Electromagnetic Analyses and an Equivalent Circuit Model of Microstrip Patch Antenna with Rectangular Defected Ground Plane

This paper presents an investigation of both electromagnetic wave model and equivalent circuit model for microstrip patch antenna (MPA) with rectangular defected ground plane structure (RDGS). The objective of the proposed design is to reduce antenna size from Wi-Fi wireless band to the Bluetooth band. The first part of the paper describes the electromagnetic wave modeling using the High Frequency Structure Simulator (HFSS (R)) software to study the effect of RDGS on antenna resonant frequency. An optimization tool together with curve fitting were then used to formulate an approximate equation that describes the identified trends from the simulations. Second part is focused on estimating, using the Advanced Designing System (ADS) software the parameters of an equivalent circuit model for MPA with RDGS. The developed equivalent circuit consists of lumped elements for both MPA and RDGS structure and also include representation of the electrical and the magnetic coupling between rectangular grounded slot and MPA. Optimum values of the equivalent circuit elements were determined, and the overall simulation results were confirmed experimentally.