Ka-Band 8 × 8 Low-Sidelobe Slot Antenna Array Using a 1-to-64 High-Efficiency Network Designed by New Printed RGW Technology

This letter proposes an 8 × 8 high-efficiency low-sidelobe slot antenna array operating at Ka-band frequencies with a feeding network designed by a new printed ridge gap waveguide (PRGW). The device consists of a slot antenna element, a PRGW unequal feeding network, and a stripline-to-PRGW transition. The substrate integrated waveguide slot antenna element fed by the PRGW through a coupling aperture has a wide bandwidth, and the isolation is also increased by adding metallized holes to the array. Compared with other gap waveguide antenna arrays, our work realizes an antenna element fed separately due to the use of a PRGW with a compact mushroom cell size, which helps improve the properties of the unequal feeding network. In addition, the transition between the PRGW and stripline is also designed with a wide band and low insertion loss. The measured reflection coefficient is less than -10 dB over a 6 GHz bandwidth (16%), the gain is more than 23.5 dBi in the working band, and the sidelobe level is -18 dB. In addition, the measured radiation efficiency of the array with a two-dimensional Taylor distribution is 41.69%.