Dielectric Waveguide Redirection Structure for OLED mmWave Leakage
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Solution Overview
Problem
Millimeter-wave antennas in mobile devices, such as smartphones, face inefficiency due to energy leakage between the OLED layer and the EMI layer, leading to a 2-5 dB efficiency drop, and current solutions like high impedance surfaces are not compatible with OLED panels without affecting their performance.
Innovation Solution
A multilayer structure with a conductive element, a conductive substrate, and a dielectric substrate forming a wave guide, including a dielectric cavity that redirects electromagnetic waves, preventing energy leakage and allowing for improved antenna directivity without galvanic grounding, suitable for mmWave and other antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mmWave antenna is embedded next to the OLED display panel, then the antenna can be integrated into the device, but energy leakage occurs between the OLED layer and EMI layer causing 2-5 dB efficiency drop
Solution Approach 1:
A dielectric substrate with specific permittivity (2.2-4.0) is introduced as an intermediary layer between the OLED display panel and the mmWave antenna. This dielectric substrate acts as a mediator that guides electromagnetic waves from the antenna away from the OLED panel, preventing energy leakage while maintaining integration. The dielectric properties of this intermediate layer are specifically tuned to achieve optimal wave guidance and reduce interference.
Solution Approach 2:
The space between the antenna and OLED panel is segmented into distinct functional layers: the OLED panel, a dielectric substrate layer with specific electromagnetic properties, and the antenna element. This segmentation allows each layer to perform its specific function - the dielectric substrate specifically handles electromagnetic wave guidance to prevent leakage, while the antenna focuses on signal transmission.
2Loss of energy
If the gap between OLED layer and EMI tape is removed by galvanic closing, then energy leakage is eliminated, but OLED panel operation is negatively affected and proper shielding becomes challenging
Solution Approach 1:
Instead of directly galvanically closing the gap between OLED and EMI layer, a dielectric substrate serves as an intermediary that achieves energy leakage prevention through electromagnetic wave guidance rather than direct conductive connection. This intermediary approach eliminates the need for galvanic contact that would compromise OLED reliability while still preventing energy leakage.
Solution Approach 2:
The mechanical/electrical approach of galvanic closing (direct conductive connection) is replaced with an electromagnetic field-based approach using a dielectric substrate. The dielectric substrate manipulates electromagnetic wave propagation to prevent energy leakage without requiring physical conductive contact, thus avoiding the reliability issues associated with galvanic closing.
3Loss of energy
If high impedance surfaces are implemented to prevent surface wave propagation, then energy leakage is reduced, but compatibility with OLED panels is lost and performance is negatively affected
Solution Approach 1:
Instead of implementing a high impedance surface that would affect the entire OLED panel structure, the solution uses a dielectric substrate with specifically tuned local electromagnetic properties (permittivity between 2.2-4.0) only in the critical region between the antenna and OLED panel. This localized approach with specific dielectric properties achieves energy leakage prevention without compromising overall OLED panel compatibility or 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 solution effectively reduces energy leakage, maintains OLED panel performance, and enhances antenna directivity, enabling efficient mmWave signal propagation without hotspot risks or heat transfer issues, suitable for a wide range of antennas including 5G mmWave common mode display-side antennas.
Implementation Method 1
a dielectric substrate, the dielectric substrate being arranged between the first conductive element and the conductive substrate, and forming a wave guide
Implementation Method 2
the dielectric cavity forms an impedance discontinuity, the wave guide having a first impedance adjacent a section of conductive material of the second conductive element or a section of conductive material of the conductive substrate, and a second impedance adjacent the dielectric cavity, the second impedance being larger than the first impedance. The second impedance causes a large part of the electromagnetic waves to be reflected back towards the antenna element
Implementation Method 3
The dielectric substrate may have a dielectric constant Dk between 1 and 4
Data Source
AI summary
A redirection structure for electromagnetic waves includes a multilayer structure and at least one antenna element. The multilayer structure includes a first conductive element, a conductive substrate, and a dielectric substrate arranged between the first conductive element and the conductive substrate and forming a wave guide. The antenna element is arranged adjacent an edge of the multilayer structure at an interface, the electromagnetic waves at least partially propagating in the wave guide along a first direction. The redirection structure further includes at least one dielectric cavity arranged at a predefined distance from the interface along the first direction. The dielectric cavity extends in a second direction away from the dielectric substrate at least partially through the conductive substrate.