Design and simulation of Microstrip M-patch antenna with double layer

Abstract

In this paper, we are going to discuss about the current trends in the design of Microstrip M patch antenna intended for various applications and it is a innovative nature never tried out earlier. This opens up a new avenue for different frequency ranges and new applications yet easily realizable with maximum advantages. In rectangular micro strip patch antennas [RMSA] with negative capacitance and inductance for bandwidth enhancement. Micro strip antennas have been found favorable because they are : 1. low profile 2. inexpensive to manufacture and compatible with monolithic microwave integrated circuit designs (MMIC). But they also suffer due to (a) low efficiency (b) Narrow impedance band width. Input impedance of an antenna tends to be sensitive to changes in frequency, hence deviation of the antennas input impedance from a real fixed value often determines the operational range of the antenna. Input impedance of MSDA depends on its with geometrical shape, dimension and the feed type. Therefore antenna input impedance is an important design parameter which controls the radiated power and the impedance bandwidth. In most application, bandwidth limitations occur due to an impedance mismatch. In the respect micro strip antenna have narrow bandwidth because of heavy reactance. As micro strip antennas have found wide variety of application areas, a number of techniques are evolved to improve its limited bandwidth. A straight forward application to improve the bandwidth is increasing the thickness of substrate supporting the micro strip patch. However limitation shall exist on the ability to effectively feed the patch on a thick substrate and the radiation efficiency can degrade with increasing substrate thickness. Techniques for overcoming this band limiting problems can be achieved by using parasitic terms elements, external matching and separating the feed and antenna. Proximity coupling method uses an impedance matching stub connected to the feed line achieving 13% bandwidth. A broadband rectangular patch antenna with a pair of vide slits at near the resonance frequency improves to 24% bandwidth. Bandwidth of 10-12% can be obtained using passive coplanar matching network. Impedance bandwidth of 60% was achieved using the L and T slots in the micro strip slot antenna, however gain and radiation pattern are distorted. Using aperture coupled antenna BW large than 20% and cross polarization level lower than -30 db can be achieved. Bandwidth of circular loop antenna can be significantly increased when one more parasitic loop in added.