Triple Feed Triangular Microstrip Antenna for Polarization Diversity

Abstract

A triangular microstrip patch antenna fed with three microstrip feeds is designed on an equilateral substrate to produce different polarization states. Quarter wavelength transformers are utilized for better impedance matching. The proposed antenna can provide a linear polarization state with wide bandwidth and right and left-hand circular polarization with acceptable axial ratio bandwidth through activating one feed at a time. Other states can be obtained with different phase shifts by involving two or more active feeds. No diodes and hence no DC or AC biasing circuits are used in this design. Various aspects of the antenna have been analyzed such as reflection coefficient Sn, ports isolation, axial ratio, far-field E and H pattern and gain are investigated and optimized through several parametric studies of the antenna variables.