Frequency band tunable antenna with parasitic element to switch between narrow band and notched UWB for Personal Area Network Applications

This paper presents a compact frequency-band tunable antenna (FBTA) capable of reconfiguring its operation between a notched ultra-wideband (UWB) mode and a narrowband mode using a single radiating element. The proposed monopole antenna incorporates a strip line feed and a non-uniform ground structure to achieve a wide impedance bandwidth from 3.6 GHz to 10.85 GHz. Frequency-band configurability is enabled through the integration of an open-ended triangular parasitic element and PIN diodes within the ground plane, eliminating the need for radiator modification. In the notched UWB configuration, the antenna exhibits effective band-rejection characteristics from 5.06 GHz to 5.93 GHz, thereby suppressing interference from Wireless Local Area Network (WLAN) systems in compliance with FCC regulations. By varying the biasing states of the PIN diodes, the antenna dynamically switches between notched UWB and narrowband responses. The antenna is realized on a compact 40 mm × 30 mm × 1.6 mm FR4 substrate, and its impedance bandwidth and radiation characteristics are evaluated under different switching conditions. The proposed design offers a simple and efficient solution for reconfigurable wireless applications requiring compact size and flexible frequency operation.