BAW Filter Circuit With SAW Harmonic Suppression for Duplexers
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Solution Overview
Problem
Bulk acoustic wave (BAW) filters in radio-frequency applications generate significant harmonics, which can interfere with circuit operations and cause problems, especially in duplexers where harmonics from transmit signals can affect receive operations.
Innovation Solution
Incorporating surface acoustic wave (SAW) resonators in conjunction with BAW resonators to suppress harmonics, specifically configuring SAW resonators as notch filters to target second harmonics, thereby reducing their amplitude and minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If BAW resonators are used for filtering signals in radio-frequency applications, then signal filtering performance is improved, but harmonic generation increases causing interference with circuit operations
Solution Approach 1:
The patent introduces SAW resonators as an intermediary component between the BAW resonators and the output. These SAW resonators are specifically configured to target and suppress harmonic frequencies generated by the BAW resonators, thereby mediating the harmful effect while preserving the beneficial filtering performance.
Solution Approach 2:
The patent converts the harmful harmonics generated by BAW resonators into a controllable parameter by designing SAW resonators with frequencies that specifically target these harmonics. The harmonics, which were previously harmful interference, become the target of suppression through the SAW resonator's notch filter configuration, transforming the problem into a solution.
2Object-generated harmful factors
If SAW resonators are added to suppress harmonics, then harmonic interference is reduced, but device complexity increases
Solution Approach 1:
The patent merges the BAW resonator assembly and SAW resonator assembly into a single integrated filter circuit. The SAW resonators are electrically connected to the BAW resonators in a compact configuration, combining multiple functions (filtering and harmonic suppression) into one unified device rather than separate components.
Solution Approach 2:
The filter circuit achieves multi-functionality by incorporating both BAW resonators for primary signal filtering and SAW resonators for harmonic suppression within a single device. This universal design allows the same circuit to perform both filtering operations and harmonic rejection without requiring separate dedicated components.
3Reliability
If multiple assemblies with different resonators are used for filtering and harmonic suppression, then duplexing functionality is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the filter circuit into distinct functional assemblies: a BAW resonator assembly for primary filtering and a SAW resonator assembly for harmonic suppression. Each assembly can be designed, tested, and manufactured independently before being integrated into the final duplexer, simplifying the overall manufacturing process while maintaining reliable duplexing functionality.
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 combination of BAW and SAW resonators effectively suppresses harmonics, improving signal filtering and duplexing functionality by reducing harmonic interference, ensuring reliable transmit and receive operations in radio-frequency systems.
Implementation Method 1
a first assembly having one or more bulk acoustic wave (BAW) resonators implemented electrically between the input node and the output node, and configured to filter a signal
Implementation Method 2
a second assembly having one or more surface acoustic wave (SAW) resonators implemented electrically relative to the first assembly, and configured to suppress one or more harmonics resulting from the filtering of the signal by the first assembly
Data Source
AI summary
In some embodiments, a radio-frequency circuit or device can include a filter circuit having an input node and an output node. The filter circuit can further include a first assembly having one or more bulk acoustic wave resonators implemented electrically between the input node and the output node, and configured to filter a signal. The filter circuit can further include a second assembly having one or more surface acoustic wave resonators implemented electrically relative to the first assembly, and configured to suppress one or more harmonics resulting from the filtering of the signal by the first assembly.