FDTD analysis of a planar spiral antennas for the ground penetrating radar

In this paper, the planar spiral antennas for the ground penetrating radar (GPR) were calculated by using FDTD method. The frequency characteristics of the impedance ware discussed by changing the expansion angle of the planar element and the winding angle of the spiral. It was observed that a wide-band characteristics can be realized by a careful design of the antenna shape. Because the transient response of a GPR antenna is very important, the transient radiated electromagnetic wave was also investigated.