Broadband and high gain waveguide‐fed slot antenna array in the Ku‐band

A broadband and high‐gain slot antenna array operating in the Ku‐band is reported in this study. The antenna is with waveguide‐fed cavity backed configuration and made entirely via simple milling process. The overall antenna structure consists of four layers. The bottom layer is a waveguide feed network to provide corporate power division. In turn, the waveguide feed network is excited by a conventional coaxial probe from the back. The waveguide network couples energy to an array of cavity via an aperture plate. These constitute the middle two layers. Each cavity then excites a subarray of 2 × 2 radiating slots in the top layer. The radiating slot elements and the feed network are designed to achieve wide bandwidth and high‐gain performance. Finally, an 8 × 8 array antenna has been designed and fabricated with about 25 dBi gain over 14.8% bandwidth, and the cross‐polarisation was around −30 dB in the boresight.