A flexible waveguide includes an inner dielectric, and a flexible external conductor disposed in a position covering an outer periphery of the dielectric, the flexible waveguide conducting a radio wave in a frequency band equal to or longer than a millimeter wave or a submillimeter wave near 60 GHz or more. The external conductor includes a metal layer, the metal layer has a shape displacement structure, a shape of an inner periphery side section of which faces the inner dielectric and is cyclic in the waveguide longitudinal direction, the shape displacement structure being a cyclic structure satisfying λmr<λch, where λmr represents a center wavelength of a main reflection band due to the cyclic structure and λch represents a cutoff wavelength in a high-order mode of the waveguide.

Provided is a dielectric waveguide having a good reflection characteristic also in a band on a low frequency side of a center frequency of a given operation band. A dielectric waveguide (1) includes: a waveguide region (12) which is defined by a first wide wall (21), a second wide wall (22), a first narrow wall (23), a second narrow wall (24), and a short wall (25) and which is filled with a dielectric; and a mode conversion section (31) which includes a columnar conductor (34) extending from a surface of the waveguide region (12) toward an inside of the waveguide region (12). A width (W.sub.2) of the short wall (25) is configured to be greater than a waveguide width (Wi) at a location (x=x.sub.1) at which the columnar conductor (34) is provided.

This microwave component (10) comprises a waveguide (12) comprising an upper layer, a lower layer, and a central layer (18) intermediate between the upper layer and the lower layer, said layers defining a zone (19) of propagation of an electromagnetic wave, the propagation zone (19) extending along a propagation axis, and comprising a cavity (32) bounded by the upper layer, the lower layer, and, laterally, by two opposite lateral edges (36) of the central layer (18).

The waveguide (12) comprises at least one dielectric strip (28) placed in the propagation zone (19), the dielectric strip (28) being defined in one of the upper layer and the lower layer or being placed in the cavity (32) away from the lateral edges (36) of the cavity (32).

An apparatus comprises a waveguide including: an elongate waveguide core including a dielectric material, wherein the waveguide core includes at least one space arranged lengthwise along the waveguide core that is void of the dielectric material; and a conductive layer arranged around the waveguide core.

A method of making a waveguide, comprises: extruding a first dielectric material as a waveguide core of the waveguide, wherein the waveguide core is elongate; and coextruding an outer layer with the waveguide core, wherein the outer layer is arranged around the waveguide core.

An electromagnetic wave transmission cable for transmitting an electromagnetic wave comprises a hollow waveguide tube and a foamed resin member. The hollowing waveguide tube includes a hollow dielectric layer formed in a tubular shape. The foamed resin member is provided over a predetermined length in a longitudinal direction of the hollow waveguide tube and covers a surface of the dielectric layer to surround an outer periphery of the hollow waveguide tube.

Aspects of the subject disclosure may include, for example, a transmission medium for propagating electromagnetic waves. The transmission medium can include a core for propagating electromagnetic waves guided by the core without an electrical return path, a rigid material surrounding the core, wherein an inner surface of the rigid material is separated from an outer surface of the core, and a conductive layer disposed on the rigid material. Other embodiments are disclosed.

The invention relates to a waveguide arrangement for guiding electromagnetic waves, which comprises a rectangular waveguide and a circular waveguide. The rectangular waveguide merges into the circular waveguide at an angle. The circular waveguide is filled with a dielectric which projects into the rectangular waveguide in a transition section. The dielectric filling is beveled at a defined angle in the transition section so that a transition surface is formed by the inner edge at the transition of the waveguide arrangement and the end face of the rectangular waveguide at the transition. The dielectric filling is preferably flush with the closing wall of the rectangular waveguide.

Disclosed is a low-loss and flexible transmission line-integrated multi-port antenna for an mmWave band. The multi-port antenna includes a plurality of antennas arranged on different substrate layers to form a multi port and a plurality of transmission lines corresponding to the plurality of antennas, respectively, in which central conductors used as signal lines of the transmission lines are integrated with corresponding electricity feeding portions of the antennas and arranged on different layers. Here, the antennas each include a dielectric substrate formed as a dielectric having a certain thickness on a ground plate, and a signal conversion portion formed on the dielectric substrate and configured to convert an electrical signal of a mobile communication terminal into an electromagnetic wave signal and radiate the electromagnetic wave signal into the air or to receive an electromagnetic wave signal in the air into an electrical signal of a mobile communication terminal.

In accordance with one or more embodiments, a guided wave launcher includes a dielectric cable having an unexposed dielectric core portion that is surrounded by a dielectric cladding portion. The unexposed dielectric core portion is configured to receive a first electromagnetic wave at the end of the dielectric cable and to guide the first electromagnetic wave along the first unexposed dielectric core portion. An exposed dielectric core portion of the dielectric cable, that is not surrounded by the dielectric cladding portion, is configured to couple a portion of the first electromagnetic wave to a transmission medium in proximity to the exposed dielectric core portion, wherein the portion of the electromagnetic wave coupled to the transmission medium propagates as a second electromagnetic wave along the transmission medium without requiring an electrical return path.