A Design of Circular Polarization Reconfigurable Array Antenna Incorporating Delay Line Switching Technique

This study presents designing and simulating a 2×2 circular polarization (CP) reconfigurable octagonal-shaped microstrip array antenna, constructed on a Teflon substrate, for the Ku-band frequency. The antenna’s ground plane features a slot line that facilitates the use of parallel and series power dividers in the implementation of both-sided MIC. Each patch is supplied with orthogonal stimulation. A delay line of λ/2 is incorporated into the microstrip line that supplies the patches horizontally to guarantee proper alignment of the horizontal field lines across all array components. Delay line switching of each patch is controlled by an SPDT switch formed by two PIN diodes. The simulated findings indicate that the antenna is capable of switching between right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP), demonstrating effective CP performance. This is characterized by a relative power level difference exceeding 25 dB and an axial ratio bandwidth of 270 MHz for both polarization senses. The array demonstrates effective impedance matching, featuring an impedance bandwidth of 1600 MHz. The gain, directivity, and efficiency results indicate that the antenna effectively transmits a focused beam in the broadside direction.