标题： 1.2 米屏蔽卡塞格林天线用于紧密排列的射电干涉仪 显示英文标题

标题： 1.2 Meter Shielded Cassegrain Antenna for Close-Packed Radio Interferometer

摘要： 干涉仪毫米波观测宇宙微波背景和星系团，需要具有角分分辨率的天线阵列。 所有天线共装在一个可跟踪平台上会限制整体重量。 提出了一种25公斤轻型新型碳纤维设计的1.2米直径卡塞格林天线。 有限元分析预测了在重力、风和热载荷下的良好结构性能。 主镜和副镜表面涂有薄层TiO$_2$作为保护。 通过基于馈电喇叭天线模拟设计并经远场波束图测量验证的高斯馈电照射模式和边缘衰减，实现了低波束旁瓣水平。 屏蔽挡板将天线间耦合降低到低于$\sim$ -135 dB。 包括一系列效率因素在内的整体天线效率估计约为60%，主要损失来自馈电溢出和次级遮挡。 使用这种新天线，在13单元阵列操作中预计每年可检测约50个星系团。 显示英文摘要

摘要： Interferometric millimeter observations of the cosmic microwave background and clusters of galaxies with arcmin resolutions require antenna arrays with short spacings. Having all antennas co-mounted on a single steerable platform sets limits to the overall weight. A 25 kg lightweight novel carbon-fiber design for a 1.2 m diameter Cassegrain antenna is presented. The finite element analysis predicts excellent structural behavior under gravity, wind and thermal load. The primary and secondary mirror surfaces are aluminum coated with a thin TiO$_2$ top layer for protection. A low beam sidelobe level is achieved with a Gaussian feed illumination pattern with edge taper, designed based on feedhorn antenna simulations and verified in a far field beam pattern measurement. A shielding baffle reduces inter-antenna coupling to below $\sim$ -135 dB. The overall antenna efficiency, including a series of efficiency factors, is estimated to be around 60%, with major losses coming from the feed spillover and secondary blocking. With this new antenna, a detection rate of about 50 clusters per year is anticipated in a 13-element array operation.