Summary
International Symposium on Antennas and Propagation
2010
Session Number:4FA2
Session:
Number:4FA2-2
Small Circularly Polarized E-Shaped Virtually Shorted Patch Antenna
Kwok Kan So, Kung Bo Ng, Hang Wong, Kwai Man Luk, Chi Hou Chan, Quan Xue,
pp.-
Publication Date:2010/11/23
Online ISSN:2188-5079
Summary:
Patch antennas have some advantages such as low profile, ease of fabrication, and conformal to structure. For small RF systems, many researchers have focused on small antenna designs. There are several techniques for reducing the size of the patch such as the use of high permittivity material [1], shorting wall [2] or pin [3], slot and tail [4]. Although, the first technique is the simplest way for reducing the size, it is expensive. The presence of a shorting wall or pin can reduce the conventional patch from half wavelength to quarter wavelength but a higher cross polarization level is generated owing to the asymmetric nature of the antenna. The approach of using slots and tails can give capacitive and inductive loadings to the patch; however, the reduction of patch size is limited to 30%. In this paper, four parasitic E-shaped virtually shorted patches are provided for miniaturizing the patch size. The shorting strip technique is combined with cutting slots and embedding tails on the patch, so as to easily generate the circularly polarization (CP) field. One end of the strips are open-circuited, the other ends are shorted to the ground plane vertically. The horizontal portion (printed on the substrate) of the strips is used as a capacitive loading whereas the vertical portion (via-hole inside the substrate) is an inductive loading. These four shorting strips arrangement is used to balance and suppress the high cross polarization radiation from the vertical shorting pins and to maintain good broadside radiation characteristics. Good agreement between simulated and measured results is obtained.