Use of the Differential Dielectric Resonator Antenna for an Independently Controllable Dual-Band Filter

In this letter, a novel concept for the dielectric resonator functioning as a differential antenna and as an independently controllable dual-band filter simultaneously is proposed for the first time. The multifunctional design takes full advantage of the virtual and reflection grounds of the differential dielectric resonator antenna (DDRA). The antenna and filter functions share a single module and a physical ground, making the proposed design compact and cost effective. In addition to high isolation between the two functions, the filter part shows two independently adjustable passbands. For demonstration, a prototype is designed, fabricated, and measured. The DDRA is designed at 2.5 GHz with an impedance bandwidth of 2.7% and the realized gain of 4.5 dBi. The dual-band filter operates at the center frequencies of 2.16 GHz and 3.51 GHz with 3 dB bandwidths of 13% and 7%, respectively. A good agreement is observed between the simulated and measured results.