A Wideband K/Ka-band Slot-coupled Microstrip Patch Antenna and Array Design

This paper presents a stacked slot-coupled antenna that operates at the K/Ka band. By a circle of metal pillars around the cross slots, a substrate integrated cavity is formed to suppress feeding network stray radiation and ground edge radiation, eliminating unwanted resonance points and zero points and improving the coupling performance. At the same time, the resonance points brought by the slot and the patch are introduced to improve the antenna bandwidth. By adjusting the patch size, slot size and feedline size, the resonance points of the three are brought close to each other to achieve a wider bandwidth. The prototype stacked slot-coupled antenna exhibits a wide impedance bandwidth of 47.45% from 18.07 GHz to 29.31 GHz and a stable radiation pattern at broadside with a gain of 7.1 dBi at 25 GHz. Finally, a power divider feeding network and a 4 × 4 total 16 elements array with a gain of 18.8 dBi at 25 GHz are designed at the operating band.