LC Resonant Antenna Decoupling for Compact Multi-Band MIMO
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Solution Overview
Problem
The challenge is to miniaturize antennas while maintaining high isolation between multiple-input multiple-output (MIMO) antenna units, particularly in notebook computers with limited space, where existing decoupling structures like the T-shaped decoupling structure are too large to accommodate the increasing screen-to-body ratio and frequency band requirements.
Innovation Solution
The proposed solution involves an antenna decoupling structure using an LC resonant structure, comprising a grounding stub and a capacitor structure, along with additional decoupling stubs, to achieve decoupling for multiple frequency bands, allowing for miniaturization by adjusting the capacitance and inductance to match resonant frequencies, thereby reducing the overall size of the antenna.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a T-shaped decoupling structure is used to increase isolation between antenna units, then the isolation between antenna units is improved, but the antenna size becomes too large to accommodate in modern terminals with limited space
Solution Approach 1:
The patent changes the fundamental parameters of the decoupling structure by transitioning from a T-shaped geometry to an LC resonant circuit configuration. By adjusting the inductance value of the grounding stub and capacitance value of the capacitor structure, the decoupling performance is optimized for specific frequency bands while minimizing the physical footprint of the antenna system.
Solution Approach 2:
The patent replaces the traditional mechanical T-shaped decoupling structure with an electrical LC resonant circuit approach. Instead of relying on the physical geometry of a T-shaped stub to achieve decoupling, the invention uses the electrical resonance properties of an LC circuit (inductor-grounding stub and capacitor-capacitor structure) to achieve the same decoupling effect with reduced physical dimensions.
2Adaptability or versatility
If multiple decoupling stubs of different lengths are added to support multiple frequency bands, then the decoupling capability for multiple bands is improved, but the total length of the antenna structure increases
Solution Approach 1:
The patent makes the LC resonant structure multi-functional by designing it to support decoupling across multiple frequency bands. The grounding stub and capacitor structure are configured with specific inductance and capacitance values that enable the same structural element to provide effective decoupling for both 2.4 GHz and 5 GHz Wi-Fi bands, eliminating the need for separate decoupling structures for each band.
Solution Approach 2:
The patent merges the functions of multiple decoupling stubs into a single integrated LC resonant circuit. Instead of having separate T-shaped stubs for different frequency bands, the invention combines the decoupling functionality for multiple bands into one unified LC structure, where the inductor and capacitor work together to provide broadband decoupling performance.
3Area of stationary object
If the screen-to-body ratio is increased to meet modern terminal design requirements, then the aesthetic and space utilization are improved, but the available space for antenna structures becomes insufficient
Solution Approach 1:
The patent utilizes the vertical dimension (z-axis) by connecting the capacitor structure between the antenna floor and the grounding stub, creating a three-dimensional LC resonant structure. This vertical arrangement allows the decoupling function to be achieved without increasing the horizontal footprint of the antenna, thereby preserving screen real estate while maintaining necessary antenna functionality.
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 approach effectively increases isolation between antenna units, allows for smaller antenna dimensions, and covers multiple frequency bands, meeting the requirements of modern notebook computers with a greater screen-to-body ratio.
Implementation Method 1
a first end of the grounding stub is connected to an antenna floor, to form an equivalent inductor; and a first end of the capacitor structure is connected to the antenna floor, and a second end of the capacitor structure is connected to a second end of the grounding stub, so that the equivalent inductor and the capacitor structure form an LC resonant structure
Data Source
Figure 1a~1c
Figure 2a~2c
Figure 2d~2e
AI summary
This application provides an antenna decoupling structure, a MIMO antenna, and a terminal. The antenna decoupling structure includes a grounding stub and a capacitor structure, where a first end of the grounding stub is connected to an antenna floor, to form an equivalent inductor; and a first end of the capacitor structure is connected to the antenna floor, and a second end of the capacitor structure is connected to a second end of the grounding stub, so that the equivalent inductor and the capacitor structure form an LC resonant structure, where a parameter corresponding to the LC resonant structure meets a decoupling requirement for at least one target decoupling frequency band. A capacitance of the capacitor structure and an inductance of the equivalent inductor L are adjusted to ensure that a resonant frequency of the LC resonant structure is the same as the target decoupling frequency band, thereby implementing decoupling for the target decoupling frequency band. Because the resonant frequency depends on the inductance and the capacitance that correspond to the LC resonant structure, antenna miniaturization can be realized by reducing a size of each portion of the decoupling structure.