Autocalibration of BiStatix® RFID Tag Read Range Test
Original Publication Date: 2001-Oct-18
Included in the Prior Art Database: 2001-Oct-18
AbstractAutocalibration of BiStatix® RFID Tag Read Range Test
By James G. Quaderer
In order to maintain quality during the manufacture of RFID tags, it is necessary to have at least an attribute (pass/fail) test of outgoing product before it is shipped to the final customer. Inductive RFID tags are almost entirely produced in electronics manufacturing facilities where RF test engineers are readily available. Because of the use of standard coils, most inductive RFID tags are of a standard size and performance so that changes in the test are few, it is good enough to have an RF test engineer design the final outgoing test equipment and not have to change that equipment for possibly years at a time.
Figure 1 illustrates a typical attribute read range test for either inductively-coupled tags or capacitively-coupled (BiStatix®) tags. In this example, the reader 2 contains an AC excitation source 4 which is set at it’s maximum continuous exciter amplitude A4 resulting in a maximum exciter field F4 produced by an exciter antenna 3. The AC amplitude vs. time graph on the right of Figure 1 illustrates that the exciter amplitude A4 does not change over time. The tag under test 1 is placed at a specified distance within the excitation field F4 from the reader 2 which results in a “pass” indication if the tag 1 is within specification.
Figure 3 illustrates the basic concepts of read range test autocalibration. The purpose of the autocalibration sequence is to allow the reader 2 to automatically select the correct excitation amplitude to be generated by the excitation source 4 for a particular style of tag 1. The procedure for autocalibration is outlined:
1. A reference tag is chosen from an early prototype lot of tags...