High-Power RF MEMS Switched Capacitors Using a Thick Metal Process

This paper presents the design and characterization of a high-power RF microelectromechanical systems switched capacitor. The switch is based on a 4-
$\mu{\hbox {m}}$
-thick metal plate and four symmetrical springs. The design has low sensitivity to residual stress and stress gradients.
$S$
-parameter measurements result in
${\hbox{Cu}}=0.01\ {\hbox{pF}}$
,
${\hbox{Cd}}=0.63\ {\hbox{pF}}$

$({\hbox{Cr}}=6.3)$
, a power handling
$>$
10 W using hot switching conditions, and a switching time of
$\sim {\hbox {20}}\ \mu{\hbox {s}}$
. The pull-down voltage (
${\rm Vp}=50$
–55 V) and release voltage (
${\rm Vr}=25$
–30 V) are stable to
$+/-$
4 V over 25
$\ ^{\circ}{\hbox{C}}$
–125
$\ ^{\circ}{\hbox{C}}$
. The design can be arrayed for
$N$
-bit switched-capacitor networks. Applications areas are in high-power phase shifters and tunable filters.