DE1902884B2 - ANTENNA SYSTEM FOR VHF AND UHF AREAS FOR DETERMINING DIRECTION - Google Patents

Description

5 6

The radiation centers of the three antennas on one side of the carrier material α

elements (dipoles ^ ₁ and d ₂ , loop antenna R) must be set bridge B (Fig. 3), by means of the two,

sen coincide in order to avoid an additional error forming a dipole half of the dipole parts of the dipoles d _v

to be avoided through decentralization. or d _{% are} conductively connected. It turns out that way

Despite the structurally interpenetrating an 5 for each dipole f /, and d _% two feed points at the

Order, the antenna elements must have electrical bridges B, to which the respective feeder

as far as possible decoupled from each other (> 40 db) energy is deposited.

and are allowed to mutually represent each other in the form of a diagram on the area free of copper foil are exactly

not affect. in the middle between the individual dipole parts of the

The above requirements are, as indicated by 10 respective dipole halves of the dipoles d _x and r / ₂ on the

Extensive experiments have shown with the carrier material ο the feed systems Tr (F i g. 3, 4) for

Sketched arrangement of the individual conductor tracks according to the individual frame parts r ₁ jr _i , r ₃ jr ₄ , r _s lr _t and C ₇ Zr ₈

F i g. 1, in which the basic arrangement (Fig. 1, 7, 8) of the loop antenna R (omnidirectional antenna)

of the antenna elements is shown to meet. arranged. As a result of the capacitive coupling

For mechanical reasons (dimensional accuracy) _{t5 is} the excited dipoles d _x and d _t lead the feed

the antenna system in the technique of printed systems Tr on the outside electricity. Since their longitudinal

Circuits (stripline technology) carried out, which increase but coincide with that of the dipoles,

also a simple and inexpensive production does not affect the radiation diagram

permitted. The individual antenna elements form dipoles.

The ends of the conductors are connected to _ao using known technology. With the arrangement described, for

one laminated on both sides with copper foil, for example a dipole </, or d _t the following measured

circular insulating material carrier plate (a, Fig. 3, 6, values of the radiation diagram: 6a). The crossed dipole systems d _t and

ί / ϋ (Fig. 1, 2) are within the loop antenna R, 3-db-width 89.5 °

which is formed from frame parts r _x to r ", symmetrical ₃₅ (theoretical limit 90 °)

trically arranged. The loop antenna R (Fig. 1) 6 db width 118.5 ... 119 °

at four diametrical points F of the circumference with (theoretical limit 120 °)

Carrier energy fed in, as will be explained in more detail later “. ..

is described (F i g. 4 to 7), the feed Nullemzuge -40 ... -50 db

systems Tr _(Figs . 3 and 4) also in stripline technology 3o angular error between executed (Figs. 6 and 6a) and in the axis of the zero indentations ... 0.3 ° ... 0.5 ° Planar dipoles d _x and d _t are arranged in recesses. The feed systems (not shown) The input resistance of a dipole is for the dipoles d _x and d ₂ , expediently also Re = (5 - j 120) ohms.

The second dipole d _t is orthogonal to the first shielding metal housing (not shown. Given a mechanically exact structure) on one side of the insulating material carrier between the two dipoles Decoupling values plate o, on which the other antennae from 50 to 60 db, perfectly balanced feed element; systems (not shown) connecting the dipole parts are provided. Bridges B (Fig. 3) built on and with these conductive 40 Die from the eight circular (D / λ = 0.25; D = connected. Fig. 3 shows a section along the diameter of R, λ = operating wavelength ) on line A-A '. F i g. 2, seen in the direction of the arrow. ordered frame parts r _y ... r "built-up frame

Since the antenna R currently used for reasons of strength is fed into the four points F (or χ and> ·) carrier material for the antenna plate (epoxy-glass, which creates a very homogeneous electricity fiber fabric, 1.5 mm), it is not particularly well distributed on the scope is achieved. has frequency properties (at 100 MHz: Di- During operation, there is then an in Fig. 4 by the electricity constant £ ^ 5.2; loss angle tan # = «sign + or - at the individual frame oiler 300 · ΙΟ- ⁴ ) the construction is carried out in such a way that marked current coating. The frame parts sine the carrier material α remains largely field-free. In order to reduce losses for reasons of adaptation as line circuits, the 50 stripline insulation technology was still used; their length / is small fabric! carrier plate α at some critical points, ie selected as a quarter wavelength (// λ <0.25), at the respective feed points F or χ unu y between the respective feed points χ and (F i g. 1. 4. 7). recessed, which also r a comparison at F and the radiating frame parts, ... r causes ₈ lie ringerung the capacitance between the adjacent an inductance L with the inductive Widerstam conductors. 55 (reactance) Xj. = 50 ... 150 ohms. The egg

In the following, the individual antenna-required, respective values of this reactance X

elements of the antenna system described in more detail. can be changed by variable short-circuit slide S (z. I

The two dipoles d _t and d ₂ are shown as two-dimensional F i g. 4) can be set.

Hertzian dipoles according to FIG. 2 (/// = 0.17; bj). = The described loop antenna R (Rundstrahlei

0.05: / = length, b = width, λ = operating wavelength) 60 provides a diagram with less than J ₁ 0.2 db Al

formed, wherein the dipole forming the deviation from the ideal circular shape.

Copper coatings on both sides of the carrier material α The feed systems Tr for the omnidirectional radiator R sin

(Fig. 3, 6. 6 a) are arranged. The individual, one designed as slot transformers, which are in stri]

other corresponding Dipolteile the dipoles </ and _d% line technology are carried out. You effect anyway

On both sides of the carrier material α , by means of 65, symmetrization as well as a transformer are located

Connections ρ (Fig. 3) at least at the corners of the radiator resistance, so that in the central "

conductive through the carrier material α feed point C, that is the point at which the vi

bound. The transmission energy is fed in at slot transformers Tr connected in parallel

185

7 8

for the omnidirectional radiator R an input resistance from system «forming the slot transformers Tr,

approximately 50 ohms (coaxial. ground point Λ /) by means of the connection ν conductively connected to one another.

results. which Deläge 1 by means of an extension of the connection

The transformation takes place as in FIG. 5 manure ν is conductively connected to the covering 2. To the

(Smith chart) is shown. 5 outputs of each slot transformer Tr (loading

The input resistance between two adjacent 2 and 3). those with the feed points .v and y of

hard road .. 'erelemenien. z. B. r ₁ and r _{2 of} the round two frame parts that belong together, e.g.

Radiator R is at Z, = 50 (0.05 - j 2.5) Ohm. T ₁ V ₂ . zn (indicated by arrows in Fig. 6

symmetrical. (Point Pl. F i g. 5). draws) there is a s \ inmetric stress for storage

By connecting the inductance L upstream with the consideration of the radiator elements r, r ₂ . λ., γ, ... of the round

Ductive resistance Xi, (line circuits) results in radiator R available. As a shield so far

Hu the respective feed points γ and y of the individual described parts of each Schlilz transformer Tr

Frame parts r ^ r.,. r _x r ,. / yr, and r- t "a resistor are further copper layers 4 and 5 on insulating material d

Z ₂ -SO (0.06 / 0) Ohm symmetrical (point Pl. Or e from PPO provided, iie a radiation after

F i g. 5). 15 outside or a coupling of interference from

The slot transformers Tr are in the wave counter- outside prevent. For this reason the copper

itand and in terms of electrical length in coverings 4 and 5 are somewhat broader than the copper

As is known, so dimensioned that this resistance Z ₂ coverings 2 and 3. D'e Kiipferbeläge 4 and 5 are by means of

on Z ₃ - 50 (5 · / 0) ohms. coaxial, the correspondingly lengthened connection ul to the is transformed

(Point P3. Fig. 5). 20 ground point M , which connects the outer conductor of the coaxial

By interconnecting the inputs of the four alen feed system. The energy is at C and W

Slot transformers Tr are obtained at feed point C by means of a connector provided with a suitable connector

against the ground point l \ f a resistor Z ₄ - 50 coaxial cable is fed in. The Kiipfer coverings 4 and 5

(1.2 ^L / 0) ohms. coaxial, as input resistance for are £ in the other end (output end, right; in

the omnidirectional radiator R (point P4. F i g. 5). 25 Fig. Ii or at the front in Fig. 6a) by means of a connection

The frequency response of the adaptation runs according to ■ application u 2 conductively connected,

the dashed curve in FIG. 5. The individual components of each SJilitztransfor-

By changing the series inductance L mator « Tr are mechanically firmly connected to one another,

(Short-circuit slide 5 of the line circuit: adjust) for example by means of two-component F.poxy resin

can be glued together for any frequency in the range from 108 to 30, being as homogeneous as possible

118 MHz point P4 of the diagram according to FIG. 5 glue joints (without air inclusions) are to be aimed for,

reach. The Feinanpassur.g to Z - 50 Ohm is due to the partial use of good high frequency

made by means of a Transformat'onsvierpols. frequency insulating materials (e.g. PPO with tan Λ -8-10 ')

The structure of the slot transformers Tr is in cause the slot transformers Tr only very much

F i e. 6 shown schematically. F i g. 6 shows the low losses.

The energy transport from the central feed point C

stood on top of each other. In reality, the and the mass point M of the omnidirectional radiator R are the

Components are closely assembled, for example to the respective feed-in points .ν and y are carried out via the

cemented together. Field between inner conductor 1 and the copper coating 3.

F i g. 6a shows a cross section on the front side 4.0. This field runs only in the low-loss PPO. That

seen. As shown in FIG. 6a, the building field between the pads 2 and 3 is interspersed with two

the same on both sides of the carrier material α , i.e. layers of PPO and a layer of epoxy glass fabric

mirror image symmetrical to the carrier material α. (tan Λ = 300 x 10 '); are the losses incurred

In Fig. 6 this symmetry is small for the sake of simplicity because the tension between the two

not completely drawn. 45, 2 and 3 would only assume small values, since the

To the losses in the slot transformers Tr stood Z ₂ between the respective feed points .v

(Fig. 6), these are wide and only about 3 ohms, and this voltage is to be kept as small as possible

going from low-loss insulating material, e.g. B. Poly from the output of the respective slot transformer Tr

phenylene oxide (PPO) with ε = & 2.55 and tan Λ = 8.10 " ⁴ (arrows on the right in Fig. 6) to the entrance (feed point C

(f = dielectric constant: tan ύ = loss angle) 30 and Λ /, left in Fig. 6) also decreases approximately linearly,

built up. Seen from the exit side (arrows on the right in Fig. 6)

The coverings 2 and 3 together form a symmetrical one on the epoxy resin / glass fabric carrier plate ο

the inner conductor of the coaxial ribbon cable can be found on both sides, which is on the input side (left in Fig. 6)

system-forming, conical (because of Z-variation) is short-circuited.

running copper coverings 1, which are at the beginning and end 55 the field between the copper coverings 2 and 3 of the

by means of a connection /? through a hole in the carrier - the respective Schiitztransformer Tr and the each

material α are conductively connected to each other, electrical shielding forming copper coverings 4 or. 5

trisch are connected in parallel. The outer conductor runs only in the low-loss PPO.

Slot transformers Tr is covered by copper coverings 2 When only the omnidirectional radiator R is in operation

and 3 on strips of insulating material h or c (made of PPO) for the individual frame parts / yV ₂ ... which are shown in FIGS. 4th

formed both sides of the support plate α . and 7 with the sign -j- or - indicated span-

On the side where the feed takes place (on the left in the feed distribution a.

F i g. 6). are the coverings 2 and 3 by means of a connection. The effect of the excited frame end trl through the carrier material α through conductive parts C ₁ V ₂ ... on the dipoles </, and d "is considered,
connected to each other and form the ground conductor M 65 Because of the symmetry to the (e.g. Fig. 8) arranged in the middle of the coaxial system of the slit transnets. Dipoles ^ ₁ and d, and the anti-phase Erreforn. disturb door. At the (symmetrical) exit end of each other on the circumference opposite one another (on the right in Fig. 6) are the inner conductors of the coaxial part of the frame. z. B. r ₃ and r _s or r, and r- in effect

2185

on the dipole r / ,, these effects cancel by radiation coupling (indicated by arrows in F i g. 7 indicated) d to the dipoles, and d ₂ practical, ie, during operation of the circular radiator R will be on the dipoles r /, and d, only small currents or no currents at all induced which could affect the circular diagram 'ft.

When excited rit / r a dipole, z. B. rf "of the cross dipole system results from capacitive coupling or beam coupling (indicated by arrows in FIG. 8) on the individual frame parts / γ V ₂ ... Those shown in FIG. 8 by the sign or - indicated stress distribution.

For comparison with the voltage distribution during operation of the omnidirectional radiator R (FIGS. 4 and 7), this is indicated by the signs (+ -) and (-) in brackets in FIG. 8 registered. As can be seen, the coupling of the radiating dipole, e.g. B. r / "on the frame parts induced voltage on the frame parts r, and r ₄ exactly in phase opposition to the voltage distribution during operation of the omnidirectional radiator. The induced voltages on opposite frame parts propagate through the slot transformers Tr turn central feed point C of the antenna (indicated by dashed arrows in FIG. 8) and are canceled out here ("virtual short circuit"). Analogous relationships apply to the second dipole d ₂ (not shown in FIGS. 7 and 8) of the crossed dipole system.

In operation of both dipoles i /, and J ₂ of the Kreuzdipolsystems thus occurs at the central feeding point C of the circular radiator R no voltage.

The virtual short-circuit is transformed via the slot transformers Tr to the respective feed points χ and ν of the omnidirectional radiator elements (frame parts / ·] ι · ₂ ...); According to the characteristic impedance and the electrical length of the slot transformers Tr (Iλ - ■ (), 12) there is an inductive reactance of about 150 ohms between the respective feed points χ and y. This is in series with the frame parts, which are excited by radiation coupling, designed as circuit lines. By connecting a capacitance 6 (Fig. 8) of suitable size (tuned to parallel resonance) in parallel to the respective feed points χ and y , a resistance of 5000 to 6000 ohms can be generated at this point, the parasitic currents on the RundstrahJerelemente T ₁ ... r ₈ largely suppressed. In the field, only the current on the _two- dimensional dipoles </, and d 2 of the crossed dipole system is effective.

The effect described above is known in the literature under the term "Tieline effect"; this effect is usually used in connection with λ / 4 table formation lines (λ - operating wavelength).

Due to the measures described for adapting the omnidirectional antenna R and the utilization of the Tieline effect to suppress parasitic currents, the antenna is of course only narrow-band.

> o You must therefore be within the VOR radio beacon internationally intended frequency range of 10? up to 118 MHz depending on the organization operating frequencies / can be set for each VOR radio beacon. The following measures are unique for this necessary:

1. Adjustment of the closing slide .S 'on.! En frame parts / ·, ... r _v . so that an optimal adaptation of the omnidirectional radiator R results.

2. Matching the capacities 6 (tube trimmer) at the ends of the slot transformers Tr (feed points .v and y) to parallel resonance (if there is a virtual short circuit in the central feed point C of the antenna).

The antenna is coated with a protective varnish to protect it against climatic influences and is additionally surrounded with a protective housing when mounted in a polarization cage.

As already indicated at the beginning, the antenna described above can also be used in connection with a single-channel amplitude direction finder in which, for example, a minimum direction finding is carried out. It can be proceeded in such a way that the loop antenna R is continuously located at the receiver input as a circular tracer until an object to be tracked has been found (search position). Then the cross dipoo! djd ₂ is applied to the input of the direction finder (position direction finding), whereby the diagram of the antenna is cardioid. Then, for example by means of a manually rotatable goniometer, the phase of the voltages recorded by the two dipoles r /, and d _{t is} changed - which causes the cardioids to rotate around their origin - until the minimum of the incident wave is reached. The bearing direction can be read off directly on a scale attached to the goniometer. Finally, it is also possible to equip an automatic direction finder with the antenna described in connection with its own display device in a manner known per se.

1 sheet of drawings

2185

Claims (13)

Patent claims: Ί. Antenna system for the VHF and UHF range for determining the direction in connection with radio navigation systems (radio beacon transmitters or direction finders), in which the radiator elements and feed elements are designed using the technology of printed circuits on a circular carrier plate, characterized in that the antenna system consists of the functional and Structural combination of a crossed dipole aiii, current-fed, shortened, elongated dipoles (cl _x and </ _a ) and one symmetrically arranged around the crossed dipole, at four feed points (X, Y) which are offset by 90 ° and are symmetrical to the dipoles of the crossed dipole Loop antenna (R) exists, and that the feed elements (Tr) for the parts (r) of the loop antenna (R) ebeti.o in the technology of printed ao circuits, but on their own carrier material and are mounted on the carrier plate (a). 2. Antenna system according to claim 1, characterized in that the loop antenna (R) and the dipoles (i / "ί / jj) of the cross dipulse are fed simultaneously for the emission of a Kar aj dioid. 3. Antenna system according to claim 2, characterized in that the dipoles (</ ,, d _t ) of the cross dipole vo .. with the same modulation frequency (z. B. 0 Hz) modulated to emit a rolling cardioid for VOR rotary radio beacons Carrier-frequency high-frequency voltages are fed • and that the loop antenna (R) is fed by the unmodulated carrier. 4. Antenna system according to claim 3, characterized in that in a known manner for the transmission of a reference signal for the purpose of azimuth measurement by phase comparison of the carrier for feeding the loop antenna (R) with the reference signal corresponding to the modulation frequency (30 Hz) is frequency modulated. 5. Antenna system according to claim 4, characterized in that each dipole half of each flat dipole executed in the art of printed circuits (e.g. J ₁ ) consists of two dipole parts on each side of a carrier plate (σ. F i g. 3 ) consists of insulating material, that the corresponding dipole parts of each dipole half on both sides of the support plate (a) by means of connections (p, Y i g. 3) are conductively connected to each other at least at the corners, and that the dipole parts on one side of the support plate (ο) are conductively connected to one another by means of a bridge ( B.F i g. 3) forming the feed point of the dipole half. 6. Antenna system according to claim 1, characterized in that the loop antenna (R) is divided into eight identical frame parts (r _t ... r _t ) which are equally distributed over the circumference, of which two each O ¹ Jr ₁ , r ₃ lr ₄ , r _h jr _t , r-, jr ^) are symmetrically fed in at diametrical points (F) of the circumference via symmetrization and transformation elements (Tr) from a common, central feed point (C) (feed points χ and y). 7. Antenna system according to claim 6, characterized in that the components of the symmetrizing and transformation members (Tr) from the central feed point (C) radially and in the middle between the individual dipole parts of the dipoles (Λ, dg) symmetrically and on both sides of the Carrier plate (a) are arranged on this. 8. Antenna system according to claim 6, characterized gekcnnzeicii.net that the symmetrizing and transformation elements (Tr) are designed as slot transformers in flat construction (F i g. 6 and 6a). 9. Antenna system according to claim 8, characterized in that the inner conductor of the coaxial system of the slot transformers (Tr) is formed from two copper coatings (1) on both sides of the carrier material (a, F i g. 6, which run ionically due to the variation in the characteristic impedance) 6 a), the input (ground point M) and output side (connection v, Fig. 6, 6 a) are conductively connected to one another so that the outer conductor of the system of slot transformers (Tr) is formed from two copper strips (2, 3 ) on disputes (b, c) made of low-loss insulating material in a mechanically solid connection with the carrier material (a) and that in order to provide a symmetrical voltage at the output of the slot transformers (Tr) against the ground point (M) in a manner known per se the (connected) the copper coatings (1) forming the inner conductor are conductively connected to one of the copper coatings (e.g. 2) forming the outer conductor at the output end (connection ν and its extension). 10. Antenna system according to claim 9, characterized in that for shielding the slot transformers (Tr) further, on the input and output earth conductively with each other and with the ground point (M) connected (connections tvI and Y.1) (F i g. 6, 6a) copper foils (4, 5) are provided on strips (U. e) made of low-loss insulating material, and that these strips (d, e) are connected to the strips (// or c) are mechanically fixed. 11. Antenna system according to claim 6, characterized in that each of the frame parts (r, ... r _g ) is formed from an approximately U-shaped line circle made of copper foil on one side of the carrier material (a) and one on the other side of the Carrier material symmetrically located within the legs of the U-shaped line circuit, designed as a mii ider-shaped conductor inductance (L. Fig. 4). one end of which is conductively connected by means of an adjustable short-circuit slide (p. while at the other end the energy is fed in (Speiscpunkk χ and »). 12. Antenna system according to claim 11, ti ulnrch characterized in that the line circuit. the inductance (L) on the same side of the. Ägeir · materials (</) are arranged and that the crossbar of the U-shaped circuit is designed so that there is no electrical connection between the other end of the inductance (L) and the crossbar. 13. Antenna system according to claim 12, characterized in that for impedance matching two frame parts (e.g. r, and r _a ) to the associated slot transformer (7r) and to the un- 3 4 suppressing parasitic current components on the fire transmitter or DF receiver), in which the Stmhler frame parts using the Tieline elements and parts in the technology of the ge effect a (variable) capacitor and the printed circuits on a circular carrier feed point (.v, y) is placed, by means of which the on plate are carried out and the set task er the feed points (.v, y) in the event of a short circuit in 5 according to the fact that the antenna central feed point (C) transforms the inductive system from the functional and structural convenience a parallel resonance circuit is added. Bination of a Kieuz dipole from electricity-fed, ver-14. The analogous use of a shortened, elongated dipole and one symmetrically arranged around the crossed antenna system according to claims 1 to 13 for dipole, at four offset around a direction finding station with a correspondingly designed io 90 ° to the dipoles of the crossed dipole receiving device. . symmetrical feeding points fed yard menantenne exists, and dall the feed elements for the parts of the loop antenna also in the technology of printed circuits, but on their own carrier The invention relates to an antenna system 15 made of material and mounted on the carrier plate for the VHF and UHF range for directional are. Determination in connection with radio navigation The invention is explained in more detail with reference to drawings systems (fan fire transmitters or direction finders). explained; the individual figures represent schematically In contrast to the most common ones up to now: VOR antennas are the circumferential direction 20 F i g. 1 generates the principle of the antenna consisting of cross characteristics (cardioids) of fixed antennas dipole and loop antenna. Reception and evaluation of the signal in the system in plan view,
Recipient takes place in a known manner. F i g. 2 a dipole of the cross dipole with measure For the VOR antennas that have been carried out so far, the circumferential directional characteristic is shown by overlaying 25 F i 3. 3 a cross section along the line AA 'of the support of the diagrams of two antenna systems: F i g. 2 to explain the arrangement of the dipole parts of the disc antenna (circular diagram) and mechanically the crossed dipole on the carrier plate,
rotating loop dipole (revolving dipole diagram. 4 the loop antenna and its structure as well grams) together generate the 30 Hz rotating arrangement of the umbilical and transfer ends Cardioids. 30 formation links for feeding the frame parts, This antenna arrangement requires a considerable amount of space. 5 is a Smith chart to explain the borrowed mechanical effort; through the rotating frequency response of the adaptation of the individual frame parts (Bearing, rotary coupling) is it wearing parts on the feed line, subject and prone to failure. F i g. 6 and 6a show the structure of the symmetrization The object of the present invention is therefore to use 35 and transformation elements as slot transformers specify an antenna system with the rotating flat design, Cardioids can be generated and that FIG. 7 the antenna system with pure one dipole has no moving radiator elements. The be of the cross dipole and the entire loop antenna Known embodiments have besides that with the feed systems (balancing and wanted Hon / ontalkomponente a considerable 40 transformation elements), to explain the Strah vertical component on the faults in coupling the loop antenna to the dipoles Azimuth measurement leads. (Frame fed), This vertical component could be through the entrance F i g. 8 the same antenna system as in FIG. 7th set of known polarization cages are suppressed to explain the radiation coupling of the dipoles However, the known antenna systems are for the Ef- 45 of the cross dipole on the loop antenna (dipole generation a rotating cardioid with fixed feeds). Radiator elements spatially too large to be used in an antenna system according to the invention such Polarisationska ^r to accommodate strength. accordingly from three structurally interconnected Durci) the present invention is therefore intended to provide a nested at: antenna elements; two crossed Di-antenna system with fixed radiator elements 50 pole i /, and d _t (Fig. 1) in the manner of a circular dipole for the generation of a rotating cardioid an- antenne can be given with appropriate feed, the sufficiently small dimensions of modulated carrier energy, z. B. via an electronics in order to suppress the undesired cal goniometer, a rotating dipole diagram, vertical components in a polarization cage and a loop antenna R supplies the azimuthal (. 55 dependent omnidirectional radiation. From the Swiss patent specification 460 095 there is again one with the modulation special embodiment of antenna known, frequency, behn V) R with 30 Hz, circumferential Karbei the radiative on a round insulating disk. The rotating dipole diagram may be at letiden elements according to the type of technology of the printed circulation do not change in its form and must be a Circuits are applied. 60 have a constant half width. That's just that To solve the task at hand, an antenna case when the diagrams of the individual orthogonal system for the radiation of rotating cardioids to dipoles ^ ₁ and d _t arranged to one another create pure circles, which practically represent functions in a polarization cage (Hertzian dipole, 3-db- Width usable diameter, which is smaller than 90 °, 6 db width 120 °). 65 The loop antenna R as an omnidirectional antenna should provide an antenna system for the best possible circular diagram (± 0.25db), VHF and UHF Berwich to determine the direction so that the degree of modulation of the VÖR signal is below in connection with radio navigation systems (radio 'all azimuth angles are largely constant.