A very compact UWB antenna with four notched bands is proposed. The antenna consists of a rectangular radiating patch with a half circle at bottom, a tapered microstrip feed-line, and a semielliptical ground plane. With a pair of Lshaped slots, complementary co-directional SRR on the patch and a pair of L-shaped slots on the ground plane, four notched bands are created to prevent interference from WiMAX /WLAN/X-band. Experimental results show that the designed antenna, with compact size 20×30mm2, has an operating band(VSWR<2) from 2.7 to 20GHz,except four stop bands of 3.1~3.7GHz, 5.13~5.48GHz, 5.74~6.04GHz, 7.3~7.96GHz. And good radiation patterns within the operating band have been observed.
Considering antenna pattern and Doppler frequency-shift separately, the theory model about targets near-field scattering is established from a simple target, using PO (physical optics) method depending on SCTE(Scattering from Complex Targets and Environments)system.Then some curves are presented which are in accordance with the results given by references. The calculated results show that the influence of the factors over targets near-field RCS are complex and important. This work has practical engineering value in the modern and high science and technology warfare.