DE1081075B - Dielectric lens - Google Patents

Description

The invention relates to a dielectric lens for microwaves which is a linearly polarized electromagnetic Wave with a given field cross-sectional image into a flat, homogeneous, circularly polarized wave transformed and also does the reverse transformation.

An electromagnetic wave with a given field cross-sectional image is understood to be a wave that is determined by a family of curves whose curves lie in a wave surface and which are either the lines of force of the electric field or the lines of force of the magnetic field of the wave, i.e. a family of curves whose curves are run on the shaft surface and to which the electric field or the magnetic field of the shaft is tangential at all points. ¹ p

The invention relates to a lens which produces a linearly polarized wave with a predetermined field cross-sectional image transformed into a flat, homogeneous, circularly polarized wave and also transformations in reverse Direction. Such a lens can be used to produce a linearly polarized, through a fix to convert waveguide guided wave into a circularly polarized space wave, and vice versa.

According to the same invention, in the special case when the ^{wave transforming to a} 5 is a Hy ₁ -WeIIe or EjV ₁ -WeIIe, the lens according to the invention is fed by a circular waveguide which is traversed by the HiV ₁ -WeIIe or the EiV ₁ -WeIIe and the lens generates a plane circularly polarized wave.

According to the same invention, in the special case when the wave to be transformed is a H ₀₁ or E ₀₁ wave, the lens according to the invention is fed with a wave that has a rotational symmetry (H ₀₁ , E ₀₁ , TEM) around the axis of the conductor, the coaxial conductor and the horns, and the lens transforms this wave into a circularly polarized wave.

Such lenses are used to either circularly polarized waves generated by a generator and fed to the lens through any waveguide delimited by a horn, into the space to emit or, conversely, to receive circularly polarized space waves to suit them To forward recipients. If the conductor is a circular waveguide, this is the one coming from the conductor and the one Lens through the horn transmitted wave a spherical wave.

The lenses according to the invention are characterized by the following features:

1. The surface of the lens is subdivided into NM sectors of the wave plane with a sufficiently small vertex angle so that the electric field of the linearly polarized wave whose HiV ₁ - or Ea ^ field image is one

Applicant:
Georges Robert Pierre Marie, Paris

Representative: Dr. B. Quarder, patent attorney,
Stuttgart O, Richard-Wagnex-Str. 16

Claimed priority:
France of April 24, 1956 and March 27, 1957

Georges Robert Pierre Marie, Paris,
has been named as the inventor

knows, can be regarded there as homogeneous, d. H. has a fixed direction and one shifts the phase of the incident waves, which in the sector of the order; ö the plane of the waves by means of a plane-parallel Plate, which is placed on the surface of the lens and has a thickness calculated as follows is dimensioned so that it produces a phase delay.

2m

brings that equal to the (N- 1) -fold angle -p

NM

which the sector bisector forms with a fixed direction of the plane of the valley.

If it is a linearly polarized HiV ₁ -WeIIe or EiV ₁ -WeUe, the plane-parallel plate arranged on the ^ -th sector of the lens has a thickness which causes a phase delay which is equal to the azimuth of this sector relative to a fixed one Direction is.

2. Each sector of the lens is covered with a sector-shaped quarter-wave plate arranged in such a way that that the angle lying between the slow and the snow axis of this quarter-turn plate is through the electric field vector is halved in this sector.

3. The lens is bounded on one side by a diopter, which covers the surface of the surface is sent out by the radiation transmitter, transformed into a plane wave. When the weight of a horn is emitted and has a spherical surface, the diopter is a spherical diopter. On the on the other hand, the lens surface is delimited by a plane on which the sector-shaped quarter-wave plates and the sector-shaped planar parallel plates are arranged.

Lenses are already known which have a first flat surface and a second spiral-shaped upper

009 50S / 284

3 4

area, which serves to create a rotationally symmetrical linear Fig. 4 the cross-sectional image of the H ₁₁ -WeIIe in one

polarized wave into a circularly polarized WeQe to round waveguide,

transform. But with these known lenses, Fig. 5 is a lens that is flat, homogeneous, circular

transforms the transformation of the linearly polarized wave into a polarized wave into an H ₁₁ wave or

circularly polarized wave performs the reverse transformation for the entire 5,

Wave surface caused by means of a phase shift, FIG. 6 shows the cross-sectional _{image of the H 31} wave in one

which is equal to the azimuth of each surface element around the circular waveguide,

Lens axis is effected. In contrast, FIG. 7 makes a lens that is flat, homogeneous, circular

Lenses according to the invention, the linearly polarized wave, or _{polarized wave transformed into an H 31 -WeIIe}

which is located in every surface element of the wave, performs the reverse transformation in io.

a circularly polarized wave transformed in the In Fig. 1 37 is a lens which is a linearly polarized

The same surface element of the wave is located, and one spherical wave emanating from the emission source A.

shifts the phase of the wave transformed in this way to transform it into a plane, linearly polarized wave, whose

an angle which is equal to the azimuth of this surface electric field vector is indicated by the arrow 38.

element around the lens axis. 15 39 is a quarter-wave plate whose fast and

This results in a lower percentage of axles that are slow to the side, designated 40 and 41, respectively

borrowed deviations. It is known that a linear angle is formed by the electric field vector

polarized wave is always halved as the sum of two circularly (arrow 38). At the exit of the quarter-wave

polarized and oppositely rotating wave plate 39 is a flat, homogeneous, circular

the same amplitude can be considered. This 20 polarized wave, whose electric field vector 42 with

Both waves each transport the same electrical direction of the field vector 38 at an angle of 2π ft

magnetic energy. In the case of the previously known lenses, runs forms, where f is the carrier frequency of the wave and i is the

one of these waves is relative to time in the given sense,

the sense of the spiral-shaped surface, so that all 43 is a second quarter-weave plate, the radiations of the various surface elements of a 25 fast and slow axes denoted by 44 and 45, respectively, are wave surface on each lying on the lens axis. This second quarter-wave plate lies in the reinforcing points. The other wave runs in the opposite direction to the extension of the first quarter-wave plate 39.
and the vector sum of the elec- S be a wave surface element when entering the Irish field vector of the first plate 39 in the opposite sense.S 'be the corresponding wave revolving wave is equal to zero for the totality 30 surface element at another cross section of one of the surface elements the wave plane, namely in every parallel wave ray emanating from S , this point lying on the lens axis. The corresponding cross-section when the beam emerges from the first energy is found in the lateral deviations of the quarter-wave plate 39 and when it enters the second. Quarter wave plate 43 lies. S " is an analog one

According to the invention, on the other hand, the linearly polarized wave surface element is locally transformed by means of a quarter-wave plate, quarter-wave plate 43. 42, the electric field is transformed into a circularly polarized wave, with vector in the wave surface element S ', and 46 being the direction of rotation of the circularly polarized wave, the reverse electric field vector in the wave surface element S ". runs like the increase in thickness of the lens, from which S" is sufficiently small that the wave here is homogeneous so that all radiations from the various sectors 40 and can be viewed linearly polarized . One amplifies oneself on the lens axis. takes z. B. Flat surface elements with a surface

This is a dielectric lens that is of the order of 1OP, where 2 is the wavelength of the

on the one hand from a combination of a plano-convex wave in free space One wants an electromagnetic

Lens is formed, which on the one hand by a die cal field. Received, its electric field vector

Wave surface of a linearly polarized wave in a plane 45 tangential to a family of predetermined curves 54

morphing diopter and runs through on the other side.

a plane provided with divided surface elements If one starts from the position in which the long surface is delimited, the surface elements being so small and fast axis 44 and 45 of the quarter wave that the electric field therein are parallel to plate 53 everywhere to the slow and itself, and which on the other hand is provided with plane-parallel fast axis 40 or 41 of the quarter-wave plate 39, dielectric plate, of which the polarization direction of the wave drawn by the arrow 46 on the surface elements of the flat lens surface is in the wave surface element S " which is applied and whose thickness is proportional to the angle equal to the direction of polarization of the wave indicated by the electric vector of the surface element with arrow 38 forms in the wave surface of a fixed direction of the wave surface, and the 55 element S, and the Vibrations 46 and 38 also point with a four telwave plate is provided, a phase difference φ against each other.
which is arranged in such a way that the angle formed by its slow If one the quarter-wave plate 43 around one and its fast axis is halved by the angle Θ with respect to the quarter-wave plate 39 entelectric vector of the surface element. opposite to the direction of rotation of the circularly polarized

All details about the invention result from the 60 shaft with electric field vector 42 rotates, rotates

following description in connection with the polarization direction 46 by an angle <9, and

Drawing in which an exemplary embodiment is shown schematically. On the other hand, the oscillation 46 with respect to the

is shown. In detail, oscillation 38 shows a phase lead Θ. Indeed it has

1 shows a schematic representation of the focussing for a circularly polarized WeEe which runs from 39 to 43

Approximation process according to the invention, 65 runs, a rotation of the quarter-wave plate 43 to

Fig. 2 shows the cross-sectional _{image of the H 01} wave in one of its axis by the angle Θ relative to the quarter-round waveguide, wave plate 39 has the same effect as a phase

Fig. 3 shows a lens that has a flat, homogeneous, circular displacement, which corresponds to an angle of rotation Θ.

polarized wave transformed into a H ₀₁ wave or so that the new phase shift between the

performs the reverse transformation, 70 oscillations 46 and 38, which has decreased by Θ ,

5 6

receives its original value φ again, must also increase when one of a

5 'and S " a plane-parallel isotropic plate 47 with a subsector passes over to the other, the angle Θ which the

a thickness e which is so great that an electric field vector 46 of the

Phase delay of Θ is generated. The thickness e is a gone wave with one that is fixed in space

determined by the equation ^{5 forms} direction Ox (see Fig, i, 2, 4l and 6) to the above

e Θ defined amount ^ -, reduced or increased by the

"^ ^ "'Angle - ^ - z, which the bisector of two adjacent

where -n form 4's (optical) refractive index of the isotropic beard sub-sectors. If a dielectric material with this magnification ΔΘ of Θ is defined as follows:
a dielectric constant £ eo one has 2 π 2 η N ^ 1

At ^{6 - the circular M 1} ^^ ^NM denoted by the vector 42

polarized wave into a linearly polarized., by which ¹ S has this magnification Θ , in order to transform the wave denoted phase-to-vector 46, one must put an increase ß of the thickness <? of the isotopic so in the beam path a quarter-wave plate 43 results in small plates, which switch on according to equation (i) , the vector 46 being calculated by the fast

and longitudinal axis 44 and 45 formed angle __ N £ 1 ".

halved and also an isotropic plate 47, whose ^ ⁰ ~ NM (η— ΪΓ * ~

Thickness e is proportional to the azimuth Θ of the electric
Field vector 46 relative "to a fixed direction. It follows that each subsector is through a

In order to determine the structure of the lens, which is formed as a quarter-wave plate, to which a plane-parallel plane, circularly polarized ÜNf or Ei ^ ₁ -WeUe in Zy! In plate is connected, the thickness of which is one

which transforms coordinates must grow as follows, before- ^ S Umtersector to the next % m Δ & . The case of being gone: H ₀ ] .- and E _or waves forms .a mathematical singular

The cross-section of the electric field of an act due to the fact that N ; = .0,
such a wave in a wave plane represents a re-. In order for equations [2) and {3} to make sense, the fetch order N represents, i. H. that the cross-sectional image must be imagined, that M is infinite, and that

j ι τ j. · I. T ^ υ - -j 2-ze 3 ° the product NM - retains a whole finite value,

of the electric field m against each other by - ^ ver _der ^ _{R denotes w} J? _{den sdL Der Zentriwin] sel 4er} flat sections is identical In order to _{localize Ujltersectors is äami leida} ^ _{and Me lens} ^ zn in this way, the anisotropic F-elements .der "~ ° K

Lens that determines the direction of the electric field is formed by K subsectors. The angle between correct, around the axis of the lens have the same repetition 33 of the slow and fast axes on the one hand and the order. The lens is therefore made up of N bisectors of the sub-sectors, on the other hand, identical, adjacent sectors with an over aE of the same, namely 45 °. The enlargement of this

, 7, ... ,, Zn is the angle at the transition from one sector to another

Central angle of - ^ r- together. ■ ^& - ^to '

τ, j. O ₁ , ·, ·.,. ., ". ,, equal to zero, because it is ■ = (M is infinite). the

Each of these sectors is on the one hand in M subsectors 4P ^{δ 6} M ^ '

which in turn are no longer identical, but equation (3) gives for the "change in the thickness of j,.,, 7 χ ■ · ι ι 2π,, ,, .. ,,, j. a subsector to the following:
have the same central angle - ^ j-. You choose that

Number M such that in each subsector the electrical Ae = —— -. (4)

Field vector essentially «has the same direction. 45 - v * ~~ ^

It was further stated that the surface of each Fig. 3 shows a lens which has a circular plane

_O1 , si ',. ".", <NioT_ ^ i _-- n polarized wave into a H ₀₁ wave (Fig. 2) or into a

Sector r- ~ - has the order of magnitude of 1OP, where R i-, _ΤΙΓ - ,, ·. "J,", n ■ *. \ L · α. Τ-ν · NM ° ' E ₀₁ -WeIIe transformed into a round hollow conductor

is the radius of the lens. If one is passed through a circular-cross-section-field image in a predetermined distance so waveguide 1 for ^ receive or transmit position on the desired symmetrical rotating shaft, rotates from the center along a circle 3 changes This circular waveguide 1 passes into a conical Mundsich the angle ß, the electric field vector 46 with piece 2 from. The lens 9 is located at the end of this mouthpiece in the radial direction OM (FIGS. 1, 2, 4 and 6).

continuously and returns to its initial value, the -um. In FIG. 3, the lens 9 has a first flat surface 21

2 π is increased, back if you: by the central angle .55 and a second convex surface 7, which is .circular

e τ. .. ". , in ,,. . , ". Grooves 10 is provided, which is a non-reflective

of a sector, namely at - ^ r-. If one _c -, · · ,,, ·, ·! -, · τ- · a · -j j.

jv ^& üchicht form, avoids the energy reflections when

passes from one sub-sector to the next, this area must be penetrated by the wave. These angles therefore vary by approximately%. The lens ^ f ¹ J ^{0 have} f ¹¹ ?. ^{Depth of} ftwaehfa quarter of the

M 6o wavelength, and the mutual distance between two

is made of anisotropic radial platelets to-adjacent cherish Direction grooves 10 is less than .a sammengesetzt that a central angle and a JG ^ AIU wavelength to the formation of waves of higher

MM to prevent order.

have such a structure that they look like quarter-wave The front surface of the lens is composed of a

platelets behave. The tiles are arranged in such a way that, 65 know the number of subsectors from a

that at the transition from one subsector to the next used waves permeable material with a dielectric

Subsector the angles that the fast and the slow rate constants ε together. There are nine in all

Axis with the bisector of the subsector, there are subsectors of the same type, -of which six,

- • υ. ,. ··, 2 «r» _o namely U to 15 and 19, shown in Fig. 3,

form, lend themselves to - enlarge. _c "n. χ χ ·· jv -u« j · ^ -ui j _Τ τ. ι _A

^J M ⁵ 70 Of course, the number of subsectors

7 8

be relatively large, but it does not need to have slow axes over the entire surface of the lens

to be nine. remains the same.

These sectors are provided with rectilinear grooves 20. The lens according to the invention consists of one

see that with the bisector of the associated ordinary lens and a quarter-wave plate 4,

Sub-sector form an angle of 45 °. The grooves 20 5 that this lens covers. This quarter-wave plate

have a depth j>, a width ö and a distance α has the shape of a circular disc with grooves 5,

from each other. These dimensions are expediently so The grooves 5 run over the entire surface of the

chosen that the subsector is a quarter-wave plate circular disc in the same direction. The quarter wave

forms. Each subsector rests with its flat side plate transforms the circularly polarized wave into

on the flat side 21 of the lens 9 with intermediate io a linearly polarized wave, and the usual one

circuit of a certain number of plane-parallel sector lens focussed, as is known from optics, a

, .. ,,, _. ,, ■, .. _a . τ .. ■, λ linearly polarized plane wave according to a module that is in

8 platelets having a thickness uniformity _lg en ^ - ^. _first ^^^ g _{a HirWeUe corresponds to} .

There is no plan below the subsector 11. FIG. 6 shows the electric field image in cross section

parallel sector plate, under the subsector 12 15 of the circular H ₃₁ -WeIIe. The lines of the electrical plate, etc., and below the subsector 19 field are denoted by 54. You can see that there are eight tiles in the field image. It follows that angular repeat symmetry of order three shows the steps between one subsector and the next.

_TT .., λ ,, j-vi- je ** The three sectors I, II and III with a central angle

a height of _-; rr have: only the descending _{abduction Hrtr} . _o . ,,,,. _{π,. ΛΟ Λη} __ _{,, τ} .

9 (w-l) ' * so from 120 are separated by the radii 48, 49, 50. Everyone

between the subsector 19 and the subsector 11 sector is in four subsectors with a central angle

,. -ρ ..., λ divided by 30 °, namely I ₁ to I ₄ , H ₁ to H ₄ and IH ₁

nat a ± ione of ^ -j. _to ^ _{In the university sectors} T _{1 to} ^ _z . _{B. is that durcll}

The axis of the lens 9 runs vertically (see. Fig. 3). the field denoted by arrow 46 one after the other - in a The lens is covered forwards by a bell 22 , 25 specific moment - radially centrifugal, tangential in which a counterclockwise inclined by 45 ° to the vertical, radially centripetal and mirror 23 is arranged, from the lens 9 tangentially in a clockwise direction.

going beam is reflected in a horizontal direction. Fig. 7 shows one of the surfaces of the lens, the other

The bell 22 can be rotated about the axis of the lens 9 and become a surface which has the shape required to produce the desired focalization in order to cast the beam in the desired direction (conversion of a spherical wave into a plane wave, for example). This other

The refractive index of a subsector 11 to 19 for page is e.g. B. convex as the surface 7 of the lens 9 in parallel to the direction of the grooves 20 polarized waves Fig. 3. The lens comprises twelve subsectors 511, 512,

513, 514, 521, 522, 523, 524, 531, 532, 533, 534 with a central angle of 30 ° each, which are formed by anisotropic plates that define the position of the subsectors I ₁ to I ₄ , H ₁ to H _{Take 4} , HI ₁ to HI ₄ of Fig. 6,
and for waves polarized perpendicular to this

Sector on the other hand, the azimuth Θ of the electric field

(a -f- V) 40 vector 46 relative to a fixed direction Ox of the plane

0 - \ - Ba T ₁₁₁₁ an angle less than - = ~ (the vector 46 jjdes

So that the path difference between the in these two subsectors I ₁ forms an angle Θ equal to Ox

τ ,. ,, '. . _{,, T7} τ, j tit. λ T ..- 1. Zero, and the vector 46 of the following subsector I ₂

Directions polarized waves the value - receiving, _4g ^ ^ _Οχ ^ _ψ ^ _Q ^ _6QO) _ _{This is alg0} ^

the grooves must have a depth f , which results from the note that has to be taken into account for equation in equations (2) and (3).

The thickness of the sector plate 511 has a loading \) ■ certain value e, and this thickness increases from

- \ - εα 5 ° one subsector to the next

λ Ν - ¹ ο ^λ «a

calculated Δ & = λ = (ο)

If one uses poly- NM {n - l) 6 (w - 1) as the material for the subsectors

thene used for which ε = 2.6, the depth must have the quarter-wave plate sectors 511-534

of the grooves 14.3 mm for a shaft of length 8 mm 55 the same structure as the sector plates 11 to 19

when a = b . of Fig. 3, that is, they are sheets of dielectric

In H _u waves (Fig. 4), the angle β of the elek material, the grooves 55 of the width δ and the depth φ

tric field vector 46 with the radial direction OM in, between which parallel ribs 56 of the

the intense field zone in which the field lines 54 are located at width α.

are approximately parallel, approximately equal to the angle or 60 They are arranged as a cover for each sub-sector in the azimuth γ (Fig. 4) between the radial direction OM and in such a way that the grooves of the covered sub- sector have a fixed direction Ox (this fixed direction is the sector at 45 ° against the electric field vector 46 line of the strongest field). The angle β is increased (Fig. 6) are inclined. The values p, a, l must be provided as the azimuth of this radial direction, which corresponds to the equation (5) below,
a, »- χ TT j. TJ. · Τ-, τ. i_ -xj. 2π,, ... _TT , 65 If the lens in the region of the visible waves be-M-th subsector averages - ^ -. _{Underutilized} ^ d, the anisotropic platelets of paraUel _can

Under these conditions, the direction of the electric quartz field vector intersected to the sixfold main axis remains 46 are made of platelets in the area of the intensive field.

approximately fixed, and the variation Ae is zero. Although the examples described in detail

From this it follows that the direction of the fast and 70 specifically describe a lens that has a flat, homogeneous,

circularly polarized wave transformed into an H ₀₁ wave, an E ₀₁ wave, an H ₁₁ wave or an H ₃₁ wave, and vice versa, it goes without saying for the person skilled in the art that lenses can also be constructed according to the invention, which can convert a circularly polarized wave into a wave with a given field.

Claims (3)

PATENT CLAIMS: 1. Dielectric lens for converting a linearly polarized wave with a given field * ° cross-sectional image in a flat, circularly polarized wave, and vice versa, characterized in that the lens is formed on the one hand from a combination of a plano-convex lens, which on the one hand by a diopter which transforms the wave surface of a linearly polarized J-5 wave into a plane and is limited on the other side by a flat surface provided with divided surface elements, the surface elements being so small that the electric field is everywhere parallel to itself, and the ao on the other hand is provided with plane-parallel dielectric plates, one of which is applied to the surface elements of the flat lens surface and the thickness of which is proportional to the angle that the electrical vector of the surface element forms with a fixed direction of the wave surface, and also with a Quarter wave plate is provided , which is arranged in such a way that the angle formed by its slow and fast axes is halved by the electrical vector of the surface element. 2. Dielectric lens according to claim 1, which serves to transform a linearly polarized spherical wave, which has a cross-sectional _{image with the structure of the modules H ^ 1} and EjV ₁ in a circular waveguide, into a circularly polarized plane wave, characterized in that it is plano-convex in that it has MN plane-parallel sector plates, where N is the order in the tangential sense of the module under consideration and M is a number such that the electric field vector of the wave has an essentially unchanged direction in an angular sector with the central angle Jr = ^ j: has that each plate has a thickness which is proportional to (N- - 1) times the angle which the bisector of the sector forms with a fixed direction, these plates being arranged side by side on the flat surface of the lens, that it has NM sector-shaped quarter-wave plates whose perpendicular fast and slow axes are arranged in such a way that each of these directions is inclined by 45 ° to the electric field vector of the linearly polarized wave in the sector, these sectors also being arranged next to one another on the surface of the lens. 3. Dielectric lens according to claim 1, which serves to convert a linearly polarized spherical wave with a cross-sectional image, which has the structure of the modules H ₀₁ , E ₀₁ in a circular waveguide, into a circularly polarized wave, characterized in that it is plano-convex that it has K plane-parallel, sector-shaped plates, where K is a number such that the electric field vector of the wave is an essentially unchanged direction in a sector with the central angle -, each sector having a thickness which is proportional to the angle that the bisector of the sector forms with a fixed direction, that the sectors are arranged side by side on the flat surface of the lens, and that it has a number of K sector-shaped quarter-wave plates, the fast and slow axes of which are arranged in such a way that each of them is inclined at 45 ° from the bisector of the sector. 1 sheet of drawings © 009 508/284 4.60