US2836824A - Antenna - Google Patents

Description

y 27, 1958 R. c. RAYMOND 7 2,836,824

7 R/CHA/PD C RAYMOND- BY Z ATTORNEYS United. '3

ANTENNA Richard C. Raymond, Pacific ?alisades, Calii, assign-or to Heller, Raymond and Brown, 1212., College, Pa., a corporation of ?ennsylvama Application April 13, 1954, Serial No. 422,812

1 5 Qlalms. (Cl. 343-795) My invention relates to an improved antenna construction particularly adapted to broadband radio-receiver operation in the portion of the spectrum above 50 mc./ s.

For certain applications, it is important to rationalize the design of an antenna so as to provide high gain over a wide frequency band and at the same time to maintain a tolerable size. High gain may be achieved by using a configuration which yields high directivity in either the horizontal or the vertical plane, or in both. Broadbanding is accomplished by keeping the antenna Q as low as possible. Size of the resulting configuration is determined by the operating frequency and by the amount of gain and directivity desired.

High gain and directivity may be obtained by various combinations of linear resonant elements. However, this technique results in a narrow-band system, and for power gains in excess of it) decibels a relatively bulky array is involved. Traveling-wave antenna, such as rhombic and V antennas, yield high gain and directivity but are necessarily large physically. Some work has been done with modified horn configurations to produce advantages over the resonant and long-wire systems, but these modifications have either been structurally weak or have not provided adequate band-width or directivity.

It is, accordingly, an object of the invention to provide an improved antenna construction.

Another object is to provide an antenna featuring high gain and broadband response within conveniently usable dimensions for the particular bandwidth. V

A specific object is to provide, in a single assembly, two broadband antennas, one responsive to horizontally polarized, and one to vertically polarized, waves.

A further specific object is to provide a modified horn antenna in which mutualy exclusive directional properties may characterize the response to vertically polarized and to horizontally polarized waves.

It is a general object to meet the above objects with a rugged and readily serviceable construction, which may be transported and assembled easily.

Other objects and various further features of novelty and invention will be pointed out or will occur to those skilled in the art from a reading of the following specification in conjunction with the accompanying drawings. In said drawings, which show, for illustrative purposes only, preferred forms of the invention:

Fig. 1 is a perspective view of an antenna construction representing one embodiment of the invention; and

Fig. 2 is a similar view of another embodiment.

Briefly stated, my invention contemplates improvement of the mechanical properties of a modified horn antenna of the type in which two opposed surfaces of a The polarization, the respective wings may be longitudinally extending, conductive strips connected at one end to the described mouth framework, and at the other end to the converging sides of the wings. If desired, a second pair of similar opposed plane-polarized wings may be connected to the same conductive framework in quadrature relation with the first pair of wings, thus defining another axis of plane-polarization, without impairing the basic rigidity of the structure, or the performance of the first set. If the conductive end of the framework is rectangular, the two pairs of opposed wings will be plane-polarized on perpendicular axes, and I have found that directional properties of the respective pairs of wings may be essentially independent.

Referring to Fig. 1, my invention is shown in application to a pyramid type of horn, in which all wings 10--1l-1213 are of the same size. To prevent interference between the two plane-polarized antenna pairs, each of the wings is slotted longitudinally. In the form shown, the slots are defined by spaced longitudinally extending conductors 14, extending generally parallel to each other and joined at their respective ends to the particular wing framework. Each wing frame may comprise a plurality of metal angle strips 15, as of aluminum, appropriately fitted or welded at the corners to define a rigid triangular framework.

From the point of view of portability and of packing convenience, as for antennas responsive to longer-wavelength radiations, each wing may comprise a plurality of complete subassemblies. In the case of the wing 1% the two conjugate subassemblies are of right-triangular form, having a common edge, as at angle members 1 6, and secured as by bolts (not shown) to each other. lf desired, reinforcement means 17 overlapping the oute r mouth edges of the joined wing panels may be added to improve the rigidity of the assembly.

Because of the right-triangular planiform of the respective halves of a wing (19), the common edge 16 of the joined frameworks may constitute one of the plurality of longitudinally extending conductors creating the planepolarized response of that part of the horn. The con ductors 14 may be merely straight tubes or rods welded in properly spaced relation parallel to the longitudinally extending common edge 16, and thus connected effectively in parallel at their respective ends to the wing framework. The effective slot spacing in a particular wing, or rather the spacing between conductors 14 defining such slots, is preferably no greater than one-half wavelength at the higest frequency for which the antenna must show a response.

To provide greater rigidity and better electrical conduction at the apex of the pyramid, the respective apices of the various horn wings may be reinforced by triangular conductive plates, as at 18 for the case of wing 16. These plates may be formed as halves welded into the preliminary subassemblies (wing halves); alternatively, they may be applied to the otherwise completely assembled wing halves, upon field assembly, in order better to tie the two halves of each wing panel together. In any case, the maximum effective transverse extent of such plates 18 is preferably no greater than one-half wavelength at the highest desired frequency. This is to prevent interference between the two sets of triangular wings.

To complete the assembly of wing panels to each other, rigid ccnne 1g means should be employed at'as many longitudinally spaced locations as needed. In the form shown, two rigid spacers l9-2-9 are provided along each pair or" adjacent edges of adjacent wings; and, in order to reduce interaction between the respective pairs of wings lb-lZ and 11-33, these spacers 19-20 are plate 18 for each of these wings.

preferably of insulating material, such as laminatedplastic blocks. 7 'At the mouth or outer end of the antenna, a rigid con- 7 'nection should also 'beprovided, but l have discovered that this can best be achieved by'employment of conductive connection means, without noticeably affecting the antenna operation or directional properties; 1 In the form of divergent conductive wings joined at the mouth by conductive spacers.

While 'I have described the invention in detail for the preferred forms shown, it will be understood that modifi-. cations may be made within the scope of the invention as defined in the claims whichfollow.

shown, separate conductive brackets 21, reinforced as needed by small gussets, are connected along adjacent edges to adjacent sides of adjacent wings. Insulating materials could be used for these connections, but metal corners are preferred because of their higher mechanical strength.

Separate electrical connections may be made to the respective convergent apices of the pairs of wings 19'12* and 1113, as by separate electrical connection to the Thus, the leads for a first output line connected to apex plates 18 for wings -12, and the leads for a second and separate output line connected to apex plates 18 for wings 1i.13, may pro vide selective availability of directional response to waves in mutually perpendicular planes of polarization.

. Through the use of two transmission lines, the assembly may be used With two receivers, 'two transmitters, or one transmitter and one receiver with little interference between the two planes of polarization.

In Fig. 2, I show an alternative constructionhaving essentially the same electrical properties as that described in Fig. 1, but perhaps better adaptable to higher frequency application because the respective wing panels 3032 and 3133 may be more conveniently assembled in a single piece, and the end frame for establishing peripheral electrical conductivity at the mouthlof the horn maybe a separate rigid structure 34. The mouth ends ticular form shown'in Fig. 2, suitably drilled output terminal elements 37 may be provided, one for each wing panel, and as an integral part of the corner rein-' forcement panel 38.

it will be seenthat I have provided a basically simple antenna construction, which may achieve the desired result of providing high gain, that is, high directivity anda broad-response band, within convenient dimensions; The response-band limits are essentially deter- 'mined at the upper cut-ofi frequency by the maximum effective transverse extent of any conductive path near the throat of the horn, as for example the maximum transverse extent of the triangular panels 18 or 38, as the V case may be. The lower cut-01f frequency is essentially determined by' the transverse extent of the conductive framework at the mouth of the antenna, this transverse extent being substantially one-half the wavelength at the lower cut-off frequency. 7

'Because the respective pairs of antenna wings are' plane-polarized in perpendicular planes, the response of one pair is substantially without coupling tothe response of the other pair; therefore, if the mouth framework is rectangular rather than square, different directional characteristics and different, cut-on: frequencies may be' achieved in the horizontally and vertically polarized planes.

of opposed wings may-be omitted from the structure, so that essentially the antenna then comprises a single pair if, as is in certain cases desirable, no directional response is needed in a given polarization plane, one pair I claim:

l. A broadband antenna comprising two opposed rigid conductive wings, each of generally triangular form and spaced for convergence at a first pair of corresponding apices, first conductive means connecting and spacing 5 said wings at a second pair of corresponding apices, and second conductive means connecting and spacing said wings at a third pairof corresponding apices, said wings being electrically insulated from each other except where connected by said first and second conductive means.

2. An antenna according to claim 1, in which the spacing provided by said first and second conductive means is the same. 7

3. An antenna according to claim 1, in which the spacing provided by said first and second conductive means is substantially equal to the extent of said wings between the second and third apices of each.

4. A broadband. antenna, comprising a conductive rectangular open framework, two opposed conductive gen erally triangular wings conductively connected along corresponding edges thereof to opposed sides of said framework, and means holding the remote ends of said :wings in more closely spaced relation than the spacing provided by the other pair of opposed sides of said framework, said last-defined means including means 616C? trically insulating said remote ends of said wings from each other. V V

5. A broadband antenna, comprising a rectangular conductive open framework, four generally triangular conductive wings each electrically connected along one side to separate sides of said framework, and means holding the remote apices of said wings in relatively closely spaced relation and electrically insulated from one another.

6. An antenna according "to claim 5, in which said 7 conducting wings are all of substantially the same size. 7.'A broadband antenna, comprising four triangular conductive wings, means holding said wingslin closely V spaced relation along adjacent edges, thereby defining an open end or mouth remote from theconverged end of;

said antenna,.said holding means including electrically conductive connections between said wings only at'the open end of the mouth of said antenna, said wings being insulated from each other at locations spaced from the mouth of said antenna. a a g 8. A broadband antenna of rectangular pyramid configuration with a first pair of opposed plane-polarized modified horn surfaces and with a second pair of plane polarized modified both surfaces at right angles to said first pair, the polarization of said respective pairs being atright angles to each'other, and electrical conductive means interconnecting saidhorn' surfaces at the month end thereof, said wings being insulated from each other at locations spaced from the mouth of said antenna.

9.A broadband antenna, comprising two opposed diverging generally triangular wings, each of said'wings diverging at an acute angle with respect to and on opposite sides of a longitudinally extending axis and converging with their apices in insulated relation and substantially on said axis, each wing comprising a plurality of sub stantially parallehtransversely spaced, longitudinally extending conductorsinsulated from eachv other for the substantiallength thereof, and means conductivelyjc'on necting the ends of said conductors in parallel. f

'l0 .A broadband antenna comprising two triangular wings diverging with respect to .a longitudinal axisfrom first'electrically insulated and closely spaced corresponding apices, each of said wingscornprising' a triangular conductive framework and-a plurality of transversely.

spaced generally parallel, longitudinally extending conductors connected at respective ends to said framework, a first conductive spacer connecting said wings at a second pair of corresponding apices, and a second conductive spacer connecting said wings at a third pair of corresponding apices.

11. A broadband antenna, comprising four triangular wings oriented in rectangular pyramid configuration, means holding said wings in insulated relation at the apex of the pyramid, means conductively connecting said wings to each other at the base of the pyramid, each said wing being efi'ectively slotted in the longitudinally extending direction, thereby defining in each wing transversely spaced longitudinally extended conductors connected in parallel.

12. An antenna according to claim 11, in which the means conductively connecting said wings at the base of the pyramid is an open rectangular conductive framework.

13. An antenna according to claim 11, in which the means conductively connecting said wings at the base of the pyramid is in each case a corner bracket secured along adjacent edges to adjacent corners of adjacent wings.

14. An antenna according to claim 11, in which the efiective slot spacing in each of said wings is less than one-half the wavelength at the upper cut-ofi frequency for said antenna.

15. An antenna according to claim 11, in which the effective spacing between the conductors defined by said slots is less than one-half the wavelength at the upper cut-off frequency for said antenna.

16. An antenna according to claim 11, in which the minimum frame spacing at the base of the antenna is substantially one-half the wavelength at the lower cutoff frequency for said antenna.

17. An antenna according to claim 11, in which each of said wings comprises a triangular framework with a corner triangular reinforcement of conductive sheet material in the apex of the pyramid, the maximum transverse extent of said reinforcement being no greater than onehalf a Wavelength at the upper cut-off frequency for said antenna.

18. An antenna according to claim 11, in which each of said wings comprises two like right-triangular sections detachably secured along corresponding edges common to the right-angle corner thereof, whereby the edge along which said halves are secured may define one of the longitudinally conductive strips of the assembled wing.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,003 Barrow May 25, 1948 1,670,553 Sharp May 22, 1928 2,175,253 Carter Oct. 10, 1939 2,364,371 Katzin Dec. 5, 194 1r 2,495,219 Beck Jan. 24, 1950 FOREIGN PATENTS 602,689 Great Britain a- June 1, 1948

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