Integrated-Antenna-Filter Based on Metal–Dielectric Heterogeneous Resonator

Cross-functional integration between antennas and filters is an effective method for reducing the size and cost of microwave systems. However, previous designs suffer from high insertion loss and narrow bandwidth. This communication presents a novel integrated-antenna-filter with a metal-dielectric heterogeneous resonator to address this issue. The heterogeneous resonator is a dielectric block with two sides covered in silver strips. For the antenna channel, the proposed resonator functions as a dielectric resonator (DR) to generate radiation, and its resonance properties after loading silver strips are theoretically investigated. Two resonant modes of the DR are combined to enhance antenna bandwidth. For the filter channel, the silver strips act as two-stage resonators and are coupled to each other through the dielectric block. The dielectric block here is considered a nonresonant dielectric waveguide (DW) with low loss, which differs from conventional integrated schemes, thereby avoiding the need for additional shielding. Meanwhile, the heterogeneous resonator offers a wide tuning range for the frequency ratios of the two channels. An impedance bandwidth of 7.7% and a peak gain of 6.7 dBi are achieved for the antenna channel, while a 3-dB bandwidth of 16.1% and an insertion loss near 0.75 dB are obtained for the filter channel with a profile of $0.076\lambda _{0}$ .