Test method for chip impedance and sensitivity of ultrahigh-frequency RFID tag

Abstract

The invention provides a test method for chip impedance and sensitivity of an ultrahigh-frequency RFID tag, comprising the following steps: obtaining the antenna impedance and antenna gain of the antenna in the tag; obtaining the tested value of the tag sensitivity of the tag; obtaining the calculated value of the tag sensitivity by traversing the chip impedance and chip sensitivity; and determining the correct chip impedance and chip sensitivity by comparing the tested value and the calculated value of the tag sensitivity. Through the test method presented by the invention, an antenna with better performance can be designed and / or a tag with higher sensitivity can be obtained.

Description

technical field [0001] The invention relates to the field of radio frequency testing, in particular to a testing method for chip impedance and sensitivity of radio frequency identification RFID (Radio Frequency Identification) tags. Background technique [0002] The UHF RFID system includes two parts: the reader and the RFID tag. The RFID tag includes an antenna and a chip, and the chip is the core part of the UHF RFID tag. When designing the tag antenna (for example, the impedance value of the antenna needs to be obtained), the chip impedance value is the main reference value. Here, the chip impedance value refers to the impedance value including the package impedance and excluding the antenna portion. Since the bare die impedance value does not include package effects, it is of little practical significance. [0003] In this field, testing the chip impedance value including package impedance has the following difficulties: [0004] (1) The area of ​​the chip is usually ...

AI Technical Summary

Problems solved by technology

[0004] (1) The area of ​​the chip is usually less than 1 square millimeter, which makes it difficult to use commonly used RF connectors such as SMA (Small Atype);

[0005] (2) The chip is a large-signal device, which has different impedance values ​​under different input powers. In principle, the load-pull method should be used, and the load-pull method requires an adapter, so the test sample is different from the actual use; in addition, in RFID Under the impedance of the chip, the loss of the tuner increases, which makes the deviation of the test results very large

[0006] (3) The chip impedance value is not the standard 50ohm, and the chip impedance Q value is usually greater than 10. As a result, when using a network analyzer for testing, the chip impedance value often appears at the edge of the network analyzer, and there is a network analyzer test The phenomenon of decreased accuracy;

[0007] (4) Different packaging forms lead to different chip impedance values ​​tested

Images