A second layer 146 of sacrificial material, such as silicon dioxide, is deposited, as shown in FIG. 4D. A hole 115 at one side of the switch 124 is then etched through the first sacrificial layer 142 and the second sacrificial layer 146 for a first portion of the transmission line 114, as shown in FIG. 4E. A corresponding hole (not shown in FIGS. 4A???4N) on the other side of the switch 124 is als