Research And Implementation On Transceiver Module For L-band Active Phased Array Radar

In the complex and changeable electromagnetic environment,active phased array radar is widely used in the fields of shipboard early warning,identification of enemy and friend,weather detection and so on,because of its fast antenna beam change speed and strong space power synthesis ability,which can reliably and efficiently complete the work of multi-target tracking and high data search.Transceiver is the core of active phased array radar architecture.Its performance directly affects the performance of radar system.Among them,the ability to suppress interference signal is one of the key indicators of transceiver.Therefore,it can improve the performance of the active phased array radar and broaden its application scenarios to design a reasonable transceiver with strong interference suppression ability and high reliability.In this thesis,an active phased array transceiver based on L-band,which can effectively suppress image interference and harmonic interference,is designed to improve the interference suppression ability of transceiver.The main work is as follows:(1)Explains the basic theory of the transceiver,including the key technical indicators and the current typical structure of transceiver.Aiming at the frequency range and image suppression indicators of this design,it is determined that the transceiver designed in this thesis adopts a digital IF structure with simple structure,strong interference suppression ability and high reliability.(2)The nonlinear distortion of low noise amplifier in transceiver is analyzed.Starting from the non-linear model,this paper introduces the causes and effects of the non-linear distortion of the low noise amplifier circuit,analyzes the principles of optimizing bias,negative feedback and harmonic terminal technology to improve the linearity and their advantages and disadvantages,and verifies the effect through simulation.The design of B3 band high linearity and low noise amplifier is completed by using optimized bias technology.The experimental results show that the gain of the circuit is 33 d B and the output power of the third-order cut-off point is is greater than 38 d Bm.(3)An active phased array transceiver is designed to effectively suppress image interference and harmonic interference.According to the technical specifications of digital IF structure and transceiver module,narrow-band filter module is introduced to reduce image interference,and the harmonic suppression ability of the circuit is improved by reasonable allocation of indicators and selection of components of each unit circuit.The results show that the output power of the receiving link is 6.7dbm,the noise coefficient is 2d B,the image rejection is greater than 57 db,the output power of the transmitting link is 39.6dbm,and the harmonic suppression system is greater than 60 dbc,which meets the requirements of the index.The circuit design is feasible and reliable.