Summary
International Symposium on Antennas and Propagation
2009
Session Number:2C2
Session:
Number:2C2-1
Wideband Stacked Square Microstrip Antenna with Slits
Takafumi Fujimoto, Atsushi Yamashita,
pp.445-448
Publication Date:2009/10/21
Online ISSN:2188-5079
Summary:
An impedance bandwidth of a microstrip antenna (MSA) is narrow inherently. Therefore, many approaches to increase the bandwidth such as using additional microstrip resonators [1], stacking parasitic patches above a fed patch (stacked MSA) [2], embedding a U-shaped slot in the radiating patch [3] and using an L-probe feed [4], have been proposed. It is desirable for wideband antennas that the frequency characteristic of the VSWR(voltage standing wave ratio) is wide and the direction of the radiation peaks is the same in the frequency range. The structure of the stacked MSA is relatively simple because it can be realized by just stacking a parasitic patch, whose geometry is the same as the fed patch, above the fed patch. In the conventional half wavelength stacked MSA, although the radiation peak in the first mode is at high elevation angle, that in the second mode is at low elevation angle [5]. Therefore the bandwidth of the stacked MSA is only enhanced in the frequency band of the first mode. The authors have proposed a wideband stacked square microstrip antenna (MSA) with two shorting plates [6]. The bandwidth of VSWR? 2 has been achieved in the frequency range between the first and the third resonant frequencies and the bandwidth of VSWR ? 2 with gain at θ = 0°? 0dBi has been achieved in the frequency range between the first and the second resonant frequencies In this paper, the improvement of the directivity in the vicinity of the third resonant frequency is examined by installing slits in the patches and changing the width of the shorting plates of the antenna proposed in the reference [6].