High gain substrate integrated waveguide beam scanning antenna with sub‐array elements

Abstract

A method to enhance the gain of substrate integrated waveguide (SIW) beam scanning antenna is proposed in this article. 2 × 2 SIW cavity-backed sub-arrays are employed in array design. The antenna is constructed on two layers. The top layer places four SIW cavity-backed sub-arrays as radiating elements and the bottom layer is an SIW transmission line to feed the sub-arrays. Beam scanning feature can be obtained due to the frequency dispersion. Moreover, through separating radiators to the other layer and using 2 × 2 SIW cavity-backed sub-arrays as radiating parts, the antenna gain is improved significantly. For a linear array, 4.1 to 6.8 dB gain enhancement is achieved compared to a conventional SIW beam scanning antenna with the same length. Then, the linear array is expanded to form a planar array for further gain improvement. A 64-element planar beam scanning array is designed, fabricated, and tested. Experimental results show that the proposed planar array has a bandwidth from 18.5 GHz to 21. 5 GHz with beam scanning angle from −5° to 11.5° and gain in the range of 20.5 to 21.8 dBi. The proposed high gain beam scanning antennas have potential applications in radar detection and imaging.