SAW Filter Module With π-Type Phase Shift for Low Reflection

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Solution Overview

Problem

Existing radio frequency (RF) communication systems face challenges in efficiently filtering and processing RF signals across various frequency ranges, particularly in 5G frequency range 1 (FR1) and frequency range 2 (FR2), due to issues with reflection coefficients and phase shifts.

Innovation Solution

The implementation of an acoustic wave filter module that includes a metal plate, a piezoelectric substrate, a surface acoustic wave (SAW) filter, capacitors, and inductors to form a π-type high pass filter, which induces a phase shift and reduces the reflection coefficient at the output of the SAW filter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a SAW filter is used to filter RF signals, then signal filtering performance is improved, but phase rotation and reflection coefficients worsen

Engineering Contradiction:

Improvesignal filtering performanceVSAvoidphase rotation and reflection coefficients

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent combines the SAW filter with a π-type high pass filter into a single integrated module. The high pass filter is formed using inductors on the metal plate and capacitors on the piezoelectric substrate, merging the filtering function with phase and reflection control in one unified structure.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The π-type high pass filter acts as an intermediary component between the SAW filter and the output. It mediates the signal by reducing reflection coefficients and minimizing phase rotation while preserving the signal filtering performance of the SAW filter.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If traditional filter configurations are used, then device simplicity is maintained, but phase control and reflection reduction capabilities are insufficient

Engineering Contradiction:

Improvefilter structure simplicityVSAvoidphase control and reflection reduction

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Multiple functions (filtering, phase control, reflection reduction) are merged into a single integrated module, reducing the number of separate components while enhancing overall performance.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated module performs multiple functions simultaneously: RF signal filtering via the SAW filter, phase shift induction via the π-type high pass filter, and reflection coefficient reduction. This multi-functionality enhances reliability without proportionally increasing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If separate components are used for filtering and phase control, then design flexibility is improved, but integration and compactness worsen

Engineering Contradiction:

Improvedesign flexibilityVSAvoidmodule compactness

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The SAW filter, π-type high pass filter, inductors, and capacitors are integrated into a single compact module with a unified structure, significantly reducing the overall volume compared to separate components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The π-type high pass filter is nested within the SAW filter structure, with inductors on the metal plate and capacitors on the piezoelectric substrate, creating a space-efficient nested configuration.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 configuration effectively filters RF signals, reduces reflection coefficients, and minimizes phase rotation, thereby enhancing the performance of RF communication systems, especially in 5G frequency ranges.

Implementation Method 1

a piezoelectric substrate mounted on the metal plate, a first surface acoustic wave (SAW) filter mounted on the piezoelectric substrate

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a first surface acoustic wave (SAW) filter mounted on the piezoelectric substrate

Methodology Applied

Scientific EffectSurface acoustic wave: Surface Acoustic Wave

Data Source

PatentUS20250080085A1Acoustic wave filter modules with integrated phase shift circuits

Publication Date: 2025.03.06 SKYWORKS SOLUTIONS INC

AI summary

An acoustic wave filter module has a piezoelectric substrate mounted on a metal plate, with a surface acoustic wave filter mounted on the piezoelectric substrate and coupled between a first input and an output of the acoustic wave filter module. A capacitor is mounted on the piezoelectric substrate and two inductors are formed on the metal plate. The two inductors and the capacitor electrically implement a π-type high pass filter coupled between the surface acoustic wave filter and an output of the acoustic wave filter module.