Design of an Air-Filled Slot Antenna and Array for Millimeter-Wave Applications

This communication introduces a new structure of wideband slot antenna with high gain and stable radiation patterns for millimeter-wave (mmW) applications. It is the first attempt to apply an air-filled I-shape slot excited by a substrate-integrated-waveguide (SIW) feed. The slot can achieve lower
$Q$
-factor contributing to a wider bandwidth. In addition, the feature of even electric field distributions across the operating bandwidth produces very stable gain performance for the proposed antenna. The proposed antenna is realized using a single-layered PCB substrate with plated-through-hole technology, which is cost effective and easy to fabricate. In addition, a
$1\times8$
antenna array based on the proposed antenna element is developed with a planar 1–8 SIW feeding network. The measurement results show that the proposed array can achieve an impedance bandwidth of 36.6% from 58 to 84 GHz with a peak gain of 16 dBi. These performances ensure that the proposed antenna array is a promising candidate for mmW communications.