Planar RF Filter Tuning Structure for Slimmer, Lighter Resonators

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Solution Overview

Problem

Conventional radio frequency filters face challenges in reducing size and weight due to their design, which requires additional conductive material for inductive or capacitive coupling, leading to increased thickness and weight.

Innovation Solution

A filter design for communication devices that includes a tuning panel with multiple tuning bars in a single layer within a dielectric material-filled space, allowing for frequency tuning by adjusting the separation distance between resonators on a resonance substrate, and incorporating a notch forming part as a single layer to enhance skirt characteristics without additional weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional conductive material is installed for inductive coupling or capacitive coupling to reinforce skirt characteristics, then the filtering performance is improved, but the weight of the filter significantly increases

Engineering Contradiction:
Improvefiltering performanceVSAvoidfilter weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent combines the coupling structure with the resonator structure itself. The coupling between resonators is achieved through their spatial arrangement and electromagnetic field interaction within the dielectric material, rather than through separate conductive coupling elements. This merging of functions eliminates additional weight while maintaining filtering performance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the coupling function from separate conductive materials and integrates it into the resonator-dielectric system. By removing the need for additional conductive coupling elements and relying on the inherent electromagnetic coupling through the dielectric material, the filter achieves the required performance without the weight penalty of extra conductive components.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If resonators are arranged in multiple layers or with complex configurations to achieve desired frequency characteristics, then the filtering performance is improved, but the thickness of the filter increases

Engineering Contradiction:
Improvefrequency characteristicsVSAvoidfilter thickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent transitions from vertical stacking (thickness direction) to horizontal arrangement (lateral direction) for achieving frequency characteristics. Multiple resonators are arranged side-by-side within a single layer, utilizing lateral spacing and electromagnetic field interaction to achieve the desired frequency response without increasing filter thickness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent combines multiple resonator functions into a single planar layer. By arranging resonators laterally within one layer and utilizing their electromagnetic field interaction through the dielectric material, the filter achieves complex frequency characteristics without the thickness increase that would result from stacking multiple layers.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If conventional cavity structures with resonators extending in thickness direction are used, then the resonance function is achieved, but the size reduction in thickness direction is limited

Engineering Contradiction:
Improveresonance functionVSAvoidthickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent fundamentally changes the resonator orientation from vertical (extending in thickness direction) to horizontal (extending in lateral direction). Resonators are arranged side-by-side within a single layer, utilizing lateral dimensions for resonance while minimizing thickness requirements. This dimensional transition enables significant thickness reduction while maintaining the resonance function.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent replaces the conventional mechanical cavity structure with an integrated planar resonator-dielectric system. Instead of using three-dimensional metal cavities with resonators extending through thickness, the invention uses two-dimensional planar resonators embedded in or on dielectric material, achieving resonance through electromagnetic field distribution in the lateral plane rather than through thickness-direction cavity resonance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This design facilitates a slim manufacturing process, reduces product weight by eliminating the need for additional conductive material, and enables fine frequency tuning, resulting in a lightweight and compact filter.

Implementation Method 1

a radio frequency device such as a radio frequency filter (including all 'communication devices') is usually composed of a connection structure of a plurality of resonators. Such a resonator is a circuit element that resonates at a specific frequency by a combination of an inductor l and a capacitor C in an equivalent electronic circuit

Methodology Applied
Scientific EffectElectromagnetic resonance: Resonance

Implementation Method 2

each resonator has a structure in which a dielectric resonance element (dielectric resonance element (DR)) or a metal resonance element is installed inside a cavity such as a metallic cylinder or rectangular parallelepiped surrounded by a conductor

Methodology Applied
Scientific EffectDielectric confinement: Dielectric

Implementation Method 3

a frequency tuning panel which includes a tuning frame having a plurality of tuning bar disposed as a single layer in the thickness direction within the dielectric material-filled space to adjust a separation distance between a plurality of resonators disposed within the dielectric material-filled space

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Data Source

PatentEP4564590A1Filter for communication device
Publication Date: 2025.06.04 KMW INC
  • EP4564590A1 patent drawingFigure 1
  • EP4564590A1 patent drawingFigure 2A
  • EP4564590A1 patent drawingFigure 2B

AI summary

The present disclosure relates to a communication device filter. Particularly, the communication device filter comprises: a filter body which is open in the thickness direction such that a part of a dielectric material-filled space is formed therein; a filter tuning cover coupled in the open thickness direction so as to cover the filter body, thereby forming the remainder of the dielectric material-filled space; a frequency tuning panel comprising a tuning frame having multiple tuning bars disposed in the dielectric material-filled space as a single layer with regard to the thickness direction so as to adjust the distance of spacing from multiple resonators disposed in the dielectric material-filled space; and a resonance substrate comprising a resonance frame disposed in the dielectric material-filled space such that the multiple resonators constitute a single layer with regard to the thickness direction.