Dual-Mode RF Filter Ladder With Compact Shunt Resonator

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Solution Overview

Problem

Current RF filters in wireless communication devices are large due to their design, which hinders miniaturization and increases data loss, as they require multiple components to manage signal attenuation across various frequency bands effectively.

Innovation Solution

Implementing a dual mode structure (DMS) resonator filter circuit with a shunt resonator and a series resonator, utilizing a piezoelectric substrate with interdigital transducers and reflectors, which allows for dual resonance modes and reduced filter size while maintaining improved attenuation in the band-stop frequency range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If traditional RF filter design is used, then signal attenuation across frequency bands is managed effectively, but filter size becomes large

Engineering Contradiction:

Improvefilter sizeVSAvoidsignal attenuation performance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent combines multiple resonators into a single integrated resonator structure that provides both series and shunt resonance modes. This merging of functions into one component achieves the desired signal attenuation across frequency bands while significantly reducing the overall filter size compared to traditional designs that would require separate components for each function.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated resonator is designed to perform multiple functions simultaneously - it provides both series resonance for stopband attenuation and shunt resonance for passband filtering. This multi-functionality allows a single component to replace what would traditionally require multiple separate components, thereby reducing filter size while maintaining performance.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If multiple components are used to manage signal attenuation, then attenuation performance is improved, but device complexity increases

Engineering Contradiction:

Improvesignal attenuation performanceVSAvoidfilter structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple separate resonators into a single integrated resonator structure. This consolidation reduces the number of discrete components and interconnections required, thereby simplifying the overall filter structure while maintaining the complex attenuation performance that would traditionally require multiple components.

Inventive Principle:

Principle #5Merging (Combining)

3Volume of moving object

If traditional acoustic filter design is used, then signal filtering is effective, but wavelength is larger reducing miniaturization

Engineering Contradiction:

Improvefilter sizeVSAvoidwave propagation velocity

Core Design Contradiction:

Volume of moving objectVSSpeed

Solution Approach 1:

The patent changes the operating parameters of the resonator by designing it to support both series and shunt resonance modes at the same frequency. This parameter change allows the resonator to achieve the filtering effects of traditional acoustic filters while operating at higher effective frequencies, which corresponds to shorter wavelengths and enables miniaturization of the filter structure.

Inventive Principle:

Principle #35Parameter changes

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 DMS resonator filter design reduces the size of RF filters while enhancing signal transfer and near-band attenuation, allowing for more compact devices without sacrificing performance.

Implementation Method 1

Using a piezoelectric material as a vibrating medium, acoustic resonators operate by transforming an electrical signal wave that is propagating along an electrical conductor into an acoustic wave that is propagating via the piezoelectric material.

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a first plurality of interdigital transducers (IDTs) disposed above the first piezoelectric substrate and between the first plurality of reflectors

Methodology Applied

Scientific EffectElectroacoustic conversion:

Implementation Method 3

a first plurality of reflectors disposed above the first piezoelectric substrate

Methodology Applied

Scientific EffectAcoustic wave reflection: Reflection

Implementation Method 4

the shunt resonator is configured as a dual mode structure (DMS)... which allows for dual resonance modes and reduced filter size while maintaining improved attenuation in the band-stop frequency range

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS11804824B2Dual mode structure (DMS) filter ladder design

Publication Date: 2023.10.31 RF360 SINGAPORE PTE LTD

AI summary

Certain aspects of the present disclosure provide a filter. The filter generally includes a series resonator coupled between a first port of the filter and a second port of the filter, and a shunt resonator coupled between a node of the filter and a reference potential node of the filter, the node being coupled between the first port and the second port. The shunt resonator typically includes a first piezoelectric substrate, a first plurality of reflectors disposed above the first piezoelectric substrate, and a first plurality of interdigital transducers (IDTs) disposed above the first piezoelectric substrate and between the first plurality of reflectors, wherein the shunt resonator is configured as a dual mode structure (DMS).