CSR 2.4GHz 天线设计参考指南
2.4GHzPCB天线
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。
[分享] 自制Wi-Fi 2.4GHz无线天线概要
![[分享] 自制Wi-Fi 2.4GHz无线天线概要](https://img.taocdn.com/s3/m/260666e46137ee06eff9182e.png)
分享] 自制Wi-Fi 2.4GHz无线天线无线自制Wi-Fi 2.4GHz无线天线花100多元，自己动手，改造AP，就可以获得较好的无线信号。
不过，有朋友说了，现在一个无线路由器才多少钱？让我多花100多，太亏了。
那么，到底有没有什么更好的方法，既少花钱，又能让无线信号得到增强呢？答案是肯定的，我们自己动手，制作一款定向天线，让您的无线网络更加顺畅，只需要两元钱！（注：DIY操作有一定危险性，14岁以下儿童请不要模仿。
）如果您认为制作定向天线，需要高超的技术以及复杂的过程，那就大错特错了。
在DIY之前，您所需最“贵重”的原材料，就是一罐可乐或雪碧！没错，就是355ML的听装饮料，现在超市最便宜卖到1.7x元，最贵也不过2元左右。
注意：请不要贪多而选择2升特惠装，否则后果自负……接下来，请打开饮料，并喝光它（如果您买的是2升装，不但材料不符，就是这第一步，恐怕您都很难完成）。
您得到一个空的饮料罐，此时有两个选择：放弃DIY，饮料罐可以卖1角钱；继续DIY，但此后饮料罐将无人回收。
此处注意，如果喝水过多引起生理反应，请及时解决。
（一罐喝光的雪碧）现在，再拿出剪子、裁纸刀、胶带（剪子、裁纸刀为非易耗品，不计入成本；胶带成本过低，可忽略不计）。
（简单的工具）拿好刀子，看准易拉罐上接缝线，一刀插下去！记住，一定要做到稳、准、狠，毫不留情！然后，顺着线笔直的割下来，这里就考验您的刀工，如果切歪了，那没得说，再换一罐吧。
这道工序，一定要注意安全，千万不要伤到自己。
根据笔者实际操作，易拉罐罐体较软，切割不会耗费很大力气。
（被开膛的易拉罐）接下来，在接缝正对面，重复刚才的操作。
这次没有线条做基准，切直线相对较难，如果您没有信心，那可以先用笔画一条直线。
在两条直线切好后，接下来的工序稍有些费力，您需要将易拉罐分成对等的两半，但不能破坏罐底。
用剪刀沿底边分别剪两个半圆，我们的定向天线已现雏形。
注意，易拉罐边缘锋利，剪的时候，如果有手套保护最好。
2.4G天线设计建议
1.天线需要严格按照我们提供的参考设计(尺寸,线宽,F的高度等等)
2.周围的外壳不能是密封金属壳体,靠近天线部分需要是塑料材质(也不能有含金属颗粒涂料的喷涂)
3.天线要远离输出级(特别当输出级为classD时更要注意)和扬声器的磁钢(如果近距离有扬声器,尽可能使用防磁扬声器).
4..天线距离其他导体的距离至少要大于15mm,并尽量靠近外壳
5.RF部分的走线要有完整的参考地,并按照50欧姆走线
6.可以考虑使用RF电缆引出,使用专用的PCB放置天线
7.天线和音频前级以及MIC的走线要尽可能远离,防止RF干扰音频
8.音频的差分走线要尽可能平行等长,两线中间不要放置地线.
9. 射频走线不能从模组下穿过,因为模组的bottom一般是一个gnd层,如果射频线走主板的top层,
又从模组下走,那么与模组bottom的gnd距离很近,对信号影响很大.另外RF走线过孔也对信号有影响,要尽量避免.
10.天线区域不能有器件或者其他走线.。
低成本2.4GHz天线设计概要
March 2011Doc ID 018585 Rev 11/28AN3359Application noteLow cost PCB antenna for 2.4GHz radio:Meander design1 IntroductionThis application note is dedicated to the STM32W108 product family fromSTMicroelectronics.One of the main reasons to use a PCB antenna is the reduced overall cost of the radio module. Well designed and implemented PCB-printed antennas have a similar performance to the SMD ceramic equivalence. In general, the footprint for a ceramic SMD antenna is smaller than that for a PCB-printed variant. For a PCB-printed antenna solution, the increased size of the PCB in relation to space required for the antenna means that the radio module is larger cost of the PCB increased. The increased cost of the PCB is smaller and less expensive than a SMD ceramic antenna.The STM32-RFCKIT RF control kit is based on an STM32W108xx RF microcontroller. It implements a PCB-printed antenna to perform RF communications.Contents AN33592/28Doc ID 018585 Rev 1Contents1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Coordinate system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52Layout specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Impedance matching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84Radiation pattern, 3-D visualization . . . . . . . . . . . . . . . . . . . . . . . . . . . 125Radiation pattern, 2-D visualization . . . . . . . . . . . . . . . . . . . . . . . . . . . 146Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27AN3359Doc ID 018585 Rev 13/28Table 1.Specification of the recommendedsubstrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Table 2.Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27AN33594/28Doc ID 018585 Rev 1Figure 1.Spherical coordinatesystem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Figure 2.Layout of Meander-like PCBantennae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Figure 3.Cross section of the PCB at antennaeregion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Figure 4.Part of the ZigBee module's PCB with Meander-like antenna (around scale 4:1 . . . . . . . . 8Figure 5.Bypassing impedance matching circuitry - direct RFconnection . . . . . . . . . . . . . . . . . . . . . 8Figure 6.Complex impedance of the Meander-like antenna on SmithChart . . . . . . . . . . . . . . . . . . . 9Figure 7.Magnitude of the S11 parameter in logarithmic scale (Cartesianplot. . . . . . . . . . . . . . . . 10Figure 8.Antenna's Standing Wave Ratio(SWR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Figure 9.Three dimensional (3-D radiation patternoverview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Figure 10.Radiation pattern on Y-Zplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Figure 11.Radiation pattern on X-Zplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Figure 12.Major planes used to visualize 3-D radiation pattern using 2-Dplots. . . . . . . . . . . . . . . . . 15Figure 13.Far field radiation pattern plotted on Y-Zplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Figure 14.normalized radiation pattern on Y-Z plan (Polarplot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Figure 15.normalized radiation pattern on Y-Z plane (Cartesianplot. . . . . . . . . . . . . . . . . . . . . . . . 18Figure 16.Far field radiation pattern plotted on X-Yplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Figure 17.Normalized radiation pattern on X-Y plan (Polarplot . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Figure 18.Normalized radiation pattern on X-Y plan (Cartesianplot. . . . . . . . . . . . . . . . . . . . . . . . . 21Figure 19.Far field radiation pattern plotted on X-Zplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Figure 20.Normalized radiation pattern on X-Z plane (Polarplot. . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Figure 21.Normalized radiation pattern on X-Z plane (Cartesian plot . . . . . . . . . . . . . . . . . . . . . . . . 24AN3359Coordinate systemDoc ID 018585 Rev 15/281 Coordinate systemFor the purpose of this document, the spherical coordinate system illustrated in Figure 1 isused.Figure 1.Spherical coordinate systemThe PCB module is orientated vertically (plane X-Z, and located in proximity to the origin ofthe coordinate system. The azimuth angle radiates from the X-axis towards the Y-axis, andthe elevation angle radiates from the Z-axis towards the horizontal plane, X-Y. Sometimes,as with geographical and navigational systems, the X-axis is called the "Nord-axis", the Y-axis is called the "East-axis" and the Z-axis is called the "Zenith-axis".Layout specificationAN33596/28Doc ID 018585 Rev 12Layout specificationPCB antennas, including the electrical parameters of PCB materials used, are layoutsensitive. STMicroelectronics recommends using a layout as close as possible to that shown in Figure 2. Figure 2.Layout of Meander-like PCB antennaeThe electrical parameters and performance of the PCB antenna are also determined by the substrate used, in particular the thickness of the core and dielectric constants . Figure 3 illustrates a typical cross-section of the substrate in a PCB-antennae area.εRAN3359Layout specificationDoc ID 018585 Rev 17/28Figure 3.Cross section of the PCB at antennae regionA substrate with the parameters in Table 1 is recommended: Table 1.Specification of the recommended substratePos. LayerDimensionDielectric Constant LabelValue Unit Value Unit 1Solder Mask, TopS10.7mil 17.78µm4.42Copper Trace T 1.6mil 40.64µm---3CoreC 28mil 711.2µm4.44Solder Mask, BottomS20.7mil17.78µm4.4εRImpedance matchingAN33598/28Doc ID 018585 Rev 13 Impedance matchingMeander-like PCB antenna can be tuned to the required 50 Ohm impedance by matchingthe impedance circuitry with the π topology. In Figure 2 the impedance matching area is marked with a dashed line. Under nominal conditions, this antenna should exhibit impedance very close to the required nominal impedance (50 Ohm.To check the performance of this design, a sample antenna was manufactured (according to the specifications covered by this document. Figure 4 shows this antenna.Figure 4.Part of the ZigBee module's PCB with Meander-like antenna (aroundscale 4:1Assuming that the manufactured sample exhibits the expected performance (no impedance matching necessary, the impedance matching circuitry was bypassed by two 100 pFcapacitors connected in series, as shown in Figure 5:Figure 5.Bypassing impedance matching circuitry - direct RF connectionAll electrical parameters of the meander-like antenna have been measured at connection to the Band Pass Filter with the frequency span covering frequencies from 2.4 GHz to 2.5 GHz.Complex impedance of the antenna is shown in the Smith diagram in Figure 6:AN3359Impedance matchingDoc ID 018585 Rev 19/28Figure 6.Complex impedance of the Meander-like antenna on Smith Chart Figure 7 shows the magnitude of the S11 parameter (in log scale. Impedance matchingAN335910/28Doc ID 018585 Rev 1Figure 7.Magnitude of the S11 parameter in logarithmic scale (Cartesian plot Figure 8 shows the Standing Wave Ratio (SWR.AN3359Impedance matchingDoc ID 018585 Rev 111/28Figure 8.Antenna's Standing Wave Ratio (SWRThe following changes will affect the radiation impedance of the PCB antenna:●slight board size variation●metal shielding●use of plastic cover●presence of other components in proximity of the antennaThe best performance impedance matching circuitry will compensate these effects so thatfor operating frequencies, the optimum 50 Ohm impedance is achieved.Radiation pattern, 3-D visualizationAN335912/28Doc ID 018585 Rev 14 Radiation pattern, 3-D visualizationA three-dimensional (3-D visualization of the radiation pattern (magnitude of the electricalfar field |E| is done for the center ISM band frequency 2.44175 GHz.Figure 9.Three dimensional (3-D radiation pattern overviewFigure 10.Radiation pattern on Y-Z planeAN3359Radiation pattern, 3-D visualizationDoc ID 018585 Rev 113/28Figure 11.Radiation pattern on X-Z planeRadiation pattern, 2-D visualizationAN335914/28Doc ID 018585 Rev 15 Radiation pattern, 2-D visualizationIn this chapter all radiation patterns are related to the magnitude of electrical far field E,which is normalized and shown in the logarithmic scale (in dB. This means that themaximum global radiation pattern (maximum magnitude of the electrical far-field E isrepresented by 0 dB level. To show antenna radiation patterns in detail, three twodimensional (2-D major cuts are presented. Consider the orientation of the module in thespherical coordinate system as shown in Figure 1.A three dimensional (3-D far field radiation pattern is visualized as three two dimensional(2-D cuts through a 3-D pattern. Three major planes are used for these cuts (Figure 12:●One horizontal X-Y plane ●Two vertical planes: X-Z plane and Y-Z plane.For the colors of the plots in Figure 12:●The "Blue" plot is drawn on the horizontal X-Y plane, where azimuth φ radiates from 0° on the X-axis towards the Y-axis until it reaches 360° on the X-axis.●The "Red" plot is drawn on the X-Z plane, where elevation θ radiates from 0° on the Z-axis towards the positive part of the X-axis until it reaches180° on the negative part ofthe Z-axis. In this plot (cut by X-Z plane, elevation θ is negative for X < 0.●The "Green" plot is drawn on the Y-Z plane, where elevation θ radiates from 0° on the Z-axis towards the positive part of the Y-axis until it reaches 180° on the negative partof the Z-axis. For this plot (cut by Y-Z plane, elev ation θ is negative for Y < 0.AN3359Radiation pattern, 2-D visualizationDoc ID 018585 Rev 115/28Figure 12.Major planes used to visualize 3-D radiation pattern using 2-D plotsThis chapter uses short dipole for comparison and clarification purposes only.The first radiation patterns in Figure 14 and Figure 15 show a normal electrical fieldradiation pattern |E| (far field on the Y-Z plane. The module orientation versus Y-Z plane andthis plot is shown in Figure 13.Radiation pattern, 2-D visualizationAN335916/28Doc ID 018585 Rev 1Figure 13.Far field radiation pattern plotted on Y-Z planeNotice the nearly constant level of the radiation—nearly omni-directional radiation on thisplane. For a vertically orientated dipole, this pattern is equivalent to the horizontal radiation.AN3359Radiation pattern, 2-D visualizationDoc ID 018585 Rev 117/28Figure 14.normalized radiation pattern on Y-Z plan (Polar plotFigure 15 shows the same radiation pattern as in Figure 14, presented as a Cartesian plot.Radiation pattern, 2-D visualizationAN335918/28Doc ID 018585 Rev 1Figure 15.normalized radiation pattern on Y-Z plane (Cartesian plotThe second far-field radiation pattern (Figure 17 and Figure 18 represents a normalizedmagnitude of the electrical field |E| plotted on the X-Y plane. The module orientation versusthe X-Y plane and this plot is shown in Figure 16.AN3359Radiation pattern, 2-D visualizationDoc ID 018585 Rev 119/28Figure 16.Far field radiation pattern plotted on X-Y planeFor a vertically orientated dipole, this pattern is equivalent to the vertical radiation. Note thatthe "dips" (between -10 and -14 dB are much less critical than for the dipole.Radiation pattern, 2-D visualizationAN335920/28Doc ID 018585 Rev 1Figure 17.Normalized radiation pattern on X-Y plan (Polar plotFigure 18 show the same far |E|-field radiation pattern on the X-Y plane as in Figure 17, presented as a Cartesian plot.AN3359Radiation pattern, 2-D visualizationDoc ID 018585 Rev 121/28Figure 18.Normalized radiation pattern on X-Y plan (Cartesian plotThe third and last radiation pattern (Figure 20 and Figure 21 represents a normalizedelectrical field radiation pattern |E| (far field on the X-Z plane. The module orientationversus the X-Z plane and this plot is shown in Figure 20.Radiation pattern, 2-D visualizationAN335922/28Doc ID 018585 Rev 1Figure 19.Far field radiation pattern plotted on X-Z planeFor a horizontally orientated dipole, this pattern is equivalent to the vertical radiation. Notethat the "dip" (about -18 dB in worse case is not as deep, in comparison to the dipoleradiation pattern.AN3359Radiation pattern, 2-D visualizationDoc ID 018585 Rev 123/28Figure 20.Normalized radiation pattern on X-Z plane (Polar plotFigure 21 shows the same far electrical field radiation pattern on the X-Z plane (Figure 20,presented as a Cartesian plot.Radiation pattern, 2-D visualizationAN335924/28Doc ID 018585 Rev 1Figure 21.Normalized radiation pattern on X-Z plane (Cartesian plotAN3359Performance Doc ID 018585 Rev 125/286 PerformanceAt center ISM Band frequency 2.44175 GHz, antennae show the following key performanceparameters:–Directivity2.21 dB–Gain1.95 dBi–Maximum intensity0.125 W/SteradianSummary AN3359 7 Summary The designed antenna occupies a small part of the module's PCB. It is inexpensive and simple to produce and shows very good performances, confirmed by measurements of the manufactured samples. Keeping the manufacturing process as close as possible to the specification detailed in this documentproduces an antenna that does not need any of the additional components usually required for impedance matching circuitry (cost reduction, increased reliability. In addition, a no tuning procedure or similar is required. The antenna impedance is close to the nominal 50 Ohm value, with excellent SWR < 1.35 together and wideband capabilities, where log (|S11| < -10 dB is satisfied for more than 150 MHz. 26/28 Doc ID 018585 Rev 1AN3359 Revision history 8 Revision history Table 2. Date 17-Mar-2011 Document revision history Revision 1 Initial release. Changes Doc ID 018585 Rev 1 27/28AN3359 Please Read Carefully: Information in this document is provided solely in connection with ST products. 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UNLESS EXPRESSLY APPROVED IN WRITING BY AN AUTHORIZED ST REPRESENTATIVE, ST PRODUCTS ARE NOT RECOMMENDED, AUTHORIZED OR WARRANTED FOR USE IN MILITARY,AIR CRAFT, SPACE, LIFE SAVING, OR LIFE SUSTAINING APPLICATIONS, NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY, DEATH, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE. ST PRODUCTS WHICH ARE NOT SPECIFIED AS "AUTOMOTIVE GRADE" MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER’S OWN RISK. Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any liability of ST. ST and the ST logo are trademarks or registered trademarks of ST in various countries. Information in this document supersedes and replaces all information previously supplied. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners. © 2011 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Philippines - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America 28/28 Doc ID 018585 Rev 1。
自己动手制作路由器2.4G定向天线
自己动手制作路由器2.4G定向天线2012-04-04 00:05本站整理Emmanuel字号：A+|A-2.4GHZ本身就是高频要求制作精度高，如果您动手能力差的话还是不要做的好许多网友看到网上的制作资料就急不可耐的去找材料，然后加班加点的制作。
等做出了天线发现效果不怎么样，或出了这样和那样的问题，才肯坐下来继续研究资料。
其实你大可研究好了再做，网上的图纸各种各样，你知道它的材料吗？因为它来自世界各地。
缩短率，平衡-不平衡转换，原理，构造，阻抗匹配等。
最起码得先了解些原理吧，比如有个网友做了个双菱形的感觉效果不怎么好就想再做个4菱形的，尺寸和原来的一样结果做出来了增益没有高，减益倒高了不少，因为双菱形的阻抗和4菱形的根本不一样。
无线系统的天线长度通常是使用频率波长的1/4，2.4Ghz由于频率高，波长当然就短，所以天线自然就特别短，因此使用 2.4Ghz系统当然就再不需要传统那样长长的拉杆天线了。
单一菱形四条边：每一边长 1/4 波长，单个菱形全长 1个波长，有些人会计入缩短系数(根据线径粗细0.96-1.05)，所以有这么多值跑出来，最好自己计算。
频率为2.4GHZ的波长是12.5cm ，2.4G波长=3*108/2.4？….*109=0.125m=12.5cm，根据频点可得不同长度。
如2.45G频率的波长12.24厘米，1.5mm铜丝的缩短系数0.96，则边长=波长*缩短系数/4=29.39毫米反射板的宽度应大于12.5CM，取140MM也是合理的，但不要太大了，能有个弧度最好为了减少杂波干扰,前面还可以制作一个挡板，过滤掉波长为几十毫米以下的杂波，当然这个工艺性要求较高，省去也是可以的。
引下线可以采用50欧姆的同轴电缆，长度计算应与阻抗相匹配。
2.4G高频信号衰减厉害，馈线最好不要超1米。
反射板屏蔽掉能获得更大增益，双棱增益10DB，屏蔽12DB ;四棱增益13DB，屏蔽 14DB一个菱形标准是 3.15dbi，加反射板多 3db，菱形每多一倍加 3db，所以双菱形是 3.15+3+3=9.15dbi; 四菱形 12.15dbi;八菱形 15.15dbi; 16 菱形 18.15dbi;32 菱形21.15dbi;64 菱形 24.15dbi;128 菱形是 27.15dbi;要达到30dbi增益需要256 个菱形!!!高增益天线应用在短距离时，其效果并不见得会比低增益天线来的好(近距离时，低增益天线的"等效截面积"，有时会比高增益天线来的大)，如果再加上于室内使用，因为多重路径的关系，高增益天线的效果也不一定会比低增益天线好下面是国外网站10db定向天线制作过程：。
自制2.4G全向天线的制作方法
本文介绍一个容易制作的802.11b/g垂直极化全向天线，该天线非常坚固耐用，大约有5-6dBi 的增益。
很多网站都有制作2.4GHz全向天线的详细说明，但是，这些天线做起来相当复杂，要用很多切割非常精确的小段同轴电缆。
同时你还必须知道所使用的同轴电缆的数据，因为大部分尺寸要以此为依据。
有些改进的同轴电缆全向天线是用黄铜棒和黄铜管制造的，但是它同样需要高精度的工艺。
不久前，做了一个8单元的同轴电缆天线。
经测试有将近8dBi增益。
制作花了N多个小时，但是机械强度却不很理想。
于是我就给同轴电缆天线缠上加固木条，并把它装进25mm 的电线导管。
当一个朋友告诉我，有人把一段铜线弯曲成一个简单的天线，就有6dBi的增益，我的好奇心被激发起来了。
这个天线有一些超越同轴电缆天线的优点，降低了制作难度，天线更小、更坚固。
虽然6dBi的增益小于8单元的同轴电缆天线，但是可以通过增加元件的数量来改进。
每两个单元可以增加3dBi的增益。
所需器件：需要的原料.. 大约300mm长，截面2.5平方毫米的铜线.. N型母接头.. 长250mm ，外径20mm的轻型电线导管.. 2 个适用于20mm电线导管的端盖当然，装配天线还需要：.. 2 个适用于20mm 电线导管的夹具或者：.. 金属支架我用的是一段截面2.5平方毫米的废旧铜线。
这种铜线的直径大约是1.6mm，不需要借助任何特殊工具就能弯曲到需要的形状。
还需要用N型母接头把天线和无线装置连接起来。
也可以用其它接头(比如：TNC,SMA 等等)，这取决于你的连接线端的接头。
我用的是下面的这种设计：一段铜线，在特定位置弯出一些圆环，就组成了天线。
各部分的尺寸是非常重要的，参考下面这张图：底部是1/2波长，中间部分是3/4波长，顶部要稍微小于3/4波长，以便减少电容的影响。
802.11b 标准使用 2.412MHz 到 2.484MHz 频率范围，其中心频率的1/2波长是61mm，3/4波长是91.5mm。
自制2.4GHz全向天线分步指南
Easy Homemade 2.4 Ghz Omni Antenna自制2.4 Ghz全向天线分步指南An easy step-by-step guide go making a homemade wireless antenna, for a fraction of the cost of commercial antenna. Uses readily available parts, and requires no specialist tools or knowledge. Or in geek speak - a diy homebrew omnidirectional colinear dipole design suitable for 802.11 wifi compatible hardware with external antenna connector.一个简单的分步指南带我们自制无线天线，其成本只是商业天线的一小部分。
使用现成的零件，而无需专门的工具和知识。
或者如geek所说——一个自制的全向的共线偶极子，设计与802.11兼容的无线外接天线。
•Introduction•Getting The Parts•Cutting The Pieces•Build A Jig•Testing•Problems•DisclaimerIntroduction介绍Most of the designs on the web for 2.4 GHz omni antenna seem to involve brass tubing and lmr-400 cable, none of which are readily available to me. I then found a coax only design for 444Mhz that was based on the same idea. The only reasonable cable I could get my hands on was RG-213 from Maplin. By scaling the 444Mhz design up to 2.4 Ghz and using RG-213 I thought I'd have a go. In order to get about 6db gain from the antenna, it would need 8 sectors, with a 1/4 wave section at the top and a fly-lead with N-connector at the bottom. It should take about 2-3 hours to build an antenna using this design, but don't worry if it takes longer, you will get quicker, especially as you only need to make the jig once.大多数网络设计的2.4 GHz的全向天线，似乎大部分涉及铜管材和LMR-400同轴电缆，对我都不适用。
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。
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无线的WIFI全向天线制作详解
这个天线结构是很简单，要求只是一根铜线，一个N接头和一个约100毫米直径金属圆盘。
完成的天线图.
该2个单元的短天线，将得到5dbi增益，而4个单元版本将有7至9 dBi的增益。
用N型接头,用3毫米的铜线
制作方法:
三. 四分之一波长〔 32毫米〕的全向天线
使用N型接头,
制作方法:
N型接头
长度底部的第1 / 2波长，该中心是第3 / 4波长，鞭节上顶端是略少于3 / 4波长，显然是为了减少电容的效果。
802.11b标准使用2.412mhz ，以2.484mhz的频率X围，所以在该中心的这一频率X围内， 1 / 2波长是61毫米，和3 / 4波长是91.5毫米。
这些方面与类似的商业天线似乎是一致的。
这个线圈的直径是15毫米
五.容易自制的2.4 GHz的全方位天线
使用15毫米或22毫米铜管和10毫米直径的RG-213电缆,37+6+6+1=50毫米,8小段+1/4波长总共天线长420毫米.
V * C 0.66 * 299792458
2 * F 2 * 2441000000
C = 光的速度 = 299792458
F = 信号频率 = 2441000000 (2.4 GHz的中间X围)
注:31mm为1/4波长。
2.4GHz天线设计-仿真报告
微波技术与天线课程设计报告仿真结果课题： 2.4GHz天线的设计院系：文正学院电子信息系专业：2012级通信工程姓名：郑富成学号：1217408034指导老师：刘学观日期：2014年12月25日一、设计名称2.4GHz 微带贴片天线二、设计目标1.设计2.4GHz的天线，使其在2.4GHz处产生谐振2.回波损耗3.驻波比4.三、设计过程微带天线主要参数如图，w为辐射贴片的宽度，L为长度。
L1为馈线的长度，w1为馈线的宽度。
1.微带辐射贴片尺寸估算微带辐射贴片的宽度：由相关数据：，f=2.4Ghz, 。
解得：W0=38.03mm辐射贴片的长度L0一般取。
考虑到边缘缩短效应后，实际上的辐射单元长度L0应为：其中为等效辐射缝隙长度，为有效介电常数。
带入，，W0=38.03mm 得所以L0=29.11mm2.馈电点位置微带线馈电点位置选在辐射贴片的中点，此时馈电点和辐射贴片边缘距离为Z=w/2=19.0153.输入阻抗如果采用微带线馈电方式，馈电点到辐射贴片边缘拐角的距离为z，则微带线的输入导纳近似为：式中：由此，计算出输入阻抗4.阻抗匹配输入阻抗一般不符合微波器件通用的系统，所以在设计微带线馈电矩形微带天线时，可加上一段的阻抗变换器。
则阻抗变换器的特性阻抗：借由此可以计算出馈线的宽度由下式及解得：四、参数汇总由以上可以得到各变量的理论值：h/mm80 80 1.16 31.25 3.06 29 1.6五、仿真过程采用如上数据，在HFSS中绘制侧馈微带天线，如图3.1所示：图3.1 理论数据建模仿真结果不理想，虽然衰减非常好，但频率偏差大约24MHz。
应该能够做得更好对L0从45.1到45.5mm进行扫描，得到图3.2图3.2 对扫描结果最终选择radition=58.11mm，是中心频率在2.4GHz。
接下来调整radition_l，最终选择radition_l=29.11mm。
最终的结果图如图3.3至3.5所示。
小型化2.4GHz微带贴片天线的设计
［ 关 键 词 ］微 带 天 线 ； 移 动通 信 ； 正万 字型贴 片 ； Ｈ ＦＳ Ｓ 仿 真
［ 文 章 编 号 ］１ ６ ７ ２ — ２ ０ ２７（ ２ Ｏ１ ４ ） ０１ － ０ ０６ ６ — ０４ （中 图 分 类 号 ］ Ｏ４３ ７ ［ 文献 标识 ｒ ｏ － ￣３ Ａ
第 １ ３卷 第 １ 期 太 原 师 范 学 院 学 报 （ 自然 科 学 版 ） ２ ０ １ ４年 ３月 Ｊ ０ＵＲＮＡＬ ＯＦ ＴＡＩ ＹＵＡＮ Ｎ０ＲＭ ＡＬ ＵＮＩ ＶＥＲＳ Ｉ ＴＹ （ Ｎａ ｔ ｕ ｒ ａ ｌ Ｓ ｃ ｉ ｅ ｎ ｃ ｅ Ｅ ｄ ｉ ｔ ｉ ｏ ｎ ）
宽且 易 与设备 共形 的特 点． 于是微 带天 线 以其 重 量轻 、 低剖面、 造 价低 、 易与 载体共 形 以及能 与有 源 电路集成 等 突 出优 点口 ］ ， 越来 越受 到广 大天线 研究 者 的青睐 ， 并且 出现 了各 种各样 的新 型微 带天 线． 目前 ， 微 带天线 已应 用 于工作 在大 约 １ ０ ０ ＭＨｚ １ ０ ０ ＧＨｚ的宽 广 频域 上 的大量 无 线 电设 备 中 ， 特 别是
Ｖｏ １ ． １ ３ Ｎｏ ． １ Ｍａ ｒ ．２ ０ １ ４
小型化 ２ ． ４ ＧＨｚ 微 带 贴 片天 线 的设 计
陈 昶
（ 太原师范学院 物理系 ， 山西 太原 ０ ３ ０ ０ ３ １ ）
［ 摘 要 ］针 对 无 线 通 信 系 统 提 出 一 种 新 型 的 工 作 频 率 为 ２ ． ４ ＧＨｚ的 小 型 化 微 带 天 线 结 构 ， 这 种
当在贴 片表 面开 不 同形式 的槽 或细缝 时 ， 切 断了原先 的表 面 电流路 径 ， 使 电流 绕槽 边 曲折 流过 而路 径变
广东得胜电子有限公司制造的2.4G指向性天线说明书
广东省电声工程技术研究开发中心 广东得胜电子有限公司制造地址：广东省惠州市博罗县龙溪镇富康一路2号电话：400 6828 333 传真：0752-******* 邮箱：xs @takstar .com 邮编：516121 网址：www .takstar .com欢迎使用2.4G 指向性天线。
本产品为24002500MH 宽频段设计，采用单根RG58 线连接适用于工程应用和户外演出。
请您在使用之前，仔细阅读说明书，以便能正确的操作，发挥出产品的性能。
~z 方便使用，具有一定的防水性能；● 宽频段(2400~2500MHz)设计● 天线的前后比高，可有效抑制后方的干扰信号。
● 单条RF● 具有一定的防水性能，可户外使用。
产品特性频率范围：2400～2500MHz天线增益：> 10dBi 天线接口：SMA/50Ω驻波比: < 2.01. 可将带有螺纹的集成式支架轻松地固定到话筒支架上。
2. 使用配送线缆RG58将天线连接到接收机。
3. 将天线对准需要覆盖的区域。
连接线天线安装为让发挥出天线的性能，应注意下列事项：1. 避免缆扭弯或扭结。
2. 不要使用方便夹（例如用钉子环绕固定线缆）让线缆改变形 状。
3. 在户外使用时，应注意采用对高频信号无衰减的材料进行遮 挡，避免造成信号衰减和暴露在外面日晒雨淋，导致缩短使 用寿命。
4. 不要在高温高湿环境中使用。
5. 不要将此天线用于发射信号。
线天线放置在固定天线时，应注意下列事项：1. 2. 3. 4. 5天线适用于2.4G 无线接收机系统。
在使用到至少两条天线以上时，天线与天线彼此相距至少1.2 米的距离。
为达到良好的效果，应尽量调整天线的位置，避开障碍物和人 群。
安装时，天线的正面尽量避开较大的金属物体，避免影响使用 效果。
. 安装时，天线应距离地面至少2米以上，以获得更好效果。
技术参数线缆维护标准配件指向性天线 一个天线延长线 一条支架座 一套2.4G 指向性天线两条天线相距至少1.2米TS-AD3Thank you for choosing Takstar 2.4G directional antenna. Please read the user manual carefully before using to make sure the correct operation and to exert the best performance of this product.• Wide frequency band design (2400~2500MHz)• High front-to-rear ratio effectively restrain the rear interference signal• Provided with one RG58 cable for convenient useFeaturesFrequency Range: 2400~2500MHz Operating Range: 40 meters Antenna Gain: >10dBi Antenna Connector: SMA/50Ω Standing Wave Ratio: <2.01. Assemble the holder supplied along with the product on the antenna, then fix the holder with a microphone tripod. Or hang the antenna directly on the wall2. Antenna should aim at the working transmittersInstallationTo keep the best performance of the uni-directional directivity, please note:1. Avoid twisting or knotting the cable2. Do not use any clip to change the shape of the cable(e.g. try to fix the cable by wrapping it on a nail)3. When being used outdoors, please use the shelter which will not attenuate the high frequency signal such as plastic material to protect the antenna from signal attenuation and exposure to sun and the rain4. Do not expose the antenna to the extreme humidity5. Do not use the antenna to transmit signalCaution1. The antenna is applicable to2.4G wireless receiver system 2. If two or more antennas need to be used simultaneously, the distance between each two antennas should be at least 1.2 meters3. To maximize the performance of the antenna, try to adjust the position of the antenna to avoid the crowd and obstacles as much as possible4. Antenna front side should avoid big metal objects5. The antenna should be installed at least 2 meters above the groundSpecificationCable MaintenanceProduct ContentDirectional antenna 1 pc Extension cable 1 pc Holder 1 set2.4G Directional AntennaDistance between 2 antennas should be 1.2m at leastTS-AD3Guangdong Takstar Electronic Co., Ltd.Address: No.2 Fu Kang Yi Rd., Longxi Boluo Huizhou, Guangdong 516121 ChinaTel: +86 752 6383644 Fax: +86 752 6383952 Website: E-mail:*****************。
2.4GWIFI交叉铜管同轴天线
2.4GWIFI交叉铜管同轴天线
同轴电缆的特征阻抗由同轴外导体内径、芯线外经、填充介质决定。
常用传输电缆的性能主要取决于填充介质，由于介质的存在，电磁波损耗将不可避免。
空气介质电缆-同轴电缆内外导体间不填充任何介质材料，由于只存在空气，所以其损耗应该是最低的。
特征阻抗50Ω空气电缆外导体内径与内导体外经的比(D/d）约为2.3。
缩短系数由于电缆介质是空气，所以缩短系数接近1；大多数空气馈管里面基本上以空气为主要介质，所以缩短系数一般比较高，有的达到0.95。
根据以上特性，设计以下WIFI交叉铜管同轴天线
1、铜管选定，首先选择内导体，这里选择3mm的铜管，由50Ω空气电缆外导体
内径与内导体外经的比(D/d）约为2.3得出外导体的内径约为6.9mm，故此选
择8mm厚0.5mm的铜管(内径为7mm)。
2、确定天线振子尺寸
λ/2长度=光速/中心频率*缩短系数
光速：3*10^8
2.4G中心频率：2440MHz
缩短系数：这里选0.95（0.9~0.98均可）
得到λ/2=58.4mm
L1取3mm,l2取3mm
最终每节振子截料长度，8mm铜管L=55.4mm，3mm铜管67.4mm
3、底部尺寸
4、固定
振子的芯线与外导体之间因为没有支撑，所以要想办法固定并保持同心，在振
子两端可以用热熔胶将其固定，以牢固就好尽量用最少的料以免影响效果。
5、调试
串入驻波表，微调20mm铜套，使驻波最少即可。
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。
2.4GHz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。
专有2.4-GHz的无线音频设计方案
1.引言计的信号范围、音质和最长播放时间方面面临着重大挑战。
为满足这些要求，工程师可以利用来自多家制造商的大量可用产品，包括（按字母顺序）Analog在典型的无线娱乐系统（图1）中，源信号通过带有可选范围扩展器的无线射频接口传输到播放器系统，例如立体声耳机或扬声器。
在播放器内，相应的无线射频接口接收信号以供编解码器、音频处理器或 DSP 处理，以创建驱动到扬声器的最终模拟信号。
一个适当的电源，通常包括一个电池和充电管理电路，完成了系统。
子系统的可用集成解决方案可以帮助工程师满足这些要求，同时降低设计复杂性和成本。
2.频带遗留问题、市场接受度和未授权带宽的可用性通常会推动无线电通信频率的选择。
同时，满足增加操作范围和延长电池寿命的要求为有用频段设置了界限。
对增加功率的需求是对更远距离操作的渴望的自然结果，但射频波长的选择在平衡范围和功率方面起着至关重要的作用。
射频波长和范围之间的关系在Friis 传输方程中进行了描述：其中Pt = 发射功率Pr = 接收功率Gt = 发射器天线增益Gr = 接收器天线增益λ = 波长d = 发射器和接收器之间的距离对于统一参数，距离成为波长的简单线性函数，因此更长波长的无线电通信等同于更大的范围。
当然，更长的波段面临着包括干扰和有效载荷带宽在内的问题。
在这种情况下，2.4 GHz ISM 频段在实际范围限制和有用带宽之间提供了良好的平衡。
2.4 GHz 解决方案的吸引力在于它们能够以低功耗提供有用的有效范围，以及它们的全球可用性。
在蓝牙等标准中使用的基于跳频扩频（FHSS）的2.4 GHz 设计具有在高度活跃的无线电环境中相对不受干扰信号影响的优势。
与较低的ISM 频段相比，这些系统还提供足够的数据带宽，以允许高质量立体声的数字传输，后者通常仅限于模拟或较低数据速率的数字音频。
蓝牙标准工作频率为 2.4 GHz，非常适合消费者的连接要求。
它的广泛使用使得基于蓝牙的无线音频播放器很可能会找到兼容的音频主机，例如计算机、笔记本电脑、平板电脑和智能手机。
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2.4GHz Inverted-F and Meander Line Antennas Application NoteMay 2007CSR Cambridge Science Park Milton Road Cambridge CB4 0WH United Kingdom Registered in England 4187346 Tel: +44 (0)1223 692000 Fax: +44 (0)1223 692001 © CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.CS-101512-ANP2ContentsContents1 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................................................................................................................... 82.4GHz Inverted-F and Meander Line AntennasNetwork Analyser........................................................................................................................................... 9 Final Tuning.................................................................................................................................................. 10 Conclusion ................................................................................................................................................... 12Terms and Definitions ........................................................................................................................................ 13 Document History ............................................................................................................................................... 14List of Figures Figure 2.1: Inverted-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....................................................................................................................... 11CS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 2 of 14Introduction1IntroductionThis document outlines two types of Printed Circuit Board (PCB) antennas used by CSR, which can be used with 2.4GHz radios.! !Inverted-F Meander LineIn addition, this document discusses the effect of placing metallic or dielectric materials near an antenna.2.4GHz Inverted-F and Meander Line AntennasCS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 3 of 14Inverted-F Antenna2Inverted-F AntennaQuarterwave2.4GHz Inverted-F and Meander Line AntennasInput OutputFigure 2.1: Inverted-F Antenna The inverted-F is a quarterwave 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 feed 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 feed point to ground and a whip antenna due to the open circuited straight section. In the PCB version, the antenna is printed on the top layer and a ground plane is placed near the antenna on the top layer. There must not be a ground plane underneath the antenna. The aim is to make the quarterwave section resonate at the midband frequency (which is 2441MHz for 2.4GHz ISM radios). The feed point (which is the input/output connection) is connected to the L-Shape at the point corresponding to 50Ω. Experiment with measurement to determine the correct location for the feed point and length of this antenna.CS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 4 of 14Meander Line Antenna3Meander Line AntennaS Ground Plane Input Output2.4GHz Inverted-F and Meander Line AntennasFigure 3.1: Meander Line Antenna The length of the meander line antenna is difficult to predict. It is usually a bit longer than a quarterwave 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 type of antenna is always a PCB version. The antenna is printed on the top layer and a ground plane is placed near the antenna on the top layer. 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 15Ω to 25Ω, 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 50Ω), 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 50Ω (Point B). Experimental measurement is used to determine the correct design.CS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 5 of 14Real Designs4Real Designs18.0mm13.5mm Width=0.8mm 6 .0mm 5 .0mm Not to scale2.4GHz Inverted-F and Meander Line AntennasGround PlaneActual SizeFigure 4.1: Approximate Dimensions of Inverted-F Antenna1.5mm1.0mm4.4mm Width=0.5mm 2.8mm8 .0 mm1.7mm Ground Plane FeedpointNot to scale1.5pF CapacitorPlaced immediately after FeedpointActual SizeFigure 4.2: Approximate Dimensions of Meander Line AntennaCS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 6 of 14Proximity to Metal Objects5Proximity to Metal ObjectsCSR recommends keeping metal objects as far away from the antenna as possible. Keeping metallic objects out of the near field is usually adequate. Near Field = 2D2/λ D is the largest dimension of the antenna. In the case of these antennas, this is approximately a quarterwave (λ/4).2.4GHz Inverted-F and Meander Line AntennasNotes:λ is the wavelength of the signal in freespace. In the 2.4GHz ISM band, λ=122mm in freespace. Substituting D=λ/4 into the Near Field equation gives Near Field = λ/8. Near Field = 122/8 mm = 15.25mm.CS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 7 of 14Proximity to Dielectric Materials6Proximity 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. Therefore, it is important to tune the antenna when it is in the product. This is done during the development of the product.2.4GHz Inverted-F and Meander Line AntennasCS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 8 of 14Network Analyser71. 2.Network AnalyserCut the PCB track (trace) just before the antenna matching network to isolate the filter and previous stages from the measurement. Connect a coaxial cable between the VNA and the PCB of the product. The coaxial cable must have ferrite beads fitted over its outer sleeve. The ferrite beads help to prevent RF currents from flowing 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. Perform 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 (displayed on the VNA) is at the centre of the Smith chart at the midband frequency 2441MHz. Repair the cut track by putting a small amount of solder over the cut.Use a vector network analyser (VNA) to perform the initial tuning of the antenna:2.4GHz Inverted-F and Meander Line Antennas3. 4. 5.6.Figure 7.1: Preparation Before MeasurementVNAFerrite BeadsAntenna 2.4GHz RadioFigure 7.2: Assembled System Ready to MeasureCS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 9 of 14Final Tuning8Final TuningAfter tuning the antenna using the VNA procedure, it is necessary to perform fine-tuning. This yields a small improvement and is the final optimisation of the antenna. It is best to perform 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 2m2.4GHz Inverted-F and Meander Line AntennasRX Antenna2.4GHz RadioSpectrum AnalyserFigure 8.1: Locating Product in Far Field of AntennaCS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 10 of 14Final TuningConnect omni directional receive antenna to a spectrum analyser Place fully assembled product approximately 2m away from receive antennaPut product into continuous transmitWatch power level of received signal on the specturm analyser 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 point2.4GHz Inverted-F and Meander Line AntennasYesIs 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 analyser. This ensures that the dominant polarisation mode of the antenna is measured.NoHas the maximum possible power level been observed on the spectrum analyser?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 ProcedureCS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 11 of 14Conclusion9ConclusionMetal 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 for the antenna to work efficiently. If that is not possible, experiment to determine an acceptable trade-off between antenna performance and product size. Even by following 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 antenna.2.4GHz Inverted-F and Meander Line AntennasCS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 12 of 14Terms and DefinitionsTerms and DefinitionsCSR ISM PCB RF VNA Cambridge Silicon Radio Industrial, Scientific and Medical Printed Circuit Board Radio Frequency Vector Network Analyser2.4GHz Inverted-F and Meander Line AntennasCS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 13 of 14Document HistoryDocument HistoryRevision 1 2 Date 24 JAN 03 24 MAY 07 History CSR reference: CS-101512-ANP Original publication of this document bcant-an-001Pa Update to make generic to 2.4GHz radio2.4GHz Inverted-F and Meander Line AntennasUnless otherwise stated, words and logos marked with ™ or ® are trademarks registered or owned by CSR plc or its affiliates. Other products, services and names used in this document may have been trademarked by their respective owners. The publication of this information does not imply that any licence is granted under any patent or other rights owned by CSR plc. CSR reserves the right to make technical changes to its products as part of its development programme. While every care has been taken to ensure the accuracy of the contents of this document, CSR cannot accept responsibility for any errors. CSR’s products are not authorised for use in life-support or safety-critical applications. If you have any comments about this document, send an email to errata@, giving the document number, title and section with your feedback.CS-101512-ANP2© CSR plc 2003-2007 This material is subject to CSR’s non-disclosure agreement.Page 14 of 14。