A hybrid mode semi circular shaped frequency reconfigurable antenna for multiband communication

This paper presents a hybrid mode semi-circular-shaped frequency reconfigurable antenna for ultra-wideband (UWB) and multiband communication. The proposed antenna is designed on a FR-4 substrate with a thickness of 1.6 mm, a relative permittivity of 4.2, and a compact size of 40 mm x 30 mm. Re-configurability is enabled by four PIN diodes, allowing the antenna to switch between UWB and various modes. The antenna operates in five different modes. In Mode 1 (all diodes OFF), the antenna operates as a UWB antenna covering 3.89 - 12.94 GHz with a peakgain of 6.93 dBi.It exhibits an axial ratio (AR) below 3 dB at 10.7 GHz, achieving a circular polarization bandwidth (AR BW) of 330 MHz from (10.53-10.86) GHz. Activating specific PIN diode combinations allows the antenna to function in different multiband configurations, supporting frequencies for 5G sub-6 GHz, WiMAX, and radar applications. This antenna's versatility, through its frequency re-configurability, makes it an ideal candidate for modern communication systems.