Travelling wave generation of millimeter waves in bimodal NLTLs

This paper presents the study of special nonlinear transmission lines (NLTLs) designed for the generation of millimeter waves with high efficiencies. In particular, so called bi-modal NLTLs are described which are characterized by a prescribed dispersion in order to establish phase matching condition for the frequencies under investigation. The underlying concept is demonstrated by second and third harmonic generation on NLTLs consisting of a periodic arrangement of suitable varactor diodes loading a coplanar waveguide.