A Spring Shaped Tunable Inductor using Electro-Thermal Actuator in SOI-MUMPs

A spring shaped tunable inductor is presented, fabricated using SOI MUMPs (Multi-User MEMS Process). The inductor has a simple planar design and is monolithically integrated in SOI wafer. The inductor is tuned using a thermal actuator on the same silicon structure layer. Thus, the complexity and cost of fabrication is greatly minimized. The device is compact in size with the dimension of 0.90 mm × 0.55 mm. In addition to cost effective design and small footprint, the device has good tuning range and Q-factor. The experimental results show that the inductor can be tuned to 20%, 17% and 15% at 2 GHz, 3 GHz, and 5 GHz, respectively. The Q-factors of 7.27 and 4.64 have been achieved in air at 2 GHz at 0V and 11.5 V, respectively. Similarly, the Q-factors of 7.21 and 5.92 have been achieved respectively at 5 GHz at 0V and 11.5V. The series resonance frequency (SRF) is >20 GHz.