CAREER: Next Generation Micromachined THz Circuits for Communication, Radio Astronomy and Biological Applications

0133514 Papapolymerou 0.5 THz至10 THz之间的电磁频谱在科学上是丰富的，并且具有许多优点：强分子吸收、宽带宽、非常小尺寸的电路、改进的空间分辨率、更快的开关速度和紧凑性。这一频率范围内的应用包括射电天文学和大气观测、DNA突变检测、病毒/化学剂检测、高分辨率成像、超宽带和隐蔽卫星通信、电子对抗、特征采集雷达和高密度集成电路中的电子/光学链路。然而，该频谱区域在技术上相对较差，这主要是由于没有低损耗和低成本的传输线以及诸如天线、滤波器和本地振荡器源的其它电路。传统上，绝大多数THz组件利用波导结构。不幸的是，在高于1 THz的频率下，波导变得如此之小，使得利用常规机械加工和电铸技术的制造变得极其困难、昂贵和/或不可能。因此，PI目前在生产可集成在基于晶闸管的电路中的低成本、低损耗和可靠的1 THz以上的THz元件方面受到技术限制。在本项目中，PI建议通过设计和研究（理论上和实验上）用于通信的新型低损耗、低成本和可靠的硅微机械太赫兹电路，射电天文学和生物/化学应用超过1太赫兹。这将通过利用独特的激光微加工技术来实现，该技术能够以1-3 μ m的精度生产任何形状的三维结构，以及最先进的有源器件（例如单片膜二极管）。 研究将包括以下结构的开发和表征：（1）微加工锥形和波纹喇叭，以及这些辐射元件在600 GHz，1.2 THz，2.4 THz和4.8 THz的阵列;（2）基于微机械腔的带通和带阻滤波器，其具有在600 GHz、1.2 THz、2.4 THz和4.8 THz的耦合膜片或槽;（3）在输入/输出处具有膜二极管和波纹喇叭的1.2THz和2.4THz的微机械平衡倍频器;（4）在4.8THz的第一个倍频器和（5）与用于增加输出功率的magic-Tee相干组合的1.2THz的微机械倍频器。所有上述结构都将以“分裂块”配置来实现，其中电路沿中心/对称线沿着分裂成两个部件，这两个部件被制造并且然后结合在一起以形成整个结构。键合和自对准问题及其对电路性能的影响将被广泛探讨，以产生微机械太赫兹电路的指导方针。沿着拟议的研究计划，PI坚定地致力于追求几个相关的教育目标。这些措施包括：（1）振兴格鲁吉亚理工学院现有的微波工程课程;（2）高年级本科生积极参与拟议的研究，以及创建一个网站数据库，用于发表有关微机械微波和太赫兹电路的论文;（3）社区外展和辅导活动，以吸引传统上在工程学方面代表性不足的学生，并吸引高-这些活动包括：（1）为在校学生开设工程学课程;（2）在国内主要的微波/太赫兹公司和国家实验室进行暑期实习;（3）组织相关主题的研讨会，由学术界和工业界的特邀演讲者主讲。PI认为，上述教育活动将有利于他在微波/太赫兹电路的研究工作;让学生接触到电路，跨学科问题和机会的新世界;在他们和工业/研究界之间提供强有力的联系;并吸引更多代表性不足的群体进入工程。

0133514PapapolymerouThe electromagnetic spectrum between 0.5 THz to 10 THz is scientifically rich and possesses a number of advantages: strong molecular absorption, wide bandwidth, very small sized circuitry, improved spatial resolution, faster switching speed and compactness. Applications in this frequency range include radio astronomy and atmospheric observations, detection of DNA mutations, detection of viral/chemical agents, high-resolution imaging, ultra-wideband and covert satellite communications, electronic countermeasures, signature acquisition radars and electronic/optical links in high-density integrated circuits. However, this region of the spectrum is relatively technologically poor due mainly to the unavailability of low loss and low cost transmission lines and other circuits such as antennas, filters and local oscillator sources. Traditionally, the vast majority of THz components utilize waveguide structures. Unfortunately, at frequencies above 1 THz waveguides become so small that fabrication utilizing conventional machining and electroforming techniques becomes extremely difficult, expensive and/or impossible. As a result, the PI is currently technologically limited from the production of low cost, low loss and reliable THz components above 1 THz that can be integrated within semiconductor-based circuits.In this project, the PI proposes to further advance the state-of-the-art by designing and studying (both theoretically and experimentally) novel low loss, low cost and reliable Silicon micromachined THz circuits for communication, radio astronomy and biological/chemical applications above 1 THz. This will be achieved by utilizing a unique laser micromachining technique capable of producing three-dimensional structures of any shape with an accuracy of 1-3 um, as well as state-of-the art active devices (e.g. monolithic membrane diodes). The investigation will include the development and characterization of the following structures: (1) micromachined conical and corrugated horns, as well as arrays of those radiating elements at 600 GHz, 1.2 THz, 2.4 THz and 4.8 THz; (2) micromachined cavity based band-pass and band-stop filters with coupling irises or slots at 600 GHz, 1.2 THz, 2.4 THz and 4.8 THz; (3) micromachined balanced doublers at 1.2 THz and 2.4 THz with membrane diodes and corrugated horns at the input/output; (4) the first ever doubler at 4.8 THz and (5) micromachined doublers at 1.2 THz coherently combined with a magic-Tee for increased output power. All of the above structures will be implemented in a "split-block" configuration where the circuit is split along a center/symmetry line into two components that are fabricated and then bonded together to form the entire structure. Bonding and self-alignment issues and their implications on circuit performance will be explored extensively in order to produce guidelines for micromachined THz circuits.Along with the proposed research program, the PI is firmly committed to pursuing several related educational goals. These will include: (1) the revitalization of the existing microwave engineering curriculum at Georgia Tech; (2) the active involvement of senior undergraduate students in the proposed research, as well as in the creation of a website database for published papers on micromachined microwave and THz circuits; (3) community outreach and mentoring activities to involve students traditionally underrepresented in engineering and to attract high-school students into engineering; (4) summer internship with the major microwave/THz companies in the country and with national labs and (5) the organization of seminars with related topics, presented by invited speakers from academia and industry. The PI believes that the above educational activities will benefit his research efforts in microwave/THz circuits; expose students to a new world of circuits, interdisciplinary problems and opportunities; provide a strong linkage between them and the industrial/research community; and attract more underrepresented groups into engineering.