Resonant Cavity Filter With Slotted Resonators for Wider Coupling

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Solution Overview

Problem

Mushroom-shaped resonators in filter apparatus trade off space efficiency for reduced coupling bandwidth, leading to increased transmission losses and compromised performance in telecommunication systems.

Innovation Solution

Incorporating apertures or slots in the outer wall of the second resonator portion allows for unhindered electromagnetic field interaction between adjacent resonators, enhancing coupling bandwidth without significant changes in resonant frequency or capacitance to the ground plane.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If mushroom-shaped resonators are used to reduce cavity height and improve space efficiency, then the volume of the resonator is reduced, but the coupling bandwidth between adjacent resonators decreases

Engineering Contradiction:
Improveresonator volumeVSAvoidcoupling bandwidth
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The resonator is divided into two separate portions: a first resonator portion (upright post) and a second resonator portion (folded skirt). This segmentation allows the electromagnetic fields to interact through the aperture in the second portion, enabling both compact volume and adequate coupling bandwidth to be achieved simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An aperture or slot is introduced in the second resonator portion to act as an intermediary that facilitates electromagnetic field interaction between adjacent resonators. This aperture serves as a coupling mechanism that maintains bandwidth performance while preserving the space-efficient mushroom shape.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the folded outer portion of the mushroom resonator is lengthened to improve capacitance and reduce resonant frequency, then space efficiency improves, but the coupling bandwidth between adjacent resonators decreases

Engineering Contradiction:
Improveresonant frequency tuning rangeVSAvoidcoupling bandwidth
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

By separating the resonator into two distinct portions with different functions, the design allows the second portion to be optimized for capacitance (affecting resonant frequency) while the aperture in this portion maintains coupling bandwidth, resolving the trade-off between frequency tuning and bandwidth.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the resonator are given different properties: the first portion provides the primary resonant structure, while the second portion with the aperture provides both capacitance for frequency tuning and coupling for bandwidth maintenance, allowing local optimization of both parameters.

Inventive Principle:
Principle #3Local quality

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 solution increases the coupling bandwidth of the filter apparatus while maintaining resonant frequency stability, thereby improving space efficiency and reducing transmission losses.

Implementation Method 1

allows for unhindered electromagnetic field interaction between adjacent resonators, enhancing coupling bandwidth

Methodology Applied
Scientific EffectElectromagnetic field interaction: Electromagnetic Induction

Implementation Method 2

A resonator is an electronic component that exhibits resonance for a narrow range of frequencies

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 3

increasing the capacitance between the resonator and an electrical ground plane of the resonator cavity. Increasing the capacitance in the resonator cavity reduces the resonant frequency of the cavity

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3731337B1Filter apparatus and method of use thereof
Publication Date: 2024.01.24 RADIO DESIGN LTD
  • EP3731337B1 patent drawingFigure 1a~1b
  • EP3731337B1 patent drawingFigure 1c
  • EP3731337B1 patent drawingFigure 2

AI summary

Filter apparatus is provided including a housing with two or more resonant cavities defined therein. Each of the two or more resonant cavities have resonator means provided therein. Each of the resonator means has a first resonator portion and a second resonator portion. A first end of the first resonator portion is located on a wall of the resonant cavity. The second resonator portion is provided at a second end of the first resonator portion. The second resonator portion defines a channel or an inverted channel therein. An opening of the channel or inverted channel is arranged to face towards the wall of the resonant cavity on which the first end of the first resonator portion is located. An outer wall of the second resonator portion has an aperture, slot or cut-out defined therein.