Folded Loop Antenna for Thin Mobile Devices
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Solution Overview
Problem
Built-in antennas in mobile devices face challenges due to the conflicting requirements of lightness, thinness, and aesthetics, which often result in degraded radiation performance due to insufficient antenna space or increased device thickness.
Innovation Solution
A loop antenna design featuring a substrate with a grounding portion, radiating portion, matching portion, and feeding portion, optimized to operate in both 2.4 GHz and 5.8 GHz bands, utilizing conductive materials and a matching portion with chip capacitors and inductors to create resonant modes, allowing for a compact size of 5 mm×20 mm while maintaining effective radiation patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If metal or conductive materials are used for appearance design to achieve lightness and thinness, then device thickness is reduced, but antenna radiation performance degrades due to insufficient antenna space
Solution Approach 1:
The antenna design transitions from a planar two-dimensional structure to a three-dimensional folded structure. The radiating element is folded back on itself multiple times, creating vertical and horizontal dimensions that allow the antenna to achieve effective radiating length while maintaining a compact footprint on the substrate, thus resolving the conflict between thinness and radiation performance
Solution Approach 2:
The antenna structure employs a nested configuration where the radiating element is folded and layered within a compact space. The element folds back multiple times, with each segment nested within or adjacent to previous segments, maximizing the use of available three-dimensional space while maintaining a thin overall profile
2Reliability
If sufficient clearance areas are provided for antenna operation, then radiation performance is maintained, but device thickness increases
Solution Approach 1:
The antenna utilizes the third dimension (vertical height) by folding the radiating element upward and backward, rather than requiring large horizontal clearance areas. This dimensional transition allows sufficient radiating length to be achieved within a constrained planar footprint and reduced thickness
Solution Approach 2:
The radiating element is divided into multiple segments connected at folding points. These segmented sections are arranged in a folded configuration, allowing each segment to contribute to the overall radiating length while the folded arrangement compactly packs the structure within a thin profile
3Area of stationary object
If antenna space is reduced to achieve compact device design, then device size is reduced, but radiation performance degrades
Solution Approach 1:
The antenna achieves extended radiating length by utilizing vertical folding rather than horizontal extension. The element folds upward and backward multiple times, converting horizontal space requirements into vertical arrangements, thus maintaining a compact footprint while achieving sufficient radiating length for good radiation performance
Solution Approach 2:
The folded radiating segments are nested within a compact three-dimensional volume, with each fold bringing portions of the element into closer proximity. This nesting maximizes the radiating length packed into a minimal footprint area while maintaining the electrical length required for effective radiation
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 loop antenna achieves desirable antenna gain and frequency coverage across 2.4 GHz and 5.8 GHz bands, satisfying the need for compact size and performance in narrow bezel electronic devices without compromising radiation efficiency.
Implementation Method 1
utilizing conductive materials and a matching portion with chip capacitors and inductors to create resonant modes
Data Source
AI summary
The present disclosure provides a loop antenna, including a substrate, and a grounding portion, a radiating portion, a matching portion, and a feeding portion that are located on the substrate. The grounding portion includes a first grounding segment and a second grounding segment. The second grounding segment is perpendicular to the first grounding segment, and a first end of the second grounding segment is connected to a first end of the first grounding segment. The radiating portion includes a first radiating segment and a second radiating segment. The first radiating segment is connected to a second end of the first grounding segment and extending from the first grounding segment towards a direction away from the first grounding segment. The second radiating segment is connected to the first radiating segment and extending from the first radiating segment towards a direction facing the second grounding segment. The matching portion is located at an end of the second radiating segment close to the second grounding segment. The feeding portion is located between the end of the second radiating segment close to the second grounding segment, and is located between the matching portion and the second grounding segment to receive and transmit a feeding signal.