Application of active electromagnetic bandgaps to the design of tunable resonators in CPW technology

Capacitively coupled resonators with wide tuning range have been proposed in coplanar waveguide (CPW) technology, based on the concept of electromagnetic bandgaps (EBGs). By loading the resonator with shunt-connected varactor diodes, the phase velocity of the line and, hence, the resonant frequency of the structure can be electrically controlled. Due to the slow-wave effect related to the presence of the varactors, a certain level of miniaturization is also achieved. Moreover, the frequency-selective properties of EBGs are used to reject the first spurious frequency of the resonators. © 2005 Wiley Periodicals, Inc.