US1697945A - Phasing of antenna - Google Patents

Description

Jan. 8, 1929.

H. H. BEVERAGE PHASING OF ANTENNA 3 Sheets-Sheet 1 1 29.1

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Jan. 8, 1929. 1,697,945

H. H. BEVERAGE PHASING OF ANTENNA Filed Aug. 3, 1926 3 Sheets-Sheet 2 IN V EN TOR.

H. H. BEVERAGE ATTORNEY Patented Jan. 8, 1929.

UNITED STATES PATENT OFFICE.

HAROLD H. BEVERAGE, OF RIVERHEAD, NEW YORK, ATSSIGNOR TO RADIO CORPORA- TION OE AMERICA, A CORPORATION OF DELAWARE.

PHASING OI ANTENNA.

Application filed August 8, 1926. Serial'li'o. 126,770.

In combining a number of antennae of any type in broadside, it is necessary to preserve certain phase and amplitude relations among the signals supplied by the various antennae. It often happens that when a station is bu1lt a single antenna is contructed which terminates at the station and later a second and even a third antenna is-constructed several miles away from the first station. These sec 0nd and third antennae are usually located at different distances from the receiving station which is the combining center and, therefore, it is necessary to bring the signals from at least all but the ,original antenna to the combining station over land transmission lines. These lines are usually of difierent length and, therefore, there is a change in the phase and amplitude of the signal reaching the receiver by different amounts in the case of the various antennae.

If the combining station were in a position as indicated by A in Fig. 1 and the two antennae were located at equal distances from it, of course the signals from each antenna 1 and 2 would arrive in phase at the combining, or in this case receiving station, but this is usually impossible, and it is, therefore, necessary to use some means to bring the signals from the antenna adjacent to the receiving station and the other antennae which are away from the station, into proper phase relationship. This has been done in the past by using a separate artificial line for each signal.

An object of my invention is to make possible the use of a single artificial line for all signals within wide frequency limits. 7 The ultimate limits are, of course, determined by the design of the artificial line. This artificial line is designed so that it has an electrical length equal to that of the transmission line which may be, for example, six miles long and the shortest wave length that can be used is limited by the cut-off frequency of each individual section of the artificial line. For the purpose of increasing the range of the artificial line it may be designed in many sections so as to make the cut-ofl:' frequency hi h.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method. of operation, together with ways in which the particular obects thereof may be attained will best be understood by reference to the following deof various sections of the artificial line together with the phase adjusting means;

Fig. 3 is a showing similar to Fig. 1, showing a means of connecting the artificial line using separate intensity adjustment for each desired frequency; and

Fig. 4 is a modification of Fig. 3'showing a potentiometric means for intenslty regulation of all frequencies simultaneously,

Fig. 5 is a further modification showing unequal transmission lines and a loading to reduce velocity in one of them; and

Fig.6 shows a single transmission line used for phasing three antennae spaced broadside.

Referring to the drawings, Fig. 1 shows a typical broadside installation consisting of two antennae 1 and 2, for example, wave antennae of the type shown in my U.-S. Patent 1,381,089.-. The antenna 1 terminates directly at the receiving station while the antenna 2 is at a point remote therefrom which for convenience of illustration may be considered as being six miles away. Assume that the signal received is travelling in the direction of the arrows shown in Fig. 1, then this signal will reach the north end of both antennw at approximately the same instant and as it travels down each antenna it will induce a Volta e in each of the antennae simultaneously whic are in phase in both and which builds up to a maximum at the south end after which it passes through the primaries of the transormer T and T thereby feeding the signal energy back over the antenna to the transmission line. The signal energy will finally appear in the secondaries of the transformers T and 'T, and up to this point the energy in each antenna remains in phase. From the secondary T the energy from the antenna 2 is brought to the receiving point over a transmission line TL which, as above stated, is assumed to be six miles, or its equivalent 9.65 kilometers, distance from the receiving point at which the antenna 1 is located. If the signal travels along the transmission line TL with the velocity of light, which is approxi-:

mately true in the usual case for open wire lines, a signal at a wave length of 9,650 meters from antenna 2 will be delayed a whole cycle, while the signal of twice that wave length or 19,300 meters will be delayed a half a cycle, with respect to the signals from the antenna 1. It is evidenced, therefore, that the trans mission line will dephase the signals a certain amount and that the amount of dephasing is a function of the wave length.

To overcome this difiiculty I propose to use an artificial line such as is shown conventionally from AL in Fig. 1 and in more detail in Figs. 2 and 3, and to make the total electrical length of this artificial line, that is, the real length plus the equivalent length qf the artificial line, the same electrical length as the real transmission line from antenna 2 to the receiving station. The artificial line is placed on the antenna 1 and will delay the signals as a result of its construction by the same amount as a real line coming from the antenna 2.-

It is well known in the art how to design artificial lines. One form of construction may be such as is shown in Fig. 2 where the series inductances are indicated by L and the shunt capacities by C. In the real lines the velocity V= for the currents flowing in the line, and the natural or surge impedg- It is a well known fact that the constants of real open wire lines are usually-such that the currents have a velocity of the order of the velocity of light and that the surge resistance is of the order of 600 ohms. By substituting these values in the above equations it is found that the inductance ance Z L should be approximately 2 millihenries per 1 kilometer of electrical length while the capacity C should be about .0055 microfarads per kilometer of electrical length. Thus, an artificial line with an electrical length of- 10 kilometers should have a total series inductance of 20 millihenries and a total shunt capacity of .055 microfarads. If the line is divided into ten equal sections, each section it that would be equivalent to one kilometer of real line. v

The more sections there are to the artificial line the higher the cut-off frequency will be, so that b usin a large number of sections it is possi le to esign an artificial line of con siderable electrical length and still keep a high cut 01f frequency. In applicants arrangement it has been found that artificial lines for long wave reception may have an electrical lengthv of between 10 to 30 kilometers with fifteen sections and the cut-off frequencies will then be about 50,000 cycles for the 30 kilometer line, and 150,000 cycles for the 10 kilometer line.j

In all cases, the artificial lines terminate in a resistance B (Fig. 2) which is equal to the surge impedance of the lineso as to prevent ing a plurality of signals and individually adjusting the intensity for each desired frequency. Each of the antennae l and 2 terminates in the transformer T and T Transformer T operates a coupling tube 0,

associated with the artificial line AL. The

transmission line TL connects the transformer T through a second transformer T at the end of this transmission of real line to-coupling tubes 0,, associated with variable couplings M. This coupling M is adjusted for equal intensity from the two antennae, and connected to the one end of its secondary is the pick-up coil L which is capable of being ad- ].usted after the fashion shown in Fig. 2 until the used portion of the artificial line is electrically the equivalent of the real linevbetween antenna 2 and 1, at which point all signals from the two antennae will be in phase. This modification would be used in cases where the attenuation characteristics of the real and artificial lines are not identical for difier'ent frequencies, causing the relative intensities of the antennae to vary with the frequency. This variation may be corrected by using several coupling tubes C associated with variable couplings M, whereby the intensities may be equalized separately for each desired frequency.

Another modification of the arrangement is shown in Fig. 4 where the relative mtensity between the two lines may be adjusted by the potentiometer p which will also serve to prevent reflections on the real line. This arrangement would be used in cases where the attenuation characteristics of the real and artificial lines are practically identical, making individual intensity adjustments unnecessary.

The energy from the transmitting line TL and from theartificial-line AL is brought to transformers T and T respectively. The transformers have one side of their secondaries serially connected and the other side directed to a receiving means in a manner similar to what has bee-n shown by the preceding figures. I

Fig. 5 shows a further modification that could be used in some cases. Here transmis sion lines of unequal length TL and TL are shown. The shorter of the two lines TL is loaded to reduce its velocity, as for example, by using series inductances or shunt capacities or both. In some cases, the desired result might be obtained by using a section of cable or twisted pair in TL It is also obvious that the same result could be obtained by speeding up TL by loading with series capacity or shunt inductance, or by other means to make the electrical lengths of the two transmission lines identical.

In Fig. 6 three antennae 1, 2 and 3 are shown as in spaced broadside. The single transmission line is then connected by coupling or other suitable means with each of said antennae and in turn connected with a receiving means. Associated with the transmission line are loading means adapted to produce infinite phase velocity. so as to be used for phasing the three antennae.

While the theory, as developed by Ein stein, that nothing can travel faster than the velocity of light is doubtlessly correct, it is possible to advance the phase by loading and thus produce an apparent phase velocity greater than the velocity of light. By this I mean, that while the actual currents in the wire do not travel faster than the velocity of light, the phase may be progressively advanced to produce the effect of a current travelling faster than the velocity of light,

as far as a steady state of conditions is consaid antennae to the same electrical length,

cerned. This advancing of the phase may be accomplished by loading the larger lines to an apparent infinite phase velocity by the use of a series capacity, a shunt inductance, or both.

While my specificationhas described means and methods adapted to bring the signals from several antennae into phase, it is ob vious that the same principles could be applied where any definite phase relations are desired, and is, therefore, not limited to the particular case of in phase condition.

It is obviousv from the disclosure that there are many ways of applying this principle and also it is clear that the same idea can be applied to. more than two or three antennae and it is, therefore, to be understood that my invention is not limited to the specific forms shown but is capable of being used with any number of antennae located at various distances from the point at which the signals are received, and I am, therefore, entitled to all modificationsthereof that fairly fall within antennae, a receiving said receiver, an artificial line inserted in said firstnamed antenna circuit, pick-up coils assoclated with said energy transfer circuits and said artificial line, and means for adjusting said pick-up coils with respectto said artificial line, said adjustment being adapted to bring the energy from each of said antennae to the same phase relationship.

2. A radio receiving system comprising, a

receiving means, a recelvlng antenna ad acent thereto, a second receiving antenna'at a point remote therefrom, a land line connection between said remote antenna and said receiver, means associated with said connecting line for controlling the signal intensity reaching said receiver, an artificial line con-.

nected with said antenna adjacent said receiver,means connected with the land line and with said artificial line for regulating the phase angle between the signals received from the said antennae, and means forcoupling.

said antennae to said receiving means.

3. A radio receiving system comprising, a receiving antenna, a second receiving antenna at a point remote therefrom, means for electrically connecting said antennae, an artificial line associated with one of said antennae, said artificial line being adapted for use over a -widely varying frequency range of received signals, means for adjusting the electrical equivalent length of said artificial line, said adjustment being adapted to bring the artificial line and the connecting line between and means for utilizing said signals,

4. A radio receiving system comprising a plurality of antennae remote from each other, a receiving system adjacent one of said antennae, a circuit connecting the other of said antennae to said receiver, artificial line means associated with said first named antenna for producing an electrical length from said an tenna to the receiver equivalent to that of the electrical circuit connecting said remote antenna to said receiver, and means for regulating the effective length of said artificial line.

5. A radio receiving system comprising a plurality of antennae remote from each other,

a receiving means adjacent one of said an tennae, a circuit connecting the other of said antennae with said receiving means, an artificial line associated with said first named antenna, said artificial line being adapted to produce an electrical length from said antenna to said receiving means equivalent to that of the electrical circuit connecting said remote antennae to said receiver, means for regulating the electrical length of said artificial line, and means for equalizing the in-' texisities of the si nals from the several antennae separately or each frequency desired.

'HAROLD H. BEVERAGE.

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