Towards a 3D printed terahertz circuit technology.

三维（3D）打印，也被称为增材制造，现在在许多行业中都很常见，并且得到了广泛的应用。一些类型的3D打印机可以以适中的价格供家庭使用。然而，与制造微波和太赫兹电路有关的详细工作以及演示装置仍处于非常早期的阶段。这些要求的精度和材料与消费产品非常不同。本提案旨在通过测量、设计和演示来评估和改进微波和太赫兹无源和二极管电路的3D打印性能。这些高频率，从10千兆赫到1000千兆赫，用于自由空间通信，安全传感和对地球大气层的远程监测。重点将放在评估频率高于约50 GHz的3D打印电路上，这些频率所需的小特征尺寸只允许最好的打印工艺竞争；使项目能够评估最先进的3D打印方法。这个令人兴奋的项目将是迄今为止世界上最全面的学术研究。伯明翰大学和STFC卢瑟福阿普尔顿实验室（RAL）的一个强大、经验丰富的国家团队将与几个英国和国际行业合作伙伴合作开展这项研究。伯明翰大学的通信和传感研究小组已经在这一领域进行了重大研究，发布的3D打印设备覆盖了0.5 GHz到100 GHz的频率范围。这项工作的重要性已经通过奖项，邀请国际演讲和评审学术出版物得到了外部的认可。伯明翰的合作伙伴，RAL空间部门的毫米波技术集团，为这些高频的传统设备的精密制造带来了广泛的专业知识，以及对新3D电路必须满足的苛刻空间和其他要求的了解。RAL工作人员将对3D打印电路进行后处理，并在温度和湿度升高的条件下进行加速寿命测量。3D打印微波和太赫兹电路将对英国工业产生重要的有益经济影响，不仅因为复杂的电路可以以低成本实现，而且因为独特的制造方法产生了新的设计方法。在项目期间，申请人将在自己的想法上工作，并与工业合作伙伴密切合作。在这项技术成为主流之前，还有许多障碍需要克服：这个提议解决了这些挑战。3D打印的优点包括可以快速生成具有复杂形状和多种功能的新型电路，使用轻量化形式的低材料体积。这使得可靠，低成本，性能优越的电路，减少浪费和缩短交货时间。需要解决的问题包括聚合物电路的金属涂层，这在生产中增加了一个额外的步骤，以及这种电路的潜在热稳定性和功率处理。如果聚合物用作微波介质，功率损失可能是一个问题。对于金属3D打印电路，功率处理和热稳定性良好，但表面粗糙度可能会降低器件性能。这些问题和其他问题都是在一个系统的研究，基于测量共振波导腔，微波等效音叉的建议。频率和衰减时间的变化表明制造质量。该项目将通过广泛分布的技术开发路线图和外部合作项目，以及提供咨询和指导，为工业界和学术界提供信息。我们的发现也将通过学术出版物和在相关会议上的演讲传达给国内和国际同事。

Three-dimensional (3D) printing, also known as additive manufacturing, is now common place in many industries and is used widely. Some types of 3D printers are available for home use at modest cost. However, detailed work, together with demonstrator devices, is still in the very early stages in relation to the manufacture of microwave and terahertz circuits. These requires a level of precision and materials very different from the consumer products.This proposal is to evaluate and improve the performance of 3D printing for microwave and terahertz passive and diode circuits through measurement, design and demonstration. These high frequencies, from 10 GHz to 1000 GHz, are used for free space communications, security sensing and remote monitoring of the Earth's atmosphere. The focus will be on evaluation of 3D printed circuits at frequencies above about 50 GHz, the small feature sizes required for these frequencies allows only the best printing process to compete; enabling the project to evaluate the most advanced 3D printing approaches. This exciting project will be the most comprehensive academic study worldwide to date.A strong, experienced, national team, at the University of Birmingham and the STFC Rutherford Appleton Laboratory (RAL) will conduct the research in collaboration with several UK and international industry partners. The Communications and Sensing research group at Birmingham University have already demonstrated significant research in this area, with 3D printed devices published covering the frequency range 0.5 GHz to 100 GHz. The importance of this work has been recognised externally through prizes, invited international presentations and refereed academic publications. Birmingham's partners, the Millimetre Wave Technology Group in the RAL Space department, bring extensive expertise in precision manufacturing of conventional devices for these high frequencies, and knowledge of the demanding space and other requirements that the new 3D circuits must fulfil. RAL staff will conduct post processing of the 3D printed circuits and perform accelerated lifetime measurements under conditions of elevated temperature and humidity.3D printed microwave and terahertz circuits will have an important beneficial economic impact on UK industry, not only because complex circuits become possible at low cost, but because new design approaches emerge because of the unique manufacturing. The applicants will both work on their own ideas, and closely with industrial partners, during the project. There are a number of hurdles to overcome before the technology becomes mainstream: this proposal tackles these challenges.The advantages of 3D printing include the availability to rapidly generate novel circuits with complex shapes and multiple functions using low material volumes in a lightweight form. This enables reliable, low cost, superior performance circuits with less waste and reductions in lead time. Considerations to be addressed include the metal coating of polymer circuits which adds an extra step in the production, as well as potentially lower thermal stability and power handling of such circuits. If the polymer is used as a microwave dielectric, power loss may be a problem. For metal 3D printed circuits, power handling and thermal stability is good, but surface roughness may reduce device performance. These problems and others are addressed in the proposal with a methodical investigation based on the measurement of resonant waveguide cavities, the microwave equivalent of a tuning fork. Changes to the frequency and decay time indicate the quality of manufacture.The project will inform industry and academia through a widely distributed technology development roadmap and external collaborative projects, as well as the provision of advice and guidance. Our finding will also be communicated to national and international colleagues through academic publications, and presentations at relevant conferences.