Quasi-Optical Transponder Using FETs and Patch Antennas

摘要

Quasi-optical planar transponder that integrates a self-oscillating mixer, an IFamplifier and two patch antennas, one for receiving RF signal (14GHz) and another for transmitting amplified IF signal (8GHz) is presented. The prototype circuit is designed in microstrip structure and fabricated on a single substrate. As an active source, GaAs FET is selected. Self-oscillating (6GHz) mixer with patch antenna in receiver front end is developed based on quasi-optical technique. To obtain enough power level of IF signal before it is transmitted, the amplifier is designed with bandpass filter which blocks undesirable mixing products except 8GHz. This prototype of transponder, which is compact and selfcontained unit as a single entity has many applications in microwave and millimeter-wave area. Transponder, Quasi-optical technique, Self-oscillating mixer, Active antenna.