US2208810A - Antenna system - Google Patents

Description

Jul 23, 1940. M, ATZIN 2,208,810

ANTENNA SYSTEM Filed Feb. 25, 1958 J A Ti: a;

/ -r RECEIVING 70 v ANTENNA v /W/RE 9 r0 ANTENNA 3 /4 m I W/RE TRANSMISSION 70 'l/NE 7 ANTENNA W/RE 5 6 l3 l4 {6 WIRE I2 7 mNNsu/ss/oN L/NE6 L INVEN TOR. M 7'IN KATZ/N ATTORNEY.

Patented July 23, 1946 UNITED STATES ANTENNA SYSTEM Martin Katzin, Riverhead, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Application February 25, 1938, Serial No. 192,447

8 Claims.

This invention relates to radio receiving and/or transmitting antennas and more specifically to the use of a single antenna structure for the simultaneous directive reception or simultaneous directive transmission of radio waves polarized in the horizontal and vertical planes. It also relates to systems for simultaneous transmission and reception.

It has heretofore been the practice, in order to mitigate fading of short-wave signals, to combine the received signals from two or more antennas in a suitable manner so that, even though the signal received from one of the antennas is at a very low level due to a fade, the signal or signals from the other antenna or antennas may still be of usable strength. This principle has been called the diversity principle and is applicable to antennas of like kind separated in space, generally denominated space diversity; to antennas operating on different frequencies, frequency diversity; and to antennas of different polarization, polarization diversity.

An object of the present invention is the application of the polarization diversity principle to a single antenna structure. This'ofliers the great advantage of a saving in land space'and antenna cost, with a consequent economic advantage.

As a further object, the present invention'involves the simultaneous transmission of both horizontally and vertically polarized waves, thus employing the diversity principle in transmission.

Another object of the present invention is to accomplish simultaneous transmission and reception on the same frequency, using a single antenna structure and without mutual interference.

Briefly, the invention consists in an antenna structure based on the theory of inclined antenna arrays which is disposed vertically as well as hori-' zontally, with appropriateapparatus at the terminals to conduct the received waves to separate receivers (in the case of reception) or to supply energy to the antenna from the transmitter (in the case of transmission). Or, alternatively, a transmitter and a receiver may be connected to the antenna for simultaneous operation. 7

Referring, now, to the drawing for a more complete disclosure of my invention, Figure 1 shows a sketch of a receiving antenna system according to the present invention, While Figures 2 and 3 show enlarged details of portions of Figure l.

As shown in Figure 1, four wires, 9, II], ll, 12,

are suspended between four poles or towers I, 2, 3, 4. Poles I and 4 are aligned in the direction from which it is desired to receive; they may be of moderate height sothat the ends of the antenna are fairly near the ground. The other 6 two poles or towers, 2 and 3, are arranged with their plane at right angles to the desired direction of reception and approximately midway between poles I and i. Poles 2 and 3 should be quite high, so that the junctions of wires 9 and 10 Ill and of H and I2 are at a suitable height above the ends of the antenna. The converging ends of wires 9 and II connect to terminals on network 5, other terminals of which connect to two transmission lines 1 and 8, and to ground. The converging ends of antenna wires Ill and I2 connect to terminals of network 6 at the opposite end of the antenna, another terminal of 6 connecting to ground. The purpose of network 5 is to separate the received signal into components due to horizontal and vertical polarization, respectively, and to effect suitable coupling of these components to transmission lines I and '8, which, in turn, conduct the respective signals to suitably located receivers;

Network 6 provides proper terminating impedances so as to insure substantially unidirectional reception. I

The principle of operation is readily understood by reference to the drawing. The antenna operates in a manner similar to that of the diamond antenna, well known to the art, in which optimum response occurs for a frequency at which the electrical length of path traversed by the signal currents in the antenna wires is a half wavelength greater than the path of the signal waves in space. For a horizontally polarized wave front arriving along the direction through poles l and-I, the currents induced in wires 9 and I0 are oppositely directed to those induced in wires II and I2, due to the fact that wires 9 and I0 slant in .opposite horizontal directions from the wave direction. In the wellknown manner the induced currents arriving at the end of each wire have, for the optimum frequency of operation, added vectorially to form a semicircle, thus giving a maximum current at the antenna terminals of network 5.

For vertically polarized signal waves, the currents induced in wires 9 and I0 are similarly directed to those induced in wires ll and I2, since they slant in the same vertical direction from the wave direction. In well-known manner, the induced currentsarriving at the end of each wire have, for the optimum frequency of operation, added vectorially to form a semicircle, thus giving a maximum current at the antenna terminals of network 5.

As shown in Figure 2, network 5 consists of two transformers 20, 2|, with their secondaries connected respectively to transmission lines l and 3. The primary of transformer 20 connects to the antenna wires 9 and H. The center tap of this primary connects to one terminal of the primary of transformer 2|, whose other primary terminal connects to ground.

It will be apparent that for horizontally polarized signal waves, the terminals El and H? of transformer 20 will experience voltages of opposite polarity, thus transferring the signal energy to transmission line I, while no difference of potential will exist between center tap l9 and ground, and therefore none of the energy due to the horizontally polarized signal waves will appear across transformer 2 i.

For vertically polarized waves, terminals l! and I8 of transformer 20 receive Voltages of like polarity, thus resulting in no energy transfer to transmission line 1. These like voltages, however, give rise to a potential difference across transformer 2|, thus resulting in transfer of energy to transmission line 8.

Network 6 provides proper terminating impedances so as to insure substantially unidirectional reception. Referring to Figure 3, elements I I3, I33 and l4, l4, acting in series, form the proper terminating impedance for horizontally polarized waves, while l3 and i4 acting in parallel with [3 and I4, this combination acting in series with IS and I6, form the proper terminating impedance for vertically polarized waves.

The specific embodiment used to illustrate the principles of this invention has been described with regard to the reception of waves of both horizontal and vertical polarization. It will be readily apparent, however, that the system is equally adapted to the art of transmission, it then being merely necessary to consolidate transmission lines I and 8 into one line feeding the two transformers to effect the radiation of both horizontally and vertically polarized waves.

Also, it is readily possible to utilize one transmission line to conduct received signals of one polarization to a receiver while the other transmission line can be used to conduct energy from a transmitter to the antenna to radiate waves of the other polarization at the same time, the

receiving and transmitting operations occurring without mutual interference due to the electrical independence of the two channels.

While I have particularly illustrated and described one form of my invention, it is to be understood that my invention is not limited to the form illustrated but modifications may be made within the scope of the invention.

I claim:

1. An antenna system comprising a pair of conductors having their ends adjacent and the pair arranged in a generally diamond shaped configuration, reflection preventing means connected between one pair of adjacent ends whereby said antenna is unidirectionally responsive to horizontally polarized signal waves, reflection preventing means connected from said one pair of adjacent ends to ground, whereby said antenna is unidirectionally responsive to vertically polarized signal waves, and means connected to the other pair of adjacent ends for separately supplying said signals to transducer means.

2. An antenna system comprising a pair of conductors having their ends adjacent, and the pair arranged in a generally diamond shaped configuration, reflection preventing means connected between one pair of adjacent ends whereby said antenna is unidirectionally responsive to a horizontally polarized component of a signal wave, the central portion of said antenna system being at a substantially different level than the ends, reflection preventing means connected from said one pair'of adjacent ends to ground, whereby said antenna is unidirectionally responsive to a vertically polarized component of a signal wave, and means connected to the other pair of adjacent ends for separately supplying said signal wave components to separate transducer means.

3. A receiving antenna system comprising a pair of conductors having their ends adjacent and the pair arranged in a generally diamond shaped plan, the central portion of said antenna system being at substantially different level than the ends, reflection preventing means connecting one end of said conductors and connecting said ends to ground, a signal responsive means connected to the other end of said conductors, said signal responsive means comprising a pair of coupling transformers each having a primary and secondary, the primary of one of said transformers being center tapped and having its end terminals connected to said conductors, the primary of the other of said transformers being connected between the center tap of the primary of the first transformer and ground, and the secondaries of said transformers connected to transmission lines.

4. In a diversity antenna system an antenna comprising a pair of conductors having their ends adjacent and the pair arranged in a generally diamond shaped configuration, the central portion of said antenna being at a substantially different level than the ends, said antenna being simultaneously and selectively operable with horizontally and vertically polarized radiant energy, a first transducer means responsive to only the horizontally polarized component for coupling said antenna to a transmission line, a second antenna and reflection preventing means at the i opposite end of said antenna.

5. An antenna system comprising an aerial comprising a pair of conductors having their ends adjacent and the pair arranged in a generally diamond shaped configuration, the central portion of said aerial being at a substantially different level than the ends, said aerial being simultaneously responsive to both vertically and horizontally polarized waves, means responsive to the horizontally polarized component only connected to said aerial, means responsive to the vertically polarized component only also connected to said aerial and a separate transmission line connected to each of said means.

6. An antenna system comprising an aerial comprising a pair of conductors having their ends adjacent and the pair arranged in a generally diamond shaped configuration, the central portion of said aerial being at a substantially different level than the ends, said aerial being responsive to both vertically and horizontally polarized waves, means responsive to horizontally polarized component only connected to one end of saidaerial, means responsive to the vertically polarized component onlyv also connected to the iii) end of said aerial, a transmission line connected to each of said means and means connected to the other end of said aerial for preventing refiection of the received waves.

7. An antenna system comprising a pair-of conductors disposed in a diamond shaped configuration, the central portion of said antenna system being at a substantially different level than the ends, reflection preventing means connected to one end of said pair and means connected to the other end for separating the vertically polarized component from the horizontally polarized component of the signal wave and means for connecting separate signal responsive means to said separating means so that each signal responsive means is responsive to only a single component of said signal Wave.

8. An antenna system comprising a pair of conductors having their ends adjacent and the pair arranged in a generally diamond shaped plan, the central portion of said antenna system being at substantially different level than the ends, reflection preventing means connected to one end of said conductors, coupling mans connected to the other end of said conductors, said coupling means comprising a pair of transformers each having a primary and secondary, the

secondary of one of said transformers being center tapped and having its end terminals connected to said conductors, the secondary of the other of said transformers being connected between the center tap of the primary of the first transformer and ground, and the primaries of said transformers connected to signal generating means.

MARTIN KATZIN.

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