Ferroelectric Coupled Resonator Filter Bandwidth Tuning Circuit

Solution Overview

Problem

Current ferroelectric acoustic resonators in wireless devices lack the ability to electrically control their operating frequency without altering their inner structure, limiting their adaptability to various radio frequency filtering requirements.

Innovation Solution

A coupled resonator filter (CRF) tuning circuit is introduced, comprising a ferroelectric input resonator, a ferroelectric output resonator, and a ferroelectric tuning resonator coupled via a coupling layer, with a tuning controller that polarizes the coupling layer relative to either the input or output resonator to modify the filter bandwidth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the inner structure of the ferroelectric acoustic resonator is changed to adjust the operating frequency, then the operating frequency can be adjusted, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improveoperating frequency adjustmentVSAvoidinner structure modification

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical/physical structure modification with an electrical control mechanism. A tuning voltage is applied to the ferroelectric layer to change its dielectric constant, which in turn adjusts the resonant frequency of the acoustic resonator. This electrical tuning method eliminates the need to physically alter the inner structure of the resonator, thereby resolving the contradiction between frequency adaptability and device complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the electrical parameter (dielectric constant) of the ferroelectric layer through applied voltage to achieve frequency tuning. By varying the tuning voltage, the dielectric constant of the ferroelectric material changes, which directly affects the resonant frequency of the acoustic resonator. This parameter-based control allows frequency adjustment without structural modification

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the inner structure of the ferroelectric acoustic resonator is changed to adjust the operating frequency, then the operating frequency can be adjusted, but the manufacturing precision requirements increase

Engineering Contradiction:

Improveoperating frequency adjustmentVSAvoidinner structure fabrication

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical/physical structure modification with an electrical control mechanism. A tuning voltage is applied to the ferroelectric layer to change its dielectric constant, which in turn adjusts the resonant frequency of the acoustic resonator. This electrical tuning method eliminates the need to physically alter the inner structure of the resonator, thereby resolving the contradiction between frequency adaptability and device complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the electrical parameter (dielectric constant) of the ferroelectric layer through applied voltage to achieve frequency tuning. By varying the tuning voltage, the dielectric constant of the ferroelectric material changes, which directly affects the resonant frequency of the acoustic resonator. This parameter-based control allows frequency adjustment without structural modification

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

This solution allows for adaptable filter bandwidth adjustment based on RF filtering needs, enhancing the versatility and performance of ferroelectric acoustic resonators in wireless devices without changing their inner structure.

Implementation Method 1

a ferroelectric input resonator and a ferroelectric output resonator that are coupled by a piezoelectric layer

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The tuning controller is configured to cause the coupling layer to be polarized relative to one of the ferroelectric input resonator and the ferroelectric output resonator to thereby modify a filter bandwidth of the CRF structure

Methodology Applied

Scientific EffectPolarization: Polarisation

Data Source

PatentUS20240333259A1Coupled resonator filter tuning circuit

Publication Date: 2024.10.03 QORVO US INC

AI summary

A coupled resonator filter (CRF) tuning circuit is provided. Herein, a CRF structure includes a ferroelectric input resonator, a ferroelectric output resonator, and a ferroelectric tuning resonator coupled to the ferroelectric input resonator and the ferroelectric output resonator via a coupling layer. In embodiments disclosed herein, a tuning controller is configured to cause the coupling layer to be polarized relative to the ferroelectric input resonator or the ferroelectric output resonator. As a result, it is possible to adapt the sustainable filter bandwidth of the CRF structure based on various radio frequency (RF) filtering requirements.