Linear-Polarization Reconfiguration of Antenna Radiation by Tunable RF Power Divider Using 90-degree Hybrid Directional Coupler for Dynamically Moving and Orienting Mobile Communications

Polarization mismatch between transmitting (TX) and receiving (RX) antennas increases the polarization loss factor (PLF), leading to significant signal degradation in mobile communications. This issue is particularly unavoidable for linear polarization (LP) when antennas are dynamically oriented. This paper investigates the design and operational mechanisms of polarization-compliant antennas that enable adaptive alignment. By employing an output-ratio tunable power divider to excite dual-polarized elements, the system can simultaneously alter polarization orientation. The divider utilizes a 90-degree hybrid directional coupler controlled by a phase shifter to achieve high-accuracy, high-resolution power division. The feasibility of this approach is demonstrated through conceptual implementations and numerical simulations, further validated by experimental measurements.