Acoustic Microwave Filter Synthesis With Parasitic-Aware Resonator Design
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Solution Overview
Problem
Current microwave acoustic wave filters face challenges in achieving improved performance, smaller size, and lower cost while incorporating tunability, especially in the frequency range of 500-3500 MHz, where existing designs struggle to meet demanding electrical and environmental requirements effectively.
Innovation Solution
A network synthesis technique is employed to design acoustic microwave filters by selecting an initial filter circuit structure with resonant and reactive elements, transforming them into acoustic resonator models, and optimizing the circuit design to achieve desired frequency response requirements, including passband and stopband specifications, using a Butterworth-Van Dyke model and incorporating parasitic effects to create a pre-optimized filter design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional image filter design methods are used with acoustic wave resonators, then the filter can achieve frequency selective functionality, but the filter size, cost, and performance are limited and cannot meet demanding requirements
Solution Approach 1:
The patent applies network synthesis theory to transform the filter design approach by changing the mathematical parameters and design methodology from traditional image methods to modern network synthesis techniques, enabling optimized element values that meet demanding performance requirements while reducing design complexity
Solution Approach 2:
The patent replaces the mechanical/circuit-based image filter design method with a mathematical network synthesis approach using polynomial ratios and complex frequency-dependent parameters, substituting traditional design mechanics with a more efficient computational methodology
2Reliability
If filter design does not incorporate parasitic effects, then the design process is simpler, but the filter cannot meet demanding electrical and environmental requirements
Solution Approach 1:
The patent incorporates parasitic effects into the network synthesis design process from the beginning, performing preliminary actions to account for real-world imperfections before finalizing the filter design, ensuring the filter meets demanding requirements without requiring complex post-manufacturing adjustments
3Reliability
If the filter design is optimized for performance, then frequency response requirements are met, but the filter size and cost increase
Solution Approach 1:
The patent uses network synthesis to optimize the parameters of acoustic wave resonators and circuit elements, achieving improved frequency response performance while minimizing the physical size of the filter through mathematical optimization rather than brute-force design
4Adaptability or versatility
If conventional filter designs are used, then manufacturing is simpler, but tunability and adaptability are limited
Solution Approach 1:
The patent enables tunable filter designs by incorporating variable elements and dynamic adjustment capabilities into the network synthesis framework, allowing the filter characteristics to be modified after manufacturing without requiring complex re fabrication processes
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 approach results in better performing and lower-cost microwave filters with improved frequency response, enabling smaller size and tunability, suitable for demanding applications in RF frontends of mobile communications devices and other telecommunications systems.
Implementation Method 1
Acoustic Wave (AW) resonators, specifically quartz bulk acoustic wave (BAW) resonators
Implementation Method 2
The equivalent circuit of an AW resonator has two resonances closely spaced in frequency called the 'resonance' frequency and the 'anti-resonance' frequency
Data Source
AI summary
Non-transitory computer-readable media to perform a method for designing a multiband filter. The method includes generating an initial circuit structure comprising a desired number and type of circuit elements; generating an initial circuit design by mapping the frequency response requirements of the initial circuit structure into normalized space; generating an acoustic filter circuit design by transferring the initial filter circuit design; generating a pre-optimized circuit design by unmapping one or more circuit elements of the acoustic filter circuit design into real space and introducing parasitic effects; and communicating the pre-optimized circuit design to a filter optimizer that generates a final circuit design comprising a plurality of resonators, wherein a first resonator exhibits a high resonant frequency, a second resonator demonstrates a low resonant frequency and the difference between the low resonant frequency and the high resonant frequency is at least 1.25 times the average frequency separation of the resonators.