Confined Planar Helix: A Novel Waveguide Structure

A helical planar slow-wave structure

“…In the present structure, the angles of conduction of the two UC screens are oblique to the y-direction and are identical; this case may be denoted as α + + . On the other hand, in the transversely confined structure studied in [2], the angles of conduction of the two UC screens are equal and opposite with respect to the y-direction (i.e., α + − ). Both confined structures have potential applications in devices such as planar traveling-wave tubes [3] and planar antennas.…”

Polarization of wall currents for a planar helix enclosed in a rectangular waveguide

“…A novel structure consisting of a pair of uni-directional conducting (UC) screens sandwiching a dielectric substrate and enclosed in a rectangular waveguide is shown in Fig 1a and Fig 1b.The dielectric regions on either side of the UC screens are different in general, as shown in Fig 2a. The UC screens consist of discrete, narrow and closely spaced conducting strips placed at regular intervals with symmetric inclination α and − α with respect to the y axis as shown in Fig 2b. A pair of UC screens, whether infinite [1] or confined in the y-direction [2], has been seen to emulate the slow wave properties of the circular helix and hence has been referred to as the 'planar helix' [1,2]. The present structure is confined in both x and y directions and has shown considerable size reduction over a corresponding dielectric-loaded waveguide [3].…”