LAB 2. Non-linearity in LNA
Objective: 1. One-tone test 2. two-tone test 3. Bias circuit design 4. Noise Circle and Input matching 5. Output matching for maximum gain 6. Final matching network design One-tone test 1. Save the final linear LNA schematic to a new name 2. Insert a HB simulation controller
Double click on VAR. Add RFfreq=2.46 and Pavs = as shown Var Eqn VAR VAR1 L=.6 RFfreq=2.46 Pavs= Change the HB simulation controller parameters as shown HARMONIC BALANCE HarmonicBalance HB1 Freq[1]=RFfreq GHz Order[1]=7 3. Insert a frequency domain source
Set the P_1Tone source parameters as shown P_1Tone PORT1 Num=1 Z=5 Ohm P=polar(dbmtow(Pavs),) Freq=RFfreq GHz 4. Rename the I_probe to Iout. Click on NANE to name the output node. Enter Vout and Vin in the dialog box and click at the output node and input node. Click Close.
5. Simulate. In the data display window, click linear plot. In Plot Traces & Attribute window, add Vin. Check Time domain signal and click OK. Also, add Vout and check Time domain signal and click OK. 2 1 ts(vout), V ts(vin), V -1-2 1 2 3 4 5 6 7 8 9 time, psec
1 = Re. In the data 2 * To obtain the output power, enter the power equation P ( V I ) display window, click Eqn. Enter the expression: Pout = 1/2*real(Vout[1]*conj(Iout.i[1])) Click OK. To convert the power into dbm, repeat above step but enter the expression Pout_dbm=1*log1(Pout/.1)
To display the power, click List in the data display window. Add Pout and Pout_dbm to Traces. Click ok. The output power is 15.7 dbm. Since the input power is dbm, the corresponding gain is 15.747 db as expected. Pout.38 Pout_dbm 15.747
6. We have seen the NF as a function of frequency. We shall investigate the effect of nonlinearity to NF. Double click on HB simulation controller. In Sweep Type drop down list, choose Single point. Enter RFfreq in Frequency edited box and check Nonlinear noise. Click Ok. Simulate. In the data display window, close List and add nf(2) to Traces. Click OK. It can be seen that the NF is.915 which is higher than we expect. Why??? noisefreq 2.46 GHz nf(2).915
Back to the schematic window, change Pavs in VAR to -1 and re-smulate Var Eqn VAR VAR1 L=.6 RFfreq=2.46 Pavs= Var Eqn VAR VAR1 L=.6 RFfreq=2.46 Pavs=-1 The NF is now closed to what we expect. This simple example shows the effect of the input and output power on the NF. noisefreq 2.46 GHz nf(2).711 We can vary the input power to see its effect on the NF. Back to the schematic window, double click on HB simulation controller. In Sweep tab, enter Pavs in Parameter to sweep edit box. Choose Linear Sweep Type and check Start/Stop. Enter value of Start, Stop and Num. of pts. as shown. Click Ok. Simulate.
In Data display window, choose Rectangular plot and add Pout_dbm to Traces. Click OK. It can be observed that non-linearity starts dbm of the input power. 3 2 Pout_dbm 1-1 -2-3 -4-3 -2-1 1 Pavs
In Data display window, choose Rectangular plot and add nf(2) vs HB.Pavs to Traces. Click OK. It can be seen that the NF increase dramatically where the transistor enters the nonlinear region. 8 m1 indep(m1)= -2. plot_vs(nf(2), HB.Pavs)=.798 noisefreq=2.46ghz 6 nf(2) 4 2 m1-4 -3-2 -1 1 HB.Pavs
We can also plot gain as a function of input power. In the data display window, click Eqn. Enter the expression: Gain = Pout_dbm-HB.Pavs Click OK. Double click on the output power plot and add Gain to the Traces. Click OK. Add two makers to the plot. Hold down the Shift key and click on both makers and turn on the Delta mode. It can be seen from the plot that the input P1-dB gain compression point is about 4 dbm. Gain Pout_dbm 3 2 1-1 -2 m2 Pavs= 4. Gain=14.85 m3 m3 ind Delta= -27. dep Delta=1.29 delta mode ON m2-3 -4-3 -2-1 1 Pavs
Two-tone Test 1. Save the previous in a different name. 2. Add variable as shown VAR Var Eqn VAR2 f_sep=2e3 tone1=rffreq*1e9+f_sep tone2=rffreq*1e9-f_sep 3. Add P_nTone to the schematic.
4. Double click on P_nTone. Choose Freq[1], enter tone 1 into the Freq edit box. Click Add. Choose, Freq[1], enter tone2 into the Freq edit box. Now the dialog box should show two frequencies. Freq[1] and Freq[2]. Next, choose P[1] and enter polar(dbmtow(pavs-3),) into the edit box. Click add. Choose P[1], enter polar(dbmtow(pavs-3),) into the dialog box. Click OK. The P_nTone should be as shown. P_nTone PORT1 Num=1 Z=5 Ohm Freq[1]=tone2 Freq[2]=tone1 P[1]=polar(dbmtow(Pavs-3),) P[2]=polar(dbmtow(Pavs-3),)
5. Double click on the HB simulation controller. Add tone1 and tone2 to simulation frequency. Set the number of Order to 7. If Non-linear noise is checked, uncheck it. Click OK. Simulate.
In the data display window, add a list. In the plot traces & attributes add Mix(1) and Mix(2) into Traces. Double click on the table. In Plot Traces & Attributes, change # of decimal digits to 5.
In the table, two fundamental frequencies use (1,) and (,1) as the mixing indexes and two 3 rd intermodulations use (2,-1) and (-1,2) as the mixing indexes. freq Mix(1) Mix(2) freq Mix 3rd Fundamental 3rd Pavs=-4.. Hz 4. khz 8. khz 1.2 MHz 2.4586 GHz 2.459 GHz 2.4594 GHz 2.4598 GHz 2.462 GHz 2.466 GHz 2.461 GHz 2.4614 GHz 4.9188 GHz 4.9192 GHz 4.9196 GHz 4.92 GHz 4.924 GHz 4.928 GHz -1-2 -3 4 3 2 1-1 -2-3 4 3 2 1-1 1 2 3-3 -2-1 1 2 3 4-2 -1 1 2 3 Pavs=-4., Mix(1). Hz 4. khz 8. khz 1.2 MHz 2.4586 GHz 2.459 GHz 2.4594 GHz 2.4598 GHz 2.462 GHz 2.466 GHz 2.461 GHz 2.4614 GHz 4.9188 GHz 4.9192 GHz 4.9196 GHz 4.92 GHz 4.924 GHz 4.928 GHz -1-2 -3 4 3 2 1-1 -2-3 4 3 2 1-1 We need two signal powers at 2.4598 GHz and 2.462 GHz and add them to obtain the total power at fundamental frequency. Hence, we insert the following equations for the fundamental frequency power. Eqn Pout_tone1=1/2*real(mix(Vout,{1,})*conj(mix(Iout.i,{1,}))) Eqn Pout_tone2=1/2*real(mix(Vout,{,1})*conj(mix(Iout.i,{,1}))) Eqn Pout = Pout_tone1+Pout_tone2 Eqn Pout_dbm=1*log1(Pout/.1) Eqn Gain = Pout_dbm-HB.Pavs The first two equations are the power for each fundamental frequency and the third equation is a total power at two fundamental frequencies. Add a rectangular plot to the data display window. Add Gain and Pout_dbm to Traces. Click OK. 2 1 Gain Pout_dbm -1-2 -3-4 -3-2 -1 1 Pavs
The third order intermodulation is calculated by combining both third order intermodulations. Insert the equations as shown. Eqn Pout_3rd1=1/2*real(mix(Vout,{2,-1})*conj(mix(Iout.i,{2,-1}))) Eqn Pout_3rd2=1/2*real(mix(Vout,{-1,2})*conj(mix(Iout.i,{-1,2}))) Eqn Pout_3rd=Pout_3rd1+Pout_3rd2 Eqn Pout_3rd_dbm=1*log1(Pout_3rd/.1) The equations are similar to the fundamental power equations but the mixing indexes are change from (,1), (1,) to (2,-1), (-1,2). Insert a rectangular plot in the data display window and add Pout_dbm and Pout_3rd_dbm to Traces. Click OK. 2-2 Pout_3rd_dbm Pout_dbm -4-6 -8-1 -12-14 -4-3 -2-1 1 Pavs The 3 rd order interception point can be calculate by using TOI = 1.5*P_fund.5*P_3rd. Where, P_fund and P_3rd are the fundamental frequency and 3 rd order intermodulation power in linear region, respectively. Insert two makers into the intermodulation plot to represent fundamental and 3 rd order power. Insert the TOI equation and a list in the data display window. The output TOI is about 33.828 dbm. Eqn TOI=1.5*m1-.5*m2 Pavs -11. TOI 33.828
We can verify the output TOI graphically by inserting two linear plots whose slope are 1 and 3. Insert the following equations. Eqn grad1 = (Pout_dbm[1] - Pout_dbm[])/(Pavs[1]-Pavs[]) Eqn grad2=(pout_3rd_dbm[1] - Pout_3rd_dbm[])/(Pavs[1]-Pavs[]) Eqn Pout_fund_ext=grad1*(Pavs-Pavs[])+Pout_dbm[] Eqn Pout_3rd_ext=grad2*(Pavs-Pavs[])+Pout_3rd_dbm[] The equations above are nothing but a linear equation. Add Pout_fund_ext and Pout_3rd_ext to the plot. It can be seen that we could not see the interception point. We need to extent the range of the input power (Pavs) from -4 1 dbm to -4 2 dbm. Back into the schematic window, double click on HB simulation controller. In sweep tab, change the Stop to 2. 4 m1 m2 Pavs= -11. Pavs= -11. Pout_dbm=5.39 Pout_3rd_dbm=-52.539 2 m1 Pout_3rd_ext Pout_fund_ext Pout_3rd_dbm Pout_dbm -2-4 -6-8 m2-1 -12-14 -4-3 -2-1 1 Pavs Simulate
Pout_3rd_ext Pout_fund_ext Pout_3rd_dbm Pout_dbm 6 4 2-2 -4-6 m1 m2 Pavs= -11.2 Pavs= -11.2 Pout_dbm=4.84 Pout_3rd_dbm=-53.144 m1 m2 m3-8 -1-12 -14-4 -3-2 -1 1 2 Pavs m3 Pavs= 17.6 Pout_fund_ext=33.67 It can be seen that the output TOI is 33.67 as predicted by the formula. The input TOI is 17.6 dbm.
易迪拓培训 专注于微波 射频 天线设计人才的培养网址 :http://www.edatop.com 射频和天线设计培训课程推荐 易迪拓培训 (www.edatop.com) 由数名来自于研发第一线的资深工程师发起成立, 致力并专注于微波 射频 天线设计研发人才的培养 ; 我们于 26 年整合合并微波 EDA 网 (www.mweda.com), 现已发展成为国内最大的微波射频和天线设计人才培养基地, 成功推出多套微波射频以及天线设计经典培训课程和 ADS HFSS 等专业软件使用培训课程, 广受客户好评 ; 并先后与人民邮电出版社 电子工业出版社合作出版了多本专业图书, 帮助数万名工程师提升了专业技术能力 客户遍布中兴通讯 研通高频 埃威航电 国人通信等多家国内知名公司, 以及台湾工业技术研究院 永业科技 全一电子等多家台湾地区企业 易迪拓培训课程列表 :http://www.edatop.com/peixun/rfe/129.html 射频工程师养成培训课程套装该套装精选了射频专业基础培训课程 射频仿真设计培训课程和射频电路测量培训课程三个类别共 3 门视频培训课程和 3 本图书教材 ; 旨在引领学员全面学习一个射频工程师需要熟悉 理解和掌握的专业知识和研发设计能力 通过套装的学习, 能够让学员完全达到和胜任一个合格的射频工程师的要求 课程网址 :http://www.edatop.com/peixun/rfe/11.html ADS 学习培训课程套装该套装是迄今国内最全面 最权威的 ADS 培训教程, 共包含 1 门 ADS 学习培训课程 课程是由具有多年 ADS 使用经验的微波射频与通信系统设计领域资深专家讲解, 并多结合设计实例, 由浅入深 详细而又全面地讲解了 ADS 在微波射频电路设计 通信系统设计和电磁仿真设计方面的内容 能让您在最短的时间内学会使用 ADS, 迅速提升个人技术能力, 把 ADS 真正应用到实际研发工作中去, 成为 ADS 设计专家... 课程网址 : http://www.edatop.com/peixun/ads/13.html HFSS 学习培训课程套装该套课程套装包含了本站全部 HFSS 培训课程, 是迄今国内最全面 最专业的 HFSS 培训教程套装, 可以帮助您从零开始, 全面深入学习 HFSS 的各项功能和在多个方面的工程应用 购买套装, 更可超值赠送 3 个月免费学习答疑, 随时解答您学习过程中遇到的棘手问题, 让您的 HFSS 学习更加轻松顺畅 课程网址 :http://www.edatop.com/peixun/hfss/11.html `
易迪拓培训 专注于微波 射频 天线设计人才的培养网址 :http://www.edatop.com CST 学习培训课程套装该培训套装由易迪拓培训联合微波 EDA 网共同推出, 是最全面 系统 专业的 CST 微波工作室培训课程套装, 所有课程都由经验丰富的专家授课, 视频教学, 可以帮助您从零开始, 全面系统地学习 CST 微波工作的各项功能及其在微波射频 天线设计等领域的设计应用 且购买该套装, 还可超值赠送 3 个月免费学习答疑 课程网址 :http://www.edatop.com/peixun/cst/24.html HFSS 天线设计培训课程套装套装包含 6 门视频课程和 1 本图书, 课程从基础讲起, 内容由浅入深, 理论介绍和实际操作讲解相结合, 全面系统的讲解了 HFSS 天线设计的全过程 是国内最全面 最专业的 HFSS 天线设计课程, 可以帮助您快速学习掌握如何使用 HFSS 设计天线, 让天线设计不再难 课程网址 :http://www.edatop.com/peixun/hfss/122.html 13.56MHz NFC/RFID 线圈天线设计培训课程套装套装包含 4 门视频培训课程, 培训将 13.56MHz 线圈天线设计原理和仿真设计实践相结合, 全面系统地讲解了 13.56MHz 线圈天线的工作原理 设计方法 设计考量以及使用 HFSS 和 CST 仿真分析线圈天线的具体操作, 同时还介绍了 13.56MHz 线圈天线匹配电路的设计和调试 通过该套课程的学习, 可以帮助您快速学习掌握 13.56MHz 线圈天线及其匹配电路的原理 设计和调试 详情浏览 :http://www.edatop.com/peixun/antenna/116.html 我们的课程优势 : 成立于 24 年,1 多年丰富的行业经验, 一直致力并专注于微波射频和天线设计工程师的培养, 更了解该行业对人才的要求 经验丰富的一线资深工程师讲授, 结合实际工程案例, 直观 实用 易学 联系我们 : 易迪拓培训官网 :http://www.edatop.com 微波 EDA 网 :http://www.mweda.com 官方淘宝店 :http://shop369289.taobao.com 专注于微波 射频 天线设计人才的培养易迪拓培训官方网址 :http://www.edatop.com 淘宝网店 :http://shop369289.taobao.com