US2028510A

US2028510A - Transmitter for electromagnetic waves

Info

Publication number: US2028510A
Application number: US638907A
Authority: US
Inventors: Kramar Ernst
Original assignee: Standard Elektrik Lorenz AG
Current assignee: Alcatel Lucent Deutschland AG; C Lorenz AG
Priority date: 1932-04-20
Filing date: 1932-10-21
Publication date: 1936-01-21
Anticipated expiration: 1953-01-21
Also published as: FR45994E; FR47380E; GB405727A; US2072268A; NL38464C; NL41765C; US2151922A; DE577350C; FR741872A; FR44879E; GB442193A; FR44877E; GB472941A; NL46080C; GB438804A; BE414649A; DE616026C; FR795983A; FR47701E; GB444005A

Description

Jan. 21, 1936. E MA 2,028,510

TRANSMITTER FOR ELECTROMAGNETIC WAVES Filed Oct. 21, 1932 2 Sheets- Sheet 1 Jan. 21, 1936; f K A A 2,028,510

TRANSMITTER FOR ELECTROMAGNETIC WAVES Filed Oct. 21, 1932 T 2 Sheets-Sheet 2 Patented Jan. 21, 1936 'U NITE*D "'s rArs's" K raANstnr'rEn son ELECTROMAGNETIC:

WAVES Ernst Kramar, Berlin -Tempelhof, Germany, assignor to O. Lorenz Aktiengeselischaft, Berlin- Tempelhof, Germany Application ottom- 21, .1932, Serial No. 638,907

Germany April 19, 1932 150mm. (01. 250-11 111 radio direction flnding systems, particularly in aerial navigation, directional antenna systems have been employed, which radiate at. acertain angle to each other and are alternately ma- (4 nipulated in accordance with the so-called a-nmethod. It has further been suggested to facilitate the landing of aeroplanes by means oi! gliding-path beams. For this purpose beams of ultra-short rays are radiated obliquely upwards.

'10 The aeroplane then descends in the line of constant fleld 'intensity. It has also been suggested to combine these two methods. In accordance with this suggestion two beams of rays are emitted at a certain angle to each other, but at=the same angle with respect to the surface of the earth. The invention is concerned with-devices for direction flndingmethods of this type; It employs, instead of directional antenna systems wh'ch'are alternately keyed, antenna arrangements, in which reflectors or only one thereof and an exciter antenna are provided. This exciter antenna is fed continuously from the high ,irequency generator, and the reflector or re- 2 flectors are keyed.

The invention is illustrated by way of example in the accompanying drawings. Figure 1=is a schematic elevation of an example of the device.

' Fig. 1a shows schematically an arrangement for differently modulating thefradiated high frequency in each direction. Figures 2, 3 and 4 are.

diagrams relating .to the method 0! operation.

n-dipoleE is continuously energized by the transmitter B. On both sides of the dipole E '35 and in hne therewith 'are arranged two dipoles Ri' and R2, which act as .reflectors; Thesereflectors are interruptedin the middle and may beclosed by relaysMl and M2. Insteadoi' interrupting the reflectors, it is possible to provide for them tobe detuned, for. example. The re- I a lays MI and M2 are alternately energized and de-energizedby a'commutator K, whichis driven by a motor A. It is as ed in the drawings that the dipole BI is opened,'that is inactive, and the g dipole m closed,t hat isaictive. Instead of the collector, a relay device may be employed. which is so'arranged that both relays. are keyed in parallel. and thereby the contacts of the one closed and those of the other, opened. s

. Figure 2 shows the radiationconditions, Ii. v both reflectors'Ri and R2 are opened, the horizontal' characteristic otthe energizer dipcle'E is a circle a:--- rr only the reflector RI isclosed, then the characteristic 1: is obtained. It only the re- .55 flector Rl is closed, the characteristic c is obtained. If both reflectors are closed, then the f characteristic d is obtained. In the normal operation for radio-beacon purposes the characteristic d can be dispensed with. For certain purposes, however, characteristics of this type are 5 desirable.

,This arrangement'which preferably operates with ultra-short waves, is quite suiilcient for the purpose in view, that is the directional characteristics are sufficientlyinten'se, as the point of in- 10 tersection' of two characteristics is utilized, for example, the point ofintersectionPl of b and c.

alternately keyed. A single reflector is quite suiflcient for a simple device.

'Figure 3 shows the influence of the between energizer E and}, for the sake 1 sim- 20 plicity, a single reflector R. The distance between E and R for the characteristic e amounts to x/5,for f M3, and for g M2, when 7L is the wavelength. r

It is thus found that by increasing this distance to M2 the directional characteristic is intensifled in a direction perpendicular to the line passing through the energizer E and the reflector R.

According to Figure 4, similar effects :may be 0 obtained by varying the length 01- the reflector it with respect to the length (ii/2Y0! theenergizer dipole E. The length ratio, however, is concerned with the formation: or maxima which extend oppositely to the intendeddirection. The characteristic 'h, corresponds to I an arrangement in which, with the same distance between theenergizenE and-reflector R as before,

the length of the reflector R is smaller than M2. The characteristic 2' applies for M2, that is for a reflector which is the same length as the energizer, and characteristic k for an arrangement in which. the reflector is longer than the energizer :and especially with ultra-short waves. The presstance aoaaaio ent invention avoids keying the high frequency radiation from said main antenna, and means for current since only the reflector or reflectors are influenced. The circuits of the relays MI and M2 carry only direct current er. low frequency alternating current and can be easily protected against high frequency, for example by choke arrangements. The conductors to the relays may also consist of resistance wire, in order to prevent the passage of high frequency currents. The-invention may also be employed in arrangements in whichinstead of transmitting signals-according to the a-n-method or the like, the radiated high frequency ismodulated with different modulation frequencies, viz. at a particular frequency-in each direction. In this case, in accordance withthe invention, the carrierfresudclnly rendering the reflection antennae alternately effective and ineffective so that only one reflection antenna is-eflective at a time, said ing a main antenna, a high frequency generator quency, which is\ conveyed to the energizer antenna, is modulated differently in the same rhythm in which the reflectors arekeyed. In this manner the characteristic modulation frequency is transmitted in the corresponding angular space. Such a modulating arrange t is shown in lj'ig. 1 wherein the high frequency of the transmitter S is modulated at one frequency h in one direction and. ate-frequency f: in the other direction, a switch at being provided to operate in rhythm withcommutator K so as to connect the appropriate modulating frequency with transmitter S as the respective reflecting antenna: R1- and R2 are keyed. v

- The keying of the reflector may be eflectechby the means A, K, Ml, M2 shown in Figure 1, and a further collector or relay arrangement-provided V for controlling the alternate modulation of the transmitter at two modulation frequencies, or a two-frequency machine may be used which is provided with a cam disc arrangement for the actua tion of contacts controlling modulation frequencies. What is claimed is:

1. A radio transmitting arrangement comprising a main antenna, a high frequency generator coupled thereto,. a reflecting antenna on either side of said main antenna and spaced in line therewith a half wavelength therefrom, and means for abruptly rendering said reflecting antennaa alternately effective and ineffective so that the supply of the one is ineffective whilst the other is efl'ective to reflect the radiation from said main antenna.

2; A radio transmittingarrangement compriscoupled thereto, a reflecting antenna on either side of said main antenna and spaced therefrom in line therewith, means for abruptly rendering said reflecting-antennae alternately eifective and ineffective so that one is ineffective whilst the other is effective to reflect the radiation from said main antenna, sources of modulating signals of two different frequencies, and means for modulatingthe high frequency from the main antenna in accordance with the signal of one of said modulatingfrequencies whilst one of said reflecting antenna is eil'ective, and by signal of the other of said modulating frequencies whilst the, other of 'said reflecting antenna: is effective.

6. A radiotransmittin'g arrangement comprisingga main antenna, a high frequency generator coupled thereto, a reflecting antenna on either side of said main antenna. and spaced therefrom in line therewith, means for abruptly rendering said'reflecting antenna alternately efl'ective and ineffective so that one is ineffective whilst the other is effective to reflect the radiation from said main antenna thereby to produce a zone of equal -fleld intensity, and means for modulating the high frequency by a signal whilst one of the reflecting antenna: is effective and by a complemental signal whilst the other reflecting antenna is effective so that said signals combine to form a continuous signal within the equal field intensity zone. I

'7, A radio transmitting arrangement comprising a main antenna. a high frequency generator coupled thereto, a reflecting antenna on either side of said main antenna and spaced therefrom in line therewith, means for abruptly rendering said reflecting antenna alternately'effective and ineffective so that one is ineffective whilst the other is effective to reflect the radiation from j said main antenna thereby to produce azone of equal fleld intensity, and means for modulating ing an energizer dipole having a length equal to a .1

half wavelength, a high frequencygenerater cou-- pied thereto, .ftwo reflector dipoles. of greater length than said energizer dipole and spaced therefrom on either side thereof and in line therewith a distance-equal to a half wavelength,

and means for abruptly rendering said reflecting dipoles alternately effective and ineffective each being ineffective whilst the other is eflective.

3.. A radio transmitting arrangement comprising an energizer dipole having a length equal to a half wavelength, a high frequency generator coupled thereto, two reflector dipoles of greater.

length than saidenergizer dipole and spaced therefrom on either side thereof and in line therewith a distance equal to a half wavelength, .-and

means for alternately opening and closing said;

reflector dipoles so that whilst one is effective the other is ineffective to reflect the radiation from said energizer dipole.

4. A radio transmitting arrangement .compris; ing a main antenna, a high frequengy generator coupled ,thereto, a plurality ofreflec'tion antennae co-operating with saidmainantenna'when effective, .to reflect and thereby make-directive the 8. A radio transmitting'arrangement compris- "ing a main antenna, a high frequency generator coupled thereto,-a reflecting antenna on either .side of said main antenna and spaced therefrom.

inline therewith, and means for abruptly rendering said reflecting antennae alternately effective and ineffectiveso that one is ineffective whilst the. other is effective to reflect the radiation from.

said main antenna.

. 9. Aradio transmitting arnangement compris ing, a main antenna, a high frequency generator coupled thereto. a reflecting antenna on either side of said main antenna. means for rendering said reflecting antenna alternately effective and ineffective so that -oneis ineffective whilst the otheris effective to reflect the radiation from said antenna, said reflecting antenna: being spaced y from the main antenna an odd multiple of a half wavelength therefrom and in such relation thereto that a portion, of the area of the reflected radiation from one reflecting antenna also forms a portion of the area of the reflected radiation from the other reflecting antenna whereby said alternate operation of said reflecting antennae produces a zone of equal field intensity in said common area.

10. A radio transmitting arrangement comprising, an energizer dipole having a length equal to spect to said energizer dipole that there is produced a zone common to the reflected radiations from the two reflector dipoles, and means for abruptly rendering said reflector dipoles alternately effective and ineflective each being ineffective while the other is effective thereby to produce in said zone a fleld of equal intensity.

11. A radio transmitting arrangement comprising, a main antenna, a high frequency generator coupled thereto, a reflecting antenna on either side of said main antenna and so disposed with respect thereto as to produce a zone common to the radiations reflected from said reflecting an-Q tenure, means for rendering said reflecting an-.

tenna alternately effective and ineffective so that one is ineffective whilst the other is efiective to reflect the radiations from said main antenna thereby to produce in'said zone a fleld of equal intensity, and means for modulating the high frequency in accordance with one signal whilst'one of the reflecting antenna: is eflective'and in accordance with a difl'erent signal whilst the other reflecting antenna is effective. 3

12. A radio transmitting arrangement compris ing, a main antenna, a high frequency generator coupled thereto, a reflecting antenna on either ,side of said main antenna, means for rendering said reflecting antennae alternately eflective and inefiective so that one is ineflective whilst the other is eflective to reflect the radiation from said antenna, said reflecting antenna being spaced from the main antenna and in such relation thereto that a portionof the area of the rea flected radiation from one reflecting antenna also forms a portion of the area of'the reflected radiation from the other reflecting antenna whereby said alternate operation of said reflecting antenme produces a zone of equal fleld intensity in said common area.

13. A radio transmitting arrangement comprising, an energizer dipole having a length equal to a half wavelength, a high frequency generator coupled thereto; two reflector 'dipoles of greater length than said energizer dipoles and spaced therefrom on either side thereof and so disposed with respectto said energizer dipole that there isv produced a zone common to the reflected radiations from the two reflector dipoles, and means for abruptly rendering said'reflector dipoles alternately effective and ineffective each being ineflective while the other is effective thereby to produce in said zone a fleld of equal intensity.

14. A radio transmitting arrangement compris in a main antenna, a high frequency generator coupled thereto, a reflecting antenna on either thereby to produce in said zone a fleld of equal intensity. 4

15. A radio transmitting arrangement comprising a main antenna, a high frequency generator coupled thereto, a reflecting antenna at one side oi. said main antenna, continuously operable means for rendering said reflecting antenna alternately effective and ineffective, said reflecting antenna being in such relation to the main antenna that a'portion of the'area of the reflected radiation also forms a portion of the area of the in radiation from the main antenna whereby the alternate operation of said reflecting antenna ERNST KRAMAR.