Substrate Integrated Waveguide Slot Array Antenna to Generate Bessel Beam With High Transverse Linear Polarization Purity

The transverse linearly polarized beam can maintain its polarization when reflected, which is important for a detection system. Most of the existing planar Bessel beam generators are implemented in a central feeding radial topology and hard to generate the Bessel beam with the transverse linear polarization. In this communication, a substrate integrated waveguide (SIW) slot array antenna is proposed to generate the transverse linearly polarized Bessel beam. The desired phase and amplitude distribution of the Bessel beam can be easily realized by such an array. With the inherent 0 degrees/180 degrees output phase of the comb-like divider considered, the desired 0 degrees/180 degrees phase distribution is implemented by placing adjacent slots on the opposite (0 degrees) or the same side (180 degrees) within a linear array and by employing adjacent linear arrays with the inverse (180 degrees) or the same (0 degrees) slot offset direction accordingly. The offset of the slot, as well as the tuning metalized vias within the comb-like divider, is modulated to generate the desired amplitude distribution. After reducing the influence of the rectangularly truncated aperture by adding a Gauss-tapered amplitude distribution, a transverse linearly polarized Bessel beam SIW slot array antenna is designed with more than 100 mm depth-of-field (DoF) and less than -25 dB cross polarization. To the best of our knowledge, it is the first design to generate the transverse linearly polarized Bessel beam by a planar array antenna.