A new active RF phase shifter using variable gain, drain Voltage controlled PHEMTs:A 2.4-GHz ISM implementation

Phase shifters operating at RF bands are an essential component of phased and adaptive arrays circuits. In this letter, an active phase shifter is proposed, using vector summing of an in-phase and a quad-phase replica of the incoming signal. The proposed scheme was designed and implemented using a Wilkinson power combiner/divider, a branch line hybrid coupler and single-stage variable gain amplifiers (VGAs), achieving continuous phase shift within the range of [0/spl deg/, 90/spl deg/]. The manufactured prototype is suitable for WLAN operations in the 2.4-GHz ISM band. Details of the phase shifter design and experimental results are presented.