Passive reciprocal transistor-based RF tuneable inductances

Where unused frequency bands become scarce, their resourceful handling is essential. Consequential, to enable best use of various frequency bands with a single device, the need for reconfigurability emerges. Complementary to already existing technologies, a novel transistor-based circuit is introduced that makes passive, reciprocal, electronic reactive tuning possible. Ultimately, a tuneable inductance was chosen as an example for reactance circuits due to its outstanding relevance for modern, reconfigurable circuit design. The general development process of the inductance circuit is outlined through an abstracted process overview. It enables a broad understanding of the challenges and possibilities of this approach. Also, by extensive circuit analysis with ideal and non-ideal element values, the gap between numerical simulation and guidelines for practical implementation can be narrowed. From the resulting analytic expression, the key figures of an electronic tuneable inductance are derived, namely the range of inductive tuning, the quality factor and the achievable frequency range. These values enable the circuit designer to set up a reasonable starting point for developing a tuneable inductance circuit and gives the means to estimate its unprecedented, passive output behaviour.