The design of the MeerKAT UHF band feed
The design of the MeerKAT UHF band feed
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DOI：
10.1109/eucap.2014.6901903
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发表时间：
2014-04
期刊：
影响因子：
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通讯作者：
R. Lehmensiek;I. Theron
中科院分区：
文献类型：
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作者：
R. Lehmensiek;I. Theron
的设计方法和预期的性能结果的UHF波段饲料的MeerKAT干涉仪，这是一个先驱的平方公里阵列（SKA），提出。该馈源由宽张角轴向波纹圆锥喇叭、喇叭匹配段、紧凑型正交模换能器（OMT）和集成定向耦合器组成。MeerKAT碟形天线是一个经典的格里高利偏置双反射面天线系统。采用基于种群增量学习的全局搜索算法和速降法相结合的混合优化算法对变幅杆进行优化设计。采用下坡法对OMT和耦合器进行了优化。预测结果表明，稳定的辐射方向图在频带上的天线效率超过71%和溢出温度低于20 K的最低频率。在较高的频率下，效率提高到78%，溢出温度低于12 K.馈源的反射系数为-20 dB，馈源对系统温度的噪声贡献（主要贡献者为OMT和定向耦合器）在整个频带内低于1.5 K。
The design methodology and the expected performance results of the UHF band feed for the MeerKAT interferometer, which is a precursor to the Square Kilometer Array(SKA), are presented. The feed consists of a wide flare angle axially corrugated conical horn, a horn matching section, a compact orthogonal mode transducer (OMT) and an integrated directional coupler. The MeerKAT dish is a classical Gregorian offset dual-reflector antenna system. A hybrid optimization algorithm comprising of a global search algorithm, namely the Population-Based Incremental Learning algorithm, and a downhill method is used as optimizer for the horn design. The OMT and coupler were optimized with a downhill method. The predicted results show stable radiation patterns over the frequency band with an antenna efficiency above 71 % and a spillover temperature below 20 K at the lowest frequency. The efficiency increases to 78 % at the higher frequencies with a spillover temperature below 12 K. The feed's reflection coefficient is -20 dB and the feed's noise contribution to the system temperature, with the main contributors the OMT and the directional coupler, is below 1.5 K across the frequency band.