Dodecagon-Shaped Frequency Reconfigurable Antenna Practically Loaded with 3-Delta Structures for ISM Band and Wireless Applications

Abstract

An edge fed, dual band, quarter-wave transformer coupled, monopole, ultra-wideband (UWB), dodecagon-shaped miniaturized frequency reconfigurable antenna for ISM and wireless applications is designed, analysed and investigated. The impedance transformer is utilized in the structure for impedance matching and hence results in lower reflection coefficient values. The antenna uses defected ground structure (DGS) in the bottom and radiating patch that is practically loaded with three numbers of delta structures. The use of DGS reduces the value of gain and provides ultra-wideband bandwidth across the designed frequency. The addition of three delta structures in the patch improves the value of gain. Miniaturizing in the size of the antenna has been achieved by reducing the ground along the width that led to a total 30.41% size reduction in the fundamental circular patch antenna. The antenna exhibits two bands 1.82–3.61 GHz and 5.24–12.43 GHz thus antenna is suitable for ISM band, PCS, 5G, Wi-Fi/WiMAX/WLAN and other wireless applications. The fabricated antenna is frequency reconfigured by utilizing the switching property of four numbers of PIN diodes (BAP64-02V). Frequency reconfigurable antenna is used flexibly and versatile for various microwave applications based on the switching conditions (more than eight digital combination cases) of PIN diodes. The prototype measured results provide good agreements with the simulated reflection coefficients values in some mode of operations. Antenna radiating patch and ground is etched on FR-4 substrate of dimension 52 mm × 59 mm × 1.6 mm using printed circuit board technology.