Ground-Coupled MIMO Antenna Structure for Wide Bands and Low SAR
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Solution Overview
Problem
Electronic devices face challenges in achieving good MIMO performance due to limited space, which restricts the frequency band coverage of MIMO antennas, leading to high specific absorption rate (SAR) and limited bandwidth.
Innovation Solution
An antenna structure with multiple antenna units electrically connected to a ground, utilizing ground energy transfer for strong coupling, enabling operation in half-wave and one-wave modes to generate multiple frequency bands, with evenly distributed currents to reduce SAR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MIMO antenna is used to provide higher data transmission rate, then productivity is improved, but device complexity increases and space requirements are not met
Solution Approach 1:
The antenna structure is divided into multiple antenna units (first antenna unit, second antenna unit, third antenna unit) with different configurations. Each unit operates at different frequency bands and polarization directions, enabling MIMO functionality through segmentation rather than a single complex antenna system.
Solution Approach 2:
The patent utilizes three-dimensional space by arranging antenna units at different positions and orientations within the electronic device. The first, second, and third antenna units are disposed at different locations with different polarization directions, effectively using spatial dimensions to achieve MIMO performance without increasing planar footprint.
2Volume of moving object
If antenna units are closely arranged to save space, then volume is reduced, but harmful factors increase due to high SAR
Solution Approach 1:
Different antenna units are designed with different local characteristics - the first antenna unit operates at first frequency band with first polarization direction, the second antenna unit operates at second frequency band with second polarization direction, and the third antenna unit operates at third frequency band with third polarization direction. This local differentiation allows compact arrangement while maintaining low SAR through diverse current distribution patterns.
Solution Approach 2:
The ground structure serves as an intermediary element that electrically connects all three antenna units. By using the ground as a common reference and coupling medium, the antenna units can be closely arranged while the ground helps distribute currents evenly, preventing concentration of electromagnetic energy and reducing SAR in localized regions.
3Length of stationary object
If ground points are closely arranged to reduce device size, then length is reduced, but energy transfer efficiency decreases
Solution Approach 1:
The ground structure is designed to dynamically adapt its electrical connection characteristics based on the operating frequency. At different frequency bands, the ground provides appropriate impedance matching and energy transfer pathways, allowing efficient energy transfer despite the fixed physical distance between ground points. The ground's electrical properties effectively change with operating conditions.
Solution Approach 2:
The patent utilizes parameter changes in the ground structure's electrical characteristics to maintain energy transfer efficiency. By designing the ground with specific geometric parameters and electrical properties, the system achieves efficient energy transfer across multiple frequency bands despite the fixed physical arrangement of ground points.
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 proposed antenna structure achieves wide band coverage, low SAR, and meets communication requirements by distributing currents evenly across antenna units, enhancing MIMO performance.
Implementation Method 1
Energy is transferred, by using the ground, between the plurality of antenna units disposed on the ground, strong coupling is implemented
Implementation Method 2
the antenna structure works in an HWM and an OWM, and a plurality of operating frequency bands are generated
Data Source
AI summary
Embodiments of this application provide an electronic device. The electronic device includes an antenna structure, the antenna structure includes a plurality of antenna units, and the plurality of antenna units are electrically connected to a ground. When a feed unit feeds the antenna units, the ground bears a part of a mode current. Therefore, energy is transferred, by using the ground, between the plurality of antenna units disposed on the ground, strong coupling is implemented, working is performed in an HWM and an OWM, and a plurality of operating frequency bands are generated. In addition, because energy is transferred between the plurality of antenna units by using the ground, currents of the antenna units are evenly distributed, and a SAR of the antenna units is low.