DE1226171B - Antenna made from a radiating line coupled to an excitation line - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

HOIq

German class: 21 a4 - 46/04

Number: 1226171

File number: C 25934IX d / 21 a4

Filing date: January 9, 1962

Opening day: October 6, 1966

. The invention relates to an antenna consisting of a powered, non-radiating antenna Excitation line and a radiating line coupled to it and lying parallel to it, the two lines having essentially the same coefficient of propagation, and have at least one conductive part in common, and the excitation line of a conductive plate and a conductive wire lying parallel to this plate in close proximity.

In a known antenna of this type, the radiating line is a helix of wire that conducts the Wire surrounding the excitation line. Such an antenna can because of the diameter of the helix cannot be built arbitrarily flat. It is also difficult for the helix to have good mechanical strength and to give it an aerodynamically favorable shape. This known antenna is therefore for applications where these properties are important are not well suited. This is especially true for in the event that the antenna is to be attached to the outside of a high-speed missile.

The disadvantages outlined are alleviated by an antenna corresponding to an older proposal already largely eliminated. The excitation line of this antenna consists of an inner conductive plate and two outer conductive plates spaced therefrom in the same plane, and the radiation conduit is formed by dielectric layers applied to the two outer panels are. This older proposal results in a very flat structure and good mechanical strength, since the Antenna consists only of plates and layers lying directly on top of one another. The antenna has, however due to some gradations not a completely smooth structure, which affects the aerodynamic properties of a fast missile.

The aim of the invention is to provide an antenna of the type specified, the external Structure is completely smooth.

According to the invention, this is achieved in an antenna of the type specified in that the radiating line from the conductive plate and a dielectric plate lying parallel to it consists, which is arranged so that the wire lies between the two plates.

The outer surface of the antenna according to the invention is formed by the outer surface of the dielectric plate, which is completely smooth. The antenna can therefore be embedded in the outer wall of a fast missile in such a way that its aerodynamic shape is completely retained. In addition, the antennas are made of one with an excitation line
coupled radiating line

Applicant:

Compagnie Generale de Telegraphic Sans FiI,

Paris

Representative:

Dipl.-Ing. E. Prince and Dr. rer. nat. G. Hauser,

Patent attorneys,

Munich-Pasing, Ernsbergerstr. 19th

Named as inventor:
Erich Spitz, Paris

Claimed priority:

France 23 January 1961 (850436)

Thermal properties are the same over the entire outer surface, so that when heated, for example when Re-immersion of the missile in the atmosphere, no problems due to different coefficients of thermal expansion of the parts exist. A heat-resistant material can be used for the dielectric plate be chosen, which also serves as a heat shield.

A particular advantage of the antenna according to the invention is that the electromagnetic Field is concentrated very close to the conductive wire. It therefore does not matter whether the senior and dielectric sheets are perfectly flat or curved, provided that the radius of curvature is at least near the wire is greater than the wavelength. The antenna can therefore easily be attached to the curved one External shape of a missile to be adapted.

This property also enables a particularly simple formation of antenna systems with several Antennas. An arrangement of four antennas, as required, for example, for monopulse radar devices is, can according to a preferred development

609 669/159

3 4

According to the invention, the phase measure / S ₂ can be written as follows

Wires of the four antennas, on the corners of a square will be:

lie that the conductive plates of the four antennas Γ 1 1

merge into one another in such a way that they have an um- ßi = ßo U + -P * u ²

form bodies of revolution, and that the dielectric s. L 2 J

Plates of the four antennas in such a way into one another exceeds ^mt

go that they have a second, .to the first coaxial _{u =}

Form body of revolution. . λ

Embodiments of the invention are in the

Drawing shown. Therein io shows where u is a coefficient corresponding to the thickness e of

F i g. 1 a perspective representation of a dielectric plate 2 depends, while for ρ the following applies:
antenna executed according to the invention,

F i g. 2 shows a section through the excitation line _e " ¹

the antenna of FIG. 1, ^ ~ ε '

F i g. 3 shows a longitudinal section through the antenna of FIG

F i g. 1 if ε is the permittivity of the dielectric

F i g. 4 is a perspective view of a plate 2.

Monopulse antenna system with four antennas according to The energy running over the excitation line is

the invention, . ■. through the coupling between the two lines

F i g. 5 and 6 transfer radiation diagrams of the antennas 20 onto the radiating line. The shiny according to FIG. 4, in the different radiation line then generates a field with the following identification levels, function:

..Fig. 7 a - longitudinal section through an antenna - _ * _ _y_

system that has a linearly or a circularly polarized / (χ, y, z) = A sin cz ■ e ^£ i · e ¹ ^ ^ J
Wave can radiate, and 25

Fig. 8. "A diagram to explain the wir- which is valid for χ> λ , where c is the coupling

like the arrangement of FIG. 7. The coefficient of the two lines is that of m and η

F i g. 1 shows a metallic plate 1, which is parallel and depends on the values L ₁ and L _2. These

dielectric plate 2 arranged for plate 1 and values L ₁ and L ₂ are propagation parameters for the

a conductive wire 3 connected between the plate 1 ₃₀ surface wave running along the dielectric plate

and the plate 2 is parallel to these parts. runs when there is no coupling between the two

The following designations are introduced: Lines exist. The coupling has the consequence that

the energy roughly according to the principle of the coupled

xyz a right-angled reference coordinate system, _{pendulum as it} progresses in the direction of which the origin is the center of the transverse _{35 z} axis from the excitation line to the radiation cut at the end of the wire 3, the _{line being transmitted back and then from this} z-axis parallel to the wire 3 cherishes and the _{will- The first} complete energy transfer takes place x-axis is perpendicular to the plates 1 and 2; _at f _o i _constricting length / of the two lines was:

h the. Thickness of the antenna without the metallic

Plate; 40 / = -. (2)

2 ce the thickness of the dielectric plate;

m is the distance of the axis of the wire 3 from the parameter L ₁ essentially determines the

Plate 1; Half width of the emitted beam in the

η is the diameter of the wire 3. «xz-plane and the parameter L _{2 is} its full width at half maximum

in the jz level. Namely, these half-widths are

This arrangement forms two coupled together, characterized by the following angles:

Lines, namely a radiating line that passes through χ

a nonradiative excitation line is excited. The A Θ ₁ =,

The excitation line (Fig. 2) consists of the metallic 5 ° ^ L ₁

Plate 1 and the wire 3. This lead is one -, w

Two-wire line 3-3 'equivalent, in which 3' the Δ Θ ₂ =.

Mirror image of the wire 3 in relation to the plate 1 π £ ₂

is. The lines of force of the electric field are

Circular arcs passing through the axes of wires 3 55 The direction of maximum radiation does not lie

and 3 'go. exactly in the direction of the z-axis if β _{2 is} not

Most of the electromagnetic energy is equal to ß ₀ .

concentrated between the wire 3 and the plate 1. As previously explained, is
The speed of propagation of the energy

this line corresponds to the Ausbreitungsgeschwin- _{fi ß} "F ₁ 1 _{2 2} 1 / vn

waves in air. ft-ftl + -i «W

The radiating line is through the metallic ^ ₁

Plate 1 and the dielectric plate 2 are formed. In it ε - 1

there is a waveguide wave of the H-field type, whose ρ =,

Magnetic field a component in the propagation 65 ^ε

has direction. The coefficient of propagation of this wave

Jiat a phase measure ß ₂ , which is essentially the same if ε is the dielectric constant of the dielectric

is the coefficient of dispersion / S ₀ in air. This record is.

Claims (7)

5 6 If ε is large, the following applies: - directed, and their ends lie on the corners of a Square. The direction of propagation ζ corresponds to iZL ^ ι cylinder axis. ^ε A dielectric filler with a dielectric 5 constants near the value 1 can be between The direction of radiation is given by the body 10 and the sleeve 20. ₁ "Λ2 -The antennas carried by wires 31 and 32 and _COS Q - fl. Pn ι L "2 _M 2 ^; ι _ _r_ the corresponding sections of the metallic ß ₂ 2 2 body 10 and the dielectric sleeve 20 is formed ίο are radiate in the yz plane of Fig. 4, while where Θ is the angle made by the main radiation from the wires 33, 34 and the corresponding direction with the z- axis. Sections of the body 10 and the dielectric It follows from this: Sleeve 20 formed antennas in the xz plane shine. In Fig. 5 and 6 are the radiation diagrams Θ ss pu; Θ ° «a 360 ° ρ - * 5 grams of the different antennas in these two λ planes as a function of the angle Θ _χ or Θ _υ in relation to For shown on the z-axis, where the angles Θ _χ and λ Θ _ν on the abscissa of a right-angled coordinate P ~ * ■> ^e ~ ~ 7Z ■ systems are applied. The wires 31 to 34 are in a manner known per se is connected in such a way that it 0 = 9 °. procedure required sum and difference deliver signals. Since β _{2 is} slightly larger than β ₀ , the length /, using the antenna described can be according to which the energy from the excitation line 25 are also formed an arrangement, the one completely transmitted to the radiating line radiates circularly polarized wave. She resembles that is, very large, because then the coupling coefficient c arrangement of F i g. 4 with the difference that in the equation (2) is small. Because one so long the metallic plates and the dielectric plates Antenna cannot be built in practice, it must be a part of cone jackets and that the wires Part of the vertical lines fed into the excitation line are parallel to the surface lines of the cones, frequency energy in a reflection-free closure F i g. 7 shows a longitudinal section through one of these be destroyed, although this is a deterioration arrangement. of the degree of efficiency. The wires 31 and 32 lie in the plane of the drawing In a practical embodiment of FIG. 7 in the conical part that is the nose built an antenna with the length / = 10 λ . One 35 of the missile 10 forms. In a corresponding way obtained Θ = 10 ° for a total thickness of the antenna of are two wires 33 and 34 in one perpendicular to the , _{n Λ c} . Drawing plane, containing the z- axis Arranged level. In Fig. 3 shows how the arrangement The apex angle of the cone is dimensioned so that can be fed. 40 these four antennas give their maximum radiation in the The outer conductor 6 of a coaxial line 7 is aligned with the direction of the z-axis. Wires 31 and 32 Plate 1 is soldered, while the inner conductor 5 on the or 33 and 34 are each fed in phase. Wire 3 is soldered. A transition 8 between which they each emit a linearly polarized wave, Inner conductor 5 and the wire 3 prevent any reversal of polarization directions at right angles flexion and eliminates the need for a transformer to be 45 to each other in the associated plane. Transition from the symmetrical to the asymmetrical F i g. 8 shows that the resulting field is linear Management. is polarized when the group 31, 32 is in phase The excitation line 1, 3 ends in a reflection with the group 33, 34 is fed,
free closure 9. If the two groups have a mutual The fact that the electromagnetic field is fed with a very 5 ° phase shift of 90 °, that is concentrated close to the conductive wire, the field is circularly polarized,
allows the use of conductive and dielectric plates with cylindrical surface, pre-claims:
exposed that the radius of curvature of this surface at least in the vicinity of the conductive wire 55 1st antenna, consisting of a fed, is not greater than the wavelength. radiating excitation line and one with this F i g. 4 shows an arrangement of four antennas of the type described above, coupled to them and lying parallel to them, which are attached to a missile radiating line, the two lines being attached and for a monopulse radar device being determined to have essentially the same coefficient of propagation. 60 cient and at least one conductive The four metallic plates of the antennas will have part in common, and the excitation line is formed by sections of the cylindrical body 10 of the one conductive plate and one parallel to the missile, and the four dielectric plates in close proximity to this plate These antennas are made up of a cylindrical wire, characterized in that the sleeve 20 is composed of dielectric material in that the radiating line is made up of the conductive line which surrounds the body 10 coaxially. The plate and a parallel dielectric wires 31, 32, 33, 34 of the antennas are seen in parallel plate, which is arranged so that the wire to the surface lines of the cylindrical body 10 lies between the two plates. 2. Antenna according to claim 1, characterized in that the two plates are flat and that the excitation line is fed by a coaxial cable, the outer conductor of which with the conductive Plate and its inner conductor are connected to the wire. 3. Antenna according to claim 2, characterized in that the inner conductor of the coaxial cable is connected to the wire via an impedance matching member. 4. Antenna according to claim 1, characterized in that the two plates are transverse to the direction of propagation are curved and the radius of curvature at least in the vicinity of the conductive wire is large against the operating wavelength. 5. An arrangement of four antennas according to claim 4, characterized in that the wires of the four antennas on the corners of a square lie that the conductive plates of the four antennas merge into one another in such a way that they form a body of revolution form, and that the dielectric plates of the four antennas merge into one another that they have a second, to the first form coaxial body of revolution. 6. Antenna arrangement according to claim 5, characterized in that the two bodies of revolution are cylinders. 7. Antenna arrangement according to claim 5, characterized in that the two body of revolution Are truncated cones with the same apex angle. Considered publications:
German Patent No. 961 444;
German interpretative document No. 1 051 919. 1 sheet of drawings