A 4 bits Reflection type phase shifter based on Ga As FET

A 4 bits digital phase shifter is designed and simulated. It is based on 3-db hybrid coupler and totally twelve switches are used. The simulation results indicate an insertion loss better than -4dB, a return loss less than -20 dB and an error phase varied between 0.01° and 0.6° at 2.45 GHz. to achieve a 6 bits phase shifter, we increased the number of stages. This phase shifter present an insertion loss better than -5dB, a return loss less than -20db and an error phase varied between 0.1° and 1.7°. But, the circuit presents a large size. The Ga As FET switch used for switching is characterized by a very low DC power consumption, a fast switching speed and a low cost. Also, an array antenna of 8 patch elements connected to a 4 bits phase sifter is designed. The simulated results of the array indicate a return loss better than -10dB over 2.4-2.5 GHz and a gain equal 14 dB.