Acoustic Wave Filter Layout With Shared Reflectors and Phase Cancellation

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Solution Overview

Problem

Existing acoustic wave filters in wireless communication devices occupy significant space, limiting the ability to reduce the size of semiconductor dies while maintaining functionality.

Innovation Solution

Incorporating phase cancelling loop circuits with shared reflector gratings between surface acoustic wave resonators, reducing the spacing between duplexers and utilizing subgratings and grounded conductive paths to minimize die size without compromising performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If acoustic wave filters are implemented in radio frequency electronic systems, then signal filtering functionality is achieved, but the semiconductor die size increases

Engineering Contradiction:

Improvesignal filtering functionalityVSAvoidsemiconductor die size

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent combines two separate radio frequency filters into a single duplexer structure on one semiconductor die. The first and second radio frequency filters are disposed on the same die and share common structures including reflector gratings and substrate, reducing the total area required compared to implementing separate filters.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The shared reflector gratings serve multiple functions: they act as reflectors for both the first and second radio frequency filters simultaneously, and the conductive paths between interdigital transducer electrodes serve both as electrical connections and as additional reflector structures. This multi-functionality reduces the overall component count and die area.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Object-generated harmful factors

If reflector gratings are placed between interdigital transducer electrodes of different resonators, then acoustic coupling is reduced, but manufacturing complexity increases

Engineering Contradiction:

Improveacoustic couplingVSAvoidmanufacturing complexity

Core Design Contradiction:

Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent merges the reflector grating structures with the electrical interconnections between resonators. The conductive paths that electrically connect interdigital transducer electrodes of different resonators also function as reflector gratings, eliminating the need for separate reflector structures and simplifying the manufacturing process.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The conductive paths serve dual purposes: they provide electrical connectivity between interdigital transducer electrodes and simultaneously act as reflector gratings to prevent acoustic coupling. This multi-functionality reduces the number of manufacturing steps and structures required.

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

The proposed solution reduces the semiconductor die size by approximately 4% while enhancing signal isolation and reducing unwanted acoustic coupling, thus allowing for more efficient use of space in electronic devices.

Implementation Method 1

a first radio frequency filter and a second radio frequency filter disposed on a die, each of the first radio frequency filter and the second radio frequency filter including a plurality of surface acoustic wave resonators

Methodology Applied

Scientific EffectSurface acoustic wave: Surface Acoustic Wave

Implementation Method 2

a portion of the first signal line including a first reflector grating disposed between first interdigital transducer electrodes included in a first surface acoustic wave resonator of the first radio frequency filter

Methodology Applied

Scientific EffectAcoustic wave reflection: Reflection

Implementation Method 3

the first loop circuit configured to generate a first anti-phase signal to a target signal at a first particular frequency

Methodology Applied

Scientific EffectAcoustic interference: Interference

Data Source

PatentUS20250293669A1Size reduced acoustic wave filter device with phase cancelling circuit electrically connected with shared reflector

Publication Date: 2025.09.18 SKYWORKS SOLUTIONS INC

AI summary

A first radio frequency filter and a second radio frequency filter disposed on a die, a first loop circuit disposed on the die, coupled to the first radio frequency filter, configured to generate a first anti-phase signal at a first frequency, and including a first signal line including a first reflector grating disposed between first interdigital transducer electrodes included in a first surface acoustic wave resonator of the first radio frequency filter and second of interdigital transducer electrodes included in a second surface acoustic wave resonator of the second radio frequency filter, and a second loop circuit disposed on the die, coupled to the second radio frequency filter, configured to generate a second anti-phase signal at a second frequency, and including a second signal line including a second reflector grating disposed between the first interdigital transducer electrodes and the second interdigital transducer electrodes.