Implementation of an Electronically Tuneable, Transistor-based, Passive, Symmetric RF Inductance

摘要

The concept of an electrically tuneable inductance based on a transistor circuit is introduced. Even though it incorporates an active circuit, passive, reciprocal behaviour is displayed at the output terminals. The resulting inductance value is tuneable through a variation of the biasing condition, constant for a wide frequency range, and it can be used in either series or parallel circuit configuration. Guidelines for the design of the circuit are presented and used to successfully simulate, build and measure the tuneable inductance. The inductance circuit is a promising approach to closing a long-existing gap, and thereby providing new possibilities of circuit design, e.g., in terms of miniaturisation through integrated circuits. It can prove beneficial for numerous applications, such as broadband matched and tuneable transmission lines, amplifier circuits, oscillators, or filters.