RU2052878C1 - Wide-band array - Google Patents

Abstract

FIELD: radio engineering. SUBSTANCE: wide-band array has flat dielectric base with metallized layers. Excitation system and radiation aperture coupled to it are manufactured in metallized layers. Radiation aperture is formed by horn radiators placed at several levels. Each horn radiator of next level is formed by pair of horn radiators of preceding level which adjacent walls cross in point lying on symmetry axis at distance greater then half length of wave to their outer walls. Aperture of horn radiator of next level is twice as much as aperture of horn radiator of preceding level. Horn radiators of zero level are connected to excitation system and their number is even. Description of invention gives relation to determine number of horn radiators in each of other levels. EFFECT: improved functional characteristics. 3 dwg

Description

 The invention relates to electrical engineering and can be used in broadband antennas where transverse and longitudinal emitters are known. Such emitters realize horn, lens, mirror, discrete antennas, surface wave antennas and antennas in the form of open longitudinal emitters (Kuhn R. Microwave antennas. M. Shipbuilding, 1967, p.95, 198, 258, 304, 373, 420).

 These antenna systems (AS) are effective devices that allow you to obtain technical parameters in a limited frequency band. When trying to create speakers with a bandwidth of several octaves, significant technical difficulties arise up to a decade with ensuring high electrical parameters (radiation pattern width (LH), low level of side lobes, gain (KU)) in the indicated frequency band.

 A technical solution is known, described in US patent N 4001834, 1977, where an assembly of a printed antenna and a transmission line made on a single board is proposed. On one side of the board (front), the main surface is occupied by a metallized (copper) conductor. On metallization, a part of the surface bounded by a cone (horn) is removed, the tapering part of which passes into a slit line. If the RF energy enters through the slot line, then the edges of the cone are forced to contact the space. The position of the point at which the microstrip is connected relative to the slot line determines the antenna impedance. On the reverse side of the board is a microstrip conductor operating as a transmitting RF line (excitation system). The microstrip runs along the slit line and provides capacitive coupling with the latter.

The disadvantages of this device are:
relatively narrow bandwidth (up to an octave);
a relatively large linear extent of several wavelengths;
significant difficulties in matching the aperture of the antenna with free space in the frequency band.

 The aim of the invention is to expand the bandwidth of the speaker to a decade; decrease in the linear length of the speakers; obtaining a dynamic amplitude-phase distribution (AFR) at the aperture, which will make it quite easy to solve the problems of expanding the bandwidth and matching speakers with free space, as well as modifying its DN; development of a broadband linear antenna array (LAR) with a high gain, a low level of side lobes and suppressed side diffraction maxima in a wide frequency band.

This is achieved by the fact that in a broadband antenna array containing a flat dielectric base with metallized layers in which the excitation system is made and the radiating aperture associated with it, the radiating aperture is formed of horn emitters placed at several levels, with each next-level horn emitter formed a pair of horn emitters of the previous level, adjacent walls of which intersect at a point lying on the symmetry axis of the horn emitter of the next level at a distance e half wavelength to their outer walls and has an aperture of 2 times more aperture horn radiator previous level, the emitters zero level associated with the excitation system and their number is even, and the number of horn radiators in each of the other levels is determined by the relation 2 ^Pm, where p is the number of level transitions, m is the number of the level. Each subsequent pair of adjacent emitters (first, second, and other levels) by crossing their inner walls forms a higher-level emitter with a metallized area in the latter’s inner region with a linear aperture size two times larger than the previous one, the process of doubling the size of the aperture continues until until the required radiating opening is achieved. This design of an LAS with a set of inhomogeneities in the form of spasmodic transitions makes it possible to implement a circuit of series-parallel systems (communication regions of length l ₁ , l ₂ , l _n ), in which conditions are created for the excitation of propagating lower and higher modes, i.e. to obtain dynamic AFR at the aperture of the AR, which makes it quite simple to solve the problems of expanding the bandwidth, matching the AR with free space, and modifying its DN in a wide frequency band.

 The invention is illustrated by drawings, in which Fig. 1 shows a broadband linear antenna array, in Fig. 2 the mechanism of re-reflections of natural waves on inhomogeneities, in Fig. 3, the principle of superposition of propagating higher and lower modes for the case of in-phase excitation of inhomogeneities of a "jump" transition.

Figure 1 marked: 1 emitter of zero level (horn (cone)); 2 emitter of the first level (guide system (communication region M ₁ ) of the first level of length l ₁ ); 3 external walls (forming) emitters of the first level; 4 internal (adjacent) walls (forming) of emitters of zero level; 5 emitter of the second level (guide system (communication area M ₂ ) of the second level of length l ₂ ); 6 emitter of the third level (guide system (communication region M ₃ ) of the third level of length l ₃ ); 7 slotted line; 8 microstrip line (excitation system); solid lines the front side of the board, the shaded part of the front board corresponds to the presence of metallization, dotted lines indicate microstrip lines on the back of the board that implement the LAR excitation system, dash-dotted lines drawn through points O, O ₁ , O ₂ , and perpendicular to the opening of the AR, are the axes symmetries, respectively, for emitters of the first, second and third levels. The points O, O ₁ , O ₂ characterize the location of the inhomogeneities for which the boundary conditions can be strictly formulated, since they are inside the guide systems formed by the continuation of the external (external) walls of the respective emitters. So, for the communication regions M _1, these extensions are segments O 'O ₁ ' and O "O ₁ ; O'O ₁ and O" O ₁ ";O'O ₁ 'and O" O ₁ ; O'O ₁ and O "O ₁ "; for the communication regions M ₂ O ₁ 'O ₂ ' and O ₁ "O ₂ ; O ₁ 'O ₂ and O ₁ " O ₂ "; for the communication region M ₃
O ₂ 'O ₃ ' and O ₂ "O ₃ ". After the points O, O ₁ , O _{2, the} linear size of the aperture doubles each time in a jump. Points O ₃ 'and O ₃ "also characterize the heterogeneity in which the third-level emitter (opening the antenna array) joins the free space.

 In the general case, the generators of the emitters do not have to be straight lines and are a continuation of the straight line, they can be exponentials, broken lines.

A LAR that implements dynamic AFR on an aperture is a set of zero-level emitters (n _o 2 ^p ) with aperture sizes greater than half the wavelength located in pairs one next to the other. Pairs of adjacent emitters can be spaced at different distances from each other, but must always be symmetrical with respect to the center line drawn through the intersection point of adjacent (adjacent) walls and perpendicular to the opening. For each pair of adjacent emitters, the external (external) walls (to the mutual from the intersection) continue to a length of l ₁ , which allows you to create n _o / 2 inhomogeneities in the form of a jump-like transition and obtain 2 ^P-1 emitters of the first level in which the conditions for excitation are realized propagating modes, both higher and lower. Then, for each adjacent pair of emitters of the first level, the outer walls are extended (until they intersect each other) to a length of l ₂ , which makes it possible to create n _o / 2 ² inhomogeneities in the form of a jump-like transition and obtain 2 ^P-2 emitters of the second level (communication region M ₂ ) in which the conditions for the excitation of propagating modes, both higher and lower, are realized. The described process with adjacent pairs of emitters of different levels continues until n _o / 2 ^P 1, where P characterizes the number of levels, jumps (for figure 1, P 3).

In this case, LAR has
the number of elements of the zero level n _o 2 ^P ;
the number of elements of the first level n ₁ 2 ^P-1 ;
the number of elements of the second level n ₂ 2 ^P-2 ;
the number of elements of the highest level mn _m 2 ^Pm 1.

 A feature of constructing the structure of the LAR is that the emitter of any level (except the zero) is constructed according to the same scheme and contains an inhomogeneity of the type of jump-like transition, which excites a guiding system for which boundary conditions can be strictly formulated. The mechanism of the formation of the field structure in the aperture of an element of any level (except the zero) is exactly the same, but they differ only in different boundary conditions.

 Emitters of any level do not have to be horns, in the general case any flat elements can be used, the generators of which are described by a separate exponential or a set of exponentials. It is desirable that the intersection of the generators of adjacent pairs of radiating elements form a point and not a smooth curve, i.e. the intersection of the generators was described by a discontinuous function.

In FIG. 2 shows re-reflections of natural waves between inhomogeneities in a guide system. For the communication region M _1, plane 1 corresponds to the joint O'O ", the part of the space to the left of the joint O'O" is designated as region 1, plane 2 corresponds to the joint O ₁ 'O ₁ ", the space to the right of the joint O ₁ ' O ₁ ", designated as area II.

For the communication regions M ₂ , M _3, plane 1 corresponds to the joints O ₁ 'O ₁ "; O ₂ ' O ₂ ", and the plane 2 corresponds to the joints O ₂ 'O ₂ "; O ₂ ' O ₃ ", respectively.

A wave E _{about a} unit amplitude of the structure H _{1 is} incident on a plane from region ₁ . Part of the energy is reflected back to region 1 in the form of the same type of wave with amplitude N _n }. "The remaining part passes into the communication region M in the form of waves H _p (solid lines) with amplitudes N _m } _1p , where p 1, 2, 3. i, j, k. The number of wave types in region M is not limited.

At plane 2, the waves H _p acquire an additional phase incursion and have amplitudes P _1p . Each of the waves H _p on plane 2 is converted into a transmitted wave of region II with an amplitude P _Ip R _pI and reflected waves of the considered types with amplitudes P _Ip {M _m } p _g , where p, g 1,2,3.i, j, k. The reflected waves again fall on plane 1, partially pass to region 1, the rest is reflected in turn in the form of a set of considered waves.

Having examined several successive reflections, we can find a number of patterns that allow us to calculate the amplitudes A $\genfrac{}{}{0ex}{}{\text{I}}{\text{m}}$ and A $\genfrac{}{}{0ex}{}{\text{II}}{\text{m}}$ field, which appeared, respectively, in regions I and II due to multiple re-reflections of waves between inhomogeneities. Amplitudes A $\genfrac{}{}{0ex}{}{\text{I}}{\text{m}}$ and A $\genfrac{}{}{0ex}{}{\text{II}}{\text{m}}$ equal to the sum of terms, the number of which corresponds to the number of waves taken into account; each term is equal to the product of the coefficient V _pI for A $\genfrac{}{}{0ex}{}{\text{I}}{\text{m}}$ and R _pI for A $\genfrac{}{}{0ex}{}{\text{II}}{\text{m}}$ by the total amplitude of the wave with index p in the region M near plane 2.

If plane 1 at the same time a few drops ₁ H waves, the reflections except the considered mechanism H _p between waves of the same structure, there will be a superposition. Due to the superposition, it is possible to select either only even or only odd waves, or to obtain a set of all waves with the necessary amplitudes, and by selecting the length of the region l to obtain the required phase shift. Figure 3 illustrates the superposition mechanism for the simplest case when only one even and one odd modes are taken into account in the communication region M (the mechanism of wave rereflections is not considered).

During the in-phase excitation of zero-level emitters by the wave H ₁ , due to the boundary conditions and the conditions for the excitation of inhomogeneous transitions in the communication regions M ₁ , M _2m M ₃ , the lower 1 ^' , 2 ^' propagate; 1 $\genfrac{}{}{0ex}{}{\text{''}}{\text{a}}$ 2 $\genfrac{}{}{0ex}{}{\text{''}}{\text{a}}$ ; 1 $\genfrac{}{}{0ex}{}{\text{''}}{\text{b}}$ , 2 $\genfrac{}{}{0ex}{}{\text{''}}{\text{b}}$ and higher ^1`` , 2 ^'' ; 1 $\genfrac{}{}{0ex}{}{\text{''}}{\text{a}}$ , 2 $\genfrac{}{}{0ex}{}{\text{''}}{\text{a}}$ ; 1 $\genfrac{}{}{0ex}{}{\text{''}}{\text{b}}$ , 2 $\genfrac{}{}{0ex}{}{\text{''}}{\text{b}}$ fashion. In this case, the modes 1 ^' and 2 ^' ; 1 $\genfrac{}{}{0ex}{}{\text{''}}{\text{a}}$ and 2 $\genfrac{}{}{0ex}{}{\text{''}}{\text{a}}$ ; 1 $\genfrac{}{}{0ex}{}{\text{''}}{\text{b}}$ and 2 $\genfrac{}{}{0ex}{}{\text{''}}{\text{b}}$ will be in phase, and 1 ^'' and 2 ^'' ; 1 $\genfrac{}{}{0ex}{}{\text{''}}{\text{a}}$ and 2 $\genfrac{}{}{0ex}{}{\text{''}}{\text{a}}$ ; 1 $\genfrac{}{}{0ex}{}{\text{''}}{\text{b}}$ and 2 $\genfrac{}{}{0ex}{}{\text{''}}{\text{b}}$ in antiphase.

As a result of superposition, in each of the regions M ₁ , M ₂ , M ₃ only the resulting mode will remain (1 ^' + 2 ^''); (1 $\genfrac{}{}{0ex}{}{\text{''}}{\text{a}}$ + 2 $\genfrac{}{}{0ex}{}{\text{''}}{\text{a}}$ ); (1 $\genfrac{}{}{0ex}{}{\text{''}}{\text{b}}$ + 2 $\genfrac{}{}{0ex}{}{\text{''}}{\text{b}}$ ) is odd, and the power transferred by this mode is equal to the sum of the powers supplied to the input.

 It must be emphasized that if in a conventional AR the field distribution at the aperture is considered to be discrete, then in the proposed LAR it is continuous (dynamic AFR), which explains the absence of side diffraction maxima and a wide passband up to a decade.

 From the foregoing, it becomes obvious that the tasks posed during the development of this technical solution are completely solved by the proposed antenna array design, which implements dynamic AFR at the aperture, which makes it quite simple to solve the problems of suppressing side diffraction maxima, expanding the passband, matching the AR with free space and modifications of its DN in a wide frequency band.

 The present invention is a perfect microstrip antenna, performed using modern technology of printed circuit boards, characterized by compactness, low weight and high adaptability. Interest in such antennas has increased significantly in recent years due to significant advances in the technology of manufacturing large printed circuit boards, as well as due to the creation of new dielectric materials for substrates. All this shows that this antenna will find wide application in electrical engineering.

Claims (1)

WIDESBAR ANTENNA ARRAY, containing a flat dielectric base with metallized layers, in which excitation systems are made and a radiating aperture associated with it, characterized in that the radiating aperture is formed of horn radiators placed at several levels, with each horn radiator of the next level being formed by a pair of horn emitters of the previous level, adjacent walls of which intersect at a point lying on the axis of symmetry of the horn emitter of the next level at a distance greater than half ovine wavelength to their outer walls, and has an aperture twice the aperture of the horn emitter of the previous level, and the horn emitters of the zero level are connected to the excitation system and their number is even, and the number of horn emitters in each of the remaining levels is determined by the ratio 2 ^{p - m} , where p is the number of level transitions, m is the level number.

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