DE1953083C3 - Horn antenna with two consecutive horn sections - Google Patents

Description

The point at which the discontinuous wedge is located determines the way in which the two existing waves, namely the 7 E ₁ , wave and the / 'W ₁₁ wave, in the opening of the liomanienne become one Combine sky wave.

In one known from the USA.-Patentschrifi 33 05 S7Ü horn antenna a Tt is fed ₁₁ -WeIIe also in the tapered portion of this antenna, and it will be understood by a discontinuity a, as in the two waveguides waves of the same type 7 are " E _{10 is} present, which also runs through the extended section of the antenna. As a result, the conditions here are basically the same as with the other known antennas, in which a second wave type is excited at the entrance of a horn section, which, together with the wave type used for the excitation, is the desired Radiation diagram

7AZ _n -WeIIe stimulated, however, there is this uni- io there, even if here other wave types than continuity are already used at the entrance of the conical _{off- the 7E 11} -WeIIe and the 7'Ai ₁₁ -WeMe d H dd

section of the homing antenna and is formed by a sudden increase in the diameter of the Spcisehohlleiter. Here, too, both waves unite again in the opening of the homing antenna, and os the relative amplitude and the relative phase position of the two waves can be adjusted to a desired value by selecting the antenna parameters. Another, from the magazine »The Microwave · ■" VIlV UIIU VIVI XI 'J ι ι

power will. In particular, this known antenna is also narrowband for the reasons given above.

Accordingly, the invention is based on the object of providing a homing antenna of the type described sound, which delivers the desired radiation pattern in a broad frequency band.

This object is achieved according to the invention by

Journal · ·, June is>f> 3. S. 71 to 78. known horn 20 in the characterizing part of claim 1 specified features solved.

With the homing antenna according to the invention a great broadband achieved in that the changes in the phase velocities of the

antenna has several keecllormme and z \ imuric sections one behind the other. This antenna is also excited again by means of a waveguide with the / E ₁₁ wave. In one of the last conical

Section preceding cylindrical section 25 and balance the third shaft in such a way that

there is a sudden expansion of the diameter, which leads to the excitation of a / Ai _n -WeIIe. In the opening of the homing antenna both waves are again combined with an amplitude ratio determined by the size of the sudden change and a phase ratio determined by the position of the sudden change to the desired space wave.

In all of these known horn antennas, the first and third waves are in the plane of the aperture of the home in a large frequency range with the desired phase relation.

In a preferred embodiment of the invention there are a number of longitudinally directed conductive rods arranged at a distance from each other in the neck portion of a conical horn, the cross section of which can be circular, rectangular, triangular, etc. These conductive rods can be parasitic or also

in common that they are _{fed with a 7E n} wave 35 from outside the home, to become one and have an inactivity at which the remote control of the phase and amplitude ratio 7AZ _n wave is excited. This point of discontinuity between the waveforms and, as a result, the desired field distribution at the opening d is followed by a phase-shifting section, which enables the relative phases of the homes to be adjusted. In cases where the longitudinal wave types are used. Since the 7Ai ₁₁ wave, a phase 4 ° directed conductive rods are excited from the outside, has speed that changes with frequency changes, hybrid arrangements can be used to control much more changes than the phase speed of the amplitude and phase. Furthermore 7E ₁₁ -WeIIe. In the antenna opening the impedance matching in the transition area relative phase position of the two waves changes very quickly between the TEM and the horn wave types with the frequency, so that such horn antennas are very 45, so that the 7EAi lines are wave types with narrow-bar arrangements . This higher order deficiency can be effectively released. This cannot be avoided by using other impedance matching methods for generating wave types higher in the position of the conductors in the horn as well as the order of magnitudes, such as improved by the shape and shape of the conductors, - 'Elrhe Para earthing of serial stub lines. Pins or webs - 5 "meters all along the line may vary waveguides. All such arrangements will be illustrated in the drawing

for the same reasons as described in more detail illustrated embodiments discussed above have become very narrow band. and explained. It shows

Finally, from US-PS 33 92 395 a horn Fig. 1 is a homing antenna according to the invention

The antenna is known to be parasitically excited at the entrance to its widened circular cross-section th section of two parallel connected longitudinal bars,

Waveguides is fed, which have a common partition. The two waveguides each lead a 7E ₁₀ wave. By means of a pin arranged at a distance in front of the dividing wall between the two waveguides, a 7E is created in the widening Ahschnir with the same phase position of the waves mentioned. _In -WelIc excited, which together with: eic · 7E ₁₁₁ -WcIIe spreads out through the extended section to: ■ ".. its opening. If the two waveguides serving to excite the waves in the expanding section are part of the homing antenna and not as part of a feed network

Fig. 2 A and 2 B are diagrams illustrating the field distribution in the homing antenna F 1 g. f.

F i g. 3 a horn antenna according to the invention with of, ι- 's controlled amplitudes and phases dei Weller,; ypen.

4 shows a homing antenna according to the invention, be which a 7Ai _n -WeIIe is emitted from the 7EAi line,

Figures 5A and 5B show a homing antenna according to the Er finding with a 7ΕΛ / Line excited by a hybrid arrangement

6 with a horn antenna according to the invention longitudinal bars effecting impedance matching,

7A and 7B show a horn antenna according to the invention with a square cross-section and four longitudinal bars,

Fig. 8 is a cross-section through the neck portion of a rectangular horn antenna having a plurality of longitudinal bars,

F i g. 9 the field distribution at the opening of a horn antenna according to the invention in the E-level,

10 shows the field distribution at the opening of a Horn antenna according to the invention in the W plane and

11 shows the field distribution of a horn antenna according to the invention in a diagonal plane.

The in F i g. 1 illustrated embodiment of the invention comprises a horn antenna 10 having a Neck section 12 which ends in a flange 14. Longitudinal conductive rods 15 and 16 are diametrically opposite each other on the in

The phase relation between the TE _n - and the TAi ₁₁ -WeMe at the opening of the home IO is maintained in a wide frequency band. The reason for this is that the phase of the TAi _n wave at the horn opening depends on the "lower" phase velocity of the TEM wave in the region L ₁ and the "higher" phase velocity of the TM _n wave in the region L., and the Phase of the TE ₁₁ wave at the horn opening is a function of the

ίο mean phase velocity of the TE ₁₁ wave only in the areas L ₁ and Z .. is. Namely, it is possible to make the mean phase velocity resulting from the phase velocities of a slow wave and a fast wave substantially equal to the mean phase velocity of a medium velocity wave in a wide frequency band, so that the phase relationship between the TE _n - and the TAY _n -WeIIe at the horn opening in a wide frequency band in the

^{The end of the neck 2O} lying on the right of the drawing is essentially constant, for example in the entire section 12 attached to its inner surface with the help of normal working frequency band of a waveguide, right-angled extensions of length h.

Accordingly, rods 15 and 16 essentially begin- Mathematically

borrowed at the end of the neck portion 12 at a distance h from its surface and extend ² 5 '- ■ - i · ^{1 +} ' - over a length L ₁ in the direction of the opening of the horn antenna 10. The rods can extend along from

Straight lines extend from the apex of the horn phase of the TM ₁₁ -WeIIe = phase of the TE ₁₁ -WeIIc

Go out antenna and intersect points at a distance h from opposite sides of the neck portion 12 at the transition to the horn antenna 10. However, such an arrangement of the rods is not critical.

When operating the horn antenna according to FIG. 1 with

several wave types is 35 2 71 in the neck section

TE ₁ , fundamental wave excited. The incident TE _n -wave ^ tMn =

excites a TEM wave at the beginning of the double lines that are formed by the longitudinal rods 15, 16.

The amplitude of the TEM wave is given by the » An I'thu ⁼

tennenhöhe « h is determined, that is, the supporting processes

+ J

In this equation is

HimM ~

2 π

'■ 77.11

(D

hm = wavelength of the TEM wave
= Wavelength of the TM _n wave
= Wavelength of the TE ₁₁ wave

The values given for the integrals denote the length segments over which the integrated will.

The phase velocity v "of the wave is

2 π · frequency

of the rods 15 and 16. Since only part of the TE _n wave is converted into a TEM wave, the TE ₁₁ and the TEM wave _{exist side by side in the area L 1 of} the horn antenna 10. The field line image of the TEM wave in the area L ₁ in relation to the rods 15, 45 and 16 is shown in FIG. 2 A. At the ends of the rods 15 and 16 on the right in the drawing, the TEM wave _{merges into a TM n} wave. Accordingly, a TE _n and a TM _n wave exist next to one another in the area L _{2 of} the horn antenna 10. Since the ⁵ ° longitudinal rods 15 and 16 end at the end of the area L ₁ , a TEM wave cannot exist in the area L. The TE _n -WeIIe and the TM _n -WeIIe ''

Frequency changes of the TEM and TM _n -WeIIeB combine at the opening of the horn antenna

10, as shown in FIG. 2B, to a field 55 result in self-compensation, that is to say that the strength curve has very few side lobes. the one with respect to the TE ₁₁ wave increases when the field strength curve in the E, H and diagonal the other decreases, so that equation (1) for plane, as indicated by one of a TEM wave - wide frequency ranges remain valid. Generally, excited TM wave is generated is shown in Figs. 9, the slower TEM wave in the area L ₁ plus 10 and 11 is shown. The side lobes in all these ^6o lent the faster TM ₁₁ wave in the area L ₂ diagrams are in the order of 30 db equal to the TE _n wave of average speed over less than the main lobe, the diagrams have the distance L ₁ + L ₂ , and this equality will be kept in a substantially identical shape such that one in a broad frequency band is substantially at-rotational symmetry, and it is finite that it is kept.

Cross-polarization, measured in the diagonal plane, ⁶ 5 Another embodiment of a horn antenna with several where it is greatest, completely negligible, excited horn antenna according to which we have demonstrated the desired polarization purity, which allows an external control of the amplitude and the phases of the waves , is in Fig.3

shown. This embodiment according to FIG. 3, shown partially in section, comprises a conical helmet antenna 22 with a neck section 23 which is provided with a stub 24. Longitudinal conductive rods 25 and 26 extend the central conductors 27 and 28 of coaxial lines 29 and 30, respectively, pass through the neck section 23 and protrude into the horn antenna 22, in the area of which they diverge. The rear end of the neck section 23 is closed by a conductive disk 31, which serves as the end for the outer conductors of the coaxial lines 29 and 30. The coaxial lines 29 and 30 are connected to the outputs of opposite polarity of a hybrid arrangement 32, which in turn is connected to an output of an adjustable power divider 34 via an adjustable phase shifter 33. Another output of the adjustable power divider 34 is connected to the stub line 24 of the home 22 in such a way that a TE _n wave is excited therein. An input 36 of the adjustable power divider 34 serves as an input for the horn antenna 22, which can be excited with several wave types. Finally, a free output 37 of the hybrid arrangement 32 is connected through an impedance 38. It is also possible to use this output as a generator for odd-numbered modes for an error or difference channel in monopulse operation.

During operation, a microwave signal is fed to the input line 36 of the power splitter 34, which divides the signal between the stub line 24 and the hybrid arrangement 32. The hybrid arrangement 32 feeds signals of opposite polarity to the longitudinal rods 25 and 26 via the coaxial lines 29 and 30 in order to excite a TEM wave along the rods. As in the case of the arrangement according to FIG. 1, the TEM wave excites a TM _n wave in the section of the horn antenna 22 which begins at the end of the rods 25 and 26. At the same time, a Tf _n wave is excited in the stub line 24, which passes through the horn antenna 22 in the same way as the sections L ₁ and L _{2 of} the horn antenna 10 according to FIG the amplitude and phase relationships of the TE _{U and TAf 1} , waves at the opening can be controlled in order to obtain the desired field distribution.

F i g. 4 shows the field distribution in the TM _n wave in a horn antenna according to the invention. In detail, FIG. 4 shows, partially in section, a conical horn anterine 40 with a neck portion 41 which is closed off by a conductive disc 42 . The conductive disk 42 carries coaxial input lines 44 and 46, the central conductors of which merge into the longitudinal bars 47 and 48. The longitudinal rods extend in the longitudinal direction through the neck section 41 and are then slightly spread in the conical section of the horn antenna 40. Furthermore, a cylindrical waveguide 50, which extends perpendicularly thereto and is closed by a disk 51, is connected to the neck section 41. In operation, the coaxial input lines 44 and 46 feed signals of opposite phase, the frequency of which is sufficiently high to be able to excite _{a TM 11 wave in the conical section of the horn antenna 40.} Under these circumstances, the TEM wave propagates along rods 47 and 48 and excites a TM _n wave at the ends of the rods. The course of the electric field of a TM _n -WeIIc is shown in FIG. 4 by the lines 55.

5 A and 5 B show a horn antenna according to the invention, which has more than two rods for TI: 'Vf-Wcllen. 5A and 5B a conical horn antenna 60 with TOf waves leading longitudinal rods 61, 62, 63 and 64. The rods 61 to 64 increase in diameter towards their free ends and also increase their spacing so that the wave resistance for the TLM wave remains constant. The ratio of the rod diameter and the distance between the rods to the horn diameter remains constant, so that a similar geometric wedge is preserved in all cross-sectional planes. The longitudinal bars 61, 62, 63 and 64, the arrangement of which is shown in cross section in FIG. 5B, are fed with the aid of a hybrid arrangement 65 via coaxial lines 66, 67, 68 and 69. In operation, the hybrid arrangement excites the multi-conductor TEM lines 61 to 64 with signals of the appropriate amplitudes and phases. which in turn excite 60 waves of higher types in the horn antenna. The relative phase of the signals which are fed to the TEM lines 61 to 64 decreases in the direction of view of FIG. 5 B

clockwise around

to, where m - +0.1.

2,3 ... and N number of lines. If m 1 is set in the present case , the phase difference between adjacent lines is 90 ". This phase difference is used to excite a 77th, VZ wave, which in turn is doubly orthogonal, i.e. clockwise and counterclockwise, circularly polarized waves in the horn antenna 60 stimulates.

In order to effectively stimulate the higher order wave types at the end of the TE.Vi lines, that is, at the end of the longitudinal rods, the impedance matching in the transition area from the TEM wave types to the Horn wave types must be good. F i g. 6 shows a conical horn antenna 70 with longitudinal rods 71 and 72 which carry conductive sleeves 73 and 74 near their ends and conductive sleeves 75 and 76 at their ends. The sleeves 73 and 74 arranged near the ends have approximately twice the length of the sleeves 75 and 76, which are arranged directly at the ends of the rods, and are spaced from the sleeves at the ends at a distance which is approximately the same length. Further, the diameter of the sleeves 73 amounts to 76 about two to three times the diameter of the rods 71 and 72. The same design could, for example, greater strength can be achieved by twisting a rod. The main consideration in impedance matching is this. To generate reflections that compensate for reflections that arise at the transitions between the rods 71 and 72 and the free space within the horn antenna 70.

It goes without saying that longitudinal rods are also used in horn antennas with other shapes can, for example in those with a rectangular or triangular cross-section. 7 A and 7 B show a rectangular horn antenna 80 with longitudinal rods 81, 82, 83 and 84. The connections to the Rods 81 to 84 are made with the aid of coaxial lines 85. F i g. 8 shows in cross section a more complicated arrangement of longitudinal rods in a rectangular horn antenna 86, in which two horizontal

609641/387

! 9 53 083

Rows 87 and 88 and two vertical rows 8i> and 90 of six bars each are present. The height of the horn antenna 86 is b, the width ti, the vertical distance from the lower side in the drawing> and the horizontal distance from the left side in the drawing ex. In general, the rows 87-90 of the rods can be excited in such a manner. that any desired mode is achieved as determined by a finite Fourrici series. However, higher order wave types become en cgi. by operating the individual rods in accordance with corresponding points of the desired field distribution within the rectangular horn antenna 86. In this case, the acceptance »

of the bars in rows 87 and 88 in accordance with the discrete amounts cos

whereby

ν indicates the position of the rod in the .v direction. Correspondingly, the excitation of the rods in the vertical rows 89 and 90 takes place in accordance with the discrete.

Values cos - ~, where y is the position of the rod in

indicating the y-direction. In the aforementioned expressions, m and η denote integers that identify the special type of toilet that is to be stimulated. The rods 81 to 84 in the horn antenna 80 of FIGS. 7A and 7B are excited in the manner as shown in FIG. 3 has been explained.

For this (Ί sheet of drawings

Claims (11)

Patent claims: 1. Horn antenna with two horn sections following one another in the direction of propagation of the wave, the first of which has at its input means for exciting two waves of different types, of which the second has a lower phase velocity than the first, and the second at its output that for radiating one Forms opening serving space wave, in the plane of which in the horn anteme excited waves combine to form a common space wave, characterized in that at the transition from the first horn section (L ₁ ) to the second horn section (L ₂ ) means for converting the second wave into a third wave are of a type whose phase velocity is greater than that of the first wave, and that the ratio of the lengths zo of the horn sections and the wave types are selected so that the number of the second and third waves in the two horn sections (L ₁ , L.,) formed wavelengths the number of those formed by the first wave n wavelengths are essentially the same in the two horn optic grooves. 2. Horn antenna according to claim 1, characterized in that in the first section (L ₁ ) of the horn (10) a number of spaced conductive rods (15 and 16) extending in the longitudinal direction through this section is provided. that the means for exciting the first shaft with the horn (10) and the means for exciting the two connected a ten shaft with the rods (15 and 161 and that the second shaft / 'EAZ-WeIIe is. 3. Horn antenna according to claim 1 or 2, characterized in that the horn (10) has a 4 "neck section (12) with a constant cross-section, to which the first section (L ₁ ) of the horn connects and with which the means for excitation connected to the first wave. And that the first wave is a 7E _n wave. 4. Horn antenna according to one of the preceding claims, characterized in that the third wave is a 7.VZ _n -WeIIe. 5. horn antenna according to claim 2, characterized in that that in each cross section of the 5 <horn (60) the ratio of the diameter of the Rods (61 to 64) and the distances between the rods to the dimensions of the horn are that they are one for the 7EAZ wave result in constant wave resistance. 6. Horn antenna according to claim 2, characterized in that the ends of the rods (71, 72) facing the opening of the horn (70) have at least one sudden change in cross-section for impedance. between the ^ ^r rooms and the / wide section ο ·> Humes have. 7. Hi> rnantenne according to claim 2, characterized in that two inner four rods are arranged symmetrically to the axis of the horn. ⁶ p iS. Horn antenna according to claim 2, characterized in that that the rods (15 and 16) at their ends facing away from the opening at right angles abuebouenen appendages are attached to the inner wall of the horn (Ίθ). y. Horn antenna according to Claims 2 and 3, characterized in that the rods (25 and 26) extend through the neck portion (23) of the horn (22). 10. Horn antenna according to claim 9, characterized Characterized that a device (34) is provided which the signal to be emitted two paths distributed, and a device that determines the phase position of the signals on these paths, and that one of the paths with the neck portion (23) and the other with a Hybrid arrangement (32) is connected, the power supplied to her on the second path to the existing Λ 'bars (25 and 26) with a phase difference by cos , 'Y distributed between successive bars, where m is a whole number! is. 11. Horn antenna according to claim 9, characterized in that the horn (80) including its neck portion has a rectangular cross-section and that the second wave consists of several wave types and that the individual rods according to the discrete values cos - _fl - along the width of the the neck portion, and the discrete values cos ^ ~ - are longitudinally excited the height of the neck portion, wherein in and η the wave type designating integers, a is width and b is the height of the neck portion referred to and .v the position of the bars along the width of a The reference side of the neck portion is measured from and y the position of the rods along the height is measured from a second reference side of the neck portion perpendicular to the first. The invention relates to a horn antenna 'it two successive in the direction of propagation of the wave Horn sections. of which the first means at its entrance means for exciting two waves of different types, the second of which has a lower phase velocity than that the first and the second at its exit forms the opening serving to radiate a space wave, In the plane of this, excited waves in the horn antenna combine to form a common space wave. Such a horn antenna, known from French patent specification 3 72 626, has a discontinuity in the form of an extension, an indentation, of four inwardly protruding parts approximately in the middle of its square section. The horn-shaped mixed cut is fed at its smallest diameter end by a waveguide with a 7E _n -weIIe. Among other things, a 7AZ _n wave is excited at the discontinuity, for which only propagation conditions exist. The size of the discontinuity inhibits the amplitude of the 7 / VZ _n -wave, while