Patch Antenna Isolating RFID Devices for End-of-Line Testing
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Solution Overview
Problem
End-of-line testing of RFID devices arranged in chains or ribbons is challenging due to difficulty in focusing electromagnetic fields and electrical conduction issues, particularly with E-THREAD technology, which often requires physical contact and is not compatible with high production rates.
Innovation Solution
The test equipment uses a patch antenna with a resonant microstrip transmission line and impedance adjustment circuits to electrically isolate an RFID device from adjacent devices, allowing for testing without physical contact, utilizing a coupler with a resonant cavity to impose a short-circuit and confine the electromagnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electromagnetic field is emitted to test RFID devices in batch, then testing efficiency is improved, but field focusing becomes difficult and adjacent devices cannot be isolated
Solution Approach 1:
The test equipment divides the batch of RFID devices into individually testable units by using multiple independently controllable electromagnetic field emission zones. Each zone can be activated separately to test one device at a time while maintaining batch processing capability, thus achieving both high productivity and precise field focusing.
2Ease of manufacture
If wire elements are used to connect RFID devices in chain, then manufacturing cost is reduced, but electrical conduction activates adjacent devices during testing
Solution Approach 1:
The patent introduces electromagnetic field emission zones as an intermediary mechanism between the test equipment and RFID devices. This intermediary allows selective activation of individual devices through controlled field emission, preventing unwanted electrical conduction through wire elements while maintaining the cost-effective chain configuration.
3Measurement precision
If physical contact is made with wire elements to isolate devices, then testing accuracy is improved, but production rate decreases
Solution Approach 1:
The patent replaces the mechanical contact-based isolation method with an electromagnetic field-based isolation system. By using controlled electromagnetic field emission zones, the system achieves device isolation without physical contact, thereby maintaining high production rates while ensuring testing accuracy.
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 enables reliable and efficient testing of RFID devices by isolating the device under test from adjacent ones, ensuring accurate results without the need for physical contact, thus supporting high production rates and improving testing reliability.
Implementation Method 1
a resonant microstrip transmission line... to electrically isolate an RFID device from adjacent devices
Implementation Method 2
utilizing a coupler with a resonant cavity to impose a short-circuit and confine the electromagnetic field
Implementation Method 3
Patch antenna for coupling a transmitting/receiving terminal to an RFID device
Data Source
Figure 1a~1d
Figure 2~3
Figure 4~5
AI summary
The invention concerns a patch antenna for electrically coupling an RFID device to a tester, the RFID device being capable of communicating at an operating wavelength. The antenna comprises a planar dielectric substrate, a resonant transmission line arranged on a first face of the substrate and a coupler for linking the resonant transmission line to the tester. The transmission line comprises a half-wave main line having a first end and a second end, first and second impedance adjustment circuits electrically connected respectively to the first and second ends of the main line to impose a voltage node at these ends when a signal having the operating wavelength propagates in the transmission line. The invention also concerns a piece of test equipment provided with such a patch antenna.