High-Gain SIW Cavity-Backed Array Antenna With Wideband and Low Sidelobe Characteristics

A 16 ×16 gain-high substrate integrated waveguide (SIW) cavity-backed slot array antenna with wideband and low sidelobe level (SLL) characteristics is proposed in this letter. The array is fed by an 8 ×8 SIW corporate-feed network in the bottom layer. A series of 2 ×2 compact SIW sub-arrays are employed as radiating elements in the top layer. The 45^° linearly polarized technique is used in the design of radiating slots, which can substantially suppress the SLL of the array. Meanwhile, benefiting by the broadband merit of the sub-array and the corporate-feed structure, the proposed array has a broad bandwidth. A prototype is fabricated to verify the array properties. The measured bandwidth is 12% from 19 GHz to 21.5 GHz and the maximal gain can reach up to 29 dBi. Besides, the low sidelobe characteristic is achieved and the measured first SLLs are below -24 dB across the entire work band.