STACKED ARRAY OF OMNIDIRECTIONAL ANTENNAS

• US 3,638,224 A
• Filed: 04/24/1970
• Issued: 01/25/1972
• Est. Priority Date: 04/24/1970
• Status: Expired due to Term

• Current Assignee: N/A
• Original Assignee: N/A
• Time in Patent Office: 641 Days
• US Class Current: 343/771
• CPC Class Codes: H01Q 13/20 Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system

Abstract

A stacked vertically polarized collinear array of a plurality of independently fed omnidirectional antennas operating at different frequencies. Each antenna consists of an array of five circumferential slots in the outer conductor of a dielectric filled shorted coaxial transmission line with a hollow center conductor for feed leads to pass through.

Claims

1. A stacked collinear array of antennas for mounting on a surface such as the outside surface of an aircraft comprising:

a plurality of different frequency antennas with each antenna comprising a coaxial transmission line consisting of an outer conductor and a hollow center conductor, a dielectric material for filling the space between said outer conductor and said center conductor, shorting caps located at each of said coaxial transmission line for electrically connecting said outer conductor to said center conductor, a plurality of slots cut into said outer conductor, and probe means for feeding each antenna;

said plurality of antennas being stacked in a collinear array with adjacent antennas being attached to each other by a coupling having openings in it for electrical leads to pass through;

a flange attached to the bottom antenna of said collinear array for attaching said array of antennas to said surface such that the hollow portion of the center conductor of said bottom antenna terminates below said surface; and

separate electrical leads connected to said probes of each antenna with each lead passing through one of said openings in said couplings and then through the hollow of the center conductor of every antenna between said one of said openings and said surface whereby the interference problem usually encountered in the stacking of omnidirectional antennas is eliminated.

2. A stacked collinear array of antennas in accordance with claim 1 wherein each of said plurality of antennas has a sleeve balun means located near each of its ends for providing isolation between the antennas in the stacked array.

3. A stacked collinear array of antennas in accordance with claim 1 wherein said probe means for feeding each antenna includes two probes connected to said center conductor 90* apart around its circumference to be fed by in-phase signals to provide uniform excitation around the circumference of the center conductor.