Stacked Resonator Filter Assembly for Compact RF Duplexers
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Solution Overview
Problem
Conventional duplexers for cellular base stations are large, heavy, and difficult to mount on phased array antennas due to space constraints, and their assembly is costly and complex.
Innovation Solution
The development of filter assemblies with stacked resonator plates and twistable tuning elements, featuring a housing with integrated ports and soldered connections, reducing size, weight, and part count while maintaining high RF performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional duplexer designs are used, then RF performance is maintained, but size and weight increase making them difficult to mount on phased array antennas
Solution Approach 1:
The filter assembly employs nested resonator cavities where smaller resonators are positioned within or between larger resonator structures. This nesting arrangement allows multiple resonant modes and frequency responses to be achieved within a compact volume, reducing the overall size of the filter assembly while maintaining the required RF performance characteristics for duplexer operation
Solution Approach 2:
The filter assembly transitions from conventional planar or linear resonator arrangements to a three-dimensional stacked configuration with resonators positioned at different vertical levels. This dimensional change enables more efficient space utilization and compact form factor while preserving the necessary RF transmission and filtering characteristics
2Ease of manufacture
If conventional duplexer assembly methods are used, then structural integrity is achieved, but assembly complexity and cost increase
Solution Approach 1:
The filter assembly integrates multiple components into unified structures, such as combining resonator supports, mounting brackets, and shielding elements into integrated assemblies. This merging reduces the total part count and simplifies the assembly process while maintaining structural integrity and RF performance
Solution Approach 2:
The filter assembly employs universal mounting interfaces and standardized connection points that can accommodate different resonator configurations and mounting locations. This multi-functionality allows the same basic assembly structure to be used across various duplexer implementations, reducing assembly complexity and manufacturing cost
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 new filter assemblies are compact, lightweight, and cost-effective, offering improved RF performance with reduced Passive Intermodulation distortion and easier assembly, suitable for duplexers, diplexers, and combiners in cellular communications systems.
Implementation Method 1
a first resonator plate having a first hole pattern formed therein mounted within the internal cavity; and a second resonator plate having a second hole pattern formed therein mounted within the internal cavity in a stacked relationship with the first resonator plate
Data Source
AI summary
The present invention provides filter assemblies, tuning elements and a method of tuning a filter. A filter assembly includes a housing having a top cover, a bottom cover and at least one sidewall, the top cover, the bottom cover and the at least one sidewall defining an internal cavity, the housing configured to receive first through third radio frequency (“RF”) transmission lines; a top metal sheet mounted within the internal cavity that has a plurality of openings that form a first hole pattern; and a bottom metal sheet mounted within the internal cavity that has a plurality of openings that form a second hole pattern. The top and bottom metal sheets are vertically spaced-apart from each other in a vertically stacked relationship within the internal cavity. The top metal sheet and the bottom metal sheet each include at least one resonator.