Novel High Performance Feed Horns for Large Format Arrays at Millimetre and Submillimetre Wavelengths.

以高灵敏度快速绘制大面积天空的能力对于毫米和亚毫米波长的许多科学目标至关重要。下一代望远镜将包含成百上千个角，将超灵敏探测器送入焦平面阵列接收器。因此，快速、可靠且成本可控地制造大量高质量的望远镜进给角的能力至关重要。传统上，射电和亚毫米望远镜接收器的焦平面阵列采用波纹角将来自天空的能量耦合到探测器上。这是因为它们在高达50%的带宽上表现出优异的波束模式。然而，为了提供所需的高性能，这些喇叭的内部必须有许多1/4波长深的方位凹槽（波纹）。这使得它们在越来越小的波长上变得极其困难和昂贵。对于下一代大格式焦平面阵列，有数百或数千个这样的喇叭，仅波纹喇叭的成本就可能占整个接收器成本的很大一部分（约50%）。波纹角的另一个缺点是，墙需要足够厚，以适应相对较深的波纹。这使得它们对于空间望远镜和微波频率通信系统等关键应用来说太重了，在这些应用中，只有几个角的重量可能会造成问题。牛津大学天体物理学小组与泰国玛希隆大学的研究人员合作，开发出了光滑壁的角，比波纹角更容易制造，成本也更低。这些喇叭只需要在喇叭喉部附近的耀斑角有一个或多个不连续点，就可以激发高阶波导模式的正确平衡。我们使用我们为此目的开发的软件套件来优化这些不连续性的位置。我们完全优化的喇叭在显著（30%）的工作带宽上显示出色的波束模式。我们的喇叭设计的相对简单的几何结构使它们能够使用快速，低成本的制造技术制造。我们已经开发了一种技术，其中包括直接加工的角，通过使用适当形状的工具钻角到一块铝。这项技术将使快速制造大型喇叭阵列成为可能，只需在一块铝板上反复钻孔即可。我们已经成功地利用该技术制作和测试了单个原型230 GHz喇叭，并发现它们在理论上给出了预期的波束模式。高性能牛津光滑壁饲料喇叭的商业机会是巨大的，在一半的价格，他们很可能在许多应用中取代传统的波纹喇叭。目标市场将包括建造毫米和次毫米天文接收机、遥感地球、天基卫星通信和地基电信和雷达应用的研究小组。在这项拨款申请中，我们要求支持开发一项全新的技术，这是科技资助委员会支持的学术研究的副产品。因此，将其带入商业化阶段所需的开发资金相对较少。这些产品包括软件许可，根据客户规格进行设计，产品成本不到现有技术的一半，交货时间也快得多。我们的商业化努力得到了牛津大学技术转移子公司Isis创新有限公司的支持。

The ability to rapidly map large areas of the sky to a high sensitivity is of prime importance for many scientific goals at mm and sub-mm wavelengths. The next generation of telescopes will incorporate hundreds or thousands of horns feeding ultra-sensitive detectors into focal plane array receivers. Therefore, the ability to manufacture large numbers of high quality telescope feed horns rapidly, reliably and at a manageable cost is vitally important. Traditionally, focal plane arrays of radio and submillimeter telescope receivers have employed corrugated horns to couple power form the sky to the detectors. This is because they exhibit excellent beam patterns over bandwidths of up to 50%. To give the required high performance however, these horns must have many 1/4 wavelength deep azimuthal grooves (corrugations) along their interiors. This makes them extremely difficult and expensive at increasingly smaller wavelengths. For the next generation of large format focal-plane arrays, with many hundreds or thousands of such horns, the cost of the corrugated horns alone can be a significant fraction (~50%) of the entire cost of the complete receiver. Another disadvantage of corrugated horns is that the wall needs to be thick enough to accommodate relatively deep corrugations. This makes them too heavy for key applications such as space telescopes and communication systems at microwave frequencies where the weight of only a few horns could prove to be problematic. The Oxford Astrophysics group have developed smooth-walled horns which are much easier and cheaper to fabricate than corrugated horns, in collaboration with researchers at Mahidol University, Thailand. These horns only require one or more discontinuities in the flare angle near the throat of the horn to excite the right balance of higher-order waveguide modes. We optimise the positions of these discontinuities, using a software suite that we have developed for this purpose. Our fully optimized horns show excellent beam pattern over a significant (30%) operating bandwidth. The relatively simple geometry of our horn designs allows them to be manufactured using rapid, low-cost fabrication techniques. We have developed a technique which involves directly machining the horns by using an appropriately shaped tool to drill the horns into a block of aluminum. This technique will make it possible to quickly fabricate large format arrays of horns by simply drilling repeatedly into a single plate of aluminum. We have successfully fabricated and tested individual prototype 230 GHz horns using this technique and found that they give the expected beam patterns by theory. The commercial opportunity for the high performance Oxford smooth-walled feed horns is massive and at half the price, they are likely to replace the conventional corrugated horns in many applications. The target markets would include research groups building mm and sub-mm astronomical receivers, remote earth sensing, space based satellite communications and earth based telecommunications and radar applications. In this grant application we are requesting support to develop a completely new technology which is a spin-off of academic research supported by the STFC. As a result a relatively small amount of development fund is required to bring it to the stage of commercialisation. The products includes software licensing, design according to customer specifications and a product at less then half the cost of existing technology and much faster time of delivery. Our effort of commercialisation is supported by Isis Innovation Limited, the technology transfer subsidiary company of the University of Oxford.