Predicting the Performance of a 26 GHz Transconductance Modulated Downconversion Mixer as a Function of LO Drive and DC Bias
Predicting the Performance of a 26 GHz Transconductance Modulated Downconversion Mixer as a Function of LO Drive and DC Bias
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DOI：
10.3390/electronics11162516
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发表时间：
2022-08-01
期刊：
影响因子：
2.9
通讯作者：
Ball, Edward A.
中科院分区：
文献类型：
--
作者：
Ball, Edward A.
RF性能对本机振荡器（LO）驱动幅度和DC偏置的依赖性是RF混频器的重要主题，特别是当载波频率增加并且RF功率的生成因此变得更加复杂时。混频器性能的预测，而不依赖于完整的电路模拟，可以提供重要的见解。在这项工作中，没有事先使用电路仿真的数学模型的开发，导致一个策略来预测的转换增益（Gc），直流电流，1 dB输入压缩点（IP1dB）和三阶输入截点（IIP3）的SiGe双极型晶体管混频器。该模型显示了权衡LO RF功率和DC偏置以实现期望性能的可能性。这些概念允许预测支持所选LO电平和所需转换增益或线性度所需的必要直流偏置。的数学模型的结果，电路仿真结果，并从一个26 GHz的单端混频器的原型测量硬件结果，并进行比较，显示出良好的协议。在一个实验室测量的示例中，LO功率从+10 dBm降低到+3 dBm，通过按照预测修改直流偏置，转换增益仅降低1 dB。模型预测的峰值转换增益在电路仿真的2.0 dB和PCB测量结果的2.5 dB范围内。与电路仿真相比，预测直流电流的RMS误差为1.9 mA或更好。
The dependency of RF performance on the local oscillator (LO) drive amplitude and DC bias is an important topic for RF mixers, especially as carrier frequency increases and generation of RF power thus becomes more complex. The prediction of mixer performance, without initial reliance on full circuit simulations, can provide important insights. In this work, mathematical models without the prior use of circuit simulation are developed, leading to a strategy to predict the conversion gain (Gc), DC current, 1 dB input compression point (IP1dB) and third order input intercept point (IIP3) for a SiGe bipolar transistor transconductance mixer. The models show the possibility to trade-off LO RF power and DC bias to achieve a desired performance. The concepts allow a prediction of the necessary DC bias required to support a chosen LO level and desired conversion transconductance or linearity. The mathematical model results, circuit simulation results, and measured hardware results from a 26 GHz prototype of a single-ended mixer are presented and compared, showing good agreement. In a lab-measured example, LO power reduction from +10 dBm to +3 dBm resulted in only a 1 dB reduction in conversion gain, by modifying the DC bias as predicted. The peak conversion gain predicted by the models is within 2.0 dB of circuit simulation and 2.5 dB of measured PCB results. The RMS error for predicted DC current, compared to circuit simulation, is 1.9 mA or better.