Acoustic Wave Filter Batch Production Using Reactive Resonator Tuning
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Solution Overview
Problem
Current technologies face challenges in co-integrating multiple acoustic wave filters on a single chip due to limitations in manufacturing processes, such as frequency dispersion and degradation of piezoelectric properties, leading to increased production costs and reduced performance, especially when covering wide frequency ranges.
Innovation Solution
The method involves using resonators with high electromechanical coupling coefficients and adding reactive elements in series and parallel to shift resonant and antiresonant frequencies, allowing for the production of filters with different bandwidths and center frequencies on a common basic structure, with the synthesis of resonator/series reactance/parallel reactance triplets to achieve the required impedances for filter operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple filters are co-integrated on a single chip using conventional methods, then production cost and assembly complexity are reduced, but frequency dispersion and degradation of piezoelectric properties occur, leading to reduced filter performance
Solution Approach 1:
The invention segments the filter design into modular elementary building blocks (resonator/series reactance/parallel reactance triplets) that can be independently designed and then co-integrated. Each building block is optimized for specific frequency ranges, allowing multiple filters to be produced on one chip without mutual interference, thus maintaining manufacturing precision while improving productivity.
Solution Approach 2:
The patent applies local quality by using different resonator structures and materials optimized for specific frequency bands within the same chip. High electromechanical coupling coefficients are achieved in specific local regions through tailored resonator designs, allowing each filter to maintain optimal performance characteristics for its designated frequency range while being co-integrated with other filters.
2Device complexity
If filters covering wide frequency ranges are produced on a single chip, then component assembly is minimized, but frequency dispersion effects dominate and affect filter performance
Solution Approach 1:
The invention introduces dynamic adjustability through variable reactive elements that can be tuned to compensate for frequency dispersion effects. The series and parallel reactances in each elementary building block can be adjusted to optimize filter performance across different frequency ranges, allowing the system to adapt to the specific characteristics of each filter position on the chip.
Solution Approach 2:
The patent utilizes parameter changes by varying the electrical characteristics of the reactive elements (capacitors and inductors) in each elementary building block. By adjusting the values of series and parallel reactances, the resonant and antiresonant frequencies can be precisely controlled for each filter, compensating for frequency dispersion effects and maintaining performance across wide frequency ranges.
3Ease of manufacture
If conventional resonator structures are used for batch production, then manufacturing process is simplified, but the ability to produce filters with different bandwidths and center frequencies is limited
Solution Approach 1:
The invention creates universal elementary building blocks that can serve multiple functions across different filter designs. The standardized resonator/series reactance/parallel reactance triplet structure can be configured to produce filters with various center frequencies and bandwidths by simply adjusting the reactive element values, maintaining manufacturing simplicity while achieving high versatility in filter frequency coverage.
Solution Approach 2:
The patent applies preliminary action by pre-optimizing the resonator structures with high electromechanical coupling coefficients before final filter assembly. The elementary building blocks are designed in advance with optimized resonator parameters, allowing rapid configuration of different filter specifications through simple adjustment of reactive elements, thus maintaining ease of manufacture while enabling wide frequency coverage.
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 approach enables the batch production of multiple filters on a single chip, optimizing production processes, minimizing component assembly, and reducing area requirements, while maintaining filter performance across various frequency bands.
Implementation Method 1
comprising a lower electrode layer, a piezoelectric material layer and an upper electrode layer
Implementation Method 2
resonators with high electromechanical coupling coefficients and adding reactive elements in series and parallel to shift resonant and antiresonant frequencies
Data Source
AI summary
A method for the batch production of acoustic wave filters comprises: synthesizing N theoretical filters, each filter defined by a set of j theoretical resonator(s) having a triplet C0ij,eq, ωrij,eq and ωaij,eq, these parameters grouped into subsets; determining a reference resonator structure for each subset, naturally having a resonant frequency ωr,ref, where ωaij,eq<ωr,ref<ωrij,eq; determining, for each theoretical resonator, an elementary building block comprising an intermediate resonator R′ij, a parallel reactance Xpij and/or a series reactance Xsij, the intermediate resonator R′ij having a triplet C0ij, ωr,ref and ωa,ref, the parameters C0ij, Xpij and/or Xsij defined so the elementary building block has a triplet: C0ij,eq, ωrij,eq and ωaij,eq; determining the geometrical dimensions of the actual resonators Rij of the filters so they have a capacitance C0ij; producing each actual resonator; associating series and/or parallel reactances with actual resonators in order to form the elementary building blocks.