24 GHZ SERRODYNE FREQUENCY TRANSLATOR USING A 360-DEGREES ANALOG CPW MMIC PHASE-SHIFTER

A 360-degrees analog CPW MMIC phase shifter is presented for the first time. The compact MMIC employs eight multilayer 3 dB quadrature coupl ers and was fabricated using low cost GaAs foundry processing techniqu es. The phase shifter was required to implement a narrow band serrodyn e frequency translator at 24 GHz. With an arbitrary, small-shift, freq uency translation of +5 KHz, the measured results demonstrated a carri er suppression of 30 dB and an image sideband suppression of 13 dB. Th is was achieved with a simple linear sawtooth signal, providing 22% of under-modulation. In addition, a 0 dB conversion loss was achieved an d almost no control power was required.