Online Parameter Extraction and Control of Reconfigurable High-Frequency Filters

本文的主要目标是研究高频滤波器的实时重构。为此，在输入新的目标特性和补偿温度漂移等各种影响后，微波滤波器的重新配置将自动进行。重新配置应该在不中断信号路径的情况下进行。目的是在平面和非平面技术中开发可调谐微波滤波器，并借助调谐系统影响其传输特性。不同的调谐技术具有不同的非线性和质量因素。其中，它可以是一个平面微带滤波器与变容管作为调谐元件或同轴谐振器滤波器与机械调谐螺钉。在这些情况下，控制是由可变电压源或步进电机实现的。本项目的一个重要方面是开发一个测量系统来确定微波滤波器在运行过程中的传输特性。在这里，不应断开滤波器结构，使可能的传输不中断。应用程序中提出了潜在的方法，必须详细检查它们的优点和缺点。例如，在时域中对信号进行研究是可能的，这样就可以通过变换得出传递函数。随后，将研究不同的调谐算法，以调整滤波器结构的传输特性。将基于运行时间和优化质量等各个方面对算法进行比较。耦合矩阵提取提供了一种有效的调优方法，但如何提供可靠和鲁棒的提取还有待研究。基于散射参数和时域分析的重构算法将被开发，这样就可以在不需要构造等效电路的情况下进行调谐。作为最后一个方面，人工神经网络将被研究，它可以用来重现未知的，甚至非常复杂的函数。最后，对微波滤波器、控制电子器件、测量系统和调谐算法组成的整个系统进行了搭建和各方面的测试。一方面，对结构升温时产生的温度漂移进行补偿，另一方面，将滤波器调谐到由新的中心频率和带宽组成的新的传输特性。

The primary goal of this proposal is to research the real-time reconfiguration of high-frequency filters. For this purpose, the reconfiguration of a microwave filter is to be performed automatically after the input of a new target characteristic and various effects, such as temperature drift, are to be compensated. The reconfiguration should take place without interrupting the signal path. The aim is to develop tunable microwave filters in planar and non-planar technology and to influence the transmission characteristics with the help of a tuning system. The different technologies for tuning have different non-linearities and quality factors. Among others, it can be a planar microstrip filter with varactors as tuning elements or a coaxial resonator filter with mechanical tuning screws. In these cases, the control is realized with variable voltage sources or stepper motors. An essential aspect of this project is the development of a measuring system to determine the transmission characteristics of the microwave filter during operation. Here, the filter structure should not be disconnected, so that a possible transmission is not interrupted. Potential approaches are presented in the application, which must be examined in detail for their advantages and disadvantages. For example, an investigation of the signal in the time domain would be possible, so that the transfer function can be concluded by transformation. Subsequently, different tuning algorithms will be investigated with which the transmission characteristics of the filter structures can be adjusted. The algorithms will be compared based on various aspects such as runtime and quality of optimization. Coupling matrix extraction provides an efficient method of tuning, but how to provide reliable and robust extraction needs to be investigated. Reconfiguration algorithms based on scattering parameters and time domain analysis are to be developed so that tuning is possible without the need to construct an equivalent circuit. As a last aspect, artificial neural networks are to be investigated, which can be used to reproduce unknown, even very complex functions. Finally, the overall system consisting of microwave filter, control electronics, measurement system and tuning algorithm is to be set up and tested under various aspects. On the one hand, the temperature drift that occurs when the structure heats up is to be compensated and, on the other hand, the filter is to be tuned to a new transmission characteristic consisting of a new center frequency and bandwidth.