Study Of Phase Shifter Used In DBS Phased Array Antenna

Phase shifter which is an important part of the phased array antenna transmit/receive (T/R) component,is widely used in the communications and radar systems, especially in the phased array antenna. The phase of radiate elements on the antenna aperture surface changed to realize the scanning of beam. In Direct Broadcast Satellite (DBS) phased array antenna, the performance of phase shifter impacts the whole DBS antenna system greatly. Along with the matures of GaAs technology based on monolithic microwave integrated circuit (MMIC), therefore the development of phase shifter is in direction of small size, light weight and high reliability. MMIC phase shifters obtain a wide range of application in the military and civilian system to improve the performance of system.Firstly, this thesis described the background and overall development of phase shifters, and then introduced the MMIC technology and MMIC phase shifters.Based on above, discussed different phase shifters in theory. Next, analyzed MMIC passive device and active device respectively, then researched various circuit forms of phase shifter. On the basic of theory analysis, selected suitable forms of phase shifter and used ADS design software to design Ku-band 5-bit digital phase shifter. After investigating, PPH25X process line from UMS was chosen to design and different topologies of phase shifter circuits were simulated by ADS software in order to meet the design objectives. Combined with practical MMIC processing line, the final design phase circuit's layout was given.The phase shifter consisted five phase shift units cascaded in a linear arrangement, the working frequency range were 11.4～12.8GHz. Over the entire working frequency band, the phase shifter's insertion loss was 7.5±1B, the input/output voltage standing wave ratio (VSWR) was less than 1.5 and its phase error (RMS) was less than 2°, which achieved the design requirements.