Differentially Inserted-Fed Compact Dual-Band Circularly Polarized Dielectric Resonator Antenna

In this letter, a differentially inserted-fed compact dual-band circularly polarized dielectric resonator antenna (DRA) is proposed. To realize a compact design, the inserted differential feeding structure composed of a pair of arc-shaped strips connecting with coaxial probes plays dual roles. It not only excites the fundamental mode HEM111 of the DRA, but also brings an additional resonant mode to form the second band. Besides, the lower and upper bands of the DRA are independently controlled by the DR and the strips, facilitating the design process of the dual-band DRA. For demonstration, a prototype is designed, fabricated, and measured. Measured results show that the proposed DRA with the profile of 0.34 $\lambda _{g}$ achieves impedance bandwidth (S(dd)11 <-10dB) of 30.4 and 18.5 and 3dB axial-ratio bandwidth of 8.06 and 6.38 with peak gain of 6.9 and 7.3 dBic for the lower and upper bands, respectively. Good agreement is observed between the simulated and measured results.