A Novel Frequency Reconfigurable Antenna for X, Ku, and K Bands Applications.

In this paper, we introduce a novel frequency-reconfigurable antenna design that leverages the principles of split ring resonator (SRR) and defected ground structure techniques (DGS). These techniques are strategically applied to the antenna’s patch and ground, respectively. Additionally, the incorporation of two PIN diodes, situated within the radiating element and the ground plane, introduces the capability to achieve distinct resonant frequencies. Notably, these frequencies span the range of 8 GHz to 26 GHz, effectively covering the X, Ku, and K bands. The configuration of the proposed antenna incorporates two PIN diodes, enabling us to achieve four distinct states. Notably, a majority of the resonant frequencies exhibit a positive gain, resulting in an average gain of 2.55 dBi. Additionally, the peak S11 value is noteworthy, and the VSWR remains consistently below 2 across all resonant frequencies. The radiation pattern in the E-plane is omnidirectional, offering broad coverage, while in the H-plane, we observe a directional radiation pattern predominant at most frequencies. To ensure the reliability of our findings, we employ CST Microwave Studio (MWS) for initial simulations and subsequently validate the outcomes using High-Frequency Structure Simulator (HFSS).