Ridge Gap Waveguide based Slot Antenna Array for Point to Point Wireless Communication

A millimeter-wave, corporate-fed slot antenna array based on ridge gap waveguide technology is presented. It consists of three metal layers separated by a small gap. The antenna sub-array comprises four cavity-backed slots arranged symmetrically in a grid-shaped pattern. This sub-array is a unit cell for a planar array. The top layer consists of radiating slots surrounded by an octagonal cavity to minimize mutual coupling between the slots and avoid grating lobes. In the middle, a cavity layer increases the impedance bandwidth of the antenna, and at the bottom there lies a feed network layer that is built on ridge gap waveguide technology. Periodic circular-shaped metal pins confine the input power both in the cavity layer as well as in the distribution layer within the prescribed paths. Equal power dividers are used for uniform excitation to keep amplitudes and phases equal at all output ports. The proposed antenna array has a relative impedance bandwidth of 11.3% with an input reflection coefficient better than -10dB from 58 GHz to 65 GHz frequency range.