RF Absorber Placement in Wireless Device Metal Shield
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Solution Overview
Problem
In mobile wireless communications devices, the RF metal shield can cause electromagnetic coupling and interference among RF components due to radiated RF energy, degrading RF performance despite its intended shielding function.
Innovation Solution
An RF absorber, such as a ferrite material or a longitudinal slot, is positioned at openings in the RF metal shield to reduce electromagnetic coupling by absorbing radiated RF energy, thereby minimizing interference between RF components within the shield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an RF metal shield is used to shield RF components, then shielding effectiveness against extraneous RF energy is improved, but electromagnetic coupling between RF components within the shield increases
Solution Approach 1:
An RF absorber material is introduced as an intermediary between the RF metal shield and the RF components. This absorber material intercepts and absorbs RF energy that would otherwise couple between components through the shield, thereby maintaining shielding effectiveness while reducing electromagnetic coupling between components.
Solution Approach 2:
The RF absorber material is strategically positioned at specific locations where electromagnetic coupling occurs most strongly, such as near RF components that radiate energy into the shield. This localized placement optimizes the reduction of electromagnetic coupling while minimizing impact on overall shielding effectiveness.
2Volume of moving object
If RF components are placed closer together to reduce device size, then device compactness is improved, but electromagnetic interference between components increases
Solution Approach 1:
The RF absorber material serves as a mediator that allows RF components to be placed in closer proximity by absorbing the RF energy that would otherwise cause interference between closely-spaced components, enabling compact device design without sacrificing RF performance.
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
The implementation of an RF absorber effectively reduces electromagnetic interference, enhancing RF performance and sensitivity by mitigating the shielding issues caused by the RF metal shield.
Implementation Method 1
An RF absorber, such as a ferrite material or a longitudinal slot, is positioned at openings in the RF metal shield to reduce electromagnetic coupling by absorbing radiated RF energy
Data Source
AI summary
A mobile wireless communications device includes a housing and circuit board carried by the housing and having RF circuitry comprising at least one RF component and plurality of other components mounted on the circuit board. An RF metal shield is secured to the circuit board and surrounds and isolates the at least one RF component and plurality of other components within the RF metal shield. An RF absorber is positioned adjacent an area of the RF component that radiates energy to aid in reducing energy radiated from the RF component into the RF metal shield.