Ultrawideband Strip-Loaded Slotted Circular Patch Antenna Array for Millimeter-Wave Applications

A novel ultrawideband millimeter wave (mmWave) slotted circular patch antenna and array are proposed in this letter, where each circular patch antenna element is loaded with three pairs of folded strips for enhancing the bandwidth and fed by a substrate-integrated waveguide through a coupling slot. As a result, a multimode antenna element with the ultrawideband characteristic can be realized, and the impedance fractional bandwidth (FBW) with | S ₁₁ | < −10 dB is up to 66.9%. Furthermore, an 8 × 8 antenna array prototype is designed and fabricated. Measured impedance FBW with | S ₁₁ | < −10 dB of 56% and measured average radiation efficiency of 73.8% are achieved. With the wideband and low-profile features, this antenna can be a promising candidate for mmWave communications.