通过改进偏置网络改善二次谐波抑制的新方法

Nonliearity is the main characteristics of power amplifier. Any amplifer behave nonliearity in large signal,so the output amplified signal is not true to the original and with many harmonics. This is include harmonics induce by single frequency and intermodulation induce by multi frequency. It's a harmful products in most application for this harmonics and intermodulaiton, and should be compressed. There are many ways of plan for compressed for intermodulation like feed forward, feed back, and predistoration. These technics is well used in moden telecommunications systems. But there seems no better ways control 2nd harmonics in ouput signal. Commonly add band pass filter in PA output, the filter should be support rated output power,ofcourse it will be degrade 2nd harmonics but only specify for lower level rated output power, further more the insertion loss will degrade PA effienciy and add cost，the size of filer also should be considered. According these issues raise my idea in changing PA output bias circuits to compressed 2nd harmonics in its amplitude. The simulation results looks better change more than 10dB for 2nd harmonics. This kinds of frame idea is a big direction and lead for changing 2nd harmonics, rise efficiency, reduce size, doesn't limit by output power, anyway this idea spread range of product application and lead the thinking in a new way.