Low-Profile Wideband Vertically Folded Slotted Circular Patch Array for Ka-Band Applications

A vertically folded slotted circular patch operating at the Ka -band is proposed in this communication. Fed by a low-profile microstrip feeding structure, the proposed circular patch resonates at its quasi-TM21 mode and exhibits a wide operational band of 23.5%, which is more superior than many reported millimeter-wave circular patch antennas. A full-corporate fed 2 × 2 linearly polarized (LP) subarray based on the proposed circular patch is designed without any additional substrate layer, which is further extended into a 4 × 4 LP array and a 4 × 4 circularly polarized (CP) sequential rotation array. Both the LP and CP arrays are fabricated and measured. A good agreement between the simulated and measured results has been observed, thus validating the proposed design techniques. With the enhanced performance, for example, wideband, low-profile, low cost, and compact size, the demonstrated array antennas can present promising candidates for some popular Ka -band applications, such as 5G millimeter-wave communications and satellite communications.