Millimeter Wave Filter Using Stacked Stripline Resonators
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Solution Overview
Problem
Existing millimeter wave filters have dimensions that are larger than the antenna elements they serve, due to the use of traditional half-wavelength resonators, which limits their integration with active antenna systems.
Innovation Solution
The design employs inductively coupled quarter wavelength stripline resonators stacked with ground planes and dielectric layers, allowing for a compact filter structure with reduced x-y dimensions and a low profile z-dimension, achieved through inductive coupling between stripline resonators using windows in the ground planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional half-wavelength resonators are used in filter design, then the filter achieves adequate filtering performance, but the x-y dimensions of the filter become much larger than the antenna dimensions
Solution Approach 1:
The patent transitions from planar resonator designs to three-dimensional stacked stripline resonators separated by ground planes. This vertical stacking approach moves the filter structure into the z-dimension, allowing the x-y footprint to be reduced to match antenna dimensions while maintaining filtering performance through multiple resonator layers
Solution Approach 2:
The patent implements nested ground planes and resonators where ground planes are positioned between and around resonator layers. The resonators are embedded within dielectric layers that are sandwiched between ground planes, creating a compact nested structure that reduces overall dimensions while maintaining electrical performance
2Area of moving object
If stacked stripline resonators separated by ground planes are used, then the x-y dimensions are reduced, but the filter remains large relative to antenna elements due to the use of half-wavelength resonators
Solution Approach 1:
The patent changes the resonator wavelength parameter from half-wavelength to quarter-wavelength designs. This parameter change reduces the length of each resonator by approximately half, allowing the stacked filter structure to achieve both reduced x-y dimensions and reduced z-height, making it compact enough for antenna integration
Solution Approach 2:
The patent utilizes the z-dimension for stacking quarter-wavelength resonators with ground planes in between. By efficiently utilizing vertical space with compact resonator lengths, the filter achieves small dimensions in all three dimensions (x, y, and z), enabling integration with antenna elements
3Adaptability or versatility
If filters are designed with dimensions commensurate with antenna elements, then integration with active antenna systems is enabled, but the filter structure becomes more complex
Solution Approach 1:
The patent divides the filter into multiple discrete resonator layers separated by ground planes, with each layer being a manageable quarter-wavelength resonator structure. This segmentation allows the complex filtering function to be achieved through simpler, repetitive modular units that can be stacked and integrated with antenna elements
Solution Approach 2:
The stacked stripline resonator structure with ground planes serves multiple functions simultaneously: it provides filtering performance through resonator coupling, achieves compact dimensions for antenna integration, and maintains structural integrity through the ground plane framework. This multi-functionality reduces overall system complexity despite the detailed filter structure
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 results in millimeter wave filters with dimensions commensurate with antenna elements, enabling smaller and more integrated filter designs that maintain effective performance.
Implementation Method 1
inductively coupled through windows formed in ground planes that separate the stripline resonators
Implementation Method 2
an end of each stripline resonator partially overlaps a window in a ground plane to capacitively couple a stripline resonator on one side of the ground plane to a stripline resonator on the other side
Data Source
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AI summary
A radio frequency filter is disclosed. According to one aspect, the filter includes N stacked planar dielectric layers, N being an integer greater than 1. The filter also includes a first pair of coupled stripline resonators lying in a plane between 5 a first pair of planar dielectric layers. The filter also includes an outermost ground plane on either side of the stack of N stacked planar dielectric layers.