A scanning phased array based on a polarization reconfigurable antenna with compact aperture size

A compact antenna with tri‐polarization switching is presented. The antenna is mainly composed of a monopole slot and a shorted loop, and the two radiating elements are connected in series and placed in a metallic box filled with dielectrics. To realize polarization switching, four PIN diodes are introduced into the antenna structure, and they cannot only suppress the excitation of the loop antenna but also vary the direction of the current flowing on the loop. Both simulated and measured results indicate that the proposed antenna can be operated in one linear polarization and dual circular polarization modes within an impedance bandwidth of around 15%; moreover, the aperture size of the antenna is about 0.09 λ02. Based on the polarization reconfigurable antenna, a 1 × 8 phased array with an aperture size of 0.3 λ0 × 2.8 λ0 is then developed. Simulated results show that the phased array operating in each polarization mode can give a gain fluctuation of smaller than 1.5 dB and a side lobe level of less than −10 dB when the beam is scanned from −60° to 60°. Experiments are also carried out, and their results have good agreements with the simulated data.