In this paper, new RF-MEMS switch configurations are proposed to enable control of the propagating (even and odd) modes in multimodal CPW transmission structures. Specifically, a switchable air bridge (a switchable short-circuit for the CPW odd mode) and switchable asymmetric shunt impedances (for transferring energy between modes) are studied and implemented using bridgetype and cantilever-type ohmic-contact switches, respectively. The switchable air bridge is based in a novel double ohmic-contact bridge-type structure. Optimized-shape suspension configurations, namely folded-beam or diagonalbeam for bridge-type switches, and straight-shaped or semicircular-shaped for cantilever-type switches, are used to obtain robust structures against fabrication-stress gradients. The switches are modelled using a coupled-field 3D finiteelement mechanical analysis showing a low to moderate pull-in voltage. The fabricated switches are experimentally characterized using S-parameter and DC measurements. The measured pull-in voltages agree well with the simulated values. From S-parameter measurements, an electrical model with a very good agreement for both switch states (ON and OFF) has been obtained. The model is used in the design of reconfigurable CPW multimodal microwave filters.
RF-MEMS switches for a full control of the propagating modes in uniplanar microwave circuits and their application to reconfigurable multimodal microwave filters
Giacomozzi, F.;Margesin, B.
2017-01-01
Abstract
In this paper, new RF-MEMS switch configurations are proposed to enable control of the propagating (even and odd) modes in multimodal CPW transmission structures. Specifically, a switchable air bridge (a switchable short-circuit for the CPW odd mode) and switchable asymmetric shunt impedances (for transferring energy between modes) are studied and implemented using bridgetype and cantilever-type ohmic-contact switches, respectively. The switchable air bridge is based in a novel double ohmic-contact bridge-type structure. Optimized-shape suspension configurations, namely folded-beam or diagonalbeam for bridge-type switches, and straight-shaped or semicircular-shaped for cantilever-type switches, are used to obtain robust structures against fabrication-stress gradients. The switches are modelled using a coupled-field 3D finiteelement mechanical analysis showing a low to moderate pull-in voltage. The fabricated switches are experimentally characterized using S-parameter and DC measurements. The measured pull-in voltages agree well with the simulated values. From S-parameter measurements, an electrical model with a very good agreement for both switch states (ON and OFF) has been obtained. The model is used in the design of reconfigurable CPW multimodal microwave filters.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
