Multi-Antenna Substrate Layout Using Intentional Impedance Mismatch
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Solution Overview
Problem
In compact antenna devices with closely packed radio antennas, electromagnetic interference leads to performance disruptions, and existing solutions to mitigate this interference often compromise the device's compactness and simplicity.
Innovation Solution
Intentionally mismatching the radio antennas' impedance with the electronic transmission and/or reception circuit by incorporating capacitive, inductive, and resistive components in the electrical connection means, which allows for functional decoupling without adding significant complexity or bulk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If radio antennas are placed close together in a compact structure, then device compactness is improved, but electromagnetic interference between antennas increases
Solution Approach 1:
The patent introduces an electromagnetic wave disturbance device with metamaterial structure as an intermediary element positioned between the two antennas. This metamaterial structure selectively disturbs electromagnetic waves in specific frequency ranges, reducing mutual coupling and interference between the closely-spaced antennas while allowing the device to maintain its compact form factor
2Object-affected harmful factors
If decoupling circuits or neutralization lines are added between antennas, then electromagnetic interference is reduced, but device complexity and bulk increase
Solution Approach 1:
The patent changes the electromagnetic parameters of the space between antennas by introducing a metamaterial structure with specific permittivity and permeability characteristics. This parameter change creates an electromagnetic environment that reduces mutual coupling without requiring additional active circuit components, thereby maintaining device simplicity
3Object-affected harmful factors
If defects are created in the ground plane between antennas, then current propagation is hindered and interference is reduced, but space between antennas increases
Solution Approach 1:
The patent employs metamaterials with composite electromagnetic properties between the antennas. These composite materials create electromagnetic disturbance and hinder current propagation on the ground plane through their unique permittivity and permeability characteristics, achieving interference reduction without requiring physical separation or ground plane defects
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 reduces electromagnetic interference between antennas, maintaining the device's compactness and simplicity while improving decoupling and intrinsic electromagnetic isolation, as demonstrated by reduced interference transmission coefficients and enhanced intrinsic insulation parameters.
Implementation Method 1
by deliberately mismatching the radio antennas by conformation, which is contrary to the teaching of the state of the art, and by re-adapting them to the electronic transmission and/or reception circuit by inserting simple capacitive, inductive and/or resistive electrical components into the electrically conductive connection means
Implementation Method 2
In patent EP 2 808 946 B1, the solution proposed is to place an electromagnetic wave disturbance device with a metamaterial structure between the two antennas
Data Source
Figure 1~3
Figure 4~6
Figure 7A~7B
AI summary
This antenna device (10) comprises at least two radio antennas (20, 22), whose electrical connection ports (20A, 20B, 22A, 22B) are arranged on the same substrate (12), and electrically conductive means (24, 26, 28) for connecting the ports (20A, 20B, 22A, 22B) of said at least two radio antennas (20, 22) to an electronic transmitting and/or receiving circuit. Each radio antenna (20, 22) is configured to exhibit an impedance mismatch with the electronic transmitting and/or receiving circuit such that its input or output reflection coefficient is greater than a predetermined threshold value in the absence of any impedance matching.But the electrically conductive connecting means (24, 26, 28) include capacitive, inductive and/or resistive electrical components (40, 42, 46) for impedance matching with the electronic transmitting and/or receiving circuit, arranged to reduce said reflection coefficient to a value lower than the predetermined threshold value.