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

虽然现代通信的带宽需求不断增长，但无线电频谱是有限的。用有限的资源增加数据吞吐量的可能性很少。高数据速率应用的一个可能解决方案是在V或w波段使用更高的载波频率。此外，还讨论了在110 GHz以上毫米波波段的应用。随着频率的增加，许多新的、低频的众所周知的设备必须进行缩放、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。虽然在较低的频率范围内，这些组件通常被实现为静态组件，但可调谐或可重构组件对于高频移动通信应用非常重要。可能的组件肯定是可调谐的高增益天线，它能够在飞行中优化波束的形状和方向，以保证几乎无处不在的连接和持续的服务质量。此外，可调过滤器是关键组件，因为它们允许重新配置整个网络。本课题主要研究适用于高频工作的可调谐滤波器的实现。以往的研究结果表明，标准的毫米波电路处理技术存在局限性。因此，本研究项目的主要目标是利用基板集成波导技术对可调谐双模lc滤波器进行基础研究。使用双模滤波器的优点是减小了尺寸，同时使通阻带转换更锐利，从而达到更好的抑制效果。除了研究这些新的电子可调谐的w波段双模SIW带通滤波器的可行性外，还将通过材料表征、EM模拟和滤波器优化进行额外的基本分析。该概念将通过w波段的可调谐双模SIW滤波器进行演示。

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.