Bandpass Filter Transmission Line for Compact Interference Mitigation
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Solution Overview
Problem
Conventional interference mitigation filters in cellular communications systems are large, complex, and costly, with limited tunability and high sensitivity to thermal variations, particularly when using the notch filter approach, which complicates manufacturing and increases passive intermodulation distortion.
Innovation Solution
The integration of a bandpass filter as the RF transmission line within the filter, replacing conventional RF transmission lines, which allows for a simpler and less expensive design with improved tunability and reduced sensitivity to thermal variations, while maintaining high performance by generating nulls within the stopband to achieve effective interference mitigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional RF transmission lines are used in interference mitigation filters, then the filter structure is simple, but the filter size is large, cost is high, and sensitivity to thermal variations is high
Solution Approach 1:
The patent merges the RF transmission line function with the bandpass filter function by integrating resonators that serve dual purposes: forming the transmission path and providing frequency-selective filtering. This consolidation eliminates the need for separate transmission line structures, reducing overall filter size while maintaining functionality.
Solution Approach 2:
The resonators in the patent perform multiple functions simultaneously: they act as the RF transmission line medium, provide bandpass filtering characteristics, and generate transmission zeros for enhanced stopband rejection. This multi-functionality reduces the number of separate components needed, thereby reducing filter size and complexity.
2Device complexity
If conventional RF transmission lines are used in interference mitigation filters, then the filter structure is simple, but the manufacturing cost is high and passive intermodulation distortion performance is poor
Solution Approach 1:
By combining the transmission line and bandpass filter into a single integrated structure using resonators, the patent reduces the number of discrete components that need to be manufactured and assembled. This integration simplifies the manufacturing process and reduces costs associated with multiple parts and assembly operations.
Solution Approach 2:
The patent employs resonators with specific geometric parameters and configurations that can be optimized during manufacturing to achieve desired performance characteristics. By designing the resonators with appropriate dimensions and coupling arrangements, the filter achieves improved passive intermodulation distortion performance through parameter optimization rather than complex structural arrangements.
3Device complexity
If conventional RF transmission lines are used in interference mitigation filters, then the filter structure is simple, but the tunability is limited and sensitivity to thermal variations is high
Solution Approach 1:
The patent incorporates adjustable coupling mechanisms between resonators that allow dynamic tuning of the filter response. The coupling coefficients between resonators can be modified to adjust passband frequency and bandwidth, providing enhanced tunability while maintaining the relatively simple overall filter structure.
Solution Approach 2:
The filter design allows adjustment of resonator parameters such as coupling gaps, resonator dimensions, and loading elements to tune the frequency response. These parameter changes enable the filter to adapt to different frequency requirements while maintaining structural simplicity and reducing thermal sensitivity through optimized parameter selection.
4Manufacturing precision
If transmission zeros are added to enhance local selectivity, then the filter response exhibits high local selectivity, but the filter complexity increases
Solution Approach 1:
The patent generates transmission zeros through the coupling between resonators that are already part of the transmission path, rather than adding separate elements. The resonators' coupling arrangements inherently create transmission zeros at specific frequencies, achieving high local selectivity without increasing overall filter complexity.
Solution Approach 2:
The resonators serve dual functions: they form the transmission path and simultaneously generate transmission zeros through their coupling interactions. This multi-functionality achieves enhanced local selectivity and stopband rejection without adding separate components, thereby maintaining filter structural simplicity.
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 solution results in smaller, less expensive filters with improved passive intermodulation distortion performance, reduced sensitivity to thermal variations, and easier tuning, enabling broader application and reduced manufacturing complexity.
Implementation Method 1
a plurality of resonant cavities within the housing, each resonant cavity including a respective notch resonator
Implementation Method 2
a bandpass filter that includes a plurality of bandpass resonators, the bandpass filter extending between the input port and the output port
Data Source
AI summary
Filters include a housing having an input port and an output port and a plurality of resonant cavities within the housing. Each resonant cavity may include a respective notch resonator. The filter may further include a bandpass filter that includes a plurality of bandpass resonators, the bandpass filter extending between the input port and the output port. The bandpass filter may replace a transmission line that is included in conventional filters.