Design and Comparative Performance Analysis of a Circular Microstrip Patch Antenna with Different Modifications

In this paper, a circular microstrip patch antenna is designed at implantable medical devices (IMDs) bands. The antenna is modified with different techniques to reduce the dimension and enhance the performance. This paper focuses the comparative performance analysis of the circular patch, the circular planer inverted F-antenna (PIFA), the circular PIFA with meandered line, the circular PIFA with meandering and defected ground structure (DGS), the multiple substrates layer circular PIFA with meandering, and finally the multiple substrates layer circular PIFA with meandering and DGS. These approaches provide the size reduction, gain enhancement, bandwidth broadening, and efficiency increment. Although this circular patch antenna offers large bandwidth, gain, and radiation efficiency; however the dimension of the antenna is quite high. The dimension of an antenna can be minimized by using circular patch PIFA. To reduce the overall size of this antenna, a circular meandering PIFA has been utilized. The circular meandering PIFA with DGS further increases the current conduction path and controls the input impedance. The increased current flow path contributes to the radiation efficiency. Moreover, the multiple substrates layer circular meandering PIFA helps to enhance the bandwidth, radiation efficiency, and frequency. The radiation efficiency can be increased more by inserting a DGS in the multiple substrates layer circular meandering PIFA.