Compact wideband bowtie dipole orthomode transducer
Compact wideband bowtie dipole orthomode transducer
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DOI：
10.1002/mop.31662
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发表时间：
2019-01
影响因子：
1.5
通讯作者：
Jin Fan;K. Zhu;Jian Yang;Yihua Yan
中科院分区：
文献类型：
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作者：
Jin Fan;K. Zhu;Jian Yang;Yihua Yan
针对500米口径球面射电望远镜0.56 - 1.12 GHz接收系统，提出了一种具有倍频程带宽的紧凑型宽带正交模换能器（OMT）。OMT在70 K的低温恒温器中工作，因此在确保良好电气性能的同时最大限度地减小其尺寸至关重要。完整的OMT包括2个蝴蝶结偶极子正交地布置在圆形波导中。由于该结构的创新，竞争模TM 01、TE 21和TE 01得到了有效的抑制，主导模TE 11的带宽达到了2.08：1。最终优化的OMT具有300 mm的长度，比流行的四脊波导OMT的一半短。室温下的测量结果与仿真结果吻合良好，在整个所需频率范围内，两种偏振的反射系数均低于−10 dB，交叉耦合水平为−30.5 dB。
A compact wideband orthomode transducer (OMT) with an octave bandwidth is proposed for a 0.56‐1.12 GHz receiver system in the five hundred meter aperture spherical radio telescope. The OMT operates in a cryostat at a temperature of 70 K and therefore it is critical to minimize its dimension while insuring good electrical properties. The complete OMT comprises 2 bowtie dipoles orthogonally arranged in a circular waveguide. Because of the innovative structure, competing modes, TM01 TE21, and TE01, have been effectively suppressed, and the bandwidth of the dominate mode TE11 has achieved to 2.08:1. The final optimized OMT has a length of 300 mm, shorter than a half of the popular quardruple‐ridged waveguide OMT. Measurements at room temperature agree well with simulation results, with a reflection coefficient below −10 dB for both polarizations and cross‐coupling levels of −30.5 dB over the whole required frequency range.