Bandwidth-Enhanced Millimeter-Wave SIW Slot Antennas Using Novel Resonant Modes

In this paper, bandwidth-enhanced millimeter-wave substrate integrated waveguide (SIW) cavity-backed slot antenna (CBSA) using novel resonant modes is proposed. Unlike conventional SIW slot antennas, the proposed slot antennas utilize the novel SIW TE101 cavity mode with electric filed parallel to the metal planes. Due to the specific structure of TE101 mode in SIW cavity, its resonant frequency is mainly determined by the cavity height i.e., the thickness of the substrate. Thus, the SIW TE101 cavity mode naturally has high resonant frequency, showing good feasibility in designing millimeter-wave slot antennas. Besides, the resonant-iris mode generated by the rectangular slots on the metallic planes of the SIW cavity is also introduced to design the slot antenna. Furthermore, a dualresonance 4×4 millimeter-wave slot antenna array under operation of TE101 mode and resonant-iris mode in a single-layer SIW cavity is designed. The radiation slots are excited by the electric field of the resonant modes without requiring power dividing structure, obtaining a simplified feeding structure. The experimental results show that the proposed MMW slot antenna array can achieve 7.1% bandwidth and 15.3 dBi peak gain.