A Printed U-Shaped Coplanar Waveguide Feed UWB Antenna for GPR Applications

Abstract

A printed U-shaped coplanar waveguide fed (CPW) ultra-wideband (UWB) antenna is designed, fabricated, and measured in this paper for ground penetrating (GPR) applications. To enhance the working bandwidth, a set of cutoffs was introduced in different parts of the antenna. The antenna was printed on the FR4-epoxy substrate in a compact size of 0.252λ0×0.3λ0×0.015λ0 at 3 GHz. The calculated results were validated by realizing and measuring a prototype. Experimental demonstrations were done with the R& S®ZNB Vector Network Analyzer, which indicates that the antenna's working bandwidth extends from 3.09 GHz to 11.07 GHz (112.71%). Additionally, the antenna's radiation patterns were measured in an isolated anechoic chamber, which shows that the proposed antenna has omni-directional radiation patterns. Moreover, acceptable gain antenna values ranging between 1.74 and 7.04 dBi and high values of radiation efficiency of more than 80% were achieved over the whole working bandwidth. Besides, the antenna presents a stable group delay with a linear phase of S21 through the UWB frequency band. To prove the efficiency of the fabricated antenna for GPR applications, the operation of the antenna was experimentally tested in a sandy soil box. The obtained results show that the proposed antenna could be a good candidate for GPR applications.

Keywords

• Coplanar Waveguide (CPW)
• Ground Penetrating Radar (GPR) Applications
• Ultra-Wideband (UWB) Antenna
• Voltage standing wave ratio (VSWR)