As the piezoelectric effect is assumed to be reciprocal transducer
input impedance can be measured and then, assuming this reciprocity, it can be used as output impedance.
Thus, the
input impedance of the hybrid microstrip antenna is calculated from
Thus, the
input impedance of the antenna with the split loop varies drastically.
Preamplifier
input impedance was designed for 1 k[ohm] using active impedance matching (R3, Fig.
Because of the body-proximity effects,
input impedance, radiation pattern, and realized gain of the tag antenna are influenced [2].
The desired antenna
input impedance has to be conjugately matched to tag chip to ensure adequate power transmission to the chip.
Input impedance is 200 k[OMEGA] single-ended or 400 k[OMEGA] differential.
The motivations of this paper is to introduce a flexible universal UHF RFID tag suitable for RFID applications all over the world, develop a systematic procedure to match the tag
input impedance to RFID chip, develop general relation to predict the dipole
input impedance and finally achieve reasonable size reduction.
By suitably adjusting the loop length "s" and loop-radiating body spacing "h", the
input impedance of the tag antenna can be complex conjugate to any desired microchip.
Finally, to match the complex
input impedance of the antenna to [Z.sub.0], a short length of microstrip line is used.