A microstrip array of aperture-coupled patches for UMTS base stations

The rising popularity of wireless communication systems has induced a demand for more and more efficient systems, able to serve larger numbers of users, to provide higher transmission speeds and to operate in more complex environments. The present limited available bandwidth and the growing request for capacity require new channels to be multiplexed. This objective can be accomplished by employing smart antenna systems at the base station. A smart antenna can be used to direct the main beam toward the desired user and to set pattern s in the direction of interferers. Such a system can be seen as channel multiplexing in the spatial domain, which increases both carrier-to-interference ratio (C/I) and system capacity. Moreover, it is important to note that dual-polarization sensors provide a diversity scheme. In this framework, ±45° slanted polarizations are preferred to vertical/horizontal (V/H) polarizations because they form identical azimuthal patterns and are equally sensible to horizontally and vertically polarized signals. A dual-polarized microstrip array panel is proposed, which can be used as a smart antenna in the framework of Universal Mobile Telecommunication Systems (UMTS).