Dielectric Filter Coupling Window Layout for Spurious Suppression

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Solution Overview

Problem

Current dielectric filters in base stations face challenges in miniaturization while maintaining high performance, leading to issues with spurious resonance and complex, costly manufacturing processes.

Innovation Solution

The proposed dielectric filter design includes a sequence of single-mode and triple-mode dielectric resonators coupled by strategically arranged coupling windows, which allow for the achievement of a transmission zero at the triple-mode high-order resonant frequency, thereby suppressing spurious resonance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the filter size is miniaturized to meet base station requirements, then the volume is reduced, but spurious resonance occurs due to high-order resonant frequencies

Engineering Contradiction:

Improvefilter volumeVSAvoidspurious resonance

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful high-order resonant frequencies into useful transmission zeros by strategically designing coupling windows. The triple-mode dielectric resonator's high-order modes, which originally caused spurious resonance, are transformed into transmission zeros at specific frequencies (e.g., 2.4GHz, 3.5GHz, 4.8GHz) that suppress spurious signals. The coupling windows between resonators are designed to create transmission zeros that coincide with the high-order resonant frequencies, thereby converting the harmful resonance into a beneficial suppression mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Ease of manufacture

If traditional dielectric filter designs are used, then manufacturing is simpler, but the filter size is larger and spurious suppression is poor

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidfilter volume

Core Design Contradiction:

Ease of manufactureVSVolume of moving object

Solution Approach 1:

The patent merges multiple functions into the coupling window structure. The coupling windows serve dual purposes: they provide the necessary coupling between adjacent dielectric resonators for signal transmission, and they simultaneously create transmission zeros to suppress spurious resonance. This integration eliminates the need for separate spurious suppression structures, maintaining manufacturing simplicity while achieving both size reduction and spurious suppression.

Inventive Principle:

Principle #5Merging (Combining)

3Object-generated harmful factors

If coupling windows are added to suppress spurious, then spurious resonance is reduced, but the structure becomes more complex

Engineering Contradiction:

Improvespurious resonanceVSAvoidstructure complexity

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The coupling windows are designed to perform multiple functions simultaneously: they provide electromagnetic coupling between adjacent dielectric resonators for the desired signal passband, and they create transmission zeros to suppress high-order resonant spurious. This multi-functionality means that the same structural elements (coupling windows) achieve both signal transmission and spurious suppression, avoiding the need for additional complex structures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 achieves improved RF performance, reduced size and weight, increased reliability, and simplified manufacturing, while effectively suppressing high-order resonant spurious and enhancing filter performance.

Implementation Method 1

adjacent dielectric resonators being coupled by coupling windows provided between their opposite surfaces

Methodology Applied

Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Implementation Method 2

a first single-mode dielectric resonator, a second single-mode dielectric resonator, and a triple-mode dielectric resonator

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS20250141076A1A dielectric filter

Publication Date: 2025.05.01 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

The present disclosure relates to a dielectric filter. It comprises a first single-mode dielectric resonator, a second single-mode dielectric resonator, and a triple-mode dielectric resonator arranged side by side in sequence in a first direction, adjacent dielectric resonators being coupled by coupling windows provided between their opposite surfaces, characterized in that the coupling windows between the first single-mode dielectric resonator and the second single-mode dielectric resonator comprise a first main coupling window and a first cross coupling window. A length of the first main coupling window measured along a second direction is greater than half of a length measured along the second direction, of a filter cross section where the first main coupling window is located, and a width of the first main coupling window measured along a third direction is less than half of a width measured along the third direction, of the filter cross section where the first main coupling window is located, the first direction, the second direction and the third direction being three dimensional extension directions of the dielectric filter. A length of the first cross coupling window measured along the second direction is less than a length of the first main coupling window measured along the second direction.