Research On V-band Power Amplifier With High Linearity

The continuous upgrading and rapid development of large capacity and high speed service demand of satellite communication system promotes the continuous development of Q/V frequency band.This frequency band has the characteristics of high bandwidth,good beam orientation and less interference sources,so now Q/V frequency band communication has the prospect of being widely used,no matter in military neighborhood or civil field.This topic for the V-band power amplifier to carry out the relevant engineering application research,through the elaboration of the development significance and application prospects of the V-band power amplifier,explained the significance of the V-band power amplifier,Through the introduction and analysis of the important indicators of power amplifier: working bandwidth,saturation power,linearity and efficiency,This thesis expounds two important aspects of V band power amplifier.The saturation power output of the power amplifier depends on the output power of the power tube.The saturation power of the power amplifier tube is through the parallel connection of multiple tube cores and then through the way of synthesizing the power of the circuit,such as T-bytes,Bridges and other ways of synthesizing and output a relatively large power,Since the input and output impedance of the power chip is standard 50 ohm,we use the microstrip waveguide structure for the test.In this thesis,the waveguide-microstrip structure is introduced in detail,and the E-plane and H-plane structures are introduced and simulated.For convenience and practical space saving,we need to synthesize the power of the two chips.In this thesis,we use a T-byte structure with high isolation degree for power sy nthesis,whose port standing wave is below-20 d B,and the isolation degree is also below-20 d B.Two power chips with high isolation are synthesized.However,this T-byte power component synthesis method is only suitable for low power synthesis.Since the waveguide spatial synthesis method is suitable for high-power synthesis,the waveguide power synthesis method is adopted in this study.After comparing the radial power component synthesis method and the binary power component synthesis method,the spatial binary synthesis method is relatively simple and easy to process.Depending on the power of output,it becomes the first choice for this project design.The maximum output is 47 d Bm at 47GHz-52 GHz through four-channel binary waveguide synthesis,that is,50 W peak power.However,for the power amplifier itself,high power and high linearity are not compatible.In the actual engineering the power amplifier of the third order intermodulation is generally back 3d B to-25 d Bc,but after measurement we found that the power amplifier back 3d B to 44 d Bm when we measured the third order intermodulation for-22 d Bc,which is obviously cannot meet the needs of use.Therefore,in order to ensure good linearity,this topic designed a c orresponding linearizer for the power amplifier,the linearizer based on Schottky diode,the structure of the traditional parallel diode has been partially improved,the use of multiple parallel diode microstrip line parallel to achieve the purpose of impr oving linearity.Firstly,the ADS simulation software is used for simulation analysis,and the actual measurement of the linearizer can improve the linearity of the power amplifier more than 3d B,so as to meet the third-order intermodulation index of the power amplifier is less than-25 d Bc,and meet the communication application requirements of the power amplifier.