Non-foster matching of an RFID antenna - New Jersey Institute of ...

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Either a voltage or a current amplifier may be used as the active device. Positivecurrent
feedback creates the current-controlled negative-driving-point impedance, while
voltage feedback is used to obtain a voltage-controlled negative impedance.
Figure 1.7 shows a practical current-feedback NIC using a pnp — npn pair [4].
Figure 1.7 Practical current-feedback NIC using a pnp — npn pair.
NICs originated in the 1920s as a means to neutralize resistive loss in circuits.
According to Merill, negative impedance circuits were used to develop a new type of
telephone repeater called the El .
Types of NICs can be listed as follows [9]:
• Voltage Inversion NIC (VINIC)
• Current Inversion NIC (CINIC)
• Grounded NIC (GNIC)
• Floating NIC (FNIC)
1.6 Range Extension
When designing for optimum read range, one should primarily consider the reader's
power, the tag's power consumption, the tag's quality factor (Q), the tag's tuning, the