Bandwidth improvement for a microstrip-fed series array of dielectric resonator antennas

The impedance and pattern bandwidth of an array of dielectric resonator antennas series fed by a microstrip line was significantly improved by replacing individual DRAs with paired DRAs. The DRAs in each pair are spaced slightly <λ_g/4 apart so that their input reflections cancel. An array of eight DRA pairs was designed and fabricated, and its performance was compared to an array of eight single elements. The 10 dB return loss bandwidth improved from 2 to 18% and the 3 dB gain pattern bandwidth improved from 12 to 17%