Broadband matching of a RFID antenna by using a T-type circuit

Abstract

RFID usage is steadily increasing in the world, and its frequency bands are assigned in each country. RFID in UHF band is mainly used in 900MHz band. Allocated frequency bands of Europe, the USA and Japan are included from 860 to 960MHz. Broadbanding of the IC and antenna is needed to manage the worldwide RFID frequency band. This paper proposes broadband matching of a RFID antenna by using a T-type circuit. The antenna consists of a meander-line and a T-type circuit that realizes conjugate impedance matching to the IC impedance. Equivalent circuits of the antenna are shown and evaluated by parametric study. Prototype of the antenna is realized and its numerical analyses are examined.