One of our customer purchase a batch of 30x50mm dual-frequency epoxy card with Mifare Plus X4K (HF) and TK4100 (LF). The cards had passed the test during fabrication. Resonant frequency test is normal, customer requirement 14.0±0.5MHz.
Reading and writing function test is normal, both universal card readers and mobile phones can read and write, including UID.
After receiving the cards, the customer found that the card could not be issued normally.
The customer wanted us to find the cause, but the reader for the project is inconvenient to provide.
Can the professional testing tool T8200Pro-G findout the problem?
It’s known to all that there are three major factors to judge a RFID product. Frequency, Q value and attenuation.
Using T8200Pro-G can test these three factors simultaneously.
Testing result
| Frequency | 13.734 MHz | Normal(green) |
| Attenuation | -1.329 dB | Normal(green) |
| Q value | 31.182 | Normal(green) |
| Communication test result | FAIL(red) | |
| 14443A UID | N/A(gray) |
Testing board: 40mmx40mm
| Frequency | 123.423 KHz | Normal(green) |
| Attenuation | -1.361 dB | Normal(green) |
| Q value | 9.558 | Normal(green) |
Testing board: LF testing board
Problem analysis and solution
HF Inlay performance problems
The frequency, Q value and attenuation tests can be displayed normally, but the dB value is found to be too small and the communication test fails. Based on experience and reasoning, it may be related to the size and design of the antenna.
New antenna design: Enlarge the size of the HF antenna.
– Original antenna:
HF and LF are arranged side by side with circular antenna.
– New antenna:
HF is replaced by a larger square antenna and place the LF antenna inside the HF antenna.
After improvement
Testing result
| Frequency | 14.174 MHz | Normal(green) |
| Attenuation | -7.499 dB | Normal(green) |
| Q value | 36.308 | Normal(green) |
| Communication test result | PASS（green） | |
| 14443A UID | 0408xxxxxxxx（7bit） | |
| Frequency | 122.523 KHz | Normal(green) |
| Attenuation | -1.741 dB | Normal(green) |
| Q value | 9.600 | Normal(green) |
Customer feedback after receiving improvement:
Conclusion
Only measured frequency and general read and write for non – standard small card or micro tag is not enough!
Except frequency, Q value and attenuation are also the key parameters to measure the performance of label!
Designing antenna or verifying label performance must use professional testing tools!