SIW Slot Array Antenna with Non-Alternating Slot Placement for Impedance Bandwidth Enhancement

This paper presents a substrate integrated waveguide (SIW) array antenna with non-alternating etched longitudinal slots to realize the impedance bandwidth enhancement. Due to the non-alternating slot placement, the impedance bandwidth of the slot array antenna can be expanded much more compared with that of a conventional slot array antenna, which has a distance of a half waveguide wavelength between two adjacent slots. Considering the dielectric filled in the SIW, the distance between two adjacent slots etched on the same side of the SIW is still less than one wavelength in air. Thus, it can guarantee the good performance. The measured linear array exhibits the enhanced impedance bandwidth of 2.29 times at a return loss of 10 dB when compared to the conventional slot array antenna with the same radiating aperture. A stable radiation pattern bandwidth of 2.27% is also obtained with a gain of 17 dBi at the central frequency of 94 GHz.