Integrated Coupled Resonator Filter with Steep Transition Band
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Solution Overview
Problem
Conventional coupled resonator filters (CRFs) suffer from poor transition band characteristics, which are inadequate for mobile technologies requiring narrow pass band to stop band transitions, and existing solutions fail to enhance this property effectively.
Innovation Solution
A method for monolithically integrating CRFs with traditional ladder or lattice type circuitry on a single substrate, utilizing a process flow that minimizes mask layers and process steps, allowing for optimal performance and substrate planarity, thereby achieving superior filter performance with enhanced transition band characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CRF structures are used, then the filter provides basic pass band and stop band characteristics, but the transition band characteristics are poor and inadequate for mobile technologies requiring narrow transitions
Solution Approach 1:
The patent combines coupled resonator filter (CRF) structures with traditional ladder or lattice type circuitry into a single integrated filter device. This merging allows the device to achieve superior transition band characteristics by utilizing the complementary strengths of CRF structures (which provide good pass band and stop band characteristics) and ladder/lattice circuitry (which provide steep transition bands), thereby resolving the contradiction between improving transition band characteristics and avoiding excessive device complexity.
Solution Approach 2:
The patent employs composite filter structures that integrate different types of resonator circuits (coupled resonators and ladder/lattice resonators) with different electrical characteristics. This composite approach enables the filter to achieve both narrow transition bands and excellent pass/stop band characteristics simultaneously, addressing the technical contradiction without requiring overly complex individual circuit elements.
2Manufacturing precision
If existing solutions are applied to enhance transition band characteristics, then some improvement is achieved, but the solutions fail to provide the steep transition bands required for mobile technologies
Solution Approach 1:
The patent optimizes key parameters of the integrated CRF-ladder/lattice structure, including the coupling coefficients of the resonators, the impedance values of the ladder/lattice elements, and the resonant frequencies of individual resonators. By carefully adjusting these parameters, the filter achieves consistent steep transition bands and reliable performance characteristics that meet mobile technology requirements, thereby improving both transition band characteristics and performance consistency.
3Manufacturing precision
If monolithic integration of CRF with ladder circuitry is achieved, then substrate planarity and optimal performance are maintained, but the manufacturing process requires precise control of multiple layers and steps
Solution Approach 1:
The patent divides the filter device into distinct functional segments: CRF sections, ladder/lattice circuit sections, and interconnecting transmission lines. Each segment can be designed, analyzed, and manufactured independently with specific requirements for substrate planarity and performance. This segmentation allows for modular manufacturing processes that maintain substrate planarity while reducing the overall complexity of the manufacturing process through standardized fabrication steps for each segment type.
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 integration of CRFs with traditional ladder circuitry on a single substrate improves filter performance by providing steep transition bands, excellent stop band and pass band characteristics, and enables mode conversion, while maintaining optimal coupling and high Q-values, thus addressing the limitations of conventional CRFs.
Implementation Method 1
a piezoelectric layer sandwiched between a first electrode and a first part of a second electrode at the first site and the second site
Implementation Method 2
forming a coupling layer on the second electrode
Data Source
AI summary
A method for manufacturing a filter device is provided. The filter device comprises a coupled resonator at a first site, a shunt resonator at a second site and a series resonator at a third site, the coupled resonator comprising a first and a second resonator. The method comprising a step of providing a substrate with a piezoelectric layer sandwiched between a first electrode and a first part of a second electrode at the first site and the second site, the piezoelectric layer sandwiched between the first electrode and a second part of the second electrode at the third site. The method further comprising the step of forming a coupling layer on the second electrode, the step of forming a further piezoelectric layer sandwiched between a further first electrode and a further second electrode at the third site and the step of removing the coupling layer at the second and third sites.