Low cost phase shifters for L-band phased array antennas

This paper discusses the methods of designing good quality PIN diode phase shifters for operation at L-band using low cost PIN diodes. This is demonstrated in the design example of a 4-bit phase shifter for possible use in an L-band vehicle mounted phased array antenna for mobile satellite communications. It is shown that the performance of the phase shifters can be of good quality over a 7% bandwidth (between 1.54 GHz and 1.66 GHz) as is required for the Mobilesat system in Australia. This quality performance is achieved by including extra compensation circuits in the biasing networks of the PIN diodes. By using these extra compensation networks, the parasitic elements are tuned out producing almost ideal on-off switches and therefore good quality phase shifters over the required frequency band.