Bandwidth Enhancement for a Millimeter-wave Dielectric Resonator Antenna

This work presents a new method for the bandwidth enhancement of the dielectric resonator antenna (DRA) at the millimeter-wave (mmW) band. This work enlarges the coupling aperture under the dielectric radiator to achieve bandwidth enhancement. Conventional aperture-coupled DRAs use a small aperture for excitation, which only consists of the fundamental mode and thus limits the operating bandwidth. The proposed large aperture coupling can excite both fundamental and higher-order modes together inside the DRA, which extends the impedance bandwidth from 6% to 30%. Comparison between using a small aperture and a large aperture for exciting the DRA shows that the large aperture can lower the input impedance of the DRA, and help achieve the wide impedance bandwidth. A 2 × 4 array with the proposed antenna element was simulated. The simulated results show that the proposed DRA array can achieve an impedance bandwidth of 30% from 25 to 34 GHz (for reflection coefficient ≤ -10 dB). Throughout the entire operating bandwidth, stable broadside radiation patterns with low cross-polarization levels under -40 dB can be observed.