Research On Resistive FET Mixer And Broadband Power Amplifier For RF Front-end

Wireless communication systems are one of the indispensable infrastructures in modern society,where mixers and power amplifiers are very important radio frequency modules in wireless communication systems.Mixers are usually used for signal modulation and demodulation;power amplifiers are used to amplify low-power signals to power levels that can drive antennas or transmission lines.With the increasing demand for working frequency and output power,there are still many problems and challenges in the design of mixers and power amplifiers.In order to achieve a terahertz harmonic mixer with low conversion loss and high port isolation,a 211～221 GHz resistive double-balanced harmonic mixer based on 100 nm In Ga As p HEMT process is designed.By analyzing and comparing the design parameters,the circuit architecture is determined.Aiming at the problems of low coupling coefficient and high transmission loss in terahertz harmonic mixers,a series of solutions are proposed:improving the transmission mode of signals,suppressing the generation and propagation of higher-order modes;using improved three-line coupled baluns,solving the problems of high loss and poor amplitude-phase balance of traditional baluns;using differential branch-line couplers,solving the problems of high insertion loss of traditional large couplers and branch-line couplers.After circuit schematic and layout design,simulation results show that at the working frequency of 211～221 GHz,the conversion loss is 14.39～14.61 d B,the input P_{1d B}is 11 d Bm,the port isolation is greater than 40 d Bc,the circuit layout area is 1950×850μm².Test results demonstrate a conversion loss of 13.1～17.8 d B,which meets the design requirements.This module can be integrated with other functional modules on a single chip.In order to achieve a broadband high-power amplifier,a broadband high-power amplifier for6～18 GHz with an output power of 43 d Bm is designed based on 0.25μm Ga N HEMT process.By analyzing the load impedance and input impedance,and combining with broadband matching theory,the structure of each stage matching network is determined,and by using flow-controlled current source equivalent to synthesize power distribution network into a two-port network,the circuit dimensionality reduction is realized to quickly solve the S parameters of matching network.By transforming the matching problem into a nonlinear regression problem and reasonably allocating weights,suitable matching network parameters are obtained,and finally the whole circuit design is completed.Simulation results show that in the range of 6～18 GHz,the output power of this power amplifier is 43.05～45.12 d Bm,the power added efficiency is 22.49～34.19%,and the overall size of the circuit is 4.6×3.8 mm².The above circuits have important application value in wireless communication systems.In the future,more advanced and higher performance radio frequency integrated circuits will be further studied and explored to meet the needs of rapidly developing wireless communication systems.