Key Circuits Design Of L-band T/R Module For Phased Array Radar

With science and technology developing fast, the requirements of the phased array radar in economic construction and national defense construction are improving constantly. And there is a T/R module set on each antenna unit of the phased array radar, and the performance of antennas will affect the performance of the radar directly. Therefore, as a key part of phased array radar, the T/R (Transmit/Receive) module is attracting more and more attentions.This paper introduces the basic structures and working principles of phased array radar T/R module and the key circuits of T/R module, such as power amplifier, low noise amplifier and phase shifter. When the T/R module is working for transmitting, phase shifters are used to change the phase of the signal between the antenna elements usually. There is usually a low noise amplifier equipped after the phase shifter in the T/R module, and a low noise amplifier will provide a large gain to amplify the emission signal of the antenna, and suppress the noise of subsequent circuits. When the T/R module is working for receiving, the signal is received by the power amplifier of the T/R module mainly, and we must use power amplifiers to amplify the power of the received signals so as to use for subsequent processing and analysis.This paper completes the design of an A class power amplifier and a low noise amplifier and the design of a 6-bit phase shifter of L band (1.2～2.0GHz) with microstrip line, and draws the circuit layouts of these circuits according to the results of the schematic and finished post-simulation. Among them, the measured power gain of power amplifier with microstrip line the is more than 15dB while input power is lower than -3dBm, output 1dB compression point is 31.740dBm and efficiency is more than 25.08%. The measured gain of the low noise amplifier is more than 18dB while the noise coefficient is less than 5.5dB, and flatness of the gain is about 1dB. The phase shifter demostrates an average RMS error of less than 6° with insertion loss of less than 3dB. Besides this, this paper completes the design of and a 6-bit phase shifter with 0.18μm CMOS technology, and makes comparations between the results of CMOS and microstrip line as well.