Novel DC-40 GHz MEMS series-shunt switch for high isolation and high power applications

• A novel series-shunt RF MEMS switch for DC-40 GHz applications is proposed.
• The mechanism relies on two series switches cascaded by a λ/4 transmission line.
• The switch is driven by a new type bidirectional thermal MEMS actuator.
• Testing results demonstrate excellent RF performance and low operation voltage.

This paper presents the design, fabrication, and characterization of a lateral contact series-shunt ohmic RF microelectromechanical systems (MEMS) switch actuated by an electrothermal actuator. Since the proposed RF MEMS switch is actuated electrothermally, it can be operated at an extremely low operation voltage of 0.16 V. In this switch, two series switches are cascaded by a quarter wavelength section of transmission line suspended over the trench of the substrate to form a series-shunt configuration according to the principle of impedance transforming. By using a single bidirectional thermal MEMS actuator to control the signal, the switch provides higher reliability when through high power microwave signal. The measured results show that an insertion loss of 1.2 dB or better is achieved from DC-40 GHz. The isolation is −50 dB at 5 GHz, −45 dB at 20 GHz and −60 dB at 35 GHz. What is more, this switch also exhibits high linearity, and high power handing for DC-40-GHz applications. In the switch OFF state, self-actuation does not happen up to the input power of 40 dBm at 1 GHz. In the switch ON state, no significant insertion loss variations or problems in the contacts, due to the RF power, can be observed below 31 dBm input power.