RU2522909C2 - Wave antenna array - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: wave antenna array has an array of radiators and an additional array; the radiators are situated in nodes of the main flat two-dimensional grid and are in form of multi-section couplings of waveguide sections that are filled with dielectric materials; the waveguide sections have axes that are parallel to each other and perpendicular to the plane of the array; the additional array is made of passive scatterers situated outside the radiators in nodes of the additional flat two-dimensional grid, which is parallel to the main flat two-dimensional grid, wherein the passive scatterers are in form of electric and magnetic dipoles whose axes are perpendicular to the plane of the array.

EFFECT: faster operation of a phased antenna array.

5 cl, 13 dwg

Description

The invention relates to antenna technology and can be used as an antenna of a radar or communication system.

Phased array antennas (PAR) are widely used in various radio systems. Among their advantages are wide functional capabilities, which are provided through the use of electrically controlled elements - phase shifters. With their help, it is possible to solve a wide range of problems, which include: viewing a space with a narrow beam (scanning), forming radiation patterns (DM) of a complex shape, for example, cosecant, a beam with a given arrangement of zeros, etc.

An important component of the PAR is its radiating part - the antenna array (AR), which provides the conversion of the guided waves in the PAR channels into radiation waves of free space and, conversely, the conversion of radiation waves into guided waves. AP largely determines such important indicators of the quality of the headlamp as its gain (KU), the scanning sector, the range of operating frequencies and several others.

Different types of AP are known. They are usually classified according to the type of emitters that form the lattice: waveguide, strip, vibrator emitters. They correspond to waveguide, strip and vibratory ARs.

The emitters AP are located periodically in the plane, which is usually called the plane of the lattice. Moreover, they form a two-dimensional-periodic structure, which may have a rectangular or hexagonal grid. They are special cases of a mesh of the most general form - oblique.

This invention relates to waveguide APs. There are known waveguide arrays in which emitters are made in the form of multi-section joints of waveguide segments that are filled with dielectrics, waveguide segments have axes parallel to each other, and the axis of the waveguide segments are perpendicular to the plane of the array (US Patent No. 3938158, 1976, Antenna element for circular or linear polarization, JDBirch, MCMohr, SRMonaghan). The implementation of the emitter AP in the form of a multi-section waveguide joint, the waveguides of which are filled with dielectrics, allows us to solve two problems. The first task is to eliminate the incident maximum radiation in the scanning sector. From the PAR theory, it is known that when the main beam (GL) of a beam deviates from the normal to the plane of the lattice for a lattice period P greater than half the wavelength in the free space λ ₀ , side maxima arise in the PD of the PD with an intensity comparable to the main maximum of the beam. The angle of deviation of the GL θ _C from the normal to the plane of the lattice, at which a secondary maximum occurs, is determined by the following known relation:

$$\sin {\theta }_C=\frac{{\lambda }_0}{P}-\mathrm{one.}\left(\mathrm{one}\right)$$

On the other hand, it is also known that the main wave, for example, of a rectangular waveguide, can propagate only when the size of its wide wall is greater than half the wavelength in the medium filling the waveguide:

where ε is the relative dielectric constant of the medium. Thus, at the same time, it is possible to have a nonzero scanning sector without incident maxima (θ _C > 0) in the waveguide AP from waveguides in the operating mode (inequality (2)) only when the waveguides are filled with media with ε> 1.

The use of emitters in the form of multisectional waveguide joints allows improving AP matching in a given scanning sector and a given range of operating frequencies. It should be noted that the possibilities of matching AP in a wide scanning sector due to the choice of parameters of multisectional waveguide joints are limited. As a rule, they can be used to achieve agreement for relatively small GL deviation angles θ <30 °.

Increasing the scanning sector to 45 ° -60 ° requires the use of additional elements. Waveguide APs are known in which additional dielectric layers parallel to the plane of the array are used to expand the scanning sector (McGill, E.G., and H. A. Weeler, "Wide Angle Impedance Matching of a Planar Array Antenna by a Dielectric Sheet," IEEE Trans, on Antennas and Propagation, Vol. AP-14, No.1, January 1966, pp. 49-53). As a rule, for structural reasons, they are placed directly in the breakage plane of AP waveguides. A drawback of AP with dielectric layers is the appearance of a lattice blind effect. This effect consists in the fact that in some directions, which are called blind angles, the lattice becomes inoperative due to a sharp increase in the reflection coefficient. At these angles, the AP cannot transmit signals and take them from there. The appearance of blind angles is due to the excitation of surface waves in the dielectric layer. These waves carry energy in a direction parallel to the plane of the lattice and prevent the energy exchange between the AP channels and the free space.

Vibrator APs are known in which an additional lattice is used to improve coordination in a wide sector of angles, the elements of which are electric dipoles whose axes are perpendicular to the plane of the lattice (Surkov V.I. Influence of matching pins on the parameters of vibrator headlamps // Transactions of MPEI, 1981, no. 553, pp. 40-44). An additional grate is made with a rectangular grid, and its plane is parallel to the plane of the vibrator AP. The use of an additional lattice makes it possible to improve the matching of APs at large angles of deviation of the ML GLs in the plane of the electric field vector E. Moreover, the matching of APs at small angles of deviation does not deteriorate by introducing vertical electric dipoles. As a result, it is possible to expand the scanning sector AP in the plane of the vector E. The disadvantage of this technical solution is that the expansion of the scanning sector is achieved only in one plane and for waves of the same linear polarization.

The closest technical solution to the claimed waveguide AP is a grating (Eom AS.-Y., Park N.-K., Jeon S.-J „et al. Shaping of flat-topped element patterns in a planar array of circular waveguides using a multilayered disk structure - Part II: Experimental study and comparison. IEEE Transactions on Antennas and Propagation, May 2003. Vol.51, N5, P.1048-1053), containing emitter lattice and additional lattice, emitters are located in the nodes of the main flat two-dimensional grid and made in the form of multisection joints of waveguide segments that are filled with dielectrics, waveguide segments have axes parallel to each other and perpendicular to oskosti lattice grid is made of additional passive scatterers which are located at the nodes of emitters is more flat two-dimensional grid, which is parallel to the principal plane of two-dimensional grid.

The disadvantages of such an AP include a narrow scanning sector, which is due to the fact that the additional grating in the known technical solution effectively matches the emitter grating for small GL deviation angles, that is, where it can be effectively matched by choosing the parameters of the waveguide joints, and for large at deflection angles, the additional lattice weakly interacts with the waves and cannot be used to match the emitter lattice. In addition, the parameters of the multi-section joints of the waveguide segments in the known technical solution are chosen non-optimal way, which additionally leads to a narrowing of the scanning sector of the waveguide AP.

The proposed technical solution is aimed at obtaining a technical result, expressed in the expansion of the scanning sector of the waveguide AP. The technical result obtained is expressed in increasing the speed and reducing the cost of the surveillance headlamp, which includes a waveguide AR. Cost reduction is achieved by reducing the number of waveguide APs in the survey headlamp required to review a given angle sector. Improving performance is achieved by eliminating mechanical scanning and the transition to electronic scanning.

The proposed waveguide AP, containing a radiator array and an additional array, emitters are located in the nodes of the main flat two-dimensional grid and are made in the form of multisection joints of waveguide segments that are filled with dielectrics, waveguide segments have axes parallel to each other and perpendicular to the plane of the array, the additional array is made of passive scatterers that are located outside the emitters in the nodes of the additional two-dimensional flat grid, which is parallel to the main two-dimensional plane with Net, solves the problem of expanding the scanning sector.

These problems are solved due to the fact that passive scatterers are made in the form of electric and magnetic dipoles, whose axes are perpendicular to the plane of the lattice.

Additional embodiments of the waveguide AP are possible. In an additional embodiment, which provides better matching mainly in the plane of the electric field vector, electric dipoles are made in the form of metal conductors whose axes are perpendicular to the plane of the lattice, and magnetic dipoles are made in the form of metal rings whose planes are parallel to the plane of the lattice.

In an additional option, which provides improved matching when scanning vectors of electric and magnetic fields in planes, electric dipoles are made in the form of metal conductors whose axes are perpendicular to the plane of the lattice, and magnetic dipoles are made in the form of resonators with split rings, the plane of which is parallel to the plane of the lattice.

In an additional embodiment, which ensures the simplicity of the waveguide AP design, electric and magnetic dipoles are made in the form of metal spirals whose axes are perpendicular to the plane of the grating.

In an additional version providing improved matching of the waveguide AP at small GL deviation angles, the main planar two-dimensional grid is square with a period P, and the multi-sectional joint of the waveguide segments is made two-section with the radiating waveguide segment and the input waveguide segment, the radiating waveguide segment is made with a square cross section and the input segment of the waveguide is made with a rectangular cross section, the radiating and input segments of the waveguides are filled with dielectrics with the same ratio dielectric constant ε, and the radiating segment of the waveguide of length L and width a _{1 is} made in accordance with the condition:

$$\frac{0.3{\mathrm{<figure-callout\; id="0"\; label="\lambda "\; filenames="00000031.png,00000032.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_0}{\sqrt{\epsilon -{\left(\frac{{\mathrm{<figure-callout\; id="0"\; label="\lambda "\; filenames="00000031.png,00000032.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_0}{2a_{\mathrm{one}}}\right)}^2}}\le L\le \frac{0.37{\mathrm{<figure-callout\; id="0"\; label="\lambda "\; filenames="00000031.png,00000032.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_0}{\sqrt{\epsilon -{\left(\frac{{\mathrm{<figure-callout\; id="0"\; label="\lambda "\; filenames="00000031.png,00000032.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_0}{2a_{\mathrm{one}}}\right)}^2}},\left(3\right)$$

where λ ₀ is the wavelength in free space at the central frequency of the working range of the waveguide AP, the internal dimensions of the cross section of the input section of the waveguide a ₂ and b ₂ are selected in accordance with the conditions:

$$a_2=a_{\mathrm{one}}\mathrm{,\; 0.48}\le \frac{b_2}{a_{\mathrm{one}}}\le \mathrm{0.58.}\left(\mathrm{four}\right)$$

Figure 1 presents one of the possible embodiments of the waveguide AP in the form of three projections of its period. The waveguide period AP contains a radiator (1), several periods of an additional grating (2). The emitter (G) is made in the form of a multi-section joint of segments of waveguides. Figure 1 shows the emitter (1), made in the form of a three-section joint of the segments of the waveguides. A segment of the waveguide (3), located opposite the additional grating (2), radiates energy into free space and therefore is a radiating segment of the waveguide, and a segment of the waveguide (4) located at the opposite end of the emitter (1) is the input segment of the waveguide. The additional lattice (2) consists of electric dipoles (5) and magnetic dipoles (6). The multisectional joint of the waveguide segments has an input plane (7) and a radiating plane (8), which are adjacent to the input waveguide segment (4) and the radiating waveguide segment (3), respectively.

Figure 2 shows the array of emitters (1), which are located in the nodes of the main flat two-dimensional grid (9), which in figure 2 is a rectangular grid. In the general case, it can have different periods along the axes 0x and 0y: P _1x and P _1y (see Fig. 1). If the periods are equal to each other, then such a rectangular grid degenerates into a square. The axes of all segments of the waveguides in one emitter (1) are parallel to each other. Also, the axes of the indicated segments of the waveguides in the emitters located in different periods are parallel to each other and perpendicular to the plane of the emitter lattice, which in Fig. 2 is parallel to the XOY plane, as well as the input plane (7) and the emitting plane (8).

Figure 3 shows an additional lattice, which consists of electric dipoles (5) and magnetic dipoles (6), which are located in the nodes of the additional flat grid (10). An additional planar grid (10) parallel to the main planar grid, in FIG. 3, the additional planar grid is a rectangular grid with periods P _2x and P _2y (see FIG. 1). Electric dipoles (5) and magnetic dipoles (6) can be at different distances h _{e, m} from the radiating plane (8).

Consider the operation of a waveguide AP. Due to the fact that the waveguide AP is a mutual device, it can be considered both in the transmitting and in the receiving modes. Consider the operation of the waveguide AP transmission (see figure 4). Let the exciting emitters (1) of the wave run along the input plane (7) along the waveguide channels of the emitters (1). They can be formed by special elements of the PAR, which includes a waveguide AP. For example, it can be a multi-channel power divider and a system of phase shifters that allow you to arbitrarily set the phase distribution of the waves in the output channels of the power divider.

The most common mode of operation of the phased array is the quasiperiodic excitation mode, when the waves in adjacent channels have the same amplitudes, and the phases of the waves depend linearly on the channel numbers. Let the number n describe the position of the channel along the axis 0x, and the number m - along the axis 0y. Then the complex wave amplitude U _{n, m} in the channel with numbers n and m is written as follows:

$$U_{n,m}=V{e}^{-in\Delta {\varphi }_x-im\Delta {\varphi }_y},\left(5\right)$$

where V is the wave amplitude in the channel with zero numbers, Δφ _x is the phase shift along the 0x axis, Δφ _y is the phase shift along the 0y axis. Let the channel with zero numbers be located at the origin.

We will consider the most interesting from a practical point of view waveguide AP with a large coefficient of directional action (KND). Such gratings have large electrical dimensions both along the 0x axis and along the 0y axis. The large electrical dimensions of the AP make it possible to neglect the edge effects arising at its boundaries and analyze it as an infinite AP (see Amitei I., Galindo V., By Ch. Theory and analysis of phased antenna arrays. M .: Mir, 1974). In this case, the waveguide AP emits a field in the form of plane waves into free space. The number of such waves depends on the periods of the emitter lattice (1): P1 _{x, y} and the wavelength in free space λ at the operating frequency f. Typically, the periods are selected so that in the operating frequency range and in the scanning sector there is one emitted wave. In this case, the waveguide AP has one main maximum of the pattern. A plane wave can be described by radiation angles θ, φ, which depend on phase shifts

$$\theta =\arcsin \frac{\sqrt{{\left(\frac{\Delta {\varphi }_x}{P_{\mathrm{one}x}}\right)}^2+{\left(\frac{\Delta {\varphi }_y}{P_{\mathrm{one}y}}\right)}^2}}{k},\left(6\right)$$

, $$\varphi =arctg\frac{\Delta {\varphi }_y}{\Delta {\varphi }_x}$$

,

. $$k=\frac{2\pi }{\lambda }$$

.

The angles θ, φ are introduced in a spherical coordinate system in a standard way: the elevation angle θ is measured from the axis 0z, and the azimuthal angle φ is measured from the axis 0x (see Fig. 4). We note that the angles θ and φ determine the position of the GL of the DN. The scanning sector is usually understood as the maximum value of the elevation angle θ _m :

$$\theta <{\theta }_m.\left(7\right)$$

The condition for the absence of incident side maxima of the pattern during scanning, for example, in the XOZ plane, is expressed by the well-known inequality:

$$P_{\mathrm{one}x}\le \frac{\lambda }{\mathrm{one}+\sin \theta }.\left(8\right)$$

A similar ratio can be recorded for scanning in the YOZ plane.

The model of an infinite waveguide AP allows you to analyze the process of radiation into free space using the equivalent circuit shown in figure 5. Such a possibility follows from the theory of infinite APs (Amitei N., Galindo V., By Ch. Theory and analysis of phased antenna arrays. M: Mir, 1974).

The source of the waveguide waves exciting the emitter (1) in Fig. 5 is modeled by a voltage source E _g with an internal resistance Z _w1 , where Z _w1 is the characteristic resistance of the input section of the waveguide (4), one end of which is located on the input plane (7) (see Fig. 1). In the general case, the multi-section joint of waveguide segments contains N sections, which are described by characteristic resistances Z _wq , propagation constants γ _wq and lengths L _wq , q = 1 ... N.

Each joint of the waveguide segments in the equivalent circuit in FIG. 5 is represented as a four-terminal network with a scattering matrix S _wq , q = 1 ... N-1. A quadripole with a scattering matrix S _ws describes the articulation of the waveguide section in contact with the radiation plane (8) with free space. Together, these multipolar and waveguide segments are a model of the array of emitters (1).

The lengths of waveguides of length h _m and h _e -h _m with characteristic impedance Z _S and propagation constant γ _S model the parts of the space between the radiation plane (8) and magnetic dipoles (6), as well as between magnetic dipoles (6) and electric dipoles (5 ) Quadrupoles with scattering matrices S _e and S _m describe the passage of waves through electric dipoles (5) and magnetic dipoles (6), respectively. Together, the four-terminal circuits and the length of the waveguide length h _e -h _m represent an additional lattice model (2).

An important fact for understanding the functioning of the waveguide AP is that the joint parameters of the segments of the waveguides Z _wq , γ _wq and S _wq are independent of the angle θ, while the parameters of the joint with the free space S _ws depend on the angle θ. For this reason, in the absence of an additional grating (2), it is possible to match the generator E _g with the load by choosing the parameters of the waveguide segments for only one selected angle θ, since for another angle the scattering matrix S _ws will be different and the load will be mismatched with the generator. As a rule, the parameters of the waveguide segments are selected based on the matching condition for a zero or sufficiently small angle θ.

Matching at large angles of deviation of the GL of the DN is a difficult task, since the reflection coefficient from the joint of the waveguide segment with free space increases sharply with increasing angle θ. This is especially true for angles close to the critical angle at which the incident maximum of the DN appears (see inequality (8)). In this range of angles, the reflection coefficient modulus can approach unity and it is practically impossible to match the generator with the load.

The matching function at large angles of deviation of the main beam is performed by an additional lattice (2). Consider its operation separately. Electric dipoles (5) and magnetic dipoles (6), regardless of their design, can be described from the electrodynamic point of view using equivalent electric magnetic currents j ^{e, m} :

$$\begin{array}{l}{j}^e=p_{e}E,\left(9\right)\\ j^m=p_{m}H,\end{array}$$

where the currents j ^{e, m are} directed along the axes of the dipoles, p _{e, m} are the dipole moments,

E, H are the components of the electric and magnetic fields directed along the axes of the dipoles.

From relation (9) it follows that currents in dipoles and, therefore, the field scattered by them appear only if the field incident on the dipoles has longitudinal components directed along their axes. Consider the structure of the field emitted by the array of emitters (1) in the particular case of a two-section joint of the radiating segment of the waveguide (3) and the input segment of the waveguide (4) (see figure 1). Let a wave polarized in the XOZ plane propagate in the radiating segment of the waveguide (3). She has a single component of the electric field E _x . Let scanning also take place in the XOZ plane, that is, in the plane of the electric field vector E. In free space, the field has the nature of a plane wave, which propagates in the XOZ plane at an angle θ to the 0z axis. Such a wave has three field components: E _x , H _y , E _z . The appearance of the longitudinal component of the electric field E _{z is} illustrated in Fig.6.

Thus, we can conclude that when scanning in the plane of the vector E, the field in free space does not have a longitudinal component of the magnetic field, but has only a longitudinal component of the electric field proportional to sinθ. It follows that this field, by virtue of relations (9), does not excite magnetic dipoles (6), but interacts only with electric dipoles (5). Therefore, only electric dipoles (5) are shown in FIG.

Electric dipoles (5) are located at the nodes of an additional flat grid (10) having periods P _{2x, у} . It is advisable to choose these periods from the inequality:

$$P_{2x,y}\le P_{\mathrm{one}x,y}.\left(10\right)$$

Inequality (10) ensures that the additional grating (2) does not have its own diffraction maxima in the scanning sector of the waveguide AP. When relation (10) is fulfilled, a fall on an additional plane grid (10) of a plane wave leads to the appearance of a reflected wave with a reflection coefficient R and a transmitted wave, which is described by the transmission coefficient T.

Figure 7 shows the calculated dependence of the modulus of the reflection coefficient on the additional lattice (2), consisting of electric dipoles (5). Curves 11-14 correspond to the following parameter values α = 0.1, 0.5, 1, 1.5. The dimensionless parameter α is equal to the product of the dipole moment p _e and the wave resistance of the free space W ₀ . From Fig. 7 it is clearly seen that at small angles θ the reflection coefficient is small, and at θ = θ it is generally zero. With increasing angle θ, it also grows. Therefore, the presence of an additional grating (2) near the emitter grating (1) does not violate its matching at relatively small angles θ, that is, where it is already matched by choosing the parameters of multi-section joints of waveguide segments. At large angles θ, waves of large amplitude reflected from the additional grating (2) appear, which return to the emitter grating (1) and can be used to match it. For this, it is necessary to choose the distance from the radiation plane (8) to electric dipoles (5) h _e so that the wave reflected from the additional grating (2) comes to the radiation plane (8) in antiphase with the wave reflected from the radiation plane (8) inside the emitter (1). In this case, these waves will compensate each other and, thus, improve the matching of the emitter (1).

A similar analysis can be performed by scanning a wave of the same polarization, but already in the plane of YOZ, that is, in the plane of the magnetic field vector H. In this case, the wave in free space has the following components: E _x , H _y , H _z . Thus, when scanning in this plane, electric dipoles (5) are not already excited, and magnetic dipoles (6) are used for matching. In this case, curves similar to those shown in Fig. 7 are obtained for the reflection coefficient. The phase of the reflection coefficient from the additional grating (2) in the plane of the magnetic field vector H may differ from the phase of the reflection coefficient in the plane of the electric field vector E. Therefore, to compensate for the wave reflected from the radiation plane (8) into the emitter (1), the distance from the radiation plane (8) to magnetic dipoles (6) h _m may differ from the distance h _e .

When scanning in the intermediate plane, electric dipoles (5) and magnetic dipoles (6) are simultaneously excited. In this case, the wave reflected from the additional lattice (2) is the sum of the waves reflected from electric dipoles (5) and magnetic dipoles (6).

Thus, we have shown that with the help of an additional grating (2), an improvement in the matching of the waveguide AP is achieved at large angles of deviation of the GL of the beam and, therefore, an expansion of the scanning sector of the waveguide AR is achieved.

In a first additional embodiment of the waveguide AP, electric dipoles are made in the form of metal conductors whose axes are perpendicular to the plane of the lattice, and magnetic dipoles are made in the form of metal rings whose planes are parallel to the plane of the lattice. Real electric currents flowing along its axis flow along the electric dipole (5), made in the form of a metal conductor. In a magnetic dipole (6), made in the form of a metal ring, the real magnetic current does not flow. However, the field that creates the metal ring can be described by virtual magnetic current (see Markov G.T., Chaplin A.F. Excitation of electromagnetic waves. M.: Energy, 1967). This magnetic current is perpendicular to the plane of the metal ring. Therefore, the magnetic dipole (6), equivalent to a metal ring, is also oriented perpendicular to the plane of the ring. Therefore, by arranging metal conductors perpendicular to the plane of the lattice, and metal rings parallel to it, we create electric dipoles (5) and magnetic dipoles (6) with axes directed perpendicular to the plane of the lattice in accordance with the main embodiment of the invention.

The dipole moments p _{e, m} depend on the design of the dipole and on the frequency. Note that many dipole designs exhibit resonant properties. In the vicinity of the resonance frequency, the dipole moment increases sharply. This phenomenon can be effectively used to increase the intensity of field interaction with an additional lattice (2). According to the first additional embodiment, electric dipoles in the waveguide grating have resonant properties (5). Resonance in them occurs when the length of the electric dipole l _e approaches half the wavelength in free space. Magnetic dipoles (6) do not have resonance properties. Therefore, the waveguide AP, made in accordance with the first additional option, has limited capabilities. The dipole moment of a metal ring may be sufficient for effective matching of the emitter lattice (1) when its diameter is comparable to the wavelength in free space. The implementation of such rings may conflict with the restrictions on the periods of the additional lattice (2), which were formulated above.

The indicated limitations on the capabilities of the waveguide AP are overcome in the second additional embodiment, in which the electric dipoles are made in the form of metal conductors, the axes of which are perpendicular to the plane of the grating, and the magnetic dipoles are made in the form of resonators with split rings, the plane of which is parallel to the plane of the grating. A fragment of a waveguide AP made in a second further embodiment is shown in FIG.

In this additional embodiment, the magnetic dipoles (6) are in the form of split ring resonators (15) (see Gay-Balmaz P., Martin O. "Electromagnetic resonances in individual and coupled split-ring resonators", Journal of Applied Physics. 2002 92 (5): 2929). The use of two closely spaced open metal rings allows you to create a structure similar to a parallel resonant circuit. Its inductance is determined by the length of the rings, and the capacitance by the distance between them. By changing these parameters, it is possible to tune the resonator (15) to the operating frequency of the waveguide AP. It is important in this case that the diameter of the resonator (15) with split rings at the resonance frequency is much smaller than the diameter of the metal ring with the same dipole moment. Due to this, the implementation of the magnetic dipole (6) with dimensions smaller than the period of the additional flat grid (10) does not cause difficulties.

A fragment of the waveguide AP (additional grating (2)), made in accordance with the fourth additional option, shown in Fig.9. In it, electric and magnetic dipoles are made in the form of metal spirals (16), the axes of which are perpendicular to the plane of the lattice. This embodiment of the waveguide AP has a simpler design, since in it the function of the electric dipole (5) and magnetic dipole (6) is performed by one element - a metal spiral (16).

This combination of functions is possible due to the fact that both circular and longitudinal (directed along its axis) electric currents flow in the spiral. The appearance of longitudinal currents is equivalent to the appearance of an electric dipole moment in a metal spiral (16), the appearance of ring currents to the appearance of a magnetic dipole moment. The advantages of this embodiment of a waveguide AP can also be attributed to the fact that the spiral is a very compact scatterer that exhibits resonant properties when its overall dimensions are significantly less than the wavelength in free space. This is due to the fact that despite the relatively short spiral length (16) h, the length of the conductor l that forms it turns out to be significantly larger:

$$l=\frac{\pi d}{p}h,\left(10\right)$$

where p is the spiral pitch (16), and d is its diameter. Since the parameter πd / p can be made very large, it follows from relation (10) that the length of the conductor l is much larger than the overall size h of the spiral (16).

The dipole moments of the spiral (16) are proportional to the length of the conductor l. It is also important to note that the spiral (16) is a resonant element. Resonance is observed when the conductor length l is close to half the wavelength in free space. Thus, it is seen that, due to the properties of the spiral (16) noted above, at the resonance frequency, its dimensions will be much smaller than the wavelength. Therefore, the spirals (16) are easily placed at the nodes of the additional flat grid (10) and at the same time have dipole moments of sufficient magnitude.

A fourth additional embodiment of the waveguide AP also provides ease of setup. The spiral (16) automatically ensures the equality of the resonance frequencies of the electric and magnetic dipole moments, since it simultaneously resonates the ring and longitudinal currents. Thus, the separate setting of electric dipoles (5) and magnetic dipoles (6) in this embodiment is excluded and replaced by the setting of one element - a spiral (16).

A waveguide AR made in accordance with a fifth additional embodiment is shown in FIG. 10. In it, the main planar two-dimensional grid is made square with a period P, and the multi-section joint of the waveguide segments is made two-section with the radiating waveguide segment and the input waveguide segment, the radiating waveguide segment is made with a square cross section, and the input waveguide segment is made with a rectangular section, radiating and input dielectric filled waveguide segments with the same relative permittivity ε, wherein the radiating waveguide segment length L and a width ₁ performs n in accordance with the conditions:

where λ ₀ is the wavelength in free space at the central frequency of the working range of the waveguide AP, the internal dimensions of the cross section of the input section of the waveguide a 2 and b2 are selected in accordance with the conditions:

This embodiment of the waveguide AP provides improved lattice matching at relatively small GL deviation angles. Improving matching is achieved by choosing the parameters of the emitter (1). At small angles of deviation of the main beam, the influence of the additional grating (2) on the functioning of the waveguide AP is insignificant, and therefore the equivalent circuit in Fig. 5 is converted to a simpler form, taking into account the presence of two segments of waveguides in the emitter (1). A simplified equivalent circuit is shown in FIG. 11.

A segment of the transmission line of length L corresponds to the radiating segment of the waveguide (3), which is characterized by the resistance Z _w2 and the propagation constant γ _w2 . The input segment of the waveguide (4) has a resistance Z _w1 and a propagation constant γ _w1 .

11 shows that the equivalent circuit describes a transmission line with a characteristic resistance Z _w1 , which includes two heterogeneities. One of them corresponds to the joint of the input segment of the waveguide (4) and the radiating segment of the waveguide (3). It is described by a four-terminal network with a scattering matrix S _w1 . Another heterogeneity is the final load in the form of a joint of the radiating segment of the waveguide (3) with free space. It is represented by a four-terminal network with a scattering matrix S _w2 , in which one input is loaded with a resistance Z _S , depending on the angle θ. We are interested in the region of small angles in which we can set θ = 0.

The scheme shown in Fig. 11 will be agreed on the generator side E _g if the reflection coefficients from the inhomogeneities are close in modulus and their phases at the generator connection point are shifted by π. The indicated reflection coefficients can be reliably calculated using modern AR electrodynamic modeling programs. Relations (11) - (13) ensuring the fulfillment of the above matching conditions for the waveguide AP are found as a result of its optimization. Inequality (11) ensures that the phase relations necessary for matching are satisfied, and relations (12) and (13) ensure the proximity of the moduli of reflection coefficients of two inhomogeneities. Inequality (12) determines the optimal ratio of the parameters of the joint of the radiating segment of the waveguide (3) with free space, and relations (13) specify the range of optimal values of the joint of the input segment of the waveguide (4) with the radiating segment of the waveguide (3).

The implementation of the main flat two-dimensional grid (9) square is necessary to achieve the maximum scanning sector in the entire half-space for z> 0 (see Fig. 4) without reducing the size of the emitter (1) in the XOY plane. It follows from inequality (8) that the scanning sector can be increased by reducing the AP period. However, reducing the period is extremely undesirable for design reasons, since it complicates the placement of other PAR elements within its period: phase shifters, amplifiers, etc. Therefore, it is undesirable to increase the period in one plane compared to the period in another plane, since this will lead to a decrease in the resulting scanning sector, and it also makes no sense to reduce it, since the resulting scanning sector will not increase, since it is determined by the smallest of the scanning sectors in the planes XOZ and YOZ.

On Fig presents the dependence of the modulus of the reflection coefficient R (θ) of the waveguide AR, made in accordance with the fifth additional option, when scanning in the plane of the vector of the electric field, and Fig.13 is the dependence of the module of the reflection coefficient when scanning in the plane of the vector of the magnetic field. Curves are obtained for the following AP parameters:

- period of the main planar grid (9) P = 15.5;

- the width of the radiating segment of the waveguide (3) a ₁ = 13.5;

- the length of the radiating segment of the waveguide (3) L = 9.8;

- the width of the input segment of the waveguide (4) a ₂ = a 1;

- the height of the input segment of the waveguide (4) b ₂ = 7.2;

- dielectric constant of the emitter filling (1) ε = 2.08 (fluoroplastic);

- the distance from the plane (8) of the radiation to the electric dipoles (5) h _e = 12;

- the distance from the radiation plane (8) to the magnetic dipoles (6) h _m = 10.1;

- the period of the additional flat grid (10) made square P _d = 12;

- magnetic dipoles (6) are made in the form of metal rings with an outer diameter of D = 10.

All dimensions are in millimeters.

From the graphs presented in FIG. 12 and FIG. 13, it can be seen that the waveguide AP is well matched up to the deviation angles of the main beam in the range 50 ° -60 °.

Thus, the above information indicates the fulfillment of the following set of conditions when using the claimed invention:

- an antenna device embodying the claimed invention is intended for use in industry, namely in the technique of antennas, for example, as an element of a receiving or transmitting HEADLIGHT radar;

- for the claimed device in the form described in the independent clause of the claims, the possibility of its implementation using the means described in the application is confirmed;

- an antenna device embodying the claimed invention allows to realize the following technical result: to expand the scanning sector of electronically controlled headlamps.

Claims (5)

1. A waveguide antenna array containing an array of emitters and an additional array, emitters are located in the nodes of the main flat two-dimensional grid and are made in the form of multisection joints of segments of waveguides that are filled with dielectrics, segments of waveguides have axes parallel to each other and perpendicular to the plane of the array, additional array is made of passive diffusers that are located outside the emitters in the nodes of the additional flat two-dimensional grid, which is parallel to the main flat two-dimensional th grid, characterized in that the passive scatterers are made in the form of electric and magnetic dipoles, the axes of which are perpendicular to the plane of the lattice. 2. The waveguide antenna array according to claim 1, characterized in that the electric dipoles are made in the form of metal conductors, the axes of which are perpendicular to the plane of the array, and the magnetic dipoles are made in the form of metal rings whose planes are parallel to the plane of the array. 3. The waveguide antenna array according to claim 1, characterized in that the electric dipoles are made in the form of metal conductors, the axes of which are perpendicular to the plane of the array, and the magnetic dipoles are made in the form of resonators with split rings, the plane of which is parallel to the plane of the array. 4. The waveguide antenna array according to claim 1, characterized in that the electric and magnetic dipoles are made in the form of metal spirals, the axes of which are perpendicular to the plane of the array. 5. The waveguide antenna array according to claim 1, characterized in that the main planar two-dimensional grid is square with a period P, and the multi-sectional articulation of the waveguide segments is made two-sectional with the radiating segment of the waveguide and with the input segment of the waveguide, the radiating segment of the waveguide is made with a square cross section, and the input segment of the waveguide is made with a rectangular cross section, the radiating and input segments of the waveguides are filled with dielectrics with the same relative permittivity ε, and the learning segment of the waveguide of length L and width a _{1 is} made in accordance with the condition:

,

,
where λ ₀ is the wavelength in free space at the central frequency of the working range of the waveguide AP, the internal dimensions of the cross section of the input section of the waveguide a ₂ and b ₂ are selected in accordance with the conditions:
a ₂ = a ₁ ,

.

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