Abstract

The radio-frequency identification (RFID) system which has become pervasive in the auto identification technology has been noticed to have several limitations. These limitations can be broadly divided into two major areas namely; application specific problems and general RFID problems. Application specific problems are common to the environment in which RFID tags are deployed such as metal, aqueous and irradiation environments. Whilst, the general problem of RFID tags include low gain, regional specifications and so on. In this paper, a new antenna prototype has been design and stimulated. The proposed antenna showed tendency of exhibiting improved gain from the previous RFID UHF antenna which is 0-1 dBi to -3 dBi and impedance bandwidth of 140 MHz. The proposed antenna is Y shaped patch with unequal monopole arms which are responsible for the different frequencies that the antenna operates and a quarter wavelengths was adopted rather than the popular half wavelength for size reduction. The fractional return-loss bandwidth for S11<10 dB and radiation efficiency are about 95% was obtained.

Key words: Passive ultra high frequency radio-frequency identification (UHF RFID) tags, microstrip antenna, impedance bandwidth.