Polarization Agile Microstrip Antenna And Miniaturized Printed Antenna Design

There is an increasing demand for the circularly polarized (CP) microstrip antennas as they can combine the good characteristics of microstrip antennas and CP waves, such as light weight, low profile, ease of construction, conformity to the supporting surface, the ability to reject multi-path reflections and rain interference.In recent communication systems, the resources of frequency, amplitude and phase have been used sufficiently. However, it just started to investigate the application of the polarization information in communications. Actually, the application of the polarization information is very useful, especially for the applications of the detection and identification of the radar targets. In order to use the polarization sufficiently, a polarization-agile microstrip antenna is usually needed. One of the targets in this work is to design a wideband microstrip antenna capable of operation for four kinds of polarization. Aiming at this, wideband highly-isolated dual-polarization microstrip element and array, wideband CP elements and array and polarization-agile element and array have been investigated in this work.As today's market demands smaller and multi-function handset, customized antenna designs play an important role. The other part of this work focuses on the wideband or multi-band small antennas for cellular application or WLAN application, which includes the PIFA and printed planar monopole antenna.