WIDEBAND STAR SHAPED MICROSTRIP PATCH ANTENNA
A new wideband and small size star shaped patch antenna fed capacitively by a small diamond shape patch is proposed.To enhance the impedance bandwidth, posts are incorporated under the patch antenna.HFSS high frequency simulator is employed to analyze the proposed antenna and simulated results on the return loss, the Eand H-plane radiation patterns and Gain of the proposed antenna are presented at various frequencies.The antenna is able to achieve in the range of 4–8.8 GHz an impedance bandwidth of 81% for return loss of less than −10 dB.
Conventional microstrip antennas in general have a conducting patch printed on a grounded microwave substrate, and have the attractive features of low profile, light weight, easy fabrication, and conformability to mounting hosts.However, microstrip antennas inherently have a narrow bandwidth and bandwidth enhancement is usually demanded for practical applications.In addition, applications in present-day mobile communication systems usually require smaller antenna size in order to meet the miniaturization requirements of mobile units.Thus, bandwidth enhancement and size reduction are becoming major design considerations for practical applications of microstrip antennas [1].Many techniques such as meandered ground plane [2], slot-loading [3, 4], stacked shorted patch [5], feed modification [6], chip loading [7] and teardrop dipole in an open sleeve structure [8] have been reported to achieve wideband and to reduce the size of microstrip antennas.In addition, the bandwidth of the patch antenna can be increased by using air substrates, [9].Another method of increasing the impedance bandwidth of a patch antenna