A compact frequency reconfigurable patch antenna with asymmetric armed U and reversed L slots for handheld wireless devices

Abstract

Abstract A frequency reconfigurable microstrip patch antenna with a combination of an asymmetric armed U-slot and a reversed L-slot etched on a rectangular base patch of 6 GHz resonant frequency designed on an FR4 substrate (ɛr = 4.4) is presented in this paper. Three RF PIN diodes are positioned at inimitable sites of these slots to achieve frequency reconfiguration. A DC bias circuitry, which includes DC blocking capacitors and RF blocking inductors, is integrated with the antenna structure for switching (ON/OFF) the PIN diodes. Six reconfigurable modes with resonant frequencies at 4.33, 4.63, 5.24, 5.87, 5.96, and 6.29 GHz is obtained with different ON-OFF combinations of these PIN diodes. These reconfigurable resonant frequencies cover two continuous bands from 4.21 to 5.43 GHz and 5.69 to 6.6 GHz and is considered to be useful for the applications like aeronautical radio navigation (4.3 GHz), sub-6-GHz 5G (4.4–5 GHz), WLAN (5.2 and 5.8 GHz) and Wi-Fi 6E (5.925–6.425 GHz). Measured gain of the antenna for all the modes varies between 5.86 dBi and 8.72 dBi.