Patent ID: 11916292
Assignee: AGENCY FOR DEFENSE DEVELOPMENT
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An antenna apparatus, comprising:
a hollow pillar shaped waveguide extending in a first direction;
at least one ridge protruding from an inner circumferential surface of the waveguide and extending in the first direction; and
an iris structure protruding from the inner circumferential surface of the waveguide along a plane intersecting the first direction,
wherein the ridge has at least one recessed groove formed in the first direction,
wherein the ridge comprises a first portion having the recessed groove and a plurality of second portions that are connected to both sides of the first portion and are not recessed,
wherein the degree of protrusion of the recessed groove of the first portion from the inner circumferential surface of the waveguide is maintained uniformly,
wherein a length in a radial direction of the waveguide of the first portion is less than a length in a radial direction of each of the second portion.