Low Loss/Low Cost Phase Shifters

The use of electronically steered array is necessary to meet performance requirements of modern airborne radar and communications systems. Phase shifters are critical components in such arrays and often become the performance limiting component of thesystem. A substantial reduction of the the DC power consumption for spaceborne, airborne and portable sysytems is a very important consideration. Very low loss phase shifters can result in the elimination of driver amplifiers for very large phase arrayradars. Depending on the Transmit power, range and the required gain over noise, G/T ratio, the number of modules can also be reduced. Microwave and millimeter wave phase shifters are currently available in ferroelectric, ferrite,pin diode and FET basedtechnologies. PIN diode phase shifters provide low loss but consume moderate power per diode. FET based phase shifters consume no DC power and are readily integrated with other functions on MMICs, thereby reducing costs but introduce substantial front endloss. Ferroelectric phase shifters have high voltage requirements and exhibit very poor temperature performance. Princeton Microwave is proposing the development of an innovative 3-BIT phase shifter that utilises MEMs technology to achieve very low lossperformance at 20 GHz and 44 GHZ applications. The proposed approach is anticipated to provide at least 6-8 dB of system improvement in a radar system when compared to ferroelectic, ferrite or FET based phase shifter designs. Phase I will be used todemonstrate the concept practically. The development of the unique low loss 3-BIT phase shifter will improve the phase array radar system performance by a margin of 6-8 dB. This is mainly due to its low loss performance, thereby reducing the RF drive andgain requirements in Transmit chain. The reduced power consumption of the T/R module with the proposed low loss phase shifter will find applications in the portable and airborne systems at 20GHz and 44GHz.