Portal Antenna Triangular Coil Null Zone Elimination
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Solution Overview
Problem
Low frequency RFID devices carried by animals moving quickly through a race often go undetected due to null zones in existing antennas, particularly with small animals like sheep that move rapidly and unpredictably, leading to inefficient and time-consuming identification processes.
Innovation Solution
A portal antenna with a portal structure and coils wound around it, featuring elongate metal radiators at an angle to the direction of animal passage, which distorts the electromagnetic field to minimize null zones and ensure effective reading of RFID devices, even with rapid animal movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional antenna is used in a stock race, then the structure is simple, but animals moving quickly through the race may pass through null zones and the RFID device may not be read
Solution Approach 1:
The antenna is divided into multiple coils (typically three coils arranged in a triangular pattern) rather than using a single conventional antenna. Each coil generates its own electromagnetic field, and together they create overlapping fields that eliminate null zones. This segmentation allows the system to maintain reliability while managing complexity through modular design.
Solution Approach 2:
The patent transitions from a single-point or linear antenna configuration to a planar triangular arrangement of multiple coils. By adding spatial dimensionality and distributing coils across a two-dimensional plane, the system creates overlapping electromagnetic fields that cover the entire race area, eliminating null zones and improving reading reliability.
2Reliability
If animals are held at some point in the race to read the RFID device, then the reading reliability improves, but the procedure becomes more time consuming and tedious
Solution Approach 1:
The portal antenna is positioned upstream in the race pathway to perform RFID reading before animals are fully processed or held. By reading RFID devices as animals naturally pass through the portal during normal flow, the system eliminates the need for subsequent holding and re-reading operations, maintaining reliability while improving productivity.
Solution Approach 2:
The portal antenna acts as an intermediary structure integrated into the race pathway that enables non-intrusive RFID reading. Animals pass through naturally without being held or restrained, and the antenna field intersects with their RFID tags during normal movement, allowing reliable reading without disrupting the flow and maintaining high processing speed.
3Productivity
If the animal moves through quickly or in an unpredictable manner, then the race efficiency is maintained, but the RFID device may not be detected due to null zones
Solution Approach 1:
Each coil in the triangular arrangement creates a localized electromagnetic field with specific coverage characteristics. By strategically positioning three coils with overlapping fields, the system ensures that every region within the triangular area has adequate field strength, eliminating local null zones and ensuring reliable detection regardless of animal position or speed.
Solution Approach 2:
The triangular coil arrangement creates a two-dimensional field coverage pattern rather than a one-dimensional or point-source field. This dimensional expansion ensures that animals moving at various speeds and positions within the race area always pass through a region with sufficient electromagnetic field strength for reliable RFID detection.
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 antenna design ensures reliable and efficient reading of low frequency RFID devices as animals pass through, reducing the likelihood of null zones and improving the integrity of the identification process by optimizing the coupling of the electromagnetic field with the RFID devices.
Implementation Method 1
at least one coil of antenna conductor wound around the portal structure to extend around the area through which an animal can pass
Implementation Method 2
at least one elongate radiator element which projects either side of the portal structure and has a longitudinal axis that is at an angle of less than 90° to a plane transverse to the direction in which an animal passes through the portal structure
Data Source
AI summary
A portal antenna (10) particularly suited for enabling low frequency RFID devices carried by animals to be read when animals are proceeding through a stock race or the like. The portal antenna includes a portal structure (11) through which an animal can pass and about which is wound at least one coil (18/19) of antenna conductor. At least one elongate radiator element (21) preferably projects to at least one side of the portal structure (11). Preferably the radiator(s) (21) is/are of ferrous/magnetically conductive metal. The radiator(s) can form a separate structure or be part of the wall structure of a stock race.