First Investigations on Electrically Tunable Dual-Mode Liquid Crystal-based Substrate Integrated Waveguide Bandpass Filters for W-Band Applications

虽然现代通信伴随着不断增长的带宽需求，但无线电频谱是有限的。在有限资源的情况下增加数据吞吐量的可能性很小。高数据速率应用的一种可能的解决方案是在V或W波段中使用更高的载波频率。此外，在毫米波段以上的110 GHz的应用进行了讨论。随着频率的增加，许多新的、在较低频率下众所周知的设备必须被缩放、调整或重新发明。除了有源放大器和混频电路外，对滤波器或天线等无源元件的需求也很大。虽然在较低频率范围内，这些组件通常被实现为静态组件，但可调谐或可重新配置的组件对于高频移动的通信应用是非常重要的。可能的组件肯定是可调谐高增益天线，它能够在运行中优化波束形状和方向，以保证几乎无处不在的链路，并保持恒定的服务质量。此外，可调滤波器是关键组件，因为它们允许重新配置整个网络。本研究计画的重点是实现可调谐滤波器，特别是适用于高频操作。以往的研究结果表明，毫米波电路的标准处理技术的局限性。因此，本研究计划的主要目的是利用基片集成波导技术对可调谐双模LC基滤波器进行基础研究。使用双模滤波器的优点是其尺寸减小，同时使通带-阻带过渡更尖锐，以实现更好的抑制。除了这些新的电子可调，双模SIW带通滤波器在W波段的可行性的调查，额外的基本分析将通过材料表征，EM模拟和滤波器优化。该概念将在W波段可调谐双模基片集成波导滤波器中得到验证。

While modern communication comes with growing bandwidth demands, the radio frequency spectrum is limited. There are only few possibilities to increase the data throughput with limited resources. One possible solution for high data rate applications is to use higher carrier frequencies in the V- or W-band. Also, applications in the mm-wave bands above 110 GHz are discussed. With the increase in frequency many new, in lower frequencies well know devices, have to be scaled, adapted, or reinvented. Beside the active amplifier and mixing circuits, there is a large demand for passive components such as filters or antennas. While in the lower frequency range these components are usually realized as static components, tunable or reconfigurable components are of major importance for high frequency mobile communication applications. Possible components are definitely tunable high gain antennas, which are able to optimize the beam shape and direction on the fly to guarantee an almost ubiquitous link with constant quality of service. Also, tunable filters are key components as they allow the reconfiguration of the whole network. This research project focuses on the realization of tunable filter especially suited for operation at high frequencies. Former research results show the limitation of standard processing technologies for mm-wave circuits. Therefore, the major objective of this research project is to conduct basic investigations on tunable dual-mode LC-based filters, using substrate integrated waveguide technology. The advantage of using dual-mode filters is its reduced size, while making the passband-stopband transition sharper at the same time, to achieve better rejection. Beside the investigations on the feasibility of these new electronically tunable, dual-mode SIW bandpass filters at W-band, additional fundamental analysis will be performed by means of material characterization, EM simulations, and filter optimization. The concept will be demonstrated with a tunable dual-mode SIW filter in W-band.