Broadband Low-RCS Circularly Polarized Antenna Array With Reconfigurable Scattering Patterns

In this article, a broadband low radar cross section (RCS) circularly polarized (CP) antenna array with reconfigurable scattering patterns is proposed. The antenna array comprises 16 reconfigurable elements and a phase reconfigurable power divider. The antenna element can switch between two scattering states by controlling the states of the p-i-n diodes, which differ by 180 degrees in the reflection phase. In addition, the polarization of the antenna element remains the same in both states but exhibits a 90 degrees phase difference. To compensate for the radiation phase difference, a phase reconfigurable power divider based on p-i-n diodes is designed, which can switch between 90 degrees and 0 degrees transmission phases. By controlling the states of the antenna elements and the output phase of the power divider, the antenna array can be switched among different scattering patterns while maintaining stable right-hand circularly polarized (RHCP) performance. Simulation results demonstrate a 10-dB reduction in the in-band RCS for the antenna array within the 8.2-11-GHz range under normal incidence. The array maintains good CP radiation performance in the 7.7-11.1-GHz frequency band. The measured results exhibit strong concurrence with the simulation results, confirming the good performance of the proposed antenna array.