DESIGN ANALYSIS AND MODELING OF DIRECTIONAL UWB ANTENNA WITH ELLIPTICAL SLOTTED GROUND STRUCTURE FOR APPLICATIONS IN C- & X-BANDS

Abstract

A modified technique to design directional ultra-wideband (UWB) antenna with slotted ground structure approach on the ground plane has been presented for applications in Cand X-bands. Initially, elliptical slot is inserted into ground and thereafter, the axis of ellipse is rotated 45 degrees in direction of the substrate. Minor axis of the ellipse is optimized to locate it symmetrically around the circular patch in order to obtain the full Cand X-band operations and also to enhance directivity. Thereafter, for further improvement in the directivity as well as gain, an elliptical slot in circular patch has also been introduced. The impedance bandwidth approximates about 95% covering the frequency ranging from 4.18–11.50 GHz. The return losses (S11) are −38 dB and −43 dB through simulation, which are −24 dB and −32 dB by measurement at 6.3GHz, 9.3GHz resonant frequencies, respectively. Simulated gain and half power beam width (HPBW) are 2.5–8.4 dB and 49–22 degrees in 4.18–11.50 GHz band, respectively. Gain and half power beam width (HPBW) of the proposed antenna improves by 1–2 dB and 5–10 degrees, respectively compared with previously designed antennas. Simulation of the antenna has been carried out on Computer Simulation Technology (CST) software on an FR-4 substrate having dielectric constant 4.3 of thickness 1.6mm. The measured results show good agreement with equivalent circuit model and CST simulation.