Design and Analysis of a Compact Printed UWB Antenna Using Non Uniform Matching and Half-Wavelength Circular Slot

In this paper, antenna ultra wideband enhancement by non-uniform matching and half-guided wavelength circular embedded slots is presented and analysed in detail. A printed compact rectangular monopole antenna with two convex circled corners has been analysed firstly. A good impedance matching is achieved in the IEEE radar engineering X-band satellite communications by lowering below -50 dB value at 9.5 GHz. The current density can reach 52 A/m with convex corners; this value is large compared to 32 A/m obtained with stepper corners. In addition, the measured radiation patterns at various frequencies show clearly that the antenna displays nearly an omnidirectional radiation pattern in the E plane (xz) and the H-plane (yz) in both co-and cross-polarizations. The group delay indicates that this antenna is reliable so that a transmitted signal will not be seriously distorted. Two circular half-wavelength slots are embedded in the radiating patch to improve S11 in the WLAN band. Accordingly ultra-wideband behaviour is achieved along a bandwidth is ranging from 3.5 GHz to 12.5 GHz. Due to its compact size of 30 x 35 mm2 and its good impedance matching especially in the X band, the designed antenna is able to satisfy some of the requirements of an airborne SAR and is also well suited for remote sensing applications.