Tunable Band Notched UWB Antenna with Wide Tuning Range and Notch Bandwidth Controllability

An ultra-wide band (UWB) antenna employing spoof surface plasmon polariton principles is introduced, offering tunable single- and dual-band rejection. Inserting slot resonators into the SSPP feed achieves band-notching. The achieved notched band can be tuned by employing varactor diodes across the slots. Single and dual-notch bands have been achieved using two varactor diodes. Tunable notches cover the frequency range of ultra-wideband systems, starting from 3.1 to 10.6 GHz. Notch band reconfigurability and notch bandwidth controllability are achieved by designing the slot geometry and the varactor diode capacitance, which change the circuit model’s $R$ , $L$ , and $C$ component values to achieve the intended quality factor and, thus, the rejection bandwidth for a specific frequency band. The proposed idea works for all notch frequencies in the UWB range. The rejection bandwidth can be tuned from 398 to 1430 MHz with superior selectivity. Moreover, the proposed SSPP-based monopole antenna can easily be integrated with active devices due to the dual-conductor structure of the feeding SSPP transmission line. The proposed SSPP-based UWB antenna shows a measured peak gain of around 4 dBi. To the authors’ knowledge, notch bandwidth controllability and tuning across a wide range of frequencies have not been reported previously.