Millimeter-Wave Broadband Antennas With Low Profile Dielectric Covers

In this paper, a low-profile broadband antenna is presented for 60 GHz applications. It is demonstrated that the entire unlicensed 60 GHz frequency band can be covered using a dielectric based aperture type antenna. The antenna consists of a single-layer dielectric superstrate and an aperture type feed, which are separated by an air-cavity. The diameter of the superstrate is 15 mm, which is $2.75\lambda _{0}$ at the lowest operating frequency of 55.2 GHz. The simulated total efficiency of the antenna is greater than 88% over the entire operating band (55.2 GHz-65 GHz), which is unprecedented relative to medium-to-high gain millimeter-wave printed antenna arrays, used for similar applications. A prototype antenna was constructed, which exhibits a measured peak gain of 19.5 dBi. This value remains greater than 17 dBi over the entire operating bandwidth. The measured 3-dB beamwidths of the proposed antenna remain between 16° to 20° in the E-plane and 19.5° to 25° in the H-plane, respectively. The proposed antenna provides broadside directed radiation patterns with cross-polarization in the order of -30 dB over the entire operating band.