MIMO Antenna Slot Layout for Compact High-Isolation Devices
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Solution Overview
Problem
The challenge of designing a multi-input multi-output (MIMO) antenna system in electronic devices with limited space and high frequency band requirements, particularly in mobile devices, is exacerbated by insufficient space, high envelope correlation coefficient, and interference between multiple communication frequency bands.
Innovation Solution
The proposed antenna structure includes a first and second antenna element with overlapping slots or radiators, utilizing symmetrical and offset central feed manners to achieve good isolation, allowing for parallel placement and reducing spatial occupancy, and employing orthogonal electric field distributions to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional antenna design is used in compact space, then antenna space is reduced, but system isolation and envelope correlation coefficient performance deteriorate
Solution Approach 1:
The patent transitions from conventional planar antenna layouts to a three-dimensional stacked configuration where antenna elements are arranged vertically with overlapping projections. This dimensional change allows multiple antenna elements to occupy the same horizontal footprint while maintaining spatial separation through vertical positioning, thereby reducing the horizontal space requirement while preserving system isolation through controlled spacing distances
Solution Approach 2:
The patent implements a nested arrangement where antenna elements are positioned within each other's projection areas, creating a compact stacked structure. The first and second antenna elements are arranged such that their projections overlap in the horizontal plane while being separated vertically, allowing one antenna to be effectively 'nested' within the spatial envelope of another, thus achieving compact integration without compromising isolation
2Adaptability or versatility
If quantity of antennas is increased for multiple frequency bands, then frequency band coverage is improved, but mutual impact and interference increase
Solution Approach 1:
The patent arranges multiple antenna elements supporting different frequency bands in a vertical stacked configuration with overlapping horizontal projections. This three-dimensional arrangement allows frequent antennas to be closely integrated in the horizontal plane while maintaining vertical separation, thereby achieving wide frequency band coverage while minimizing mutual interference through controlled spacing and orthogonal polarization
Solution Approach 2:
The patent employs asymmetric spacing distances between different antenna elements, where the spacing between first and second antenna elements is optimized to be less than a quarter wavelength to achieve frequency selectivity and reduce mutual coupling. This asymmetric arrangement allows different frequency bands to coexist with minimized interference by creating frequency-dependent coupling characteristics
3Area of stationary object
If antenna elements are placed closer to reduce space, then space occupancy is reduced, but isolation between antenna elements deteriorates
Solution Approach 1:
The patent achieves compact integration by arranging antenna elements in a vertical stack with overlapping horizontal projections, reducing the horizontal area occupied while maintaining isolation through vertical spacing. The spacing distance between elements is controlled to be less than a quarter wavelength, creating a compact structure that preserves isolation through the three-dimensional arrangement rather than relying solely on horizontal separation
Solution Approach 2:
The patent optimizes the spacing distance parameter between antenna elements to be less than a quarter wavelength, which creates a specific electromagnetic coupling condition that reduces mutual interference. By carefully controlling this critical dimension parameter, the patent achieves both compact size and high isolation simultaneously, resolving the trade-off between space occupancy and isolation
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 design enhances radiation efficiency and bandwidth while maintaining high isolation between antenna elements, enabling effective operation in compact electronic devices with multiple frequency bands.
Implementation Method 1
the electric field generated by the first antenna element is orthogonal to the electric field generated by the second antenna element
Data Source
AI summary
According to embodiments, an antenna structure may include a first antenna element and a second antenna element. A first slot of the first antenna element and a second slot of the second antenna element extend in a first direction and are spaced apart in a second direction, and projections of the first slot and the second slot in the second direction at least partially overlap, where the second direction is perpendicular to the first direction. A first feed point of the first antenna element is disposed in a central region of the first slot, or disposed at an end of the first slot, and a second feed point of the second antenna element is disposed at an end of the second slot. An operating frequency band of the first antenna element is the same as or adjacent to an operating frequency band of the second antenna element.