Radio Frequency Micro Electro Mechanical Systems Inductor Configurations for Achieving Large Inductance Variations and High Q-factors

To determine a micro electro mechanical systems (MEMS) inductor configuration that gives large inductance variations and high Q -factors, air-suspended MEMS inductor configurations are studied: (a) an inductor with two angularly meandered lines, (b) a solenoid inductor with a pair of movable shields, (c) a planar spiral inductor with a patterned shield of different areas, and (d) a planar spiral inductor with a metallic frame of different sizes. The configuration of (a) is shown to give a large inductance variation of 115%. However, its Q -factor is only about 10, and difficulties in fabrication are also expected. The configuration of (b) could be a reasonable engineering solution. The inductance variation is 67%, and the maximum Q -factor is over 22. The solenoidal inductor configuration is thus considered suitable for realizing an RF MEMS variable inductor with large inductance variations and high Q -factors.