Polarized RFID Antenna Switching With 90-Degree Phase Distribution
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Solution Overview
Problem
The complexity in designing wiring patterns for antenna configurations that require a 90-degree phase difference between horizontally and vertically polarized wave antennas for circularly polarized wave output leads to asymmetrical wiring patterns, making it difficult to predict and adjust phase differences, thereby complicating the design process.
Innovation Solution
An antenna apparatus with a distributor applying a 90-degree phase difference between its terminals, coupled with switches that control conduction between antennas, allows for symmetrical wiring patterns and efficient switching between polarized waves, including circularly and diagonally polarized waves, by ensuring a controlled phase difference between horizontally and vertically polarized wave antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If asymmetrical wiring patterns are used to provide 90-degree phase difference between horizontally and vertically polarized wave antennas, then circularly polarized wave output is achieved, but wiring pattern design becomes complicated and phase differences become difficult to predict
Solution Approach 1:
The patent applies asymmetry in reverse - it uses symmetrical wiring patterns combined with a phase difference generation unit to create the required 90-degree phase difference. This resolves the contradiction by maintaining wiring symmetry (reducing design complexity) while still achieving the asymmetric phase relationship needed for circularly polarized wave output through the phase difference generation unit
2Length of stationary object
If linearly polarized wave switching method is used to ensure communication distance, then power supply is switched between horizontally and vertically polarized wave antennas, but RFID tags at orientations corresponding to the other polarized wave cannot be read
Solution Approach 1:
The patent implements dynamic switching capability that allows the system to adapt between linearly polarized wave mode (for long-distance communication) and circularly polarized wave mode (for reading RFID tags at various orientations). The switching unit enables the system to dynamically change its operational mode based on the specific application requirements, thus resolving the contradiction between communication distance and adaptability to different tag orientations
3Adaptability or versatility
If circularly polarized waves are used to read RFID tags regardless of orientation, then reading speed for various orientations is improved, but communication distance decreases to about 70%
Solution Approach 1:
The patent implements dynamic switching capability that allows the system to adapt between linearly polarized wave mode (for long-distance communication) and circularly polarized wave mode (for reading RFID tags at various orientations). The switching unit enables the system to dynamically change its operational mode based on the specific application requirements, thus resolving the contradiction between communication distance and adaptability to different tag orientations
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 solution simplifies the wiring pattern design, enables efficient switching between polarized waves, and improves the output of circularly and diagonally polarized waves, enhancing the antenna's functionality and usability in reading RFID tags at various orientations.
Implementation Method 1
a distributor that has a first distributor other-side terminal and a second distributor other-side terminal, and distributes the electric power supplied via the first switch to the first distributor other-side terminal and the second distributor other-side terminal with a phase difference of 90 degrees
Implementation Method 2
a horizontally polarized wave antenna for emitting horizontally polarized waves as radio waves; a vertically polarized wave antenna for emitting vertically polarized waves as radio waves
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
An antenna apparatus is capable of switching between a plurality of types of radio waves (electromagnetic waves) having differing polarization planes, and emitting the plurality of types of radio waves. The antenna apparatus includes: a switch (60) that has a single one-side terminal (61) and four other-side terminals (62 to 65); and a distributor (90) that distributes electric power supplied via the switch (60) to a terminal (93) and a terminal (94) with a phase difference of 90 degrees. The antenna apparatus further includes a switch (70) that switches to either of a state in which conduction is achieved between an other-side terminal (62) of the switch (60) and a horizontally polarized wave antenna (41), and a state in which conduction is achieved between the terminal (93) of the distributor (90) and the horizontally polarized wave antenna (41). The antenna apparatus further includes a switch (80) that switches to either of a state in which conduction is achieved between an other-side terminal (63) of the switch (60) and a vertically polarized wave antenna (42), and a state in which conduction is achieved between the terminal (94) of the distributor (90) and the vertically polarized wave antenna (42). The antenna apparatus further includes a control unit (21) that controls the conduction state of the switches (60, 70, 80).