Multi-mode Cavity Filter Excitation Device
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Solution Overview
Problem
Conventional multi-mode filters for frequency division duplexers in telecommunication applications face challenges in minimizing spurious responses and achieving precise control over mode coupling, leading to increased manufacturing costs and complexity.
Innovation Solution
A multi-mode cavity filter design incorporating a dielectric resonator body with a conductive layer and strategically positioned apertures for simultaneous excitation of multiple modes, utilizing an excitation device such as a probe, patch, or quarter-wave resonant line to couple signals into and out of the resonator, while minimizing spurious responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional multi-mode filters use typical excitation structures to excite multiple modes, then the filter can achieve multi-mode operation, but spurious responses increase and manufacturing complexity increases
Solution Approach 1:
The patent introduces a single-mode resonator as an intermediary component between the input port and the multi-mode resonator. This single-mode resonator is configured to couple to multiple modes of the multi-mode resonator simultaneously, acting as a mediator that enables clean excitation of multiple modes without directly introducing spurious responses. The intermediary structure filters out unwanted excitations while maintaining the desired multi-mode operation.
Solution Approach 2:
The patent replaces complex mechanical excitation structures (multiple probes, patches, or coupling mechanisms) with a simpler electromagnetic field-based coupling approach. By using a single-mode resonator that naturally couples to multiple modes through electromagnetic field interaction, the design eliminates the need for complex mechanical adjustment mechanisms, thereby reducing spurious responses and simplifying manufacturing.
2Adaptability or versatility
If conventional multi-mode filters use typical excitation structures, then the filter can operate in multiple modes, but the device complexity and manufacturing costs increase
Solution Approach 1:
The patent merges the functions of multiple excitation structures into a single integrated component. Instead of using separate probes, patches, or coupling mechanisms for each mode, the design combines all excitation functions into one single-mode resonator that simultaneously couples to multiple modes. This merging reduces the number of components, simplifies the overall structure, and lowers manufacturing complexity while maintaining full multi-mode operation capability.
Solution Approach 2:
The single-mode resonator is designed to perform multiple functions simultaneously: it serves as the input coupling structure, acts as a mode selector, and provides isolation between modes. This multi-functional design eliminates the need for separate dedicated structures for each function, thereby reducing device complexity and manufacturing costs while maintaining versatile multi-mode operation.
3Ease of manufacture
If single-mode filters are used with discrete resonators, then the filter can be easily manufactured with discrete components, but the filter size increases making it unsuitable for compact applications
Solution Approach 1:
The patent merges multiple discrete resonators into a single integrated multi-mode resonator body. Instead of assembling separate resonator components as in conventional single-mode filters, the design uses one monolithic resonator structure that supports multiple modes simultaneously. This merging dramatically reduces the overall filter volume while maintaining the ease of manufacture through standardized fabrication processes for monolithic resonators.
Solution Approach 2:
The patent implements a nested structure where a single-mode resonator is positioned within or adjacent to the multi-mode resonator, creating a compact nested arrangement. This nesting allows the smaller single-mode resonator to be integrated within the overall filter structure without significantly increasing the external dimensions, achieving compact size while maintaining discrete component advantages for manufacturing and adjustment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design reduces spurious responses and enhances control over mode coupling, resulting in a more efficient and cost-effective filter with improved filtering characteristics, suitable for compact telecommunication equipment.
Implementation Method 1
at least one excitation device for at least one of: establishing an electromagnetic field external to, but immediately adjacent to, at least one face of the dielectric resonator body
Implementation Method 2
the piece of dielectric material having a shape such that it can support at least a first resonant mode and at least a second substantially degenerate resonant mode
Implementation Method 3
extracting energy from an electromagnetic field located external to, but immediately adjacent to, at least one face of the dielectric resonator body
Data Source
AI summary
A multi-mode cavity filter, including at least one dielectric resonator body incorporating a piece of dielectric material having a shape to support first resonant mode and a second substantially degenerate resonant mode; excitation device(s) for at least one of: establishing an electromagnetic field external to, but immediately adjacent to, a face of the dielectric resonator body or for extracting energy from an electromagnetic field located external to, but immediately adjacent to, a face of the dielectric resonator body, a layer of conductive material in contact with and covering the dielectric resonator body on the face of the dielectric resonator body: at least one aperture in the layer of conductive material for inputting signals to the dielectric resonator body and/or outputting signals from the dielectric resonator body, wherein the excitation device is located, in at least two dimensions, at an electrical center of the face of the dielectric resonator body.