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A new systematic methodology for the design of T-match based UHF-RFID tags is proposed. The great majority of commercial UHF-RFID tags are based on dipole antennas using a modification of a T-match network. The literature contains examples of models that describe the T-match, but they are not sufficiently accurate to synthesize the tag geometry. Using the(More)
The radiation properties of split-ring resonators (SRRs) at their second resonance frequency are studied for the first time in this work. In particular, the electric and magnetic dipole moments of the edge-coupled SRR are calculated analytically under the assumption of strong coupling between the internal and external rings. Based on these results, the(More)
In this work, a passive ultra-high frequency radio-frequency identification UHF-RFID tag based on a 1.25 wavelengths thin dipole antenna is presented for the first time. The length of the antenna is properly chosen in order to maximize the tag read range, while maintaining a reasonable tag size and radiation pattern. The antenna is matched to the RFID chip(More)
In this work, novel UHF-RFID tags able to modify the operation frequency without increasing the tag size have been presented. This has been achieved by coupling an electrically small resonator to the antenna (meander type). Different tags have been designed, fabricated, and characterized. Good agreement between the theoretical (simulated) and measured read(More)
The definition of a precise illumination region is essential in many applications where the electromagnetic field should be confined in some specific volume. By using conventional structures, it is difficult to achieve an adequate confinement distance (or volume) with negligible levels of radiation leakage beyond it. Although metamaterial structures and(More)
This paper presents electromagnetic band gap (EBG)-based periodic microstrip lines and balanced (differential) microstrip lines. Specifically, it is shown that through a proper modulation of the strip width in a microstrip transmission line, a stopband with controllable characteristics can be obtained. These EBG structures are then applied to differential(More)
A study was carried out wherein during the period August 1979 to January 1980, samples of raw and fermented cacao were analyzed monthly. These included two varieties: Arriba, taken from a farm in "Quevedo", and the EET-19, grown in "Pichilingüe" by the Instituto Nacional de Investigaciones Agropecuarias (INIAP). Taking the ear of cacao as a basis, the(More)
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