Flexible Circuit Board Layout for Foldable RF Signal Integrity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Foldable electronic devices with flexible circuit boards, such as FRCs, are prone to damage from repeated folding and unfolding, and are susceptible to electric field interference from metal components, leading to RF signal impedance mismatch.
Innovation Solution
A flexible circuit board design with multilayer areas connected by a highly-bendable section, featuring laminated copper clad laminates and ground wires to enhance flexibility and prevent electric field interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible circuit board is disposed across a folding area to enable folding and unfolding, then the device achieves foldability and compactness, but the circuit board is likely to be damaged by repeated folding and unfolding
Solution Approach 1:
The circuit board is divided into multiple layers with different functions: signal transmission layers and ground wire layers are separated. The ground wires are positioned adjacent to signal wires to create localized shielding zones, segmenting the electromagnetic environment and reducing interference during folding operations.
Solution Approach 2:
Ground wires act as intermediary elements between signal wires and the external environment. These ground wires are strategically placed to intercept and dissipate electromagnetic interference before it can affect the signal transmission, serving as a protective mediator in the circuit board structure.
2Strength
If metal members are used in the electronic device to provide structural support, then the device achieves mechanical strength, but electric field interference occurs causing impedance mismatch of RF signals
Solution Approach 1:
The harmful electromagnetic interference is extracted and isolated from the signal transmission path by introducing dedicated ground wire layers. These ground wires capture and redirect interfering electric fields away from the signal wires, effectively removing the harmful effect from the signal path while maintaining the metal structural support.
Solution Approach 2:
The circuit board design implements local quality by positioning ground wires specifically adjacent to signal wires only where interference is expected. This localized shielding approach provides targeted protection against electric field interference in critical areas without requiring complete shielding of the entire circuit board, maintaining structural integrity while reducing interference.
Data Source
AI summary
A flexible circuit board and a foldable electronic device includes a first multi-layer region, a second multi-layer region and a highly bendable region disposed between the first multi-layer region and the second multi-layer region. The first multi-layer region and the second multi-layer region include a structure in which a plurality of copper clad laminates (CCLs) are stacked. The highly bendable region includes a structure in which a single CCL extending from one CCL among the plurality of CCLs in the first multi-layer region and the second multi-layer region is stacked. The single CCL may be configured such that a first ground wire, a second ground wire, and a plurality of sub wires disposed to be spaced apart between the first ground wire and the second ground wire transmit a single RF signal.