Capacitive probe-compensation-fed wideband patch antenna with U-shaped parasitic elements for 5G/WLAN/WiMAX applications

Abstract

A novel single layer, single capacitive probe-compensation fed wideband patch antenna is presented and investigated. The antenna consists of a rectangular patch and two identical U-shaped parasitic patches. The two U-shaped patches are incorporated around the radiating edges and non-radiating edges of the rectangular patch. For maintaining a relatively small antenna size, the length and width of this rectangular patch are 1/2λg and 1/4λg, respectively. A novel capacitive compensation technique, that is an annular gap which is concentric with the fed-probe, can introduce an annular gap capacitor to compensate the inductance caused by the fed-probe. By incorporating the U-shaped parasitic patches, an additional resonant frequency is introduced, which incorporates with the original resonant frequency produced by the rectangular patch, thus the wideband performance is achieved. The measured impedance bandwidth with S11 ≤ −10 dB is 40% (1.99 GHz) from 4.03 to 6.02 GHz, which covers 4.8-4.99 GHz band of 5G operation in China, WLAN 5.2 GHz (5.15-5.35 GHz), WLAN 5.8 GHz (5.725-5.825 GHz), and WiMAX 5.5 GHz (5.25-5.85 GHz). The measured peak gain is 9.1 dBi. An equivalent circuit model is established to provide a clear physical insight into the operation of the proposed antenna.