Broadband and High-Gain SIW-Fed Slot Array for Millimeter-Wave Applications

A broadband and high-gain substrate integrated waveguide (SIW)-fed slot antenna array is demonstrated at Q-band. Aperture coupling is used for interconnecting the two adjacent substrate layers. It is proposed to improve the impedance matching and the gain of the antenna element simultaneously by stacking a metallic cross-shaped radiating slot atop a cross-shaped coupling slot. For proof of concept, a 4 × 4 antenna array with a low-loss SIW feeding network is further designed and measured. The measured impedance bandwidth of the proposed 4 × 4 antenna array is 20.5% from 42.4 to 52.1 GHz for |S
₁₁
| ≤ -10 dB. The measured peak gain is 19.4 dBi at 50 GHz. The measured and simulated results are in good agreement.