A novel design for low insertion loss, multi-band RF-MEMS switch with low pull-in voltage

Abstract

A B S T R A C TThis paper presents a new type of capacitive shunt RF-MEMS switch. In the proposed design, float metal concept is utilized to reduce the RF overlap area between the movable structure and central conductor of CPW for improving the insertion loss of the device. This has been achieved without affecting the downstate response. Further, float metal also makes the down-state behavior predictable in terms of resonant frequency. For reducing the pull-in voltage, the switch is implemented with cantilever type of structure on either side of the transmission line. This structure also has the capability to inductively tune the isolation optimum value to the different bands and thus can be used in the reconfigurable RF systems. The device shows an insertion loss less than 0.10 dB, a return loss below 36.80 dB up to 25 GHz as compared to 1.00 dB insertion, 7.67 dB return loss for the conventional switch. In the OFF state, proposed device shows two isolation peaks i.e. 48.80 dB at 4.5 GHz and 54.56 dB at 9.7 GHz, when either or both cantilevers are electro-statically actuated to the down-state position respectively. The conventional device has a single isolation peak in the X-band. In addition, improvement of around 3 times in the bandwidth has also been achieved. The designed switch can be used at device and sub-system level for the future multiband communication applications.

Design and analysis of enhanced capacitive radio frequency MEMS switch based on Nb2O5 and HfO2 dielectric for satellite payload applications

“…Initially, the switch is in ON state in shunt configuration where there is a physical connection between the two RF ports of the transmission electrode. 6 The freely deflecting membrane made of gold material over the CPW is the MEMS switch. The electro-mechanical analysis is carried out using Hafnium oxide (HfO 2 ) and Niobium Pentoxide (Nb 2 O 5 ) as dielectric material with a dielectric constant ( r ) of 14 and 41 respectively.…”

“…The suggested RF MEMS switch structure comprises of a coplanar waveguide (CPW) with 50 Ω as characteristic impedance ( Z o ) and an electrode width of 100 μm for transmission of RF signal. Initially, the switch is in ON state in shunt configuration where there is a physical connection between the two RF ports of the transmission electrode 6 . The freely deflecting membrane made of gold material over the CPW is the MEMS switch.…”

Design and simulation of mems shunt capacitive switch for lower switching time

“…Mostly used actuation mechanism is Electrostatic actuation since it has many practical advantages such as low power requirement and small sized device. Despite of having various advantages, MEMS switches lack in switching speed and requirement of low pull in voltages [6][7]. Various techniques are currently being used to overcome the problems associated with these switches.…”

Beam and dielectric materials impact on improvement of the performance of a novel capacitive shunt RF MEMS switch

“…From the above literature survey, we observed high pull‐in voltage and less isolation for RF MEMS switches . In this work, firstly, an approach on a novel capacitive structure of the RF MEMS shunt switch when compared with conventional switches was presented.…”