UWB Filtenna with Reconfigurable and Sharp Dual-Band Notches for Underlay Cognitive Radio Applications

In this paper, a compact UWB antenna with a reconfigurable and sharp dual-band notches filter to cancel the interference with some critical applications (5G WLAN, and X-band satellite downlink) is proposed for underlay cognitive radio (CR) applications. The dual notched bands are produced by coupling a pair of π-shaped resonators on both sides of the feed line and by etching a U-slot inside the feed line of the antenna. The proposed UWB filtenna in this configuration has a surface area of 22 × 31 mm2 and produces simulated (measured) reconfigurable notched frequencies at 5.466 GHz (5.7 GHz) and 7.578 GHz (7.44 GHz) with an impedance bandwidth of 3.024–10.87 GHz (2.825–10.74 GHz). Three PIN diodes are used to switch the presence of the dual-band notch. Two PIN diodes that turn ON-OFF simultaneously (D1A & D1B) are inserted within a pair of π-shaped resonators to control the 5G WLAN band notch, and a single diode (D2) is embedded within a quarter wavelength resonator which is located inside the feed line of the antenna for controlling the X-band band notch. The simulation and measured results reveal that the proposed filtenna effectively covers UWB with controlled cancellation for interference with the intended bands. The realized gain is 4.5 dBi through the passband except in the notched frequencies, where it is decreased to less than −11 dBi in both notch frequencies. In other words, the proposed filtenna has a very high VSWR of greater than 20 at the notched frequencies. © 2022, Electromagnetics Academy. All rights reserved.