A Compact Wideband Printed Slot Antenna with Gain Enhancement for GPR Applications

This paper presents a printed wide slot antenna fed by double-shaped feeding strip with a modified slot for gain enhancement. The inverted U-shaped slot of the original slot antenna is modified by adding the wide rectangular slot. In addition, the small rectangular slots are etched on the bottom edge of the radiating slot to improve impedance matching, especially at lower frequencies. The proposed antenna has dimensions of 230 mm × 270 mm, which provides a very wide impedance bandwidth, covering the frequency range from 0.3 to 3.564 GHz. Moreover, a stable and bi-directional radiation pattern is observed within the frequency lower than 1 GHz for subsurface imaging application. The proposed antenna has maximum realized gain about 8.8 dBi at 2.5 GHz, while improving the gain of original antenna about 1 dBi without increasing the antenna size.