Foldable Antenna Module Signal Routing Across a Hinge
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Solution Overview
Problem
Foldable electronic devices experience signal loss and impedance changes due to the folding operation, particularly with high-frequency mmWave antenna modules, as the flexible radio frequency cable or coaxial cable is physically broken and its impedance characteristics change, leading to degraded performance.
Innovation Solution
The electronic device incorporates a flexible printed circuit board (FPCB) to deliver digital or I/Q signals between processors and antenna modules, maintaining signal integrity and preventing impedance changes during folding, thus reducing signal loss and maintaining antenna module performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible radio frequency cable or coaxial cable is used to connect antenna modules across the folding joint, then the device can achieve foldable form factor, but the impedance characteristics change during folding operation causing signal loss
Solution Approach 1:
The patent replaces the mechanical flexible cable system with a rigid printed circuit board structure that has controlled impedance. The FPCB maintains stable electrical characteristics during folding by using rigid substrate materials and controlled trace geometries, eliminating the impedance variations that occur with flexible cables during bending and folding operations.
Solution Approach 2:
The patent changes the electrical parameters of the transmission medium by transitioning from flexible cable geometry to rigid PCB trace geometry. This involves controlling trace width, substrate thickness, and dielectric properties to maintain consistent impedance values regardless of the folding state, thereby stabilizing signal transmission characteristics.
2Adaptability or versatility
If flexible cable is used for signal transmission across folding joint, then device flexibility is achieved, but the cable may be physically broken with increased folding operations
Solution Approach 1:
The patent replaces the flexible cable mechanical system with a rigid FPCB structure that achieves flexibility through the folding mechanism itself rather than through cable bending. This substitution eliminates the fatigue and breakage issues associated with repeated cable bending while maintaining the foldable form factor through rigid board construction.
Solution Approach 2:
The patent uses excessive rigidity in the FPCB construction to compensate for the folding stress. By making the PCB structure sufficiently rigid with appropriate substrate thickness and reinforcement, it can withstand the mechanical stresses of repeated folding operations without deforming or breaking, thereby extending the device's operational lifespan.
3Speed
If high frequency mmWave antenna modules are used for 5G communication, then communication speed is improved, but signal loss increases due to frequency and transmission line length
Solution Approach 1:
The patent replaces the lossy flexible cable transmission system with a controlled impedance FPCB transmission line system. The rigid PCB structure provides consistent electrical characteristics and controlled impedance matching, reducing signal reflections and losses that are prevalent in flexible cable systems, especially at high mmWave frequencies.
Solution Approach 2:
The patent optimizes transmission line parameters including trace width, substrate dielectric constant, and trace length to minimize signal loss at high frequencies. By carefully controlling these parameters, the FPCB achieves lower insertion loss and better signal integrity for mmWave communications compared to flexible cable alternatives.
Data Source
AI summary
An electronic device is provided. The electronic device includes a first part, a second part, a connection part disposed and coupled to the first part and the second part such that the first part and the second part are rotatable, a first antenna module disposed in the first part and includes an antenna array, a second antenna module disposed in the second part and includes an antenna array, a processor disposed in the first part, an IFIC disposed in the first part and electrically connected to the first antenna module and the processor, a second IFIC disposed in the second part and electrically connected to the second antenna module and the processor and an FPCB disposed over the first part, the connection part, and the second part, and is configured to transfer a digital signal or a baseband I/Q signal between the processor and the second IFIC.