US3254343A

US3254343A - Lattice tower supporting interior dipoles with reduced interference

Info

Publication number: US3254343A
Application number: US224935A
Authority: US
Inventors: Laub Helmut; Kristkoiz Karl-Heinz
Original assignee: Siemens Corp
Current assignee: Siemens and Halske AG; Siemens Corp
Priority date: 1961-09-27
Filing date: 1962-09-20
Publication date: 1966-05-31
Anticipated expiration: 1983-05-31
Also published as: GB950716A; DE1303212B

Description

United States Patent 12 Claims. (a. 343-796) The present invention relates to an antenna system with an antenna support constructed in the form of a lattice mast or the like, in connection with which the radiators, for instance full-wave dipoles, are arranged substantially within the mast.

An antenna system is known in which the radiators which are fed as whole-wave dipoles are arranged in the form of a polygon which in its turn is arranged within the corner posts of a supporting lattice mast. The individual radiators are in this case connected in the voltage node by special struts with the corner posts of the mast. The horizontal members of the mast are in the known systems arranged approximately in the center between the radiator polygons. In such antenna systems, the influence of the mast on the radiation can be kept very small, as long as the length of the side of the square mast does not exceed certain limits referred to the wavelength of the energy radiated. If, on the other hand, with constant external dimensions of the mast, the wavelength of the energy radiated is reduced or in case of constant wavelength, the dimensions of the mast are increased, then changes are produced in the radiation pattern, as a result of electrical resonances, particularly on the horizontal members of the mast.

The object of the present invention is in particular to make possible, also for large mast cross-sections as compared with the wavelength, the use of radiators arranged on the inside of lattice masts without the radiation pattern being changed by the influence of the mast. The same masts can thus be used for larger frequency ranges, for instance for an entire television band, and more stable constructions are obtained, such as is desirable in particular for antenna systems of high gain and correspondingly great structural heights. Such antenna systems can therefore also serve as supports for other stacked antennas of other frequency ranges. While in the known systems with radiators arranged within the mast, no cross-bracings were as far as possible arranged in the vicinity of the radiators, and the horizontal diagonal braces between the corner posts of the mast were therefore arranged as far as possible in the center between two radiator polygons, arranged one above the other, the present invention, differing from these concepts, points out an entirely different manner by which a solution of the mechanical and electrical problems of such an antenna system is possible.

In accordance with the present invention, which is concerned with an antenna system of the initially indicated type, the radiators are arranged in the region of a horizontal diagonal brace serving for the reinforcing of the corner posts of the mast, and are held preferably directly or indirectly to the members of the horizontal diagonal bracing. It has surprisingly been found that with mast cross-sections which go beyond the size customary heretofore with similar antenna systems, disturbances in the radiation patterns, particularly in case of omnidirectional radiation, can be avoided. As compared with the known antennas with radiators arranged within the mast, there is also the additional advantage that the members of the horizontal diagonal bracing can simultaneously also be ice used as direct or indirect mounts for the antenna elements so that additional supports are no longer necessary.

Particularly favorable arrangements of the radiators, referred to the members of the horizontal diagonal bracing are obtained if the radiators extend transversely to the members immediately adjacent to them and on which they are preferably also mounted. It is furthermore advisable to develop the horizontal diagonal bracing as simple crossed bracing in connection with which the radiators are arranged at right angles to the members bearing them. When using whole-wave dipoles as radiators of the antenna system, the latter can be conductively connected at the voltage node or near it to the members of the horizontal diagonal bracing.

In order to obtain radiation patterns which exhibit the least possible influence by the mast, it is advisable also to select for the side bracing extending on the sides of the mast special arrangements of the members which result in suflicient mechanical strength and exert as little disturbing effect electrically as possible.

An advantageous further development of the invention accordingly contemplates for the side members extending on the sides of the mast between the corner posts, a simple zig-zag bracing, in the corners of which are arranged the horizontal transverse bracings bearing radiators. In this connection, it is advisable to arrange the zig-zag lateral bracing in such a manner as to produce zig-zag strips which extend parallel to each other in the developed view of the side bracing. The influence of the side bracing on the radiation characteristic is particularly slight if the inclination of the members of this bracing is selected as large as possible, and if a radiator polygon lies in each corner formed by the members of the side bracing. In cases in which sufficient inclination for the members of the zigzag shaped side bracing is not possible, disturbing resonance phenomena can be prevented by the provision of cavity resonators on the members of the side bracing.

Further details of the invention will be explained with reference to the accompanying drawings showing an embodiment of an antenna mast serving for the radiation of meter or decimeter waves, and particularly waves in the ultra-shortwave radio range or the television range.

FIG. 1 shows in perspective a lattice mast 1 of square cross-section, the corners of which are formed by the

corner posts

2, 3, 4 and 5. The

radiator elements

6, 7, 8 and 9, which operate as whole-wave dipoles, are also arranged in a square within the mast in such a manner that the corners of the mast and the corners of the square formed by the radiator are staggered 45 from each other. The corners of the square formed by the radiators lie accordingly in the center of the side planes of the mast 1. In order to obtain a strongly focused vertical characteristic, a plurality of such radiator polygons are arranged one above the other, of which only the system formed of the

radiators

14, 15, 16 and 17 is shown. The horizontal diagonal 'bracings necessary for the mechanical stiffening of the mast consist of the members 22 extending from the corner post 2 to corner post 4, and the members 21 connecting

corner posts

3 and 5. The

radiators

6, 7, 8 and 9, and 14, 15, 16 and 17 respectively are arranged in the region of the

members

21 and 22 forming the horizontal diagonal bracing, which members when whole-wave dipoles are used can be conductively connected with the

members

21 and 22 respectively directly in the voltage node of the voltage distribution of a standing wave designated in FIG. 2 by the reference letter U, or in its vicinity.

When using other radiator arrangements, the mechanical mounting of said radiators can also be effected by the

members

21 and 22, in which case the radiators should be supported on the members with the use of insulators.

The side bracing provided on the sides of the mast consists of simple

uncrossed members

23, 24, 25 and 26 which are arranged in zig-zag form and the corners of which lie in each case in the region of the radiator polygon and thus in the region of the horizontal diagonal bracings. In this way, disturbing resonances at the members of the side bracing are substantially avoided. The members of the side bracing on the individual sides of the mast are so associated with each other that in developed view zig-zag strips extending parallel to each other are formed. The radiation patterns of such antenna systems lie, even in case of side lengths of the mast corresponding approximately to an average wavelength, within the sphere of the requirements established for omni-directional patterns.

FIG. 2 shows the lattice mast as seen from the top thereof. The full-

wave dipoles

14, 15, 16 and 17 are placed under voltage via the

feed lines

27 and 28. The balancing and

transformer units

31, 32 are advantageously arranged between the radiator planes and can in given cases be fastened to a central ladder 30. The wholewave dipoles extend transversely to the

members

21, 22 of the horizontal diagonal bracing, which support them and form therewith an angle of 90. In this way, the whole-wave dipoles extend in each case parallel to the member of the horizontal diagonal bracing which does not support them and which lies symmetrically in the center between the whole-wave dipoles which extend in each case parallel toeach other. In this manner are avoided disturbing influences from the struts of the horizontal diagonal bracing on the radiation properties of the radiator polygon.

The feeding of these radiators is advantageously effected by causing a circular current to develop on the radiator polygon, whereby the radiators lying opposite each other are traversed by currents of the same magnitude but in opposite directions. The horizontal diagonal bracing is developed as a simple cross-wise bracing. The center point of the horizontal diagonal bracing formed by the

members

21 and 22 and the center point of the radiator polygon both lie in the axis of the mast. The device for the connecting in parallel of the four whole-wave dipoles of the cube, as well as for the unbalancing for connection to a feed cable is suitably fastened to a frame between the two dipole planes or to a ladder which is preferably arranged at the center.

Every two cubes lying above each other are advantageously mutually displaced by 90 in the vertical axis.

Changes may be made within the scope and spirit of the appended claims which define what is believed to be new and desired to have protected by Letters Patent.

We claim:

1. An antenna system comprising an antenna supporting mast of lattice-type construction having corner posts and horizontal diagonal brace members which serve to stiffen such corner posts, and whole wave dipole radiators arranged substantially within the mast, disposed adjacent the corners of the mast and supported on such diagonal brace members.

2. Antenna system according to claim 1, wherein the radiators extend transverse to those members of the horizontal diagonal bracing which they'immediately adjoin and on which they are mounted.

3. Antenna system according to claim 2, wherein the horizontal diagonal bracing is constructed as a simple cross-type bracing, perpendicular to the members of which are arranged the radiators held thereby.

4. Antenna system according to claim 3, wherein the radiators are fed by pairs as whole-wave dipoles, said radiators being arranged in a polygon with corners staggered with respect to the corner posts of the mast.

5. Antenna system according to claim 4, wherein the radiators form a square which is staggered 45 with respect to the lattice mast which is likewise developed with a square cross-section.

6. Antenna system according to claim 5, wherein the centerpoint of the horizontal diagonal bracing and the centerpoint of the radiator polygon both lie in the axis of the mast.

7. Antenna system according to claim 4, wherein each of the whole-wave dipoles is conductively connected in the vicinity of the voltage node thereof with the members of the horizontal diagonal bracing.

8. Antenna system according to claim 1, wherein the balancing device and the distributing lines are arranged between the radiator planes and are fastened to a central ladder.

9. Antenna system according to claim 1, wherein the side bracing extending between the corner posts on the sides of the mast is developed as a simple zig-zag shaped bracing in the corners of which are arranged the horizontal transverse bracings supporting the radiators.

10. Antenna system according to claim 9, wherein the zig-zag side bracing is so arranged that in developed view, there are produced zig-zag strips extending parallel to each other.

11. Antenna system according to claim 1, wherein every two cubes located one above the other are mutually displaced by in the vertical axis.

12. Antenna system according to claim 10, wherein a radiator polygon is disposed in each corner formed by the members of the side bracing, the inclination of the zig-zag bracing being such that disturbing resonance phemomena is reduced.

References Cited by the Examiner UNITED STATES PATENTS 2,254,697 9/1941 Godet 343798 X 2,583,287 1/1952 Andrews 343875 2,771,606 11/1956 Kandoian 343-890 FOREIGN PATENTS 332,352 8/ 1958 Switzerland.

OTHER REFERENCES Electronics, August 1955, pp. and 131.

HERMAN KARL SAALBACH, Primary Examiner.

ELI LIEBERMAN, Examiner.

Claims

1. AN ANTENNA SYSTEM COMPRISING AN ANTENNA SUPPORTING MAST OF LATTICE-TYPE CONSTRUCTION HAVING CORNER POSTS AND HORIZONTAL DIAGONAL BRACE MEMBERS WHICH SERVE TO STIFFEN SUCH CORNER POSTS, AND WHOLE WAGE DIPOLE RADIATORS ARRANGED SUBSTANTIALLY WITHIN THE MAST, DISPOSED