Anotace:
A compact (27.5×16.5×0.8 mm3) co-planar waveguide fed printed ultra-wideband antenna operating in the impedance band of 1.75-10.3 GHz with two wide frequency notch bands at 2.2–3.9 GHz and 5.1–6 GHz, is introduced. Dual notch is achieved by inserting U-slot on the radiator and with inverted patch shaped downscaled parasitic load at the opposite end of feed line. Maximum antenna gain augmentation by about 5 dBi is achieved without changing the bandwidth, by incorporating a dual layer reflective frequency selective surface (FSS) of dimension 33×33×1.6 mm3 below the antenna. The antenna-FSS composite structure exhibits maximum radiation in the broadside direction with a peak gain of 9 dBi and an average radiation efficiency of more than 80% in the operating band. Antenna transfer function and group delay are experimentally studied in ground coupling mode of ground penetrating radar (GPR). Linear magnitude response of transfer function and consistent, flat group delay are achieved, that ensure minimal antenna dispersion and its ability for GPR application.