Wide Band Polarization Detector for Sub–6 GHz 5G Applications

This paper presents the analysis and the design of a polarization detector for sub–6 GHz 5G applications. The proposed design operates in the frequency range from 2 to 4 GHz to cover the 5G NR frequency bands n40/n41/n78. The proposed polarization detector consists of a six-port network with two input and four output ports. The two input ports of this six-port network are connected to two identical orthogonal linearly polarized wideband antennas; vertical and horizontal. Two orthogonal tapered slot antennas are designed for this purpose. On the other hand, the other four outputs of the six-port network are connected to power amplitude detectors. These four power magnitudes are used to determine the ratio of the vertical to horizontal components of the field incident on the polarization detector. They are also used to determine the phase difference between the vertical and horizontal components. Based on the relative magnitude and the phase difference between the horizontal and vertical components of the incident field, the polarization parameters of the incident field are obtained; like the tilt angle, the axial ratio and the direction of rotation. To obtain the phase difference between the two inputs, a reference wideband differential phase shifter is included in the six-port network. This wideband differential phase shifter is implemented by using a modified Schiffman phase shifter. From the experimental results, the proposed polarization detector proved its reliability in detecting the polarization and discriminating the direction of the wave rotation; left or right hand rotation.