Advanced filter design technique based on equivalent circuits and coupling matrix segmentation

Abstract

This paper presents a technique for the efficient design of bandpass waveguide microwave filters using a segmentation technique applied to an equivalent circuit. The technique is based on first developing an equivalent circuit that synthesizes the desired transfer function. Then, the different parts of the real physical structure are optimized by segmenting this equivalent circuit. The technique was originally developed for in-line filters, and the main contribution of this paper is in the combination of this technique with the coupling matrix formalism. In this way, we adapt for the first time this design strategy to the design of complex coupling topologies, beyond the in-line configuration. As an example, a complex sixth-order dual-mode filter, implemented in all-inductive waveguide technology, is designed using the new coupling matrix segmentation technique, showing the effectiveness of the presented theory. A prototype of the filter has been manufactured, and the accuracy of the design technique is verified by measurements on the real prototype.

Filter design for folded canonical topologies based on equivalent circuit segmentation

“…A reduced number of elements is optimized at each step (only two elements, namely the last coupling and resonator added to the structure). This technique has also been used, more recently, for the design of waveguide dual-mode filters in all inductive technology [16]. This is a complex topology that introduces cross-couplings between the two resonators hosted by one cavity with two other resonators placed in adjacent cavities.…”

“…The main characteristic of these topologies is that they employ cross-couplings between non-adjacent resonators to implement transmission zeros in the filter response. Due to the introduction of these cross-couplings, the segmentation technique presented in [14,15,16] cannot be directly applied to this type of structures.…”

“…First, the theory for scaling the coupling matrix from the normalized coupling matrix using the physical parameters of a particular filter implementation, will be reviewed. Since the theory for scaling the coupling matrix was presented before in [16], only a brief review will be presented in this work, together with final expressions needed for its practical implementation. Although in [16] the work was developed using series resonators, the final expressions in this paper will be particularized for the case of parallel resonators, which are more appropiate to represent folded canonical topologies.…”

Design and Implementation of disruptive techniques of Ku/Ka band tunable filters

“…This process leads to a filter response, which is always close to the target one. This technique was also expanded in [Martínez-Martínez et al, 2018] to dual-mode using all-inductive waveguide technology.…”

Investigación en técnicas numéricas basadas en ecuación integral para el análisis y diseño de dispositivos de microondas para comunicaciones espaciales

“…The explanation for this issue is the following. We use the magnetic vector modal functions of the arbitrary waveguide of It is also important to mention that, for the design process, we use the segmentation method proposed in Martinez Martinez et al (2017). This technique divides the design of the structure into different steps (partial optimization steps).…”