Scalable Contact-Capacitive MEMS Switches With High Capacitance Ratio for Millimeter-Wave Applications

• Published in: IEEE access Vol. 10; pp. 37360 - 37368
• Main Authors: Zhang, Yulong, Liu, Huiliang, Sun, Jianwen, Liu, Zewen
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Capacitance; contact-capacitive switch; Contacts; Coplanar waveguides; Design optimization; high capacitance ratio; high linearity; Insertion loss; Insulators; Mechanical systems; Microelectromechanical systems; Millimeter waves; MIM capacitors; Performance evaluation; Radio frequency; RF MEMS; scalable; Switches; Topology
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2022.3160423

This paper proposes a series of optimized scalable contact-capacitive radio frequency micro- electro-mechanical systems (RF MEMS) switches for millimeter wave applications. Due to the contact-capacitive topology, the ON-state and OFF-state of the switch can be designed separately to obtain smaller <inline-formula> <tex-math notation="LaTeX">C_{ON} </tex-math></inline-formula> and larger <inline-formula> <tex-math notation="LaTeX">C_{OFF} </tex-math></inline-formula>, which results in high capacitance ratio (<inline-formula> <tex-math notation="LaTeX">C_{r} </tex-math></inline-formula>). The <inline-formula> <tex-math notation="LaTeX">C_{ON} </tex-math></inline-formula> is defined by capacitance of the contacts, and it is optimized for low insertion loss (<inline-formula> <tex-math notation="LaTeX">IL_{ON} </tex-math></inline-formula>). The <inline-formula> <tex-math notation="LaTeX">C_{OFF} </tex-math></inline-formula> is defined by the metal-insulator-metal (MIM) capacitor, and it is designed for working band and scalable performance. The measurements of the fabricated devices show acceptable agreements with design and simulation. The optimized switches perform well with <inline-formula> <tex-math notation="LaTeX">IL_{ON} </tex-math></inline-formula> better than 1.5dB and capacitive ratio about 124. The switches follow scaling rules from 20GHz to 110GHz. Linearity (IIP3) of the switches are tested to be higher than 60dBm, and calculated to be higher than 80dBm. Performances of the switch can be further improved and optimized in the future study.