Wideband Millimeter-Wave Substrate Integrated Waveguide Slotted Narrow-Wall Fed Cavity Antennas

A technique to design substrate integrated waveguide (SIW) slotted narrow-wall fed cavity antennas is presented and investigated for millimeter-wave systems. The proposed antenna consists of a feeding SIW and a slotted narrow-wall fed high permittivity dielectric loaded substrate integrated cavity (SIC) in a co-planar configuration. First, the cavity modes are analyzed for selecting the feeding structure. Then, the equivalent circuit of the feeding structure is formulated to reveal the mechanism of wideband operation of the proposed antenna. The antennas and arrays operating at 35 and 60 GHz bands fabricated with printed circuit board (PCB) technology are exemplified to validate the concepts. The prototypes with single cavity achieve a bandwidth of 10% for 15-dB return loss and gain of 6 dBi at both 35 GHz and 60 GHz. The 2 × 2 35-GHz SIC antenna array shows a bandwidth of 11.7% for 15-dB return loss and gain of up to 10.8 dBi. The SIW-fed SIC millimeter-wave antenna arrays feature a wideband operation with low loss, low cost, low profile, easy integration configuration.