Design And Implementation Of An X-band Power Amplifier Used In AESA

Nowadays,active electronically scanned array(AESA)technology is growing rapidly and becomes the new-generation radar technology,as the core component of which,T/R module has been used behind each radiating element in AESA.The performance of T/R module is in direct relation to the various index of radar system,moreover,the key to the design of T/R module is the power amplifier(PA)module.With the reduction of feature size and the increase of working frequency,the development of SiGe BiCMOS devices is limited in cut-off frequency.In addition,the design of PA in SiGe BiCMOS process is facing enormous challenges in high output power.This dissertation presents a brief introduction on AESA and T/R module.The content mainly include: overseas and domestic research status of these areas,basic principle and technology indicators of PA,techniques for increasing linearity and efficiency,SiGe BiCMOS process,etc.And on this basis,an X-band PA has been presented,including DC bias setting,harmonic impedance optimization,and layout design.Finally,this PA operates at AB Class and is designed using cascode topology with linear two-stage single-ended structure.Input and output matching networks are integrated on chip.A simple linearizer biasing circuit is achieved to reach high gain and linear output power.What’ s more,this PA is fully integrated,including all the passive devices.Based on 0.18μm SiGe BiCMOS 7WL process technology,the measurement results of the PA shows that the small signal gain could reach up to 21.8 dB,and output 1 dB compression point is 10.4 dBm at 8.5GHz of power supply 3.3V.The amplifier is well-matched to deliver the maximum output power,and the total area is only 1.4mm×0.8mm,which realizes integration with T/R chip and meets the demand for output power and gain of power amplification in T/R module.Further more,the differences between simulated result and measured result are analyzed,and the improving method is brought forward.