A resistive linear antenna for ground-penetrating radars

Abstract
The resistive vee dipole (RVD) loaded with the Wu-King profile has many advantages for use in ground-penetrating radar (GPR) applications. It can be designed to transmit a temporally-short pulse to a small spot on the ground. The shape of the transmitted pulse is simply related to the input signal, e.g., a derivative. The RVD also has a low radar cross section. In addition, it can be easily manufactured using a circuit board and discretely loading it with chip resistors. One drawback of the RVD is that the input impedance of the RVD increases significantly with decreasing frequency and, therefore, has a high voltage standing wave ratio (VSWR) at low frequencies, which limits the low-frequency response of the antenna. To improve the low-frequency response, a discretely-loaded resistive linear antenna (RLA) has been developed, whose basic principle of operation is the same as that of the RVD. The RLA has curved arms loaded with a modified Wu-King profile instead of straight arms loaded with the Wu-King profile. With an appropriate selection of the curve and the loading profile, the low-frequency response is significantly better for the RLA than for the RVD. The RLA has been developed using a method of moments code. The performance of the RLA is validated both numerically and experimentally.