Flexible Cable High-Frequency Filter Integration
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Solution Overview
Problem
Current small electronic devices with wireless communication capabilities face challenges in downsizing due to the size requirements of high-frequency filters, which degrade the Q value of inductors and filters, leading to suboptimal bandpass and attenuation characteristics.
Innovation Solution
A signal transmission cable with a high-Q value band-elimination filter is implemented, featuring a flexible flat base body with a multilayer structure, where the inductor and capacitor are integrated within the cable, allowing for a larger inductor design and reduced thickness, and a series resonance inductor is connected in series to the capacitor to attenuate specific frequency bands while minimizing transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the high-frequency filter is mounted or formed on the front end board, then the filter can be integrated with the circuit board, but the shape of the front end board becomes larger by the volume of the high-frequency filter
Solution Approach 1:
The patent merges the high-frequency filter with the flexible flat cable by forming the inductor and capacitor directly on the cable's insulating layer. This integration eliminates the need for separate filter components and reduces the overall volume of the front end board assembly, as the filter functionality is embedded within the existing cable structure rather than adding external volume.
Solution Approach 2:
The patent transitions from planar filter designs on rigid circuit boards to a three-dimensional flexible cable implementation. By utilizing the thickness dimension of the flexible flat cable and forming立体 (three-dimensional) inductor patterns, the filter achieves compact integration without increasing the planar footprint of the front end board.
2Volume of moving object
If the high-frequency filter is downsized, then the volume of the filter is reduced, but the line width of the inductor is reduced and constraints are imposed on the shape of the inductor, degrading the Q value
Solution Approach 1:
The patent utilizes three-dimensional inductor patterns formed on the flexible cable, allowing the inductor to achieve sufficient inductance value with smaller planar dimensions. By using vertical stacking and multi-layer configurations, the inductor maintains adequate line width and shape flexibility while reducing overall filter volume, thus preserving the Q value.
Solution Approach 2:
The patent changes the geometric parameters of the inductor by utilizing the flexible cable's thickness dimension and forming立体 patterns with optimized turn ratios and winding configurations. This allows the inductor to maintain high Q value through improved current distribution and reduced parasitic effects, even with compact dimensions.
3Volume of moving object
If the line width of the inductor is reduced to downsize the filter, then the Q value of the inductor is degraded, resulting in degraded filter characteristics
Solution Approach 1:
The patent employs three-dimensional inductor patterns on the flexible cable that utilize vertical stacking and multi-layer configurations. This dimensional transition allows the inductor to achieve required inductance values with smaller line widths while maintaining adequate current carrying capacity and low parasitic resistance, thus preserving filter characteristics including steep attenuation characteristics.
Solution Approach 2:
The patent uses composite structures combining the flexible cable's insulating material with conductive patterns formed on and within the cable layers. This composite approach allows optimization of both mechanical flexibility and electrical performance, maintaining high Q value and precise filter characteristics even with compact inductor dimensions.
4Ease of manufacture
If mount-type components are used for the inductor and capacitor, then the filter can be assembled, but the area available for inductor design is limited and flexibility in inductor designing is reduced
Solution Approach 1:
The patent merges the inductor and capacitor into the flexible flat cable structure itself, eliminating the need for separate mount-type components. The inductor patterns are formed directly on the insulating layer, and capacitors are implemented as overlapping conductor patterns between layers. This integration provides unlimited design flexibility for optimizing inductor geometry, coupling, and layout while simplifying assembly to a single manufacturing process.
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 enables the creation of compact communication device modules with excellent communication characteristics without degrading transmission and reception quality, achieving steep attenuation characteristics and a wider capacitance range.
Implementation Method 1
a series resonance inductor is connected in series to the capacitor to attenuate specific frequency bands
Data Source
AI summary
A signal transmission cable including a high-Q value band-elimination filter includes a first signal line conductor pattern including a first capacitor conductor portion and an inductor conductor portion on a first base layer. The first capacitor conductor portion includes a flat conductor, and the inductor conductor portion has a spiral shape. A second signal line conductor pattern including a second capacitor conductor portion is provided on a second base layer. The inductor conductor portion constitutes an inductor, and the first and second capacitor conductor portions and the first base layer constitute a capacitor. The inductor and the capacitor are connected in parallel by transmission conductor portions on the first and second base layers and an interlayer-connector conductor on the first base layer.