In order to detect the polarization properties of the target, a dual-polarized monopulse Cassegrain antenna at W-band is proposed. The antenna is composed of the main-reflector, the sub-reflector, the feed horns, the orthomode transducer, and the sum-differential network. The aperture diameter of the antenna is 137 mm, the feed contains five horns, the orthomode transducer is designed using the tapered waveguide, and the sum-differential network is realized by the planer coupler. The feed horns, orthomode transducer, and sum-differential network are integrated designed to reduce the insertion loss and compress the size of the antenna. The measured results showthat the impedance bandwidth of the antenna is about 3. 7 GHz, the polarization isolation is greater than 35 dB, the maximal gain of the sum beam is about 37. 9 dBi, the sidelobe level is below-15 dB, and the null depth of the differential beam is better than-25 dB. The antenna shows good dual-polarized monopulse performance at W-band.%为了探测目标的极化特性, 研制了工作在W波段的双极化单脉冲卡塞格伦天线.天线由主反射面、副反射面、馈源喇叭、正交模耦合器及和差器组成.天线主反射面口径为137 mm, 馈源为五喇叭形式, 正交模耦合器采用渐变波导匹配方案, 和差器通过平面型定向耦合结构实现.通过将馈源喇叭、正交模耦合器及和差器集成设计, 减小了连接损耗, 压缩了天线纵向尺寸.测试结果表明, 天线驻波带宽约3. 7 GHz, 极化隔离度优于35 dB, 和波束增益大于37. 9 dBi, 副瓣电平优于-15 dB, 差波束零深优于-25 dB.天线在W波段实现了较好地双极化单脉冲性能.
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