Antenna feed with mode conversion and polarization conversion means
AssigneeRCA Corporation
InventorDavid F. Bowman
Life of this patent
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Abstract
The configuration of a waveguide antenna feed is determined by a shaped body of solid dielectric material which is coated with a conductive material. The conductive material functions as a waveguide wall for constraining electromagnetic wave propagation within the dielectric body. The body includes a mode converter and a coupler to a lead-in structure. A polarization converter, if desired, can be integral with the dielectric body.
Claims16
An antenna feed of the waveguide type for operation over an operating range of frequencies comprising:
- a body comprising a solid dielectric material having a given dielectric constant, said body having a radiating end, a coupling end and an exterior lateral surface therebetween;
- a layer of conductive material formed on said exterior lateral surface of said body in a tubular configuration having an interior surface which conforms to said exterior lateral surface of said dielectric body, said tubular layer of conductive material being effective as waveguide wall for constraining the propagation of electromagnetic waves within said dielectric body;
- a mode converter located within said body between said coupling end and said radiating end for selectively converting to a second mode a part of the energy in a wave propagating in a first mode from said coupling end toward said radiating end, said mode converter having a converter dielectric constant having a different value than said given dielectric constant, said mode converter having a thickness in the direction of wave propagation in said body and a thickness profile across said body which is proportional to the amplitude profile across said body of said second mode;
- and
- means for coupling between a linearly polarized first mode wave propagating in said dielectric body of said feed and a signal propagating in a lead-in structure, said means for coupling being disposed in the vicinity of said coupling end.
An antenna feed of the waveguide type for operation over an operating range of frequencies comprising:
- a body comprising a solid dielectric material having a given dielectric constant, said body having a radiating end, a coupling end and an exterior lateral surface therebetween;
- a layer of conductive material formed on said exterior lateral surface of said body in a tubular configuration having an interior surface which conforms to said exterior lateral surface of said dielectric body, said tubular layer of conductive material being effective as a waveguide wall for constraining the propagation of electromagnetic waves within said dielectric body;
- a mode converter located within said body between said coupling end and said radiating end for selectively converting to a second mode a part of the energy in a wave propagating in a first mode from said coupling end toward said radiating end;
- said mode converter including a converter region within said body having a converter dielectric constant, said converter dielectric constant having a value which is lower than the value of said given dielectric constant;
- said lower value of said converter dielectric constant resulting from at least one void in the dielectric material of said body;
- said at least one void extending to an external surface of said body;
- and
- means for coupling between a linearly polarized first mode wave propagating in said dielectric body of said feed and a signal propagating in a lead-in structure, said means for coupling being disposed in the vincinity of said coupling end.
Dependencies are inferred from the claim text.