A Low-RCS Multifunctional Shared Aperture With Wideband Reconfigurable Reflectarray Antenna and Tunable Scattering Characteristic

This article presents a low radar cross section (RCS) single-layer multifunctional shared aperture (MSA) with tunable manipulation of radiation and bistatic scattering patterns over the same wide frequency band. A low-cost positive-intrinsicnegative (p-i-n) diode is used in the unit cell to evoke the 180 degrees +/- 20 degrees reflection phase difference for x-polarized incident waves; thus, the wideband beam steering and tunable bistatic scattering patterns can be generated. By integrating the interdigital capacitance (IC) into the unit cell, the reflection bandwidth limitation for y-polarized waves at a higher frequency band is broken. Furthermore, the optimized multielement phase cancellation (OMEPC) method is adopted to maximize the RCS reduction (RCSR) bandwidth of y-polarization. A 16 x 16-element MSA prototype is fabricated and measured. The experimental results show that the 3 dB gain bandwidth of the MSA is from 5.5 to 9.5 GHz with the fractional bandwidth (FBW) of 53.3%, and the common frequency band of 10 dB RCSR for x- and y-polarized waves is in the range of 4.5-9.6 GHz (FBW = 72.3%). The low RCS MSA with tunable control of radiation and scattering patterns over a wide frequency band can be used in military radar and low detectable systems.