A reconfigurable antenna is an antenna with parameters that can be varied according to the requirements of a particular situation. Under variable parameters we can understand the operating frequency range, radiation pattern, polarization, as well as various combinations of these parameters. In this paper, we propose the design of a reconfigurable microstrip antenna with tunable frequency and polarization, and investigate its radiation pattern and polarisation properties. The antenna has compact dimensions and can be used in wireless communication systems operating in the 2–7 GHz range. 5 pin diodes are included into the antenna design to change the resonant frequency and polarization of the antenna by turning the diodes on and off. The simulation of the proposed antenna was performed in the FEKO program and the main parameters of the antenna were obtained. The analysis of the simulation results showed that for the lower part of the studied frequency range (2.05, 2.45 and 3.7 GHz), the polarization is linear. When operating in the higher sub-range (5.4, 5.6 and 5.75 GHz), the antenna is circularly polarized, and the direction of the polarisation vector rotation depends on the connection of the diodes. This ability to switch polarization to orthogonal at the same frequency allows to perform efficient signal reception in the conditions of multipath propagation.
