This paper presents a tunable comb resonator by mechanically altering the suspension configuration to change its spring constant. The change of the stiffness of the resonator is achieved using electrostatic MEMS actuators. The MEMS actuators mechanically change the length of the beams to increase their spring constant and therefore the resonant frequency. The resonant frequency changed from the original value of 10.8 kHz to 17.6 kHz and 21.4 kHz depending on the spring configuration. The tunable mechanical resonator has been designed numerically using Coventorware and validated with experimental characterization. The device is built using a silicon-on-insulator (SOI) process.

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This paper presents a tunable inductor for radio frequency applications. The inductor is built using the commercial process MetalMUMPs. The tuning principle is based on the change of the area of a loop inductor. The loop is formed by two pre-bent beams where one end is anchored and the second end is attached to an array of thermal flexure actuators. Upon actuation, the beams buckle and the area of the loop increases, therefore increasing the inductance of the loop. To reduce the substrate loss and thus increase the quality factor of the inductor, the silicon underneath the loop is etched away. A detailed mechanical and electrical analysis is conducted to predict the tuning range of the inductor using analytical methods and simulation tools such as Coventorware and HFSS. Measured results are obtained to prove the concept of the design. The achieved ratio of the maximum inductance to the minimum inductance is 2.1.

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We have developed a CMOS-compatible micromachining process that allows us to build high quality, tunable radio frequency inductors. Inductors play a key role in wireless front ends; the additional flexibility offered by tunability can offer adaptability to devices such as filters, matching circuits and voltage-controlled oscillators. Our inductors have a tuning range of up to 30% with a quality factor of 25 and self-resonance over 35 GHz.

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A novel 3-D fabrication technique is presented to achieve very high quality factor and high inductance values for solenoid inductors. The solenoid inductor is at the same time embedded and suspended. Metal traces are deposited using a single plating step. Measured peak quality factor for the first generation of the device realized on low resistivity silicon substrate is 32. The 1 nH inductor has been fabricated with a one and a half turn solenoid.

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