Modelling and Analysis of Composite Antenna Superstrates Based on Grids of Dipoles and Wires

A new planar superstrate, proposed for the gain enhancement of dipole antennas, is modelled and analyzed. The superstrate consists of two closely located parallel grids of short dipoles and one grid of continuous wires in between the dipole grids. Also the situation when the wire grid is absent is studied. An analytical model based on the local field approach has been derived in order to extract the transmission and reflection responses of the superstrates. The responses have been compared with the results predicted by Ansoft-HFSS. A finite size superstrate has been designed for a dipole antenna, and the simulations show that a significant gain enhancement can be achieved with the proposed design