A Compact Wideband Millimeter-Wave Substrate-Integrated Double-Line Slot Array Antenna

A novel slot array antenna based on substrate-integrated double-line (SIDL) technology is proposed in this article. By using the SIDL technology, the feed network of the array is simplified and the high-order mode is suppressed. As a consequence, the proposed antenna can obtain a compact size, a wide bandwidth, and a high radiation efficiency. To excite the proposed antenna, the microstrip-to-SIDL transition is designed by adopting coupling slots at the bottom plate of the SIDL. A 16 × 8 element slot array antenna is designed and fabricated for verification by using multilayer printed circuit board (PCB) technology. The measured -10 dB impedance bandwidth is from 23.35 to 27.55 GHz (16.5%). A 21.6 dBi gain is obtained at the designed frequency of 25.8 GHz in the measurements. The measured 1 dB gain bandwidth and simulated radiation efficiency are 12.5% and 75%, respectively. The measured results agree well with the simulated results. The proposed antenna can be used to develop compact and high-efficiency millimeter-wave systems.