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Low-Noise active inductor

Active filterActive inductorInformatica Tsd EnLow noiseTunable filter


This patent describes a new approach for the design and implementation of tunable, low noise, high quality factor active inductor suitable for relatively high signal power handling applications at RF and microwave.

Technical features

A team of researchers has developed an innovative active inductor, i.e., an electronic circuit simulating the behavior of an inductance, which allows at least partially obviating the existent drawbacks regarding the prior art, while ensuring a very low noise. The active inductor developed by the team, simulates the behavior of an inductance by means of resistors and transistors, with very low losses, even for high power. The low noise property makes it the ideal candidate for the realization of medium power RF and microwave applications such as filters, oscillators and VCOs.

Possible Applications

  • Telecommunications;
  • Radio surveillance;
  • Aerospace;
  • Mobile telephony;
  • Radio mobile and static apparatuses;
  • Radar apparatuses;
  • Jammers;
  • Tuning circuits.


  • Use of feedbacks with consequent reduction of the noise contribution of the circuit;
  • Possibility to have a Noise Figure lower than insertion losses, as resonant element in the filters;
  • Tuning of the active inductor obtained exclusively through variable linear networks;
  • Possibility to vary both the inductance and the series resistance;
  • High Q (quality) factor.