Band Switchable Monopole Antenna for UWB, 5G and Cognitive Radio Applications

This paper presents a printed monopole antenna with a novel band switching mechanism to switch between UWB, sub-6 GHz and 3–4 GHZ bands. The antenna uses a capacitively coupled parasitic line near the partial ground plane whose electrical length is controlled using two pin diodes. For the third band, a stub is added near the radiator. The VSWR < 2 bandwidth when the pin diodes are OFF is from 2.9 GHz to 10.2 GHz (UWB) and for ON case it gives sub-6 GHz band from 2.9 GHz to 5.7 GHz and the stub gives the third band from 3–4 GHz. The effect of adding a parasitic line in the partial ground plane is studied using surface current distribution. The proposed antenna is fabricated and tested for its VSWR and radiation characteristics. The measured results indicate that the antenna is suitable for UWB, sub 6-GHz
$5\mathbf{G}$
and cognitive radio applications.