copper ground plane. Note that 3 the signal is now fed single-ended and that the ground plane acts as the return path. Figure 3. Quarter-Wave Antenna
Contents
1 2 3 4 5 6 7 Introduction ...............................................................1 Antenna Basics.........................................................2 Antenna Types .........................................................4 Choosing an Antenna ...............................................5 Antenna Parameters.................................................5 Antennas for Cypress PRoC/PSoC BLE ..................8 Cypress-Proprietary PCB Antennas .........................8 7.1 Meandered Inverted-F Antenna (MIFA) ...........8 7.2 Antenna Feed Consideration ......................... 10 7.3 Antenna Length Considerations ..................... 12 7.4 Inverted-F Antenna (IFA) ............................... 13 8 Chip Antennas ........................................................ 16 9 Wire Antennas ........................................................ 18 10 11 Antenna Comparison .............................................. 19 Effect of Enclosure and Ground Plane on Antenna Performance ............................................ 20 11.1 Effect of Ground Plane .................................. 20 11.2 Effect of Enclosure ........................................ 20 12 Guidelines for Enclosure and Ground Plane .......... 21 13 Antenna Tuning ...................................................... 22 13.1 Tuning Procedure .......................................... 23 14 Summary ................................................................ 29 15 Appendix A: Checklist ............................................ 30 16 Appendix B: References ......................................... 31 Worldwide Sales and Design Support ............................. 33
【选择攻略】2.4GHz 频段天线选择
2.4GHz 频段天线选择天线(antenna)是一种能量变换器，它把传输线上传播的导行波，变换成在无界媒介中传播的电磁波，或者进行相反的变换。
对于设计一个应用于射频系统中的小功率、短距离的2.4GHz无线收发设备，天线的设计和选择是其中的重要部分，良好的天线系统可以使通信距离达到最佳状态。
2.4GHz天线的种类也很多，不同的应用需要不用的天线。
天线简介图1 天线传输原理为保证天线的传输效率，天线的长度大约是电磁波波长的1/4，所以信号频率越低，波长越长，天线的长度越长；信号频率越高，波长越短，天线的长度越短。
则常用的2.4GHz 频段频率高，波长短，天线的长度短，可用内置天线，也可以用外置天线。
天线做的更短，如1/8波长或1/16波长，也可以使用，只是效率会下降。
某些设备会采用“短天线+LNA”的方式，也能达到长天线的接收效果。
但是短天线要达到长天线的发射效果，就需要提升发射功率了，因此对讲机需要发射信号，都是长的外置天线，而FM收音机只收不发，有内置接收天线。
例如2G(900MHz)、4G(700-2600MHz)、WIFI和蓝牙(2.4GHz)、GPS(1.5GHz)，这些常用的物联网通信方式，可以做内置天线。
对于手持机、穿戴设计、智能家居等小尺寸产品，很少使用外置天线，普遍采用内置天线。
集成度高，产品外观更美观，性能比外置天线略弱一点。
物联网、智能硬件产品，要联网传输数据，都需要有天线。
空间越小、频段越多，天线设计越复杂。
外置天线一般都是标准品，买频段合适的，无需调试，即插即用。
例如快递柜、售货机这些，普遍使用磁吸的外置天线，吸在铁皮外壳上即可。
这些天线不能放在铁皮柜里面，金属会屏蔽天线信号，所以只能放在外面。
优点是使用方便、价格便宜，缺点是不能用在小尺寸产品上。
天线类别那如何从众多的2.4GHz天线中选择出适合自己无线收发设备的2.4GHz天线，接下来就通过对2.4GHz天线的分类和分类对比来介绍如何选择2.4GHz天线。
天线无线DIY大全 2.4G
天线制作大全 本天线制作教程仅供无线ＤＩＹ交流群学习交流 图片教程收集于网络商业天线(24 dBi/27 dBi,覆盖范围4公里)这个反射面天线尺寸是：宽度： 87厘米长度： 91厘米反射面网格尺寸： 2.5厘米×1厘米反射面伸出到偶极子的方管长度是30厘米和面积是2.5厘米× 2.5厘米。
收集器的尺寸:天线FA20的设计. (18..22 dBi).尺寸图纸如下:天线成品图片:2.4Ghz Yagui天线(17dbi和60cm垂直极化) 设计图的尺寸:从左向右1,2 (21)铜线的直径2毫米序号长度(mm) 位置(mm)1 60.3 0.02 54.0 19.653 50.8 41.04 49.2 66.55 48.3 93.76 45.8 127.47 45.8 154.48 45.8 181.49 45.8 208.410 45.8 235.411 45.8 262.412 44.2 289.413 44.2 316.414 44.2 343.415 44.2 370.416 44.2 397.417 36.6 424.418 42.6 451.419 42.6 478.420 45.6 505.421 35.6 530.4环形八木天线 2.4GHz 14 dBi实际图:设计图:反射面R1的尺寸:(黄铜板直径123毫米x0.5毫米厚)使用的铜管直径为12毫米,圆环使用的铜线直径为1.5毫米. 1米的长度和22个圆环，使增益大约为14dbi50厘米长度和11个圆环的天线,使增益大约为11dbi序号周长位置反射面 1 123mm直径0 mm反射面 2 135mm 42mm 接驳器123mm 55mm 导向器 1 114mm 70mm 导向器 2 114mm 81mm 导向器 3 114mm 105mm 导向器 4 114mm 129mm 导向器 5 114mm 146mm 导向器 6 114mm 177mm 导向器 7 114mm 225mm 导向器 8 114mm 273mm 导向器 9 114mm 321mm 导向器 10 114mm 369mm 导向器 11 114mm 417mm 导向器 12 114mm 465mm 导向器 13 110mm 513mm 导向器 14 110mm 561mm 导向器 15 110mm 609mm 导向器 16 110mm 657mm 导向器 17 110mm 705mm 导向器 18 110mm 753mm 导向器 19 110mm 801mm 导向器 20 110mm 849mm 导向器 21 106mm 897mm直径4毫米x 长度60毫米的一根铜管。
飞思卡尔2.4GPCB天线设计
Freescale Semiconductor Application Note AN2731Rev. 1.2, 11/20041Introduction Good antenna design is the most critical factor in obtaining good range and stable throughput in a wireless application. This is especially true in low power and compact designs, where antenna space is less than optimal. However, several compact, cost efficient, and very effective options exist for implementing integrated antennas.To obtain the desired performance, it is required thatusers have at least a basic knowledge about howantennas function, and the design parameters involved.These parameters include selecting the correct antenna,antenna tuning, matching, gain/loss, and knowing therequired radiation pattern.This note will help users understand antenna basics, andaid in selecting the right antenna solution for theirapplication.Compact Integrated Antennas Designs and Applications for the MC13191/92/93Contents1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 12Antenna Terms . . . . . . . . . . . . . . . . . . . . . . . . 23Basic Antenna Theory . . . . . . . . . . . . . . . . . . 24Impedance Matching . . . . . . . . . . . . . . . . . . . 65Miniaturization Trade-offs . . . . . . . . . . . . . . 136Potential Issues . . . . . . . . . . . . . . . . . . . . . . 147Recommended Antenna Designs . . . . . . . . 148Design Examples . . . . . . . . . . . . . . . . . . . . . 16Antenna Terms2Antenna TermsAntenna Gain A measure of how well the antenna radiates the RF power in a given direction, compared to a reference antenna, such as a dipole or an isotropic radiator. The gainis usually measured in dB’s. A negative number means that the antenna in questionradiates less than the reference antenna, a positive number means that the antennaradiates more.Decibel (dB) A logarithmic scale used to represent power gain or loss in an RF circuit. 3 dB isa doubling of the power, -3 dB is half the power. -6 dB represents half the voltageor current, and quarter the power.Radiation Resistance The part of antenna’s impedance which produces radiated power. The measured impedance of an antenna is comprised of radiation resistance and loss.3Basic Antenna TheoryEvery structure carrying RF current generates an electromagnetic field and can radiate RF power to some extent and likewise an external RF field can introduce currents in the structure. This means that theoretically any metallic structure can be used as an antenna. However, some structures are more efficient in radiating and receiving RF power than others. The following set of examples explains this concept. Transmission lines (striplines, coaxial lines etc.) are designed to transport RF power with as little radiation loss as possible because these structures are designed to contain the electromagnetic fields. To obtain any appreciable radiation from such a structure, requires excessively high RF currents which causes low efficiency due to high losses. Likewise, the ability to introduce RF currents into the structure is of importance, described by the feed point impedance. If the feed point impedance is very high, low, and/or highly complex, it is difficult to introduce RF current with good efficiency.The antenna structure should be of reasonable size compared to the wavelength of the RF field. A natural size is half a wavelength, which corresponds to approximately 6 cm at the 2.4 GHz ISM band. This size is effective because when fed with RF power at the center point, the structure is resonant at the half wave frequency. Reducing the size below 6cm tends to make the antenna less visible to the RF field and not resonant which causes low efficiency. Not all structures make an efficient antenna.Numerous structures have been devised that provide good efficiency and impedance match, but most of these are derived from a few basic structures. A short description of these basic antennas, and some good advice on how to implement these with success is provided later in this note.This note does not include complicated formulas concerning antenna theory because it is beyond the scope of this note. The intention of this note is to provide basic information about how antennas work, which should allow users to achieve reasonable performance with a minimum number of attempts.If users are interested in performing complex calculations and antenna simulations, they should consult the abundant and widely available literature concerning antenna theory and design. Note that simply copying an existing design does not necessarily ensure reasonable performance. A lot of external factors affect antenna tuning, gain, radiation patterns, etc. An antenna tuned for one set of environmental factors may not perform at all if put into a new environment, and may require a lot of tuning to achieve even reasonable performance.Basic Antenna Theory 3.1Basic Antenna Variations3.1.1 3.1.1 Dipole AntennaThe dipole is one of the most basic antennas. The dipole is a straight piece of wire cut in the center and fed with a balanced generator or transmission line. As previously stated, this structure is resonant, ornon-reactive, at the frequency where the conductor length is 1/2 wavelength. For the ISM band, this length is approximately 6 cm or about 2 ½ inches. At this length, the dipole shows resonance, the feed impedance is resistive, and is close to 73 Ohms. This also holds true for a very thin wire in free space.Figure1. Basic DipoleA practical dipole of some thickness, loaded with different dielectric materials (PCB etc.), and perhaps relatively close to ground, shows resonance at a slightly shorter length than calculated, and the radiation resistance drops somewhat. For dipoles not too close to ground, the shorting factor is typically in the range of 5-20%, the shorter being more heavily dielectric loaded, and radiation resistance is in the range of 35-65 Ohms.This dipole setup exhibits a relatively good match to a 50 Ohm generator, but the feed is differential. A small ceramic balun can be used for single-ended feed. The bandwidth is typically 2-5%, depending on the return loss required. The radiation pattern in free space is doughnut-shaped, with pronounced dips along the direction of the wires.To fill out these dips, the outer ends of the antenna can be bent at a 45 degree angle. Several configurations are possible, including the “broken arrow” shape. Any materials close to the antenna can distort the radiation pattern.Basic Antenna TheoryFigureTo reduce the size of the dipole, several options exist: •Replacing some of the wire length with loading coils •Bending the dipole ends back on the dipole•Folding the dipole into a meander pattern•Hairpin or coil loading of the center•Capacitive loading of the dipole endsBasic Antenna TheoryFigure3. Dipole Loading ExamplesIn general, the smaller the antenna, the lower the radiation resistance and the lower the efficiency. The antenna should also be removed somewhat from the ground plane, preferably at least ¼ wavelength (3 cm) but not less than 1 cm. Sometimes a loading technique is employed where the dipole ends are bent close to the ground plane, or even loaded with small capacitors to ground. This technique shorts the dipole considerably but causes heavy RF currents to flow in the ground plane, resulting in low efficiency. Often some of the other loading techniques result in better performance.Impedance Matching4Impedance MatchingFor heavily loaded antennas and antennas close to ground, the radiation resistance may deviate considerably from 50 Ohms which causes a poor match. An Inductive/Capacitive (LC) matching network may be employed, but better efficiency is possible by raising the feed impedance.These techniques may also be employed if an impedance higher than 50 Ohm is required.The current and voltage distribution on a dipole is such that the impedance is low in the center and raises towards the ends. By tapering the dipole at some distance from the center, an appropriate match can be found. The tapering may take the form of Gamma, Delta or Capacitive tapping as shown in Figure 4. This allows for matching impedances from 2 up to 300 Ohms. Some loading may be required to take out the reactance introduced by the tapering, or the antenna could be slightly offset tuned to compensate for the added reactive component.Another approach is using the folded dipole. This is where two parallel wires are placed closely together. Due to the tight coupling, the current distribution is approximately proportional to the surface area of each wire. This means that in two equal wires, the current in the feeding wire is approximately half the value of the wires together. Half the current at the same power means twice the voltage, or four times the impedance of 73 Ohms (292 Ohms). In practice, the impedance is somewhat lower, as in the normal dipole case. however, by changing the relative wire diameter, or even introducing several wires, it is possible to tune the impedance from less than 100 Ohms to several hundred Ohms.Impedance MatchingFigure5. The Folded DipoleAll the different dipole types, loading techniques, and feeding networks total up to an enormous amount of possible combinations, each with its own advantages and disadvantages. Selection of the correct design for your application is best found using case-by-case assessment.4.1Monopole AntennasIf one part of a dipole antenna is removed and replaced by an infinite ground plane, the remaining half of the dipole “mirrors” itself in the ground plane, much in the same way that one sees their own reflection in water.For all practical purposes, the monopole behaves as a “half” dipole. That is, it has the same doughnut shaped radiation pattern, the radiation resistance is half that of the dipole (37 Ohm), it can be bend and be folded like the dipole, and the same loading and feeding techniques can be applied.However, one very important difference remains in that the antenna feed point is not balanced, but single ended. Because of this and because most RF circuits are of the unbalanced type, this antenna type has been immensely popular and a lot of variations of the monopole theme exist, most designed to match 50 Ohms.FigureIt is important to note that the “whip” is only half the antenna and that the remainder is made up of the ground plane, or counter weight, as it is sometimes called. In a practical application, the ground plane is often made up of the remainder of the PCB (ground and supply planes, traces, and components).Impedance MatchingThe ground plane should be a reasonably sized area compared to the antenna, and should be reasonably continuous. If a monopole is used on a very small PCB, perhaps even with only a small area of copper, efficiency suffers, and the antenna is difficult to tune. Components and tracks introduce additional losses and affect the feed point impedance.As for the dipole, resonance is obtained at a length slightly shorter than one quarter wavelength, typically 5-15% shorter. Typical lengths are slightly more than an inch or two or 3 to 5 cm. The radiation resistance is caused by bending the antenna, and like the dipole, the marked dip in the radiation pattern can be eliminated. By bending the antenna closer to ground, the radiation resistance and efficiency drops, so the antenna should not be placed too close to ground. Like the dipole, the monopole can also be folded and bent around corners, if board space requires this, or it can be loaded with series coils.Of the many variations that exist, the following sections highlight the most common.4.1.1PCB Whip, Quarter Wave Monopole, or Quarter WaveIf board space allows, a full-size quarter wave antenna is quite efficient and often provides a reasonable match to a 50 Ohm system. Slight folding or bending of the ends has negligible impact on performance.4.1.2Open Stub, Tilted WhipIf the monopole is bent and traced along the ground plane, it will be more compact and the null in the radiation pattern is partly eliminated. The antenna should not bee too close to ground, preferably not closer than 1/10 wavelength (1 cm), or efficiency suffers too much. At this close spacing, the radiation resistance is so low (in the order of 10 Ohms) that a matching network is usually needed. If the monopole is very close to ground, it resembles a transmission line, with little or no radiation at all.4.1.3The F-AntennaThe F-antenna can be thought of as a tilted whip, where impedance matching is done by tapping the antenna at the appropriate impedance point. Because this antenna is reasonably compact, has an omnidirectional radiation pattern, good efficiency, and is very simple, it is used extensively in applications, including the mobile communications business. It should be noted that the currents in the ground leg are high, and that a good sized ground plane is necessary to provide good efficiency.Impedance Matching 4.1.4The HelixIf a quarter wavelength is coiled up, a very compact antenna can be made which still has reasonable efficiency. Some experimentation may be required to find resonance, because the length of the wire is not exactly related to a quarter wavelength. This type of antenna is very popular at lower frequencies.4.1.5The SpiralA spiral antenna, with the windings in one plane like a pancake, is well suited to be implemented on a PCB. Performance is similar to the helix.4.1.6The Meander AntennaThe meander antenna or meander pattern, is an antenna with the wire folded back and forth where resonance is found in a much more compact structure than can otherwise be obtained.The meander, spiral, and helix antennas are similar in that resonance is obtained in a compact space by compressing the wire in different ways. In all three cases, the radiation resistance, bandwidth, and efficiency drops off as size is decreased, and tuning becomes increasingly critical. Impedance matching can be implemented by tapping, as in the F-antenna. The meander and helix antenna, or a combination of these two, are easily implemented in a PCB, and many chip antennas are based on these types of antenna.Figure8. Meander Pattern (Tapped for Impedance Match)Impedance Matching4.2Loop AntennasLoop antennas can be divided in two groups:1.Half-wave antennas2.Full-wave antennasThe term wave refers to the approximate circumference of the loop.4.2.1Half-wave LoopThe half wave loop consists of a loop approximately half a wavelength in circumference, with a gap cut in the ring. It is very similar to a half-wave dipole that has been folded into a ring and much of the statements about the dipole apply to the half-wave loop. Because the ends are very close together, there exists some capacitive loading, and resonance is obtained at a somewhat smaller circumference than expected. The feedpoint impedance is also somewhat lower than the usual dipole, but all the usual feeding techniques can be applied to the half-wave loop. By increasing the capacitive loading across the gap, the loop can be made much smaller than a half wavelength. At heavy loading, the loop closely resembles a single winding LC tuned circuit. The actual shape of the loop is not critical. It can be shown that the efficiency is determined by the area enclosed by the loop. The half-wave loop is popular at lower frequencies. However, at higher frequencies, the tuning capacitance across the gap becomes very small and critical.4.2.2Full-wave LoopAs the name implies, the full wave loop is approximately one wavelength in circumference. Resonance is obtained when the loop is slightly longer than one wavelength, typically 10-15% longer. The full wave loop can be thought of as two end-connected dipoles. As is with the half-wave loop, the shape of the full wave loop is not critical, but efficiency is determined mainly by the enclosed area. The feed impedance is somewhat higher than the half-wave loop, typically around 120 Ohms.Loading can be done by inserting small coils or hairpins in the loop, thereby reducing the size. As is with the dipole and half-wave loop, there exists numerous ways for impedance matching, including gamma match and tapering across a loading coil or hairpin. The main advantage of the full-wave loop is that it does not have the air gap in the loop, which is very sensitive to load and PCB capacitance spread.Impedance Matching4.2.3Slot AntennasSlot antennas are used extensively in aircraft and radar applications. The basic slot antenna is a half wave slot cut in a conducting sheet of metal. The feed point is across the center of the slot and balanced. The feed impedance is high, typically several hundred Ohms. Because the slot antenna is the opposite of a dipole, that is, a non-conducting slot in a sheet of metal, as opposed to a conducting rod in free air, the slot antenna shows similarities to a dipole but also exhibits interesting differences as well.•The feed point is across the center, instead of in series, so the feed point impedance is high instead of low• E and H fields are switched, so that the polarity is opposite• A horizontal slot is equivalent to a vertical dipole•The slot antenna may be of interest, if the RF unit has to be placed in a metal enclosure, where the slot antenna could be made in the enclosure itself•If the slot antenna is cut in the center, a quarter wave slot antenna is created, which is equivalent to the monopole•Impedance matching can be done by tapping across the slot close to the shorted endThe slot antenna could be used if a metal enclosure is required, or if considerable board area is available. If the slot antennas are implemented in FR4 PCB, considerable dielectric loading occurs which causes the physical length to be shorter than expected.Impedance MatchingFigure10. Half-wave and Quarter-wave Slot Antennas4.2.4Patch AntennasPatch antennas are a group of antennas with a very low profile and are capable of working very close to a ground plane. However, they require a fair amount of board space. The radiation pattern may be omnidirectional or unidirectional. A few examples are shown, but design and tuning is not straightforward and is best left to an experienced antenna engineer. Some types of chip antennas that show unidirectional characteristics are of this design.4.2.5Chip AntennasMany different chip antennas are available commercially. To many, these antennas seem to work for no apparent reason, but careful investigation reveals that most of these antennas are based on a helix, meander, or patch design. To ensure proper operation it is very important to follow the manufacturer’s recommendations regarding footprint, ground areas, and mounting of the chip antenna. The “keep out” area around the antenna is especially important. Even following the recommendations does not always guarantee good performance due to de-tuning by nearby objects. It is to be expected that fine tuning of the antenna and/or a matching network is required to ensure satisfactory performance. Because chip antennas normally, but not always, use a ceramic material with higher dielectric constant and lower loss than the usual FR4, it is possible to make smaller antennas with reasonable efficiency.The efficiency is not exceptionally high, typically in the range of 10-50%, which corresponds to 3-10 dB loss (-3 to –10 dBi). The lower number being inferior products with high inherent losses. As already stated, buying a chip antenna does not guarantee good performance. However, they do provide the smallest antenna solution possible but the size reduction comes at a cost both in performance and pricing.If a slightly larger PCB area is available than is required by the chip antenna, and the “keep out” area can be allocated to a PCB antenna, it is possible to implement a PCB antenna with the same or better performance than a chip antenna but at a much reduced cost.4.2.6BalunsMany of the above antennas mentioned are single-ended and designed to have a feed point impedance close to 50 Ohms. To interface these antennas to a balanced output/input, a device called a balun is required. The balun converts a single ended input to a balanced output together with an optional impedance transformation. The output is differential. That is, the output voltage on each pin is of equal magnitude, but off opposite phase. The output impedance is normally stated differential. That is, measured betweenMiniaturization Trade-offs the two output pins. Because the balun is a discrete device, it is bidirectional. The balanced port can be both input or output.Several discrete circuits are available that perform as baluns. Most of them are sensitive to input and output loading and PCB layout which requires cumbersome fine tuning. And all of these require at least two chip inductors. In the 2.4 GHz band, small ceramic baluns exist which are easy to use and are less sensitive to the PCB layout. Standard output impedances are 50, 100 and 200 Ohms.The cost of a discrete balun is comparable to, or higher than, the ceramic balun, and the ceramic balun requires less board space. Therefore, the ceramic balun is recommended for most designs.To interface with the MC13192/92/93, the standard component 50–200 Ohm balun is recommended. A 50–400 Ohm device provides slightly better performance, but it is not an off-the-shelf device.5Miniaturization Trade-offsAs previously stated, reducing antenna size results in reduced performance. Some of the parameters that suffer are:•Reduced efficiency (or gain)•Shorter range•Smaller useful bandwidth•More critical tuning•Increased sensitivity to component and PCB spread•Increased sensitivity to external factorsAs stated, several performance factors deteriorate with miniaturization, but some antenna types tolerate miniaturization better than others. How much a given antenna can be reduced in size depends on the actual requirements for range, bandwidth, and repeatability. In general, an antenna can be reduced to half its natural size without much impact on performance. However, after a one half reduction, performance gets progressively worse as the radiation resistance drops off rapidly. As a rule, one half the antenna size equals one quarter the radiation resistance. As loading and antenna losses often increase with reduced size, it is clear that efficiency drops off quite rapidly.The amount of loss that can be tolerated depends on the range requirements. Bandwidth also decreases, which causes additional mismatch losses at the band ends. The bandwidth can be increased by resistive loading, but this often introduces even more loss than the mismatch loss. The low bandwidth combined with heavy loading requires a spread analysis to ensure adequate performance with variations in component values and PCB parameters. As shown by these facts, it is often better not to reduce antenna size too much, if board space allows. Even if range requirements do not require optimum antenna performance, production problems and spread are minimized. It is also best to keep some clearance between the antenna and nearby objects. Although the antenna may be retuned to compensate for the loading introduced by the surroundings, tuning becomes more critical, and the radiation pattern can be heavily distorted.Potential Issues6Potential IssuesNumerous things can go wrong with an antenna design. The following list provides a few do’s and don’t’s which may server as a good checklist in a final design. Many of these items seem obvious to the experienced antenna designer, but many of these issues are routinely encountered in practice. This is obviously not a complete list.•Never place ground plane or tracks underneath the antenna•Never place the antenna very close to metallic objects•Be careful about the wiring in the finalized product, not too close to the antenna• A monopole antenna should have a reasonable ground plane to be efficient•Do the final tuning in the end product, not in free air•Never install a chip antenna in a vastly different layout than the reference design, and expect it to work without tuning•Do not use a metallic enclosure or metallized plastic for the antenna•Test the plastic casing for high RF losses, preferably before production•Never do a cut and paste antenna design and expect it to work without testing•Never use low-Q loading components, or change manufacturer without retesting•Do not use very thin PCB tracks, the tracks should be fairly wide7Recommended Antenna DesignsTwo antenna designs are employed for the MC13192/93 hardware.1.Dipole (lowest cost implementation)2.F-antennaHowever, most antenna designs are intended to interface with the usual 50 Ohm industrial standard. This is certainly true for all chip antennas. For interfacing the MC13191/92/93 to a single-ended 50 Ohm antenna, it has been shown that the smallest and most cost-effective solution are two ceramic baluns and an RX/TX switch.The MC13192-EVB, which is included in the MC13193EVK-A00, provides an example of this setup. Users can omit the RX/TX switch and add two chip antennas, but in most cases the switch is less costly than another antenna. Any other 50 Ohm, single ended antenna design can be added if required. This includes among others the F-antenna, monopole, helical, and the usual commercially available chip antennas. The single-port, 50 Ohm solution has the added advantage that by adding a ceramic bandpass filter for improved performance is easy. For a very low cost, low bill of materials (BOM) count solution, users should consider interfacing the antenna(s) directly to MC13191/92/93, and integrate both antennas and matching components into the PCB.This setup does have some unique requirements, due to the input/output requirements of theMC13191/92/93. To achieve a good match to the MC13192/92/93, the antenna should include the following properties:•Balanced designRecommended Antenna Designs•Feedpoint impedance of 2-300 Ohm•Easily loaded to smaller size, with PCB or lumped loading•Provide a DC feed to the TX port•Easy to implement in FR-4 PCBOf the different antenna types, the following are especially suited to interface with the MC13191/MC13192:•Dipoles with gamma match, or folded dipoles•Half or quarter wave loops•The slot antenna may also prove useful in some casesBecause the MC13192/92/93 has separate RX and TX ports, two antennas will eliminate RX/TX switching. The two antennas should ideally be placed at least ¼ wavelength apart to reduce coupling, but due to the low power requirements, closer spacing can be allowed. The following list shows the results from testing with dipole antennas and shows the typical isolation. The values are empirical, and depend somewhat on the surrounding layout etc., but they should provide a reasonable indication of the isolation obtainable.•On each side of a PCB, on top of each other: – 3 to – 4 dB•Very close, on the same side of the PCB: – 6 dB•15 mm apart: – 10 dB•25 mm apart: – 13 dBFor the MC13192/92/93 to show optimum performance, at least 6 dB of TX to RX isolation is required or the ESD protection diodes in the RX input cause some TX power loss and perhaps also increased 3rd harmonic output. However, placing the RX and TX dipoles on top of each other, with only 3 dB of isolation results in the smallest design possible, and only reduces TX power a few dB, which is entirely acceptable in most cases. The RX side works well with any isolation available. When the antennas are very close, the coupling results in some interaction in the tuning of the two antennas. With just a few attempts, users should be able to optimize performance.。
2.4G天线设计完整指南(原理、设计、布局、性能、调试).pdf
2.4G 天线设计完整指南（原理、设计、布局、性能、调试）2018-09-07 知明而行q...转自孤城夜影修改微信分享：本文章使用简单的术语介绍了天线的设计情况，并推荐了两款经过测试的低成本PCB天线。
这些PCB天线能够与PRoC?和PSoC?系列中的低功耗蓝牙(BLE)解决方案配合使用。
为了使性能最佳，PRoC BLE和PSoC4 BLE2.4GHz射频必须与其天线正确匹配。
本应用笔记中最后部分介绍了如何在最终产品中调试天线。
1、简介天线是无线系统中的关键组件，它负责发送和接收来自空中的电磁辐射。
为低成本、消费广的应用设计天线，并将其集成到手提产品中是大多数原装设备制造商(OEM)正在面对的挑战。
终端客户从某个RF产品(如电量有限的硬币型电池)获得的无线射程主要取决于天线的设计、塑料外壳以及良好的PCB布局。
对于芯片和电源相同但布局和天线设计实践不同的系统，它们的RF(射频)范围变化超过50%也是正常的。
本应用笔记介绍了最佳实践、布局指南以及天线调试程序，并给出了使用给定电量所获取的最宽波段。
图1.典型的近距离无线系统设计优良的天线可以扩大无线产品的工作范围。
从无线模块发送的能量越大，在已给的数据包错误率(PER)以及接收器灵敏度固定的条件下，传输的距离也越大。
另外，天线还有其他不太明显的优点，例如：在某个给定的范围内，设计优良的天线能够发射更多的能量，从而可以提高错误容限化(由干扰或噪声引起的)。
同样，接收端良好的调试天线和Balun(平衡器)可以在极小的辐射条件下工作。
最佳天线可以降低PER，并提高通信质量。
PER越低，发生重新传输的次数也越少，从而可以节省电池电量。
2、天线原理天线一般指的是裸露在空间内的导体。
该导体的长度与信号波长成特定比例或整数倍时，它可作为天线使用。
因为提供给天线的电能被发射到空间内，所以该条件被称为“谐振”。
图2. 偶极天线基础如图2所示，导体的波长为λ/2，其中λ为电信号的波长。
2.4G天线设计完整指南（原理、设计、布局、性能、调试）
2.4G天线设计完整指南（原理、设计、布局、性能、调试）本文章使用简单的术语介绍了天线的设计情况，并推荐了两款经过测试的低成本PCB天线。
这些PCB天线能够与PRoC?和PSoC?系列中的低功耗蓝牙(BLE)解决方案配合使用。
为了使性能最佳，PRoC BLE和PSoC4 BLE2.4GHz射频必须与其天线正确匹配。
本应用笔记中最后部分介绍了如何在最终产品中调试天线。
1、简介天线是无线系统中的关键组件，它负责发送和接收来自空中的电磁辐射。
为低成本、消费广的应用设计天线，并将其集成到手提产品中是大多数原装设备制造商(OEM)正在面对的挑战。
终端客户从某个RF产品(如电量有限的硬币型电池)获得的无线射程主要取决于天线的设计、塑料外壳以及良好的PCB布局。
对于芯片和电源相同但布局和天线设计实践不同的系统，它们的RF(射频)范围变化超过50%也是正常的。
本应用笔记介绍了最佳实践、布局指南以及天线调试程序，并给出了使用给定电量所获取的最宽波段。
图1.典型的近距离无线系统设计优良的天线可以扩大无线产品的工作范围。
从无线模块发送的能量越大，在已给的数据包错误率(PER)以及接收器灵敏度固定的条件下，传输的距离也越大。
另外，天线还有其他不太明显的优点，例如：在某个给定的范围内，设计优良的天线能够发射更多的能量，从而可以提高错误容限化(由干扰或噪声引起的)。
同样，接收端良好的调试天线和Balun(平衡器)可以在极小的辐射条件下工作。
最佳天线可以降低PER，并提高通信质量。
PER越低，发生重新传输的次数也越少，从而可以节省电池电量。
2、天线原理天线一般指的是裸露在空间内的导体。
该导体的长度与信号波长成特定比例或整数倍时，它可作为天线使用。
因为提供给天线的电能被发射到空间内，所以该条件被称为“谐振”。
图2. 偶极天线基础如图2所示，导体的波长为λ/2，其中λ为电信号的波长。
信号发生器通过一根传输线(也称为天线馈电)在天线的中心点为其供电。
2.4G RF天线的设计情况
本文章使用简单的术语介绍了天线的设计情况，并推荐了两款经过赛普拉斯测试的低成本PCB天线。
这些PCB天线能够与赛普拉斯PRoC™和PSoC®系列中的低功耗蓝牙(BLE)解决方案配合使用。
为了使性能最佳，PRoC BLE和PSoC4BLE2.4GHz射频必须与其天线正确匹配。
本应用笔记中最后部分介绍了如何在最终产品中调试天线。
1.简介天线是无线系统中的关键组件，它负责发送和接收来自空中的电磁辐射。
为低成本、消费广的应用设计天线，并将其集成到手提产品中是大多数原装设备制造商(OEM)正在面对的挑战。
终端客户从某个RF产品(如电量有限的硬币型电池)获得的无线射程主要取决于天线的设计、塑料外壳以及良好的PCB布局。
对于芯片和电源相同但布局和天线设计实践不同的系统，它们的RF(射频)范围变化超过50%也是正常的。
本应用笔记介绍了最佳实践、布局指南以及天线调试程序，并给出了使用给定电量所获取的最宽波段。
设计优良的天线可以扩大无线产品的工作范围。
从无线模块发送的能量越大，在已给的数据包错误率(PER)以及接收器灵敏度固定的条件下，传输的距离也越大。
另外，天线还有其他不太明显的优点，例如：在某个给定的范围内，设计优良的天线能够发射更多的能量，从而可以提高错误容限化(由干扰或噪声引起的)。
同样，接收端良好的调试天线和Balun(平衡器)可以在极小的辐射条件下工作。
最佳天线可以降低PER，并提高通信质量。
PER越低，发生重新传输的次数也越少，从而可以节省电池电量。
2.天线原理天线一般指的是裸露在空间内的导体。
该导体的长度与信号波长成特定比例或整数倍时，它可作为天线使用。
因为提供给天线的电能被发射到空间内，所以该条件被称为“谐振”。
如图2所示，导体的波长为λ/2，其中λ为电信号的波长。
信号发生器通过一根传输线(也称为天线馈电)在天线的中心点为其供电。
按照这个长度，将在整个导线上形成电压和电流驻波，如图2所示。
2.4GHz RF TX RX PCB准则
2.4GHz RF TX/RX PCB 准则文件编码文件编码：：HA0224SPCB Layout 时可能需注意事项RF 部分可连接一个无源贴片天线或天线连接器。
RF 连接在PCB 上，其引脚2 & 3连接至Matching & Balun 电路，如图1所示。
图1 RF 板原理图天线的阻抗需同发送/接收器的50欧阻抗匹配。
50欧微带状线的宽度W 由介质厚度H 、Trace 宽度T 和介电常数决定。
RF 微带状线总体设计建议：• 微带状线的长度越短越好，标准PCB 上将避免其长度超过2.5cm(1 inch)及无额外屏蔽。
• 微带状线和顶层铺地区域间的距离至少与介质厚度相同，否则地将吸收微带状线上的RF 能量。
• RF 连接器的走线应远离设计中的数字部分。
• 为减少信号影响，微带状线应避免以尖角形式走线，斜面或圆角最好以矩形方式走线；最好以45度斜角或弧角的方式进行绕线而避免使用90度角的走线方式。
• RF 部分或功率放大器的下面避免RF 连接器的走线。
Matching & Balun 电路范例：图2 典型4层PCB截面图基板1 = 7 mil基板 2 = 20 mil基板 3 = 7 mil总厚度= 40 mil (1.0mm)铜顶层= 1.8 mil (0.5oz)铜中间层1 = 1.2 mil (0.5oz)铜中间层2 = 1.2 mil (0.5oz)铜底层= 1.8 mil (0.5oz)特性阻抗≅ 50若介电常数为4.5，估算后的微带状线宽度= 12 milRF微带状线宽度= 12 mil间隙宽度≧ 12 mil基板厚度= 7 mil零件放置原则部份零件放置原则MCU部份•零件摆设时优先考虑重要信号线，尽可能使零件间拉线距离愈短愈好。
•零件摆设时须预留VCC、GND的走线宽度。
•天线端_除天线匹配零件外，尽量避免摆放零件，以避免影响RF特性。
走线原则(Routing)部份走线原则MCU部份•由于直角易积电，放电亦大，容易影响PCB的稳定度，因此建议电性信号尽量以45度斜角或弧角的方式进行绕线。
2.4GHZ天线全解
车载天线特点：2.4GHz扩频通信汽车移动终端设计的一种中等增益车台天线.车台天线采用塑料模压方法,将高强度特点：车台天线采用塑料模压方法，将高强度磁钢和馈线压接成一体，天线体积小，重量轻，性能稳定可靠，安装使用方便。
板状天线应用:2.4GHz WLAN /WiFi基站系统 2.4GHz ISM/ UNII频段λ点对点或点对多点互联网热点覆盖λ特点:增益高、驻波小垂直极化防腐能力强λ内置NK接头提供可调角抱杆安装套件λ抛物面天线特点：天线采用异型馈源使初级照射方向图与口面相适应，保证天线工作于最佳状态。
增益高，作用距离远，结构轻巧，架设方便，风阻小。
应用：2.4GHz WLAN 系统支持IEEE 802.11a,g 长距离传输点对点，点对多点系统无线桥接特点：压铸铝切割栅状抛物面天线，其口面切割与馈源照射方向图相适应,保证天线工作于最佳状态。
增益高,作用距离远,结构轻巧,架设方便,风阻小。
应用：背射天线八木天线特点：增益高，工作频带宽，前后辐射比大，抗干扰力强，不锈钢结构简单坚固，架设方便。
应用：2.4 GHz WLAN 系统 2.4GHz ISM 频段点对点, 点对多点系统终端天线特点：天线是专门为2.4G通信系统的终端机设计生产的。
该天线结构小巧，外形美观，安装方便。
波VSWR ≤1.8益Gain 3dBi极化型式Polarization Vertical最大功率Maximum input power 50W输入阻抗Impedance 50Ω接口型式Input Connector IPEX天线尺寸Dimensions of Antenna Φ16×120 mm 量Weight 25g号Model Q24-7BA2400-2483/5150-5250/5725-5850MHZ特点：天线是专门为2.4G通信系统的终端机设计生产的。
该天线结构小巧，外形美观，安装方便内置天线（PCB）2.5dBIVertical50W50ΩVertical50W50Ωi-pex50Ωi-pex，sma应用：2.4GHz WLAN系统 2.4GHz UNII/ISM 系统WiFi 系统λ点对点或点对多应用支持IEEE802.11a/b/gλ特点：高增益、低驻波采用双频技术设计λ天线结构小巧，外形美观室内使用，环境适应性好壁挂安装λ特点：我公司生产的玻璃钢天线系列，采用低损耗、高强度的优质玻璃钢材料封装，辐射振子为单元或多单元直线阵，天线功率容量大，电压驻波比小、性能稳定、安装方便，抗风，防水、防腐性能佳，是各类组网所需的理想通讯天线。
2.4Ghz远距离低功耗LoRa扩频PCB板天线SX1280无线模块使用教程
产品概述E28系列产品是公司设计生产的2.4GHz射频收发模块，通信距离远；具有极低的低功耗模式流耗。
此模块为小体积贴片型(引脚间距1.27mm)，模块自带高性能PCB板载天线。
E28系列产品采用Semtech公司的SX1280射频芯片，此芯片包含多样的物理层以及多种调制方式，如LORA,FLRC,GFSK。
特殊的调制和处理方式使得LORA和FLRC调制的传输距离大大增加；是一款高性能物联网无线收发器，并可以兼容蓝牙协议。
出色的低功耗性能、片上DC-DC和Time-of-flight使得此芯片功功能强大，可用于智能家居、安全系统、定位追踪、无线测距、穿戴设备、智能手环与健康管理等等。
SX1280支持RSSI，用户可以根据需要实现深度的二次开发；SX1280亦集成飞行时间(time of flight)，适用于测距功能。
E28系列产品为硬件平台，无法独立使用，用户需要进行二次开发。
产品型号载波频率发射功率参考距离(PCB/IPX)封装形式天线形式E28(2G4M12S) 2.4GHz12.5dBm3000m贴片IPX/PCBE28(2G4M20S) 2.4GHz20dBm6000m贴片IPX/PCB 1.技术参数产品型号核心IC尺寸模块净重工作温度工作湿度储存温度E28(2G4M12S)SX128025*14*0.8mm0.9±0.1g-40~85℃10~90-40~125°C E28(2G4M20S)SX128026.5*15*2.8mm 1.2±0.1g-40~85℃10~90-40~125°C 1.1.E28(2G4M12S)参数类别Min Typ Max单位发射电流424550mA接收电流91011mA关断电流123μA发射功率1212.514dBm接收灵敏度-126-128-130dBm 推荐工作频段240024302500MHz 供电电压 1.8 3.3 3.6V通信电平 1.8 3.3 3.6V1.2.E28(2G4M20S)因采用高增益PA,为保证线性度和效率，SX1280不需配置为最大功率输出，建议SX1280的功率输出寄存器设置成16（输出功率为-2dBm）。
2.4g天线
2.4g天线简介2.4G天线是一种用于无线通信的天线，广泛应用于各种设备中，如无线路由器、无线网络适配器、无线摄像头等。
本文将会介绍2.4G天线的工作原理、特性和常见应用。
工作原理2.4G天线是一种微带天线，采用共面垂直波导（CPW）结构。
它通过射频信号的辐射和接收来实现信号的传输。
2.4G天线的工作频率范围是2.4GHz到2.4835GHz，属于无线局域网（WLAN）应用的标准频率范围。
2.4G天线的辐射器通常由导电材料构成，如铜，通过与地板之间的介电基片保持一定的距离，以实现天线的工作。
天线的尺寸会根据工作频率进行调整，以保证天线与信号的匹配。
在2.4G天线的寄生负载矩形辐射器上，有一根连接到射频接口的铜柱。
这根铜柱被称为同轴馈线（Coaxial Feeder），它负责将无线信号引入到天线内部，并从天线外部引出射频信号。
通过这种方式，2.4G天线实现了无线通信信号的直接传输和接收。
特性2.4G天线具有以下特性：1.工作频率范围广泛：2.4G天线适用于2.4GHz到2.4835GHz的工作频率范围，可以满足无线通信领域的需求。
2.小巧轻便：2.4G天线通常采用微带天线的设计，尺寸小巧，重量轻，非常适合集成在各种设备中。
3.辐射效果好：2.4G天线采用CPW结构设计，通过调整天线尺寸以匹配信号频率，保证辐射效果优良。
4.易于安装：2.4G天线通常具有标准尺寸和接口，因此很容易安装在各种设备上。
5.成本低廉：由于2.4G天线采用常规的制造工艺和材料，因此具有成本低廉的优势。
常见应用2.4G天线在无线通信领域有着广泛的应用，下面是几个常见的应用场景：1.无线路由器：2.4G天线常用于无线路由器中，用于接收和发送无线信号，提供无线网络覆盖。
2.无线网络适配器：2.4G天线也被用于无线网络适配器中，将有线网络信号转化为无线信号，实现无线网络连接。
3.无线摄像头：2.4G天线可以用于无线摄像头中，将视频信号通过无线方式传输到接收设备，实现无线监控。
一种PCB天线仿真工具HFSS简介
一种PCB天线仿真工具HFSS简介引言随着无线射频技术和电子电路技术的发展，射频模块的体积变的越来越小，高精密度，高性能的射频电路设计和高发射增益天线越来越收到行业内的重视。
由此，一种可靠的功能强大的天线仿真软件应运而生——HFSS天线仿真软件。
通过设计2.4G天线为例子，简单了解到HFSS软件设计天线的整个过程。
1、估算天线长度①已知工作频率（2.4~2.4835Ghz）,中心频率取2.45Ghz②已知PCB板信息，分别包括介质材料是FR4,Er = 4.4、板厚1mm、天线走线宽1.6mm、PCB板尺寸65*40mm、参考地大小40*40mm。
由①②得到天线总长度= 2.4Ghz时1/4自由空间波长和1/4个FR4介质波长的中间值也就是[ (3 * 10^8) / (2.45 * 10^9) / 4 +122 / (√4.4) / 4 ] / 2 =22.7mm由于是倒L天线，所以其中垂直长度8mm，水平长度14.7mm2、创建参数化模型a. 打开软件新建一个HFSS工程，并且命名为ILA，插入HFSSDesign，设置仿真方式DrivenTerminal，工程单位为mm。
如下图1。
图1b.定义各种设计变量的名称和对应的参考值如下图2图2c.重复b操作设置另外一些需要设置的天线信息变量。
得到图3。
图33、设置扫描条件在设置HFSS扫描条件之前，我们一般是先要设置天线的辐射端口，辐射端口默认阻抗为50欧姆（国际标准），在设置好端口之后就要设置仿真的辐射边界，辐射边界取1/4工作波长。
然后就可以设置其扫描条件，这个天线的中心频点是2.45G,为了节约仿真时间扫描的起始段设为2Ghz到3Ghz，扫描间隔为0.01Ghz。
设置完所有量就得到下图4了。
图44、分析结果，优化设计我们进行单一长度的参数扫描分析。
得到图5，显然由图5可以看出我们所设置的天线长度最佳的工作频率是在2.65Ghz左右，这并不是我们想要的。
2.4GHz天线设计-仿真报告
2.4GHz天线设计-仿真报告简介天线设计是通信系统中非常重要的组成部分，对系统性能有着重要的影响。
本文将介绍2.4GHz频段的天线设计及其仿真报告。
在这个频段，许多通信系统都采用这个频段进行通信，因此这个频段的天线设计十分必要。
设计简介本文的天线设计采用费率斯特结构，该结构由一根不对称的金属元件组成，其中一个角被钳住，可将它固定在电路板上。
该结构因为其简单而且设计易于制造，在芯片级系统中使用非常广泛。
设计参数参数值工作频率 2.4GHz阻抗50Ω天线长度31.3mm天线结构为了使我们的天线尽可能高效，我们需要优化其结构。
在本文设计的天线中，将金属元件下方的地平面延长，以提高阻抗匹配性和辐射特性。
结构图及尺寸天线的结构图如下所示：_______________________| || L || | |_______|__________|_________ || || _______ ||___________| |____________其中，L表示金属元件的长度，为31.3mm，另外每个部分的尺寸比例应根据实际应用进行调整。
仿真简介通过使用如ADS等仿真工具，可以对设计的天线进行仿真，以此来验证其性能。
设计环境本文中使用的仿真工具为ADS 2016.01，仿真环境为2.4GHz频段。
仿真结果可以通过仿真结果来验证设计的天线是否优秀。
下面是本文天线设计的仿真结果：s11参数s11参数描述天线的阻抗匹配性能。
通常情况下，我们希望s11参数越小越好。
如下图所示，我们的设计中s11参数在2.4GHz处约为-16dB，阻抗匹配性能良好。
######################### ## s11 parameter ## #########################单极化辐射特性本文的仿真结果中，天线展现出明显的指向性，如下图所示：######################### ## radiation pattern ## #########################效率天线的效率是指其输入功率有多少被辐射出来，是衡量天线性能的重要参数。
2.4G天线在PCB板上的设计资料
2.4G天线在PCB板上的设计资料展开全文主要讨论的是2.4G PCB天线，如果不考虑成本及体积，可以选用其它天线，如贴片天线（小尺寸、中性能、中成本）或外置的鞭状天线（大尺寸、高性能、高成本），而 PCB 天线是最低成本、中等尺寸，只要设计得当又能获得足够性能的天线。
包括三种天线：超小型 PIFA 天线：用于 Nano Dongle 的 PCB 天线，由于 PCB 空间受限，最大增益会比其它几种天线小6dB 左右，即工作距离会短一半。
由此天线及MCU 做成的完整板子大小为11mm*18mm 左右。
正常 PIFA 天线：用于 Normal Module 的 PCB 天线，所占 PCB 空间最大，最大增益可以达到 1.5dB，如 PCB 面积足够，建议用此天线。
由此天线做成的 RF Module 板子大小为 15mm*18mm 左右。
正常Wiggle 天线：用于Normal Module 的PCB 天线，所占PCB 空间比第二种稍小，增益也稍差1dB，可以用于对体积稍有要求的无线终端，如对于空间比较紧凑的无线鼠标等设备。
由此天线做成的 RF Module 板子大小为 13mm*18mm 左右。
1、小尺寸 Nano Dongle 用PIFA天线设计天线具体尺寸如下图（板材为两层 FR4,板厚 0.6mm）：其中天线线宽 A：0.15mm；B：0.25mm；C：0.4mm天线性能 S11 如下，工作频段覆盖整个 2.4G ISM 频段:2D和3D增益如下，该天线最大增益只有－5dB 左右:2. 更大尺寸 Normal Module用PIFA 天线设计该天线结构就是 Normal Module 完整 Layout 中的 PIFA 天线。
天线具体尺寸如下图（板材为两层 FR4,板厚 1.0mm），如果板子厚度和板子大小与此不一致（板厚和地面积大小影响性能），则Layout 时需加长天线末端尺寸，如增加最后端4.8m的长度，供调试天线用。
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2.4GHZ 2.4GHZ倒F及弯曲线 及弯曲线PCB蓝牙 PCB蓝牙天线 蓝牙天线设计指导 设计指导1Contents1 2 3 4 5 6 7 8 9 Introduction .................................................................................................................................................... 3 Inverted-F Antenna ........................................................................................................................................ 4 Meander Line Antenna................................................................................................................................... 5 Real Designs .................................................................................................................................................. 6 Proximity to Metal Objects ............................................................................................................................ 7 Proximity to Dielectric Materials................................................................................................................... 8 Network Analyser........................................................................................................................................... 9 Final Tuning.................................................................................................................................................. 10 Conclusion ................................................................................................................................................... 12Terms and Definitions ........................................................................................................................................ 13 Document History ............................................................................................................................................... 14List of Figures Figure 2.1: Inv erted-F Antenna ............................................................................................................................... 4 Figure 3.1: Meander Line Antenna .......................................................................................................................... 5 Figure 3.2: Input Impedance of Two Meander Line Antennas................................................................................. 5 Figure 4.1: Approximate Dimensions of Inverted-F Antenna................................................................................... 6 Figure 4.2: Approximate Dimensions of Meander Line Antenna ............................................................................. 6 Figure 7.1: Preparation Before Measurement ......................................................................................................... 9 Figure 7.2: Assembled System Ready to Measure ................................................................................................. 9 Figure 8.1: Locating Product in Far Field of Antenna............................................................................................ 10 Figure 8.2: Final Tuning Procedure....................................................................................................................... 11第 2 页 共 13 页1IntroductionThis document outlines two ty pes of Printed Circuit Board (PCB) antennas used by CSR, which can be used with 2.4GHz radios. ■ Inverted-F ■ Meander Line In addition, this document discusses the effect of placing metallic or dielectric materials near an antenna.第 3 页 共 13 页2Inverted-F AntennaQuarterwaveInput OutputFigure 2.1: Inverted-F Antenna The inv erted-F is a quarterwav e antenna. It is bent into an L-shape. The shorter side is connected to earth. The longer side is left open-circuit at the end. The f eed point is located somewhere between the earth end and the open end. The resulting structure resembles the letter F and possesses the properties of both a loop antenna due to the circulating current from the f eed point to ground and a whip antenna due to the open circuited straight section. In the PCB v ersion, the antenna is printed on the top layer and a ground plane is placed near the antenna on the top lay er. There must not be a ground plane underneath the antenna. The aim is to make the quarterwav e section resonate at the midband frequency (which is 2441MHz f or 2.4GHz ISM radios). The f eed point (which is the input/output connection) is connected to the L-Shape at the point corresponding to 50∧ . Experiment with measurement to determine the correct location for the feed point and length of this antenna.第 4 页 共 13 页3Meander Line AntennaS Ground Plane Input Output第 5 页 共 13 页Figure 3.1: Meander Line Antenna The length of the meander line antenna is difficult to predict. It is usually a bit longer than a quarterwav e but dependent on its exact geometry and proximity to the ground plane.Note:In Figure 3.1 the ground plane is shown in black. S is the distance from the ground plane. See Figure 4.2 for approximate dimensions. This ty pe of antenna is alway s a PCB version. The antenna is printed on the top lay er and a ground plane is placed near the antenna on the top lay er. There must be no ground plane underneath the radiating section of the antenna.Smith ChartABFigure 3.2: Input Impedance of Two Meander Line Antennas The real part of the impedance of this antenna is about 15∧ to 25∧ , depending on geometry and proximity to the ground plane. The impedance matching is done by adjusting the length of the antenna until the input impedance is at the unity conductance circle (when normalised to 50∧ ), in the top half of the Smith chart (Point A). A shunt capacitor is then connected between the antenna input and ground to match to 50∧ (Point B). Experimental measurement is used to determine the correct design.4Real Designs18.0mm13.5mm Width=0.8mm 6 .0mm 5 .0mm Not to scaleGround PlaneActual SizeFigure 4.1: Approximate Dimensions of Inverted-F Antenna第 6 页 共 13 页1.5mm1.0mm4.4mm Width=0.5mm 2.8mm 1.7mm Ground Plane Not to scale1.5pF CapacitorPlaced immediatel y after F eedpoint8 .0 mm FeedpointActual SizeFigure 4.2: Approximate Dimensions of Meander Line Antenna第 7 页 共 13 页5Proximity to Metal ObjectsCSR recommends keeping metal objects as far away f rom the antenna as possible. Keeping metallic objects out of the near field is usually adequate. Near Field = 2D / λ D is the largest dimension of the antenna. In the case of these antennas, this is approximately a quarterwav e (λ/4).Notes:2λ is the wav elength of the signal in f reespace. In the 2.4GHz ISM band, λ=122mm in freespace. Substituting D=λ/4 into the Near Field equation giv es Near Field = λ/8. Near Field = 122/8 mm = 15.25mm.第 8 页 共 13 页6Proximity to Dielectric MaterialsDielectric materials (like plastic or FR-4) detune an antenna by lowering its resonant frequency. The effect is not as serious as placing an antenna next to metal objects and can be corrected by reducing the length of the antenna. Theref ore, it is important to tune the antenna when it is in the product. This is done during the dev elopment of the product.第 9 页 共 13 页71. 2.Network AnalyserCut the PCB track (trace) just before the antenna matching network to isolate the f ilter and previous stages f rom the measurement. Connect a coaxial cable between the VNA and the PCB of the product. The coaxial cable must hav e f errite beads fitted over its outer sleeve. The f errite beads help to prev ent RF currents from f lowing on the outer sleeve, which would disturb the measurement. Solder the outer sleeve of the coaxial cable to the ground plane of the PCB as close as possible to the input of the antenna-matching network. Perf orm a One-Port calibration on the VNA with Open, Short, Loads connected at the end of the coaxial cable inside the product. Solder the inner conductor of the coaxial cable to the input of the antenna-matching network. Tune the antenna by adjusting the values of any “matching network” components, the feed point of the antenna or the length of the antenna until the S11 trace (display ed on the VNA) is at the centre of the Smith chart at the midband f requency 2441MHz. Repair the cut track by putting a small amount of solder over the cut.Use a v ector network analyser (VNA) to perform the initial tuning of the antenna:3. 4. 5.6.Figure 7.1: Preparation Before MeasurementVNAFerrite BeadsAntenna 2.4GHz RadioFigure 7.2: Assembled System Ready to Measure第 10 页 共 13 页8Final TuningAfter tuning the antenna using the VNA procedure, it is necessary to perf orm fine-tuning. This y ields a small improv ement and is the f inal optimisation of the antenna. It is best to perf orm this procedure in an anechoic chamber, but when this is not possible, an indoor or outdoor test range can be used. It is important to minimise radio signal reflections. Avoid metallic objects such as lab-benches, filing cabinets, lampposts and cars.Approximately 2m RX Antenna2.4GHz RadioSpectrum Analy serFigure 8.1: Locating Product in Far Field of Antenna第 11 页 共 13 页Connect omni directional receive antenna to a spectrum analyser Place fully assembled product approximatel y 2m away from receive antenna Put product into continuous transmitWatch power level of received signal on the specturm anal yser while moving receive antenna ±10cm in each of x,y,z planes to ensure it is not located in a null point. A sudden dip in received power indicates a null pointYesIs antenna located in a null point?No Rotate product around in the x,y,z planes until the maximum power level is observed on the spectrum anal yser. This ensures that the dominant polarisation mode of the antenna is measured.NoHas the maximum possible power level been observed on the spectrum anal yser?Yes Record power level observed on the spectrum analyser. Turn off product, disassemble it and make adjustments to length of antenna, feed point or matching componentsReassemble product and place it in the same location and orientation as beforeNoHas the maximum receive power been obtained?Yes End of procedure Repeat process on multiple devices to ensure results are repeatableFigure 8.2: Final Tuning Procedure第 12 页 共 13 页9ConclusionMetal objects should be kept at least 15.25mm away from the Inverted-F and Meander Line types of antennas in the 2.4GHz ISM band f or the antenna to work efficiently. If that is not possible, experiment to determine an acceptable trade-off between antenna performance and product size. Ev en by f ollowing these rules, antenna detuning can occur. This usually results in lowering the resonant frequency of the antenna. Correct this by reducing the length of the antennaTerms and DefinitionsISM PCB RF VNA Industrial, Scientific and Medical Printed Circuit Board Radio Frequency Vector Network Analyser第 13 页 共 13 页。