毫米波全息/红外镜面反射式复合紧缩场设计与分析OA

A millimeter wave(MMW)/infrared(IR)compound compact range(CCR)based on a beam combiner with MMW holographic transmission from its front surface and IR specular reflection from its back surface is proposed.First,the geometric layout of the MMW/IR CCR is designed.Then,the substrate of the beam combiner is designed via the transmission line theory.Meanwhile,the IR mirror composed of multilayer dielectrics on the back surface of the beam combiner is designed and optimized through the design and optimization method of radio frequency/optical multilayer dielectrics.The binary coded amplitude hologram on the front surface of the beam combiner is generated according to the electric field distribution on the surface generated from the MMW feed with the computer-generated hologram theory.In order to suppress the edge diffraction,the amplitude taper is introduced in the hologram design.To analyze the MMW field uniformity and IR imaging characteristics,the aperture field integration method is adopted.In order to verify the design and analysis method,a CCR example is designed and simulated.The simulation results show that the approximately spherical wave can be converted into a plane wave because of the effect of the hologram on the front surface of the beam combiner.In particular,the MMW field ripple indicators of the peak-to-valley value of the relative amplitude(Epv),the peak-to-valley value of the relative phase(φpv),the root mean square value of the relative amplitude(Erms),and the root mean square value of the relative phase(φrms)decrease from 7.28 dB,37.01°,1.05 dB,and 6.52°(before amplitude tapering)to 1.17 dB,6.87°,0.22 dB,and 1.58°(after amplitude tapering),respectively.Meanwhile,the defocus aberration from the mirror caused by self-weight deflection is small enough to allow its influence on the IR imaging quality being neglected.The imaging quality can still reach the diffraction limit in the IR waveband.