Design of a High-Gain, Low-RCS, Multipolarization Reconfigurable Antenna Array

In this letter, a high-gain, low radar cross section (RCS), multi-polarization reconfigurable antenna array is proposed, achieving a novel integration of functions not realized in prior designs. The units of the antenna array have a three-layer stacked structure, in which a resistive absorber layer and a bottom square patch are separated by an air gap, forming a frequency-selective absorber (FSA) structure. The bottom patch serves dual functions of radiation and absorption, and is fed through a reconfigurable power divider. Polarization reconfigurability is achieved with p-i-n diodes embedded in the divider, enabling fast switching amongx-,y-, and right-hand circular polarization (RHCP) modes. When the reconfigurable power divider is set to CP mode, the antenna array can effectively reduce the in-band and out-of-band RCS underx-andy-polarized incident waves. Measurement results show that thex-andy-polarized modes of the antenna array operate over the 5.2-6.05 GHz band with a peak gain of 15.3 dBi, while the RHCP covers 4.9-6.1 GHz with a peak gain of 14.8 dBic. Furthermore, over the range of 2.7-9.5 GHz, the antenna array achieves a monostatic RCS reduction greater than 10 dB for bothx-andy-polarized normal incident waves.