Differentially Fed Duplex Filtering Dielectric Resonator Antenna with High Isolation and CM Suppression

A differentially fed duplex filtering dielectric resonator antenna (DFDRA) is proposed. This DFDRA combines the functions of the duplexer, the filter and the antenna into one highly integrated multifunctional module. A dual-mode substrate integrated waveguide (SIW) cavity working as the common feeding structure operates at two orthogonal modes at the lower and higher channel and is differentially fed by two pairs of differential input ports. The DRA working as the common radiation element operates at two orthogonal modes at two channels respectively and is excited by two cross slots etched on the top of the SIW cavity. High-isolation between the two channels is realized due to the two pairs of orthogonal operating modes of the DRA and SIW cavity. Measured results show that the balanced DFDRA can operate with differential mode 10dB impedance bandwidth of 2.7% (5.07-5.21 GHz) and 2.6% (5.72-5.87 GHz), the peak realized gains of 4.6-4.9 dBi and 4.8-5.1 dBi for two channels respectively. The isolation between the lower and higher channels is greater than 75dB. Good common mode suppression is realized.