Tunable capacitor capacitance value

What is a tunable MEMS capacitor?

The capacitor in this example is a typical component in various microelectromechanical systems (MEMS) for electromagnetic fields in the radio frequency range 300 MHz to 300 GHz. Figure 1: The tunable MEMS capacitor consists of two metal plates. The distance between the plates is tuned via a spring connected to one of the plates.

What is a variable capacitor used for?

Variable capacitors are often used in L/C circuits to set the resonance frequency, e.g. to tune a radio (therefore it is sometimes called a tuning capacitor or tuning condenser), or as a variable reactance, e.g. for impedance matching in antenna tuners.

How to tune the distance between the plates of a capacitor?

For tuning of the distance between the plates the capacitor includes a spring that attaches to one of the plates. If you know the characteristics of the spring and the voltage between the plates, you can compute the distance between the plates. This application shows an electrostatic simulation for a given distance.

What is variable capacitance?

Variable capacitance is sometimes used to convert physical phenomena into electrical signals.

What is a COMSOL tunable parallel plate capacitor?

This model is licensed under the COMSOL Software License Agreement 5.5. All trademarks are the property of their respective owners. See In an electrostatically tunable parallel plate capacitor you can modify the distance between the two plates when the applied voltage changes.

What is a variable capacitance diode?

Any diode exhibits this effect (including p/n junctions in transistors), but devices specifically sold as variable capacitance diodes (also called varactors or varicaps) are designed with a large junction area and a doping profile specifically designed to maximize capacitance.