Coil Antenna Design for Mutual Interference Suppression
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Solution Overview
Problem
Existing antenna devices for RFID systems face challenges in minimizing size and interference between multiple antennas sharing the same frequency band, leading to complex configurations, increased size, and reduced communication range due to the need for conductive and soft magnetic members.
Innovation Solution
The design incorporates a first coil antenna with one coil conductor and a second coil antenna with two coil conductors, where the magnetic fields form a closed circuit, allowing for minimal coupling and eliminating the need for conductive or soft magnetic members, enabling a compact, low-loss antenna device capable of operating in multiple communication systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conductive members or soft magnetic members are disposed between two antennas to suppress mutual interference, then mutual interference is reduced, but eddy-current loss increases and communication range decreases
Solution Approach 1:
The invention removes the conductive members and soft magnetic members from the antenna configuration. By extracting these problematic components, the patent eliminates the source of eddy-current loss while maintaining mutual interference suppression through the closed magnetic circuit design of the second coil antenna alone.
Solution Approach 2:
The patent replaces the mechanical approach of using physical barriers (conductive and magnetic members) with a field-based solution. The closed magnetic circuit configuration creates a self-contained magnetic field structure that suppresses interference without requiring additional material components, thus eliminating eddy-current losses.
2Object-affected harmful factors
If conductive members or soft magnetic members are disposed between two antennas to suppress mutual interference, then mutual interference is reduced, but device size and complexity increase
Solution Approach 1:
The invention extracts and removes the unnecessary conductive members and soft magnetic members from the antenna system. This simplification reduces device complexity and size while the closed magnetic circuit configuration of the second coil antenna maintains the interference suppression function through its inherent field structure.
3Adaptability or versatility
If two coil antennas are disposed at 90 degrees to enable wide angular communication, then angular compatibility is improved, but device size and configuration complexity increase
Solution Approach 1:
The patent transitions from a spatial arrangement approach (90-degree physical separation) to a field configuration approach. The closed magnetic circuit of the second coil antenna creates a self-contained three-dimensional magnetic field structure that provides wide angular compatibility without requiring specific orientation or increased device footprint.
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 configuration results in a small-sized antenna device with a long communication range and reduced manufacturing costs, while maintaining independence between antennas, allowing for wide angular relationships and high radiation efficiency.
Implementation Method 1
two coil conductors are disposed and wound such that a magnetic field that is generated by the two coil conductors defines a closed magnetic circuit
Implementation Method 2
a magnetic field that is generated by the two coil conductors defines a closed magnetic circuit that circulates in or substantially in an area inside the coil conductor of the first coil antenna or circulates in or substantially in an area outside the coil conductor of the first coil antenna via the coil conductor of the first coil antenna
Implementation Method 3
a predetermined communication is performed between an antenna of a reader-writer and an antenna of an RFID tag via a magnetic field or an electromagnetic field
Data Source
AI summary
An antenna device includes a first coil antenna and a second coil antenna. The first coil antenna includes a coil conductor having a rectangular or substantially rectangular spiral shape and located on a non-magnetic insulating base member. The second coil antenna includes two coil conductors located on a non-magnetic insulating base member. The two coil conductors are disposed and wound such that loops of a magnetic field that is generated by applying a current to the two coil conductors are perpendicular or substantially perpendicular to a coil axis of the coil conductors.