Beam Scanning Antenna for RFID Multipath Interference
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Solution Overview
Problem
RFID tag communication systems face challenges in covering wide areas without incommunicable regions due to multipath interference and the need for multiple antennas with high directivity, which increases antenna size and complexity.
Innovation Solution
A beam scanning antenna is used to narrow the radio wave beam in specific directions, intersecting with reflecting surfaces to reduce multipath interference and allow for a wider communication area with fewer antennas, employing phase shifters for scanning without mechanical adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an antenna having high directivity is used, then communication quality is improved, but the communication area becomes narrower
Solution Approach 1:
The patent employs a beam scanning antenna that dynamically changes the direction of its high-directivity beam over time. By sequentially scanning the beam across different directions, the system maintains high communication quality when the beam is pointed at a tag while eventually covering a wide communication area through the scanning motion.
Solution Approach 2:
The patent adds the time dimension to the spatial coverage problem. Instead of attempting to cover a wide area simultaneously with a wide beam, the system covers the area sequentially by scanning the narrow beam through different directions over time, effectively trading spatial coverage for temporal coverage.
2Area of stationary object
If an antenna having low directivity is used, then the communication area is widened, but communication quality deteriorates due to multipath interference
Solution Approach 1:
The beam scanning antenna dynamically switches between narrow beam modes (for high quality) and wide area coverage (through sequential scanning). This dynamic operation allows the system to achieve both wide communication area and high communication quality without the multipath interference problems of static low-directivity antennas.
3Reliability
If a number of antennas are used to cover a wide communication area with high directivity, then communication quality is maintained, but the device complexity and antenna size increase
Solution Approach 1:
The patent combines multiple functions into a single beam scanning antenna. Instead of using multiple separate high-directivity antennas to cover different directions, one antenna performs beam scanning to sequentially cover all directions, merging the functionality of multiple antennas into a single device.
Solution Approach 2:
The beam scanning antenna serves multiple purposes: it provides high-directivity communication when pointed at a tag, covers wide areas through scanning, and replaces what would otherwise require multiple separate antennas. This multi-functionality reduces overall system complexity.
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 effectively enlarges the communication area, reduces incommunicable regions, and simplifies antenna deployment by using fewer, smaller antennas while maintaining communication quality across a larger space.
Implementation Method 1
employing phase shifters for scanning without mechanical adjustments
Implementation Method 2
communicating with an RFID (Radio Frequency Identification) tag through a radio wave
Implementation Method 3
intersecting with a reflecting surface that generates a relatively high intensity reflection
Data Source
AI summary
An RFID reader/writer performs a radio communication with an RFID tag. An antenna for tag communication used in the RFID reader/writer is a beam scanning antenna that can perform scanning with the beam of a transmitted radio wave. The beam has a high directivity in a certain scanning direction. The scanning with the beam is performed so that a plane including the certain scanning direction intersects with a floor surface as a reflecting surface on which the strongest reflected wave is generated.