A Filtering Hemispherical Dielectric Resonator Antenna

A filtering hemisphere dielectric resonator (DR) antenna (DRA) is presented. It consists of a conventional hemisphere DR, a ladder-like feeding line, and three slots etched in the ground. In this antenna, three modes, which are the fundamental TE111 DR mode and two slot modes are excited simultaneously. By making use of the mode-cancelling effect, two independently tunable radiation nulls are obtained beside the passband, producing filtering responses. Simulated results show that our antenna has a -10-dB impedance bandwidth of 17.4%, a gain of ~5.7 dBi, and a suppression level of 19 dB.