US2821709A - Antennas - Google Patents

Description

Jan. 28, 1958 s, ucc 2,821,709

ANTENNAS Filed March 21, 1952 I -l IS F 2! l I Z L. r 35/ .3 l M 1, l5- i I i INVENTOR. I SALVATORE Fuccl H/s HTTORNEYs ANTENNAS Salvatore Fucci, New London, Conn.

Application March 21, 1952, Serial No. 277,889

7 Claims. (Cl. 343-793) (Granted under Title 35, U. S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to improvements in antennas, and more particularly pertains to improvements in very high and ultra high frequency around-the-mast antennas.

Antennas constructed for use on surface craft, aircraft or land installations, and conventional submarine antennas, are not sufficiently pressureproof and do not meet the minimum requirements of structural rigidity that are desired of an antenna employed in submarine operations. Multiple antennas heretofore installed on submarines employed an insulator to separate the upper and lower radiating elements, but such an insulator subjects the device to the serious disadvantages of weakening the antenna mechanically and complicating inordinately the problem of pressureproofing. In such antennas, the sole support for the upper radiating section of the antenna is the inner conductor of the transmission line, which extends through the insulator. In such structure, extension of the antenna mast is not feasible, and multiple antenna arrays cannot be provided conveniently.

The subject device overcomes the foregoing disadvantages of the prior structures and provides a pressureproof, structurally rigid multiple radiator adapted for use on extensible submarine antenna masts. These results are accomplished by substituting a quarter-wave isolating section between the upper and lower radiating elements for the insulator heretofore employed, such section also serving to compensate for the reactive component of the antenna and to assist in extending the frequency range of a single unit; by the folding back of the upper radiating element to form another quarter-wave section that isolates this upper radiating element electrically from the extended mast, thus permitting the stacking of additional antennas on the single mast; and by feeding the antenna 01f center by means of a separate cable, thereby eliminating the need of breaking the mast at the center.

The principal object of this invention is to provide an around-the-mast antenna that meets the pressureproofing and structural rigidity optimum requirements of extensible multiple-stack submarine antenna.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

Fig. 1 is a fragmentary longitudinal cross section of an around-the-mast antenna, showing a preferred embodiment of the invention;

Similar numerals refer to similar parts throughout the several views.

The antenna is supported on a retractable mast 11,

Fig. 2 is a section taken on the line 2-2 of Fig. l;

nited States Patent I assists Patented Jan. 23, 1958 which is a cylinder adapted to receive telescopically a cylinder 13 of smaller diameter, part of said cylinder 13 extending beyond the end of the mast l1.

A tubular radiator 15 is formed as an invertedor ope bottomed cup and the conductive closed end 17 of said cup is secured to the cylinder 13 in any suitable manner. Said closed end 17 is provided with a first small bore or aperture 19 through which a first coaxial conductor 21 is passed, and a second small bore or aperture 23 through which a second coaxial conductor 25 is passed. A second tubular radiator 27 is secured to the cylinder 13 in any suitable manner, such as by means of conductive mounting ring 29. Said radiator 27 is isolated from cylinder 13 by means of a quarter wavelength section of coaxial transmission line formed by the portion 31 of the outer surface of the cylinder.13 projecting above the closed end 17 and the inner surface 33 of the coaxially disposed portion of the radiator 27.

The radiator 27 has a folded back portion 35 that serves as a radiating element. A second quarter wavelength isolating section is formed by the coaxial line section comprising the inner surface 37 of the folded back portion 35 and the outer surface 39 of the coaxially disposed portion of the radiator 27, thereby insuringthat no radiation from the radiator 27 spills over around the edge of said radiator.

Direct off-center feed is accomplished by connecting the inner conductor 41 of the coaxial cable 21 at a point on the junction of the folded back portion 35 and the coaxially disposed portion of radiator 2'7. The outer conductor of cable 21 is connected to the radiator at the closed end 17, as shown in Fig. I. Said cable 21 is secured upon cylinder 13.

A similar antenna can be mounted on the cylinder 13 and disposed vertically above the radiator hereinbefore described. Such superstructure can be of the same construction as the antenna described hereinabove, except that it is preferably scaled down in physical dimensions to be resonant at a desired higher frequency. Such similar antenna is fed through conductor 25. The elements of such superstructure are designated in the drawing by the reference numerals of their corresponding elements in the radiator described hereinabove, but with the subscript a added to each such designation.

It is apparent that as many such radiators as are desired can be mounted as above described in superposed relation. For example, still another cylinder 13b for mounting a third antenna can be secured by means of the mounting ring 29a. It is also apparent that the radiating sections can be conical, or can have other shapes suited to the production of desired frequency characteristics, and that other geometric configurations to produce directionality can be employed in lieu of the described structure that provides a substantially omnidirectional radiation pattern. Since the antenna described requires no insulation to be introduced at any point in its construction, very high structural strength can be achieved and pressureproofing is facile in view of the fact that only the end seals of the external feed cables need to be pressureproofed.

Obviously many modifications and variations of the present invention are possible in the light of the teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

I claim:

1. An ultra-high-frequency antenna for a high-frequency energy transducer comprising a support, a first tubular radiator mounted on said support,--.afs e ond.ta-

each radiator to said support, high-frequency isolating means between said support and one of said radiators, and transmission line means connecting said radiators to such transducer.

2. The antenna as defined in claim 1, wherein, said sup; port is coaxially disposed relative said first and second radiators. i i i h a t na a ie rl n a m h ei a d t an mission line means comprise a coaxial conductor having, an inner conductor connected toone of said radiators and,

an outer conductor connected to the other radiator, said coaxial conductor being secured on said support.

4. An ultra-high-frequency antenna system for a highfrequency energy'transducer comprising a stacked coaxial arrangement of tubular radiators, pairs of said radiators being adapted to be energized at frequencies oi operation diflerent from that of other pairs, transmission, means coupled to said radiators, aconirnon support disposed coaxi'ally with respect to said radiators, said radiators being mounted in vertical alignmenn onfsaid support, and. conducti've elements coupling similarly disposed ends of each of said radiators to said support.

5 Thesystem as defined in claim, 4 further comprising wave-trap means comprising quarter wavelength sections of high-freqnency transmission lines for isolatin'gI-y spacing alternate radiators from, said support.

6 An nltra-high freguency broadband antenna system 9; an, energy transducer comprising a conductive suprz t ins mas fir t bu ar. ua -w e a ia es 4% ewn-a tached to said mast by means of a conductive disc at the endof said radiator distal the base of said mast, a second tubular quarter-wave radiator, a third tubular isolating cylinder concentric with said second radiator, said second radiator being attached to said mast by means of a conductive disc at the similar end thereof through said third cylinder, and transmission line means connecting said radiators to such transducer.

7. An ultra-high frequency broadband antenna system for an energytransducer comprising a conductive supporting mast and a plurality. of spaced antenna arrays mounted on said mast in spaced relation, each array comprising a first tubular quarter-wave radiator attached to said mast by means of a conductive disc at the end of said radiator distal the base-ofsaid'mast, a second tubular quarter-wave radiator, a third tubular isolating cylinder concentric with said second radiator, said second radiator being attached to. said mast by,mean s of: a conductive disc at the similar end thereof throughsaid third cylinder, and transmission line means connecting said radiators to such transducer.

References Cited in the file of this patent UNITED TAT S, PATENTS

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