Exact two-port study of symmetric and asymmetric microstrip crossed antennas

Two-port planar antennas are commonly used to generate circular polarization, switchable linear polarization or to achieve dual frequency radiating sources. Unfortunately, most analyses rely on a theoretical study of the corresponding one-port structure assuming a perfect isolation between the two ports at the operating frequency. This paper presents a rigorous study of microstrip crossed antennas using the integral equations technique. The simulation of matched terminations makes it possible to consider the antenna as an actual two-port network and to extract its scattering parameters and any component of its radiation patterns. This is necessary to understand the electromagnetic behavior of this antenna over a wide frequency range. This approach is applied to the study of two different configurations: the first one involves identical crossed dipoles and can be used to produce circular polarization; in the second case one dipole is shortened in order to obtain a dual frequency operating mode.<>