Patent ID: 8598967

Claim:
A continuously tunable delay line comprising at least a first ridge waveguide with tunable propagation characteristics comprising: a waveguide body; and a metal ridge longitudinally extending within said waveguide body and having a longitudinal end surface separated by an air gap with variable width from a confronting waveguide element, wherein said ridge is inserted into said waveguide body through an air slot formed in a wall of said waveguide body opposite said waveguide element, and is connected to an actuator arranged to continuously move said ridge through said air slot so as to vary the width of said air gap and thereby tune the continuously tunable delay line, and wherein said ridge is arranged to operate according to a hybrid fundamental propagation mode comprising both transversal electric and transversal magnetic components, and at an operating frequency falling in a frequency range where the propagation constant varies substantially linearly with frequency over a whole displacement range of the ridge.