Planar Inductive Electromagnetic Bandgap Structure for Thin Device Antennas
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Solution Overview
Problem
Conventional electromagnetic bandgap structures in electronic devices, such as mobile phones and tablets, face challenges in maintaining antenna efficiency due to the proximity of metal back covers, which affects radiation and requires increased pillar lengths to lower operating frequency, compromising device thickness and aesthetics.
Innovation Solution
Incorporating a planar inductive element between conductive elements in the electromagnetic bandgap structure, connected via conductive pillars, to increase equivalent inductance without lengthening the pillars, thus lowering the operating frequency and maintaining device thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the length of the conductive pillar is increased to lower the operating frequency, then the equivalent inductance increases, but the height of the electromagnetic bandgap structure increases, making the device thicker
Solution Approach 1:
The patent transitions from a vertical inductance structure (conductive pillar extending in height) to a planar inductance structure (inductive element extending in horizontal area). This dimensional change allows the equivalent inductance to be increased without increasing the height of the electromagnetic bandgap structure, thereby lowering the operating frequency while maintaining a thin device profile.
Solution Approach 2:
The patent changes the geometric parameters of the inductive element (area, shape, trace pattern) to adjust the equivalent inductance value. By modifying these planar parameters instead of vertical parameters, the operating frequency can be tuned without affecting the overall height of the structure.
2Reliability
If a slot is formed at the metal back cover to allow current flow, then the antenna radiation efficiency is improved, but the overall appearance of the metal back cover is affected
Solution Approach 1:
The patent extracts the current return path function from the metal back cover itself and relocates it to a dedicated electromagnetic bandgap structure with an inductive element. This separation allows the metal back cover to maintain its aesthetic appearance without slots or openings, while the EBG structure provides the necessary current path for antenna operation.
Solution Approach 2:
The electromagnetic bandgap structure with planar inductive element serves as an intermediary between the antenna and the metal back cover. It provides the current return path functionality that would otherwise require modification of the metal back cover, thus mediating between the electrical requirements and the aesthetic requirements.
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 solution effectively lowers the operating frequency of the electromagnetic bandgap structure without increasing pillar lengths, allowing for thinner electronic devices while maintaining antenna efficiency and aesthetics by integrating the bandgap structure into the metal housing.
Implementation Method 1
A planar inductive element is used in the electromagnetic bandgap structure to increase an equivalent inductance and keeps the electronic device thinner
Data Source
AI summary
An electromagnetic bandgap structure and an electronic device having the same are provided. The electromagnetic bandgap structure includes a first conductive element, a second conductive element and a planar inductive element. The planar inductive element is disposed between the first conductive element and the second conductive element. Furthermore, the planar inductive element is electrically connected to the first conductive element via a first conductive pillar, and it is electrically connected to the second conductive element via a second conductive pillar.