A Six-Port Transceiver for Frequency-Division Duplex Systems

In this letter, a six-port transceiver for frequency-division duplex (FDD) systems is proposed and experimentally demonstrated. The proposed transceiver that consists of a single six-port correlator and four Schottky diodes can realize both modulation and demodulation simultaneously at different frequencies. To verify the proposed architecture, the six-port transceiver system prototypes are developed, and modulation and demodulation performances are evaluated by using quadrature amplitude modulation signals at 2.9 and 2.68 GHz, respectively. Moreover, the heterodyne demodulation for a six-port transceiver is proposed to mitigate the interferences from baseband modulation signals. The error vector magnitudes of FDD systems based on the proposed transceiver are found below 2%.