Design of Physically Connected Wideband SIW Cavity-Backed Patch Antenna for Wide-Angle Scanning Phased Arrays

A novel wideband substrate integrated waveguide (SIW) cavity-backed antenna element and its array are proposed in this letter. The proposed linearly polarized array element consists of a SIW cavity, stacked patches, and a coaxial probe. The SIW cavity-backed array element is implemented with physically connected stacked patch. The coaxial pin is directly connected to the two patch radiators. Blind and buried vias were avoided, this work significantly reduces the manufacture cost and complexity. The array features light weight and simple feed structure. The proposed element exhibits an impedance-matching bandwidth of 18.2% (14.5–17.4 GHz) for |
S
₁₁
|<−10 dB. Simulation results illustrate that the infinite array can scan up to ±80° in the
H
-plane with 8% bandwidth (14.4–15.6 GHz), under the criterion of active voltage standing- wave ratio (VSWR) ≤ 3. For verification purposes, a 4 × 16 active phased array antenna prototype is fabricated using the conventional microwave multilayer printed circuit board (PCB) process. The measured results agree very well with simulations.