The Baryon acoustic oscillations from Integrated Neutral Gas Observations (BINGO) telescope is a 40-m~class radio telescope under construction that has been designed to measure the large-angular-scale intensity of HI emission at 980--1260 MHz and hence to constrain dark energy parameters. A large focal plane array comprising of 1.7-metre diameter, 4.3-metre length corrugated feed horns is required in order to optimally illuminate the telescope. Additionally, very clean beams with low sidelobes across a broad frequency range are required, in order to facilitate the separation of the faint HI emission from bright Galactic foreground emission. Using novel construction methods, a full-sized prototype horn has been assembled. It has an average insertion loss of around 0.15 dB across the band, with a return loss around -25 dB. The main beam is Gaussian with the first sidelobe at around $-25 dB. A septum polariser to separate the signal into the two hands of circular polarization has also been designed, built and tested.

中文翻译：

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来自综合中性气体观测的重子声学振荡：宽带波纹喇叭结构和测试

来自综合中性气体观测（BINGO）望远镜的重子声波振荡是正在建造的 40 米级射电望远镜，旨在测量 980--1260 MHz 的大角尺度 HI 发射强度，从而限制暗能量参数。需要一个包含 1.7 米直径、4.3 米长波纹馈源喇叭的大型焦平面阵列，以便最佳地照亮望远镜。此外，需要在很宽的频率范围内具有低旁瓣的非常干净的光束，以便将微弱的 HI 发射与明亮的银河前景发射分离。使用新颖的构造方法，已经组装了一个全尺寸的原型喇叭。它在整个频段的平均插入损耗约为 0.15 dB，回波损耗约为 -25 dB。主波束是高斯波束，第一个旁瓣约为 $-25 dB。还设计、制造和测试了隔膜偏振器，用于将信号分成两个圆偏振手。