Designing a Planar T-match Antenna to have a 2nd-order Chebyshev Band-Pass Filter Frequency Response for the Purpose of UHF RFID

Abstract

Radio Frequency Identification (RFID) uses radio communication to identify physical objects that have transponders attached. Supply chain management is one of the main applications that has pushed the development of these transponders, called tags, over the last two decades. The T-match antenna is a common antenna type used by engineers designing RFID tags. To make T-match-based RFID tags more efficient at wider bandwidths, their power transfer efficiency (PTE) frequency responses have been designed to match those of band-pass filters that meet the user's desired frequency requirements. In this thesis, the equivalent circuit of the T-match antenna is shown to have the same form as a 2nd-order band-pass filter, and an existing RFID tag antenna's response is redesigned to match that of a 2nd-order Chebyshev filter. Three antenna designs are simulated that greatly increased the bandwidths over conventional T-match design procedures. This increased bandwidth can potentially allow the RFID tags using these antennas to be read at longer distances, or allow the power needed to read them at a particular distance to be reduced.