Six circularly polarized patch antennas with electromagnetic band gap（EBG）arranged at different locations were studied.These EBG antennas were compared in terms of impedance bandwidth,axial ratio（AR）bandwidth and radiation patterns.When the EBG cells were placed closer to the edge of the substrate,the EBG antenna had a larger front radiation and a narrower bandwidth.Integrating the EBG cells closer to the center of the patch resulted in a wider impedance bandwidth,a wider axial ratio bandwidth and a decreased front gain.
The electromagnetic properties of wire medium are studied by analyzing its transmission coefficient, and a homogeneous uniaxial effective permittivity tensor with one spatially dispersive component is obtained. In order to evaluate the validity of the equivalent model for scattering problems, the bistatic and monostatic radar cross sections （RCS） of a block of wire medium are investigated with the finite-difference time-domain （FDTD） method. The difference of RCS from the physical wire medium and the corresponding equivalent model has been compared and analyzed under va- rious parameters of wire medium, which clearly demonstrates the accuracy of the equivalent model of wire medium.
