A GaAs Multi-Band Digitally-Controlled 0° - 360° Phase Shifter

A monolithic GaAs active phase shifter is demonstrated over UHF, L-, S- and C-bands. This device, in combination with a hybrid 90-degree coupler, can generate phase shift from 0 to 90 degrees in 11.25-degree steps. The phase shifts can be digitally programmed within 2 degrees in a narrow band application. The maximum phase errors are within 5 degrees, with the maximum amplitude variations no more than 2.5 dB among various phase states at frequencies from 1 to 8 GHz. The fabricated chip size is 45 × 45 × 20 mils. Applications for multi-band and multi-octave phase shifters are discussed.