Millimeter-Wave Widebeam Dielectric Resonator Antenna and Its Wide-Angle Beam-Scanning Phased Arrays Using the Field Distribution of Quasi-TE112 Modes

A millimeter-wave (mm-wave) dielectric resonator (DR) antenna (DRA) with compact size and wide half-power beamwidth (HPBW) is investigated. This DRA consists of a square DR and a microstrip-coupled slot located beneath the DR, which functions as both radiator and DR feeding structure. By making the operating frequency of the slot mode, more exactly, the DR-loaded slot mode, close to the resonance frequency of the (unexcitable) DRA TE112 mode, the DR shows a quasi-TE112 mode field distribution in its interior, which radiates as an equivalent magnetic current parallel to the ground plane, thus realizing wide HPBWs of 228 degrees in E-plane and 132 degrees in H-plane without requiring any additional parasitic element. Based on this novel DRA element, an E-plane and an H-plane eight-element linear phased array capable of wide-angle beam scanning are further designed, showing a scan range of +/- 72 degrees with 2.5-dB gain fluctuation and a scan range of +/- 65 degrees with 0.5-dB gain fluctuation. For experimental demonstration, three feeding networks (FNs) with fixed phase differences of 0 degrees, 90 degrees, and 165 degrees are designed, fabricated, and connected to the proposed E-plane phased array to verify three beam-scanning states of 0 degrees, 32 degrees, and 72 degrees, and reasonable agreement between the measured and simulated results is observed.