Toroidal inductors for radio-frequency integrated circuits

Toroidal inductors achieve low loss by constraining magnetic flux to a well-defined path and away from ground planes and semiconducting substrates. This paper presents a micromachined implementation of the toroidal inductor, with focus primarily on microwave integrated circuits on a low-resistivity silicon wafer achieving a Q of 22 and a self-resonant frequency greater than 10 GHz. A verified analytic model is developed.