24 GHz serrodyne frequency translator using a 360/spl deg/ analog CPW MMIC phase shifter

A 360/spl deg/ analog CPW MMIC phase shifter is presented for the first time. The compact MMIC employs eight multilayer 3 dB quadrature couplers and was fabricated using low cost GaAs foundry processing techniques. The phase shifter was required to implement a narrow band serrodyne frequency translator at 24 GHz. With an arbitrary, small-shift, frequency translation of +5 KHz, the measured results demonstrated a carrier suppression of 30 dB and an image sideband suppression of 13 dB. This was achieved with a simple linear sawtooth signal, providing 22% of under-modulation. In addition, a 0 dB conversion loss was achieved and almost no control power was required.>