A Phase-Controlled Parabolic Reflector for Wideband Microwave Focal-Plane Imaging

For focal-plane imaging of electromagnetic interference, the size of the point spread function (PSF) of the system varies significantly with frequency according to the Rayleigh criterion. For an imaging system with limited array sensors, high-frequency signals may be lost due to small PSF and spatial undersampling. To reduce the frequency variation in imaging systems, a wideband phase-controlled reflector (PCR) is proposed and verified in this article. First, the phase control element (PCE) is modeled and analyzed regarding the phase response of the reflected electromagnetic wave. Then, the distribution of the PCE on the reflector is designed and optimized considering the oblique incidence and periodic structure interference. The experimental results show that the proposed PCR can broaden the 3 dB beamwidth of the PSF by 60.71% averagely over the frequency range of 8 GHz to 12 GHz.