US2425716A - Electromagnetic horn - Google Patents

Description

Patented Aug. 19, i947 UNITED STATES PATENT OFFICE ELECTRMAGNETIO HORN Application July 24, 1937, Serial No. 155,489

d Claims.

The present invention relates to electric communication. Y

The invention will beodescribed more `fully in connection with the accompanying drawing, the single gure of which is a diagrammatic View of circuits and apparatus embodying Vthe present invention, showing,` .in longitudinal section, an electromagnetic horn Aconnected to a coaxial pipe.

An electromagnetic'horn 83, or" circular or annular dared-out conformation,` is shown at the free open end of an elongated tubularor pipe body portion or section Btg that may extend over any desired distance from the small end or throat of the horn. Thehorn may be constituted of metal, such as copper or aluminum, or it may be constituted of other material i1" its inner wall is otherwise rendered a conductor of the waves. The electromagnetic horn is provided with a, guiding surface or guiding walls that connect the small endor the throat and the large end lor the mouth of the horn.V The horn thus operates to guide waves traveling within it and tangentially along its surface in the longitudinal direction,` smooth- 1y and Without interruption. In reception, electromagnetic Waves received from space at the mouth of the horn are guided to the throat end of the horn. Intransmission,V electromagnetic waves generated at the small end of the horn are directed forward out into space.

The pipe `,.leconstitutes the outer tubular conductor of a coaxial-cable or `co'aXial-lineor coaxial-feed transmitting system 912, 94, the extended inner or central conductor. $2` of which maybe supported substantiallycentrally i nvand spaced from the `walls o f, the tube im, largely along the axis of the pipe 9d andthe horn 88, by insulating members (not shownh The central conductor 92 extendsinside the tubular member 94, 83, and into the throat ofthe hln t3, Where it terminates, to provide therein a free terminal beyond which the conductor 92 does notextend. The portion of the conductor S2 in the neighborhood of the free terminal is shown vdeparting somewhat iromthe` Said axis.` This free terminal is continuously joined to one end of an Aexciting or absorbing loop antenna rod El, the other end I of which is shown connected to the horn et.

The rod 8l isillustrlated as disposed in a plane through, and substantially at right angles to, the said axis. Itis shown positioned approximately centrally directly in the throat of the horn, outwardly of any portion of thejhorn, such as the pipe 94, that may be of substantially uniform cross section. f y f output circuit.

,2 Y The rod 8l thus constitutes a connecting conductor, disposed inside the tubular membe1` 88;.941,

for connecting the said free terminal of the conductor 92 to the tubular member 94, thus to provide a continuous conducting path'fo-r carrying current between the tubular member 94 `and the conductor 92 of the coaxial line. This construction enables the rod Vlil to excite Vor intercept -electromagnetic waves.

To this end, the rod 8l may be connected to terminal apparatus, as by means of two-wire connecting leads lil and l2. One oi the leads, vasthe wire It, may be connected to the outer tubular conductor et, and the other lead, as the Wire I2, to the central conductor 92 of the `coaxial-'feed line. The terminal apparatus may be connected to sending or receiving apparatus, at a sending or receiving station. For sending, the leads l0 land l2 may be connected to means for energizing the antenna 3l'. For receiving, they may be connected to means for Aevidencing the received waves absorbed by the antenna 8l.

The horn is shown Vconnected to a transmitting system comprising a radio-frequency oscillator 2, provided with a modulator 3, which may be modulated in any desired way, as by means of a microphone 4. The modulated output may be fed to a radio-frequency amplifier E that may be coupled to a circuit 8 having the leads l0 and I2 in its The described means of connecting the horn 83 to the coaxial-line "92194 provides an exciting rod lll substantially tranverse to the axis of the pipe and the horn for beam transmission. The modulated ultra-high-frequency energy may be taken by the conductors lil and l2 from the sending apparatus and delivered to the antenna tl in the small end of the horn. Current waves in the antenna 81 become impressed from the central conductor 92 upon the rod 8l. The antenna Sl will excite modulated ultra-high-frequency electromagnetic` waves of horn type, or horn waves, near the small end of the horn. The Waves will be transversely polarized, that is, the electric intensity will be entirely in surfaces normal to the direction of propagation. These transversely polarized waves will be propagated through the interior of the horn toward the large end or the mouth thereof, and finally beyond the mouth of the horn, into free space, `as ordinary radio waves. A beam will be radiated from lthe horn mouth of character appropriate to the horn itself; rather than to the antenna 8l and the other apparatus.

Similar but reverse operation will take place for reception of the waves, the large end or the mouth of the horn being electromagnetically open to space to permit the horn to receive electromagnetic waves from space. Modulated ultrahigh-irequency electromagnetic waves, received at the mouth of the horn, will be communicated to the antenna 8l, by which they will be absorbed, after which the energy will be conducted down the horn and the pipe to be delivered to the receiving apparatus (not shown), Where the signal comprising the intelligence will be recovered by demodulation.V

A coaxial-type wave transmitted along the tubular member 94 and the conductor 92 disposed therein, therefore, will be converted into a transverse-electric-type Wave in the tubular member 94 beyond the connecting conductor 81; or vice versa, a transverse-electric-type wave in the tubular member beyond the connecting conductor 81 may be converted into a coaxial-type Wave transmitted along the tubular member and the conductor 92 disposed therein. 'I'he waves will not be more fully described herein because they will be understood without further description by reference to a paper by L. J. Chu and W. L. Barrow, entitled, Electromagnetic waves in hollow metal tubes of rectangular cross section, proceedings of the Institute of Radio Engineers, vol. 26, No. 12, December, 1938, commencing at page 1520, and also to a paper by Barrow, entitled, Electromagnetic-horn radiators, Union Radio Scientifique Internationale, No. 79, p. 277, containing a revision of a paper presented at the Joint Meeting of the said Union and the Institute of Radio Engineers, at Washington, D. C., April 30, 1938. See also a paper by W. L. Barrow and L.. J. Chu, entitled, Theory of the electromagnetic horn, Proceedings of the Institute of Radio Engineers, vol. 27, No. 1, January, 1939, commencing at page 51, and also a paper by W. L. Barrow and F. D. Lewis, entitled, The sectoral electromagnetic horn, Proceedings of the Institute of Radio Engineers, vol. 27, No. 1, January, 1939, commencing at page 41.

The invention is not limited to the exact embodiment thereof that is illustrated and described herein. Modiiications may be made by persons skilled in the art without departing from the spirit and'scope of the invention, as defined in the appended claims.

What is claimed is:

1. An electric system having, in combination, an electromagnetic-wave-guide horn having a small end and a large end, the large end being electromagnetically open to space to permit the horn to receive electromagnetic waves from space or to radiate electromagnetic waves out into space at the large end, absorbing or exciting antenna means disposed in the horn at the small end, the horn having guiding walls between the large end and the small end for guiding the waves received from space at the large end to the antenna means at the small end in order that the received waves may be absorbed by the antenna means or for guiding to the large end for radiation out into space the waves excited by the antenna means at the small end, coaxial-line means for connecting the antenna means with means for evidencing the received waves absorbed bv thel antenna means or with means for energizing the antenna means to excite at the small end the Waves to be radiated out into space, the coaxial-line means having a substantially centrally disposed conductor connected to the antenna means and an outer tubular conductor connected to the horn, and means for connecting the antenna means to the outer tubular conductor.

2. An electric system having, in combination, an electromagnetic-wave-guide horn having a small end and a large end, the large end being electromagnetically open to space to permit the horn to receive electromagnetic Waves from space or to radiate electromagnetic waves out into space at the large end, absorbing or exciting antenna loop means disposed in the horn at the small end, the horn having guiding walls between the large end and the small end for guiding the waves received from space at the large end to the antenna means at the small end in order that the received waves may be absorbed by the antenna means or for guiding to the large end for radiation out into space the waves excited by the antenna means at the small end, coaxial-line means for connecting the antenna means with means for evidencing the received waves absorbed by the antenna means or with means for energizing the antenna means to excite at the small end the Waves to be radiated out into space, the coaxialline means having a substantially centrally disposed conductor connected to one portion of the loop means and an outer tubular conductor connected to the horn, and means for connecting another portion of the loop means to the outer tubular conductor.

3. An electric system having, in combination, an absorber or radiator for receiving electromagnetic waves from space or radiating electromagnetic waves out into space, absorbing or exciting antenna means disposed in the absorber or radiator, coaxial-line means for connecting the antenna means with means for evidencing the received waves absorbed by the antenna means or with means for energizing the antenna means to excite the waves to be radiated out into space, the coaxial-line meansA having a substantially centrally disposed conductor connected to the antenna means and an outer tubular conductor connected to the absorber or radiator, and means for connecting the antenna means to the outer tubular conductor.

4. A conductor of electromagnetic waves having, in combination, a coaxial line comprising a conducting tubular member and a conductor disposed substantially centrally of the tubular member and terminating inside the tubular member to provide in the tubular member a free terminal beyond which the conductor does not extend, and means comprising a connecting conductor in the tubular member connecting the free terminal to the tubular member and carrying current between the tubular member and the conductor disposed therein to convert a coaxial-type wave transmitted along the tubular member and the conductorl disposed therein into a transverseelectric-type wave in the tubular member beyond the connecting conductor, or to convert a transverse-electric-type wave in the tubular member beyond the connecting conductor into a coaxial type wave transmitted along the tubular member and the conductor disposed therein.

WILMER L. BARROW.

REFERENCES CITED The following references are of record in the file of this patent:

(References on following page) 5 UNITED STATES PATENTS Number l Number Name Date 2,052,339 Dallenbach Aug. 25, 1936 2206683 2,106,768 Southworth Feb. 1, 1938 2,044,413 Weyrich June 16, 1936 5 2,129,712 Southworth Sept. 13, 1938 Number 2,129,711 Southworth Sept. 13, 1938 466 063 2,054,896 Dallenbach Sept. 22, 1936 798579 2,943,347 Clavier June 9, 1936 430646 2,161,292 Hahnemann June 6, 1939 10 2,039,812 Leib May 5, 1936 1,696,304 Hutchison Dec., 25, 1928 741,622 Brown Oct. 20, 1903 986,806 DAntono Feb. 14, 1911 1,828,705 Konter oct. 20, 1931 15 284 309 Name Date Darbord Aug. 22, 1933 Southworth July 9, 1940 Wolff July 2, 1940 FOREIGN PATENTS Country Date Great Britain May 21, 1937 France Mar. 10, 1936 Great Britain June 21, 1935 OTHER REFERENCES Annalen der Physik V. 21, Oct. 1934, pp. 113-138 (Copy in Patent Ofce Library.)

Bell System Tech. Journal, Apr. 1936, V. 15, pp.

(Copy in DV. 16.)

Images