A Sub-6 GHz/Millimeter-Wave Dual-Wideband Shared-Aperture Antenna by Reusing the Mushroom Structure

In this communication, a novel dual-wideband shared-aperture patch antenna with flexible frequency ratio is proposed. The dual-band antenna consists of a main radiating patch and two eight-element mushroom-shaped structure arrays. The dual-function mushroom-shaped structures act as parasitic structure for bandwidth enhancement in microwave (MW) band and radiators in millimeter-wave (MMW) band. In MW band, broadband performance is achieved based on the fusion of fundamental mode from main patch and higher order mode from the combination of main patch and parasitic structure. In the MMW band, taking the mushroom-shaped array on one side as an example, two mushroom-shaped structures are reused as an MMW element, forming a $1\times 4$ MMW array. Experimental results show that the impedance bandwidth of the MW band is 15.8% (4.31–5.05 GHz) with the peak gain of 5.64 dBi and that of the MMW band is 12.2% (26.2–29.6 GHz) with the peak gain of 11.33 dBi, and good radiation performance is obtained at both the MW and MMW bands. The MMW array can support beam-steering angles of ±40°. All these results indicate that the proposed design could be a promising candidate for 5G communication application scenarios.