In this paper, nonlinear transmission lines (NLTLs) consisting of coplanar waveguides periodically loaded with shunt connected varactor diodes, periodically perturbed by varying the slot width, are studied. To our knowledge, this is the first time that these structures, combining a distributed nonlinearity with an electromagnetic bandgap (EBG), are investigated. A prototype device with a cutoff frequency near 1 GHz and designed to inhibit power transmission within a narrow frequency gap near cutoff has been fabricated. Harmonic balance simulations as well as nonlinear measurements indicate that power transfer to the second harmonic is enhanced if the third harmonic lies within the forbidden gap. The work opens the door to a major design flexibility of NLTL frequency multipliers and phase shifters by adding the EBG concept to the structure. © 2003 Wiley Periodicals, Inc.
- Coplanar waveguide technology
- Electromagnetic bandgaps (EBGs)
- Frequency multipliers
- Nonlinear transmission lines (NLTLs)