A Distributed Mixer-Based Nonreciprocal CRLH Leaky Wave Antenna for Simultaneous Transmit and Receive

A nonreciprocal composite right/left-handed (CRLH) leaky wave antenna (LWA) based on a distributed mixer (DM) is proposed to achieve simultaneous transmit and receive (STAR). The DM structure consists of field-effect transistors (FETs) as mixing devices with a CRLH transmission line (TL) as the drain line and a microstrip line as the gate line. In the receive mode, the carrier LO signal in the gate line and the RF signal in the drain CRLH TL are along the same direction, while in the transmit mode, the RF signal is injected from the drain CRLH line at the opposite direction of the carrier LO signal from the gate line. Owing to distributed mixing principle, it will be shown that the reverse conversion gain for the down-converted IF signal can provide isolation between the transmit and receive operation, i.e. RF signals of opposite directions, thereby enabling the simultaneous transmit and receive characteristic.