Planar Antenna Element with Segmented Loop for Multi-Band Mobile Devices
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Solution Overview
Problem
The challenge is to design a small-size, multi-band antenna for thin mobile communication devices that can accommodate reduced space without additional matching circuits, while covering a wide range of frequency bands such as LTE/WWAN from 1710 MHz to 2690 MHz and 824 MHz to 960 MHz.
Innovation Solution
A planar antenna element with a loop metal element and a branch metal element is used, where the loop metal element is divided into segments with a gap, and the branch metal element is coupled through an inductive element to the loop metal element, forming resonant modes that cover multiple frequency bands without additional matching circuits, and is fabricated on an FR4 substrate with a thickness of 0.4mm and dimensions of 10×35 mm2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the antenna element uses a conventional design to cover multiple frequency bands, then the frequency band coverage is achieved, but the antenna size becomes large and requires additional matching circuits
Solution Approach 1:
The loop metal element is divided into multiple segments (first segment, second segment, third segment) separated by gaps. This segmentation allows each segment to contribute to different resonant modes, enabling multi-band operation while maintaining a compact overall structure that would not be possible with a continuous loop of the same size.
Solution Approach 2:
The patent transitions from traditional planar antenna designs to a three-dimensional folded loop structure. By folding the loop in multiple directions and utilizing vertical spacing between segments, the antenna achieves equivalent electrical length for multi-band operation within a smaller footprint area.
2Area of moving object
If the antenna element is designed to be small-size for thin devices, then the space requirement is reduced, but the bandwidth and frequency coverage are limited
Solution Approach 1:
The gap configurations between loop segments are designed to be adjustable or variable. By changing the gap sizes or positions, the resonant frequencies and bandwidth can be tuned dynamically, allowing the same compact antenna structure to adapt to different frequency band requirements and expand its operational bandwidth.
Solution Approach 2:
The antenna employs a composite structure combining metal elements with dielectric substrate materials. This composite design enables the small antenna to achieve enhanced bandwidth by utilizing the electromagnetic properties of both materials, where the dielectric provides impedance transformation and the metal provides conductive paths for multiple resonant modes.
3Adaptability or versatility
If additional matching circuits are added to achieve multi-band coverage, then the frequency band coverage is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The antenna structure merges the radiating elements with the impedance matching functions into a single integrated design. The loop segments and gaps themselves serve as the matching mechanism, eliminating the need for separate matching circuits. This unified approach reduces device complexity while maintaining multi-band coverage capability.
Solution Approach 2:
The antenna structure is designed to be self-matching through its geometric configuration. The specific arrangements of loop segments and gaps create natural impedance transformations that provide broadband matching across multiple frequency bands without requiring external matching components, making the antenna self-sufficient.
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 antenna element provides a bandwidth of at least 1500 MHz, covering high and low frequency ranges effectively, with impedance bandwidth increased by bevel edges and resonant mode combination, suitable for thin tablet communication devices and meeting the requirements of mobile communication products.
Implementation Method 1
The antenna element can provide at least two wide frequency bands to cover multi-band operations of mobile communication products. The above two wide frequency bands are generated by exciting the loop metal element and the branch metal element, respectively.
Data Source
AI summary
A communication device including a ground element and an antenna element is provided. The antenna element is disposed adjacent to an edge of the ground element. The antenna element includes a loop metal element and a branch metal element. The loop metal element has a first end and a second end. The first end is coupled to a signal source. The second end is coupled to the ground element. The loop metal element includes a first segment and a second segment. The first segment is separated from the second segment by a gap. The first segment includes the first end, and the second segment includes the second end. The branch metal element has a third end and a fourth end. The third end is coupled through an inductive element to a connection point on the loop metal element. The fourth end is open.