An 0.04–10.32 nH Ultracompact Tunable Inductor Based on Flexible Magnetic Coupling Tuning Technique

The miniaturized and low-cost reconfigurable transceivers show promising prospects in brain-machine interfaces, implantable devices, and wearable devices. As basic elements of transceivers, further improvement of tuning range, operating frequency, and area of tunable inductors are extremely needed. In this work, a magnetic coupling ultrawide range inductors tuning technique is proposed and analyzed with the process-based coupling circuit model. The model simulation and test chip verification results are in good agreement. From dc to 30 GHz, an inductance value of 0.04–10.32 nH (self-inductance is 1.03 nH), a tuning range of 99.61%, and a quality factor (Q) of 145.6 are achieved. This indicates that a 10.02-fold increase in inductance value can be obtained without increasing the chip area compared to a fixed inductor with an area of
$95 \times 130 \, \mu $
m. The tuning technique and model can be employed for the design of tunable matching networks and filters to further improve the integration of reconfigurable radio frequency (RF) transceivers.