Shared-Radiator MIMO Antenna Structure for High Isolation
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Solution Overview
Problem
The limited space within electronic devices restricts the frequency band coverage of MIMO antennas, and existing antenna designs struggle with high isolation and multi-band requirements, particularly in 5G wireless communication systems.
Innovation Solution
An antenna structure with a first circuit that excites half-wavelength and one-time wavelength modes of both CM and DM modes, utilizing symmetrical and anti-symmetrical feeding elements and inductors/capacitors to ensure different current paths for each mode, achieving high isolation and expanded bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If antennas share a radiator to reduce device volume, then space utilization is improved, but isolation between antennas deteriorates
Solution Approach 1:
The patent divides the single radiator into multiple independent radiating elements (first radiator, second radiator, third radiator, fourth radiator) arranged in a specific geometric pattern. Each radiator can be independently controlled through separate feeding circuits, allowing simultaneous operation at multiple frequency bands while maintaining spatial separation to achieve high isolation between antenna ports.
Solution Approach 2:
The patent employs asymmetric feeding network design where different radiators are connected to different ports through unequal path lengths and different impedance transformations. This asymmetric configuration creates distinct current distribution patterns on each radiator, enabling frequency selective surfaces to effectively separate signals at different frequency bands and maintain high isolation.
2Productivity
If MIMO technology is implemented to achieve high-speed data transmission, then data transmission speed is improved, but device complexity increases
Solution Approach 1:
The patent designs a multi-functional antenna system where a single antenna structure supports multiple frequency bands (sub-6GHz and mmWave) and multiple MIMO ports through shared ground structures and integrated feeding networks. The frequency selective surfaces serve dual purposes of radiation control and signal isolation, reducing overall system complexity while enabling high-speed data transmission.
Solution Approach 2:
The patent merges multiple antenna functions into a single integrated structure. The ground structure serves as both the reference plane for radiation and the isolation barrier between frequency bands. The feeding network combines multiple signal paths into a compact configuration, and the frequency selective surfaces simultaneously control radiation patterns and provide port isolation, reducing the number of separate components needed.
3Adaptability or versatility
If frequency selective surfaces are used to achieve multi-band operation, then bandwidth is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies frequency selective surfaces with different local characteristics to different regions of the antenna structure. Each surface is designed with specific pattern densities and geometries tailored to its local frequency band requirements. This localized optimization allows each surface to be manufactured with standard precision while achieving the desired multi-band performance through the collective effect of all surfaces.
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 high isolation and expanded bandwidth, enabling efficient multi-mode resonance and reduced volume, suitable for various communication technologies including 5G.
Implementation Method 1
a first circuit of the antenna structure excites modes such as a half-wavelength mode, a one-time wavelength mode, and a three-half-wavelength mode of a CM mode, and may further excite modes such as a half-wavelength mode, a one-time wavelength mode, and a three-half-wavelength mode of a DM mode
Implementation Method 2
The first feeding element is electrically connected to the third port and the fourth port, and the electrical signal of the first feeding element has a same phase on the third port and the fourth port. The second feeding element is electrically connected to the third port and the fourth port, and the electrical signal of the second feeding element has opposite phases on the third port and the fourth port.
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
Embodiments of this application provide an electronic device, and the electronic device may include an antenna structure. A first circuit of the antenna structure excites modes such as a half-wavelength mode, a one-time wavelength mode, and a three-half-wavelength mode of a CM mode, and may further excite modes such as a half-wavelength mode, a one-time wavelength mode, and a three-half-wavelength mode of a DM mode. The antenna structure can operate in the CM mode and the DM mode, and the antenna structure still has a plurality of resonances and a plurality of modes while having high isolation, which greatly improves practicability. In addition, because an antenna operating in the CM mode and an antenna operating in the DM mode share a same radiator, a volume of the antenna structure can also be effectively reduced.