Folded Cavity Filter Structure for Low-Loss Slim RF Modules
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Solution Overview
Problem
Conventional radio frequency filters face challenges in reducing size and weight due to the need for joining processes and material coupling, which increases insertion loss and limits the use of printed circuit boards.
Innovation Solution
A foldable base plate made of conductive or non-conductive material forms a cavity with protruding resonators, eliminating the need for conventional joining methods and reducing thickness through a simple folding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional joining processes are used to form cavity and position resonators, then structural stability is improved, but insertion loss increases and manufacturing complexity increases
Solution Approach 1:
The patent integrates the cavity structure and resonator positioning into a single molded housing component. The cavity walls directly form the resonator mounting structures, eliminating separate joining processes. This merging of functions reduces the number of manufacturing steps, eliminates insertion loss from coupling, and simplifies the overall manufacturing process while maintaining structural stability.
2Manufacturing precision
If filter tuning cover is deformed through punching process to tune distance to resonator, then band-pass characteristics are improved, but thickness reduction is limited
Solution Approach 1:
The patent employs post-molding deformation processes that can adjust the cavity-resonator distance after the main molding is complete. This allows precise tuning of band-pass characteristics while enabling greater thickness reduction than traditional punching methods, as the deformation can be applied to thinner-walled structures without compromising structural integrity.
3Manufacturing precision
If additional conductive components are installed for coupling, then skirt characteristics are improved, but weight increases
Solution Approach 1:
The patent integrates coupling structures directly into the molded housing and resonator components. Conductive features are formed as integral parts of the plastic components through molding, eliminating the need for separate conductive components. This reduces weight while maintaining the necessary coupling characteristics for proper filter operation.
4Length of stationary object
If dielectric ceramic filter is used for direct coupling, then thickness is reduced, but double-sided PCB use is limited
Solution Approach 1:
The patent designs the filter housing with universal mounting capabilities that accommodate various PCB configurations. The housing includes standardized mounting features and flexible coupling structures that work with both single-sided and double-sided PCB arrangements, providing adaptability while maintaining reduced thickness through the molded construction approach.
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 configuration reduces insertion loss, minimizes product thickness, and enhances communication reliability while allowing for a slim design without increasing overall size.
Implementation Method 1
Each resonator has a structure in which a dielectric resonance element (DR) or a metallic resonance element is installed in a cavity... Each resonator allows only an electromagnetic field of a unique frequency corresponding to a processing frequency band to exist within the associated cavity, thereby enabling high-frequency resonance.
Implementation Method 2
Such resonators are circuit elements that resonate at specific frequencies through a combination of an inductor (L) and a capacitor (C) in terms of equivalent electronic circuits.
Implementation Method 3
a base plate made of a conductive material, and manufactured in an unfolded state, the base plate being configured foldable such that, upon folding, a cavity is formed inside while simultaneously positioning a plurality of resonators to protrude... in the cavity
Data Source
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AI summary
Disclosed herein may be a filter for communication devices. The filter may include a base plate made of a conductive material, manufactured in an unfolded state and configured to be foldable such that, upon folding, a cavity is formed inside while simultaneously positioning a plurality of resonators to protrude by a set length in a thickness direction or a width direction in the cavity. The plurality of resonators each have a distal end portion having a wider width than a remaining portion, and include a resonance characteristic end formed by curling opposite widthwise ends of the distal end portion in a rounded shape in one thickness direction from a leading end of the remaining portion. The aforementioned configuration provides advantages of facilitating a slim product design, reducing insertion loss, and enhancing resonance characteristics.