Improvement in Rectangular Microstrip Patch Antenna Parameters Using Metamaterial with Active Devices

In this paper an inset fed rectangular microstrip patch antenna is designed and its parameters like return loss, directivity, band width are analysed. Then a metamaterial structure of "Interconnected Hexagonal Rings" is designed such that it exhibits negative permittivity and negative permeability at the same frequency as that of inset fed rectangular microstrip patch antenna. Here NRW parameters are used to verify negative permittivity and negative permeability. This structure is then superimposed on the microstrip patch antenna and its parameters are again analysed. Improvements are seen in the above parameters. Then a varactor diode as active device is added to the metamaterial structure and again parameters are analysed using CST microwave studio software. Further improvement in above parameters are observed.