Principle of RF MEMS switches

I am studying mechanical engineering at university and am trying to design an RF MEMS switch. In "RF MEMS Switch Li-Feng Wang, Qing-An Huang, and Lei Han" says "When an adequate voltage is applied between the signal line and the membrane bridge, the membrane bridge is pulled down by the electrostatic force and finally contacts with the dielectric layer. A relatively large capacitance is now formed between the signal line and the ground line, the input RF/ MW signal at specific frequency band can be reflected, and the switch is at its offstate.", but I don't have much knowledge about electricity and electromagnetism, so I don't know why the signal can be reflected? .

Image citation: Dynamics of RF Micro-Mechanical Capacitive Shunt Switches in Coplanar Waveguide Configuration DOI: 10.5772/28251

• Where did you get this image from? Please cite the source and provide a link if available. Provide more information; not just an image. Use the edit option to add these details into the question.
– AJN
Commented Dec 28, 2023 at 12:28
• You also need to ask an actual question. Commented Dec 28, 2023 at 13:35

1 Answer

RF MEMS switches are just switches. Like light switches, or outlet switches.

That switch shorts out the RF power. Shorting out RF power reflects it: the RF power is reflected to the source.

MEMS switches may be Ohmic, or Capacitive. At radio frequencies, capacitors can be used to short out RF power.

• In "RF MEMS Switch Li-Feng Wang, Qing-An Huang, and Lei Han" says "When an adequate voltage is applied between the signal line and the membrane bridge, the membrane bridge is pulled down by the electrostatic force and finally contacts with the dielectric layer. A relatively large capacitance is now formed between the signal line and the ground line, the input RF/ MW signal at specific frequency band can be reflected, and the switch is at its offstate." Can you explain in more detail why the signal can be reflected?
– Yuu
Commented Jan 1 at 9:35
• @Yuu I don't think that StackExchange is the right place for "How do electromagnetic fields work?" - it's really more oriented to specific questions. Commented Jan 1 at 23:36
• For example, kites are blocked by wind. I want to know what is blocking/reflecting the signal. Then I'll find out the details myself later.
– Yuu
Commented Jan 2 at 3:27
• The short circuit is reflecting the signal. Commented Jan 3 at 3:07