The coplanar waveguide-fed electronically tunable slotline ring resonator

A coplanar waveguide (CPW)-fed slotline ring resonator has been developed and integrated with varactor diodes to create an electronically tunable planar resonator. The resonator can be electronically tuned over a 23% bandwidth from 3.03 to 3.83 GHz with a 4.5+or-1.5-dB variation in insertion loss. A wider tuning range can be obtained for a greater insertion loss variation. The resonator is truly planar, offering ground planes and a center conductor on one side of the substrate which allows easy series or shunt insertion of devices. Monolithic implementation can be accomplished without via holes to ground devices which should reduce processing complexity and increase yields.<>