Zero-Output Coupled Resonator Filter for Smaller RF Circuits
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Solution Overview
Problem
Current RF filters, particularly those based on SAW and BAW resonators, face challenges in achieving flat passbands, steep filter skirts, and reduced size while supporting multiple wireless communication technologies, which increases complexity and demands for improved performance.
Innovation Solution
The introduction of a zero-output coupled resonator filter (ZO-CRF) that functions as a shunt resonator in RF filter circuits, comprising coupled resonators with adjustable voltages to modify resonance frequency, reducing the total inductance and footprint of the filter circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional CRF with output port is used, then signal transmission is enabled, but device complexity and footprint increase
Solution Approach 1:
The patent removes the output port from the conventional coupled resonator filter, extracting only the essential filtering function while eliminating the signal transmission path. This creates a zero-output CRF that serves purely as a resonant element in the filter circuit, reducing complexity without sacrificing the required signal processing capability through the resonator itself
Solution Approach 2:
The zero-output CRF is designed to serve multiple functions: it provides frequency selectivity, impedance transformation, and resonant coupling all within a single component structure. By eliminating the dedicated output port, the resonator itself becomes the interface for both input and output signals, enabling multi-functionality with reduced device complexity
2Adaptability or versatility
If fixed resonance frequency resonators are used, then manufacturing is simplified, but adaptability to different frequencies is reduced
Solution Approach 1:
The patent implements variable capacitance elements that allow the resonance frequency of the CRF to be dynamically adjusted. By incorporating tunable capacitors in parallel with the resonator, the circuit can adapt its resonant frequency to different communication standards and requirements while maintaining a relatively simple manufacturing process based on standard resonator structures
Solution Approach 2:
The invention changes the electrical parameters of the resonator circuit by introducing adjustable capacitance values. This allows the resonance frequency to be modified without changing the physical structure of the resonator itself, enabling frequency adaptability while keeping the manufacturing process simple and based on established resonator fabrication techniques
3Area of stationary object
If larger inductance is used in filter circuit, then filtering performance is improved, but filter circuit footprint increases
Solution Approach 1:
The patent replaces traditional large inductance elements with a resonator-based filtering mechanism. The coupled resonators provide the necessary frequency selectivity and filtering performance through their resonant properties rather than relying on large inductance values, thereby reducing the physical footprint of the filter circuit while maintaining or improving filtering effectiveness
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 ZO-CRF enables flexible resonance frequency adjustment and reduced inductance, leading to smaller RF filter circuits with improved performance and compatibility with multiple wireless communication technologies.
Implementation Method 1
a first piezoelectric plate disposed between the first electrode and the second electrode
Implementation Method 2
Acoustic resonators, such as surface acoustic wave (SAW) resonators and bulk acoustic wave (BAW) resonators
Data Source
AI summary
A zero-output coupled resonator filter (ZO-CRF) and related radio frequency (RF) filter circuit are provided. In examples discussed herein, the ZO-CRF can be configured to function as a shunt resonator(s) in an RF filter circuit (e.g., a ladder filter circuit). The ZO-CRF includes a first resonator and a second resonator that are coupled to each other via a coupling layer. The first resonator and the second resonator receive a first voltage and a second voltage, respectively. The first voltage and the second voltage can be configured in a number of ways to cause the ZO-CRF to resonate at different resonance frequencies. As such, it may be possible to modify resonance frequency of the ZO-CRF in an RF filter circuit based on signal connection. As a result, it may be possible to reduce total inductance of the RF filter circuit, thus helping to reduce footprint of the RF filter circuit.