RU2738332C1 - Linear vertical array of vertical polarization with circular azimuth pattern and built-in antenna channel of glonass/gps standard - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to superhigh-frequency equipment, specifically to transceiving antennae with circular pattern in azimuth plane, intended for radiation/reception of vertical polarization waves, and can be used in active radar systems with active response, in particular automatic dependent surveillance-broadcasting stations (ADS-B) and multi-position surveillance systems (MPSS), equipped for the purpose of synchronization and determining own location of GLONASS/GPS navigation equipment. Disclosed technical result is achieved due to that vertical polar array of vertical polarization with circular azimuth pattern includes vertical support in form of hollow metal cylinder with metal screen in upper end part, distribution system, which is an N-channel power divider (N is an integer), outputs of which are connected to inputs of N identical power dividers in halves, and N identical emitters arranged along support axial line, each of which consists of two conformal slot radiators unfolded by 180° relative to each other in horizontal plane, and in-phase excited by power divider in two, wherein the distribution system and the radiators are made on the basis of the conformal symmetrical stripline line in the form of a multilayer structure consisting of five odd current conducting layers and four even dielectric layers, which are concentrically conjugated with the outer surface of the support, forming a topology of strip conductors and screens of the N-channel power divider, power dividers in half and conformal radiators and releasing the upper and inner parts of the support for embedding the GLONASS/GPS antenna channel, and connection of outputs of N-channel power divider with corresponding inputs of dividers in halves is made in form of N current conducting jumpers and N current-conducting U-shaped screens, passing through all layers of structure and forming together sections of symmetrical strip line.

EFFECT: high operating frequency range while maintaining high gain, possibility of expanding the working sector in the elevation plane when forming a beam pattern of a special shape, in particular coaxial, as well as having an internal GLONASS/GPS antenna channel.

3 cl, 5 dwg

Description

The invention relates to microwave technology, namely to transmitting and receiving antennas with a circular radiation pattern in the azimuthal plane, designed to emit / receive waves of vertical polarization, and can be used in active radar systems with an active response, in particular, automatic dependent surveillance-broadcasting stations (ADS-V) and multi-position surveillance systems (MPSN), equipped with navigation equipment of the GLONASS / GPS standard for synchronization and determination of their own location.

Known linear antenna arrays with omnidirectional and weakly directional azimuthal radiation pattern (BP) with axial polarization (see MV Indenbom Antenna arrays of mobile surveillance radars. Theory, calculation, designs. M., "Radiotekhnika", 2015, S. 307- 315), which consist of a distribution system and plate radiators located on a single printed circuit board. The unevenness of the non-directional azimuthal pattern provided by this design does not exceed 1.3 dB. The disadvantage of this arrangement is the increase in the transverse (horizontal) size of the antenna, as well as the complexity of the implementation of the plate radiator and the need to adjust it to achieve the specified irregularity of the azimuthal pattern.

The closest analogue identified by the authors as a prototype of the claimed device is an omnidirectional antenna system with a special directional pattern (patent No. 2639563 C1 (RU), publ. 12.21.2017, bul. No. 36), which consists of a vertical support in the form of a hollow metal columns with transverse dimensions 0.18 ... 0.25λ, (where λ is the wavelength) with two reflectors installed on it, continuous along the entire length of the hollow metal column, a distribution system placed inside the column and representing an N-channel power divider (N - an integer), the outputs of which are connected to the inputs of N identical power dividers in half, and N identical emitters installed along the column at a distance of about λ / 2, each of which is based on two conformal strip emitters connected through matchers with the outputs of the power divider in half, in this case, conformal strip emitters have rectangular cutouts on the side faces and are placed on the opposite on the positive sides of the column, repeating the shape of its cross-section. This design makes it possible to form a special shape pattern in the vertical plane, in particular cosecant pattern, with pattern irregularity in the horizontal plane of no more than 0.3 dB in the absence of tuning. To increase the level of the cosecant BP in the region of angles close to the axis of the metal column, an additional emitter of circular polarization is installed in the upper part of the antenna system, and the number of channels of the N-channel power divider is increased to N + 1.

However, the disadvantage of this invention is the problematicness of increasing the operating frequency range without reducing the gain of the antenna system, which is associated with the need to equalize the channel lengths of the N-channel divider with an accuracy of ± λ / 2, which makes it possible to implement the phase distribution required to form a given elevation pattern in the entire operating range frequencies. In this case, it is assumed that the lengths of most of the channels will increase, which, at N> 10, will lead to a significant increase in the transverse size of the divider, and its placement inside a vertical support, the maximum transverse size of which is limited by λ / 4, will be impossible. The solution to this problem requires a miniaturization of the topology of the N-channel power divider with a corresponding deterioration in the efficiency of the distribution system, and therefore in the antenna gain.

In addition, with this arrangement, the possibility of expanding the working sector of the antenna pattern in the elevation plane without the appearance of diffraction lobes is limited, since the location of the radiating elements along the support of the antenna system with a pitch of less than λ / 2 is difficult, which is determined by the vertical size of the conformal strip radiator. Therefore, in the upper part of the antenna system, in order to increase the level of the cosecant pattern at elevation angles close to the vertical axis of the support, it is required to install an additional emitter of circular polarization, which leads to the complication of the N-channel power divider due to the need to increase the number of its channels to N + 1 and the problematic nature of embedding the GLONASS / GPS standard into the antenna channel design. It should also be noted that a decrease in the vertical size of a conformal strip emitter, achieved by increasing its electrical length using rectangular cutouts on its lateral faces, leads to an increase in the level of the cross-polarization component of the MD.

The aim of the invention is to increase the operating frequency range while maintaining a high gain, expand the working sector in the elevation plane when forming a special shape pattern, in particular cosecant, and create a construct that provides for embedding a GLONASS / GPS antenna channel.

This goal is achieved due to the fact that the linear antenna array of vertical polarization with a circular azimuth directional pattern, includes a vertical support in the form of a hollow metal cylinder with a metal screen in the upper end part, a distribution system, which is an N-channel power divider (N is an integer ), the outputs of which are connected to the inputs of N identical power dividers in half, and N identical emitters located along the centerline of the support, each of which consists of two conformal slot emitters rotated 180 ° relative to each other in the horizontal plane, and in-phase excited by the power divider in half, while the distribution system and emitters are made on the basis of a conformal symmetric strip line in the form of a multilayer structure consisting of five odd conductive layers and four even dielectric layers, which are concentrically conjugated with the outer surface of the support, forming a topology yu strip conductors and screens of N-channel power divider, power dividers in half and conformal emitters, and freeing the upper and inner parts of the support for embedding the antenna channel of the GLONASS / GPS standard, and the connection of the outputs of the N-channel power divider with the corresponding inputs of the dividers in half is made in the form N conductive jumpers and N conductive U-shaped screens passing through all layers of the structure, and jointly forming segments of a symmetrical strip line.

The essence of the invention is illustrated using graphic material, where:

- in Fig. 1 shows a block diagram of a linear antenna array;

- in Fig. 2a shows a general view of a linear antenna array;

- in Fig. 2b shows an exploded view of a linear antenna array structure;

- in Fig. 3 shows the design of a conformal slot radiator driven by a symmetrical strip line;

- in Fig. 4 shows the azimuthal directional diagram of a linear antenna array;

- in Fig. 5 shows the elevation diagram of the linear antenna array.

FIG. 1 shows a block diagram of a linear antenna array consisting of a distribution system (1) including an N-channel power divider (2), the outputs of which are connected to the inputs of N identical power dividers in half (3) and N identical radiators (4), each of which contains two conformal slot emitters (5), excited by a divider in half (3). The outputs of the N-channel divider (2), the dividers in half (3) and the radiators (4) are installed with a pitch S along the vertical support (6), which is also used to accommodate the built-in antenna channel (7), consisting of an external active antenna for receiving signals GLONASS / GPS standard (8) and radio frequency cable (9). Items (10) and (11) in FIG. 1, respectively, the input of the distribution system (1) of the linear antenna array and the input of the antenna channel (7) are indicated.

A general view of the linear antenna array as well as an exploded view of the structure are shown in FIG. 2a and FIG. 2b, where the following reference designations are introduced: 1 - distribution system, 2-N-channel power divider, 3 - power divider in half, 4 - radiator, 5 - conformal slot radiator, 6 - vertical support, 7 - built-in antenna channel, 8 - external active antenna for receiving signals of the GLONASS / GPS standard, 9 - radio frequency cable, 10 - input of the linear antenna array, 11 - input of the antenna channel of GLONASS / GPS standard, 12 - U-shaped screen, 13 - support flange, 14 - upper screen, 15 - ring power divider, 16 - ballast resistor, 17 - jumper, 18 - radio-transparent fairing, 19, 21, 23, 25, 27 - odd conductive layers, 20, 22, 24, 26 - even dielectric layers, A - type of reference flange with inputs (10) and (11), B - view of a fragment of the topology of the N-channel divider (2), C - view of the topology of the divider in half (3), D - type of connection of the output of the N-channel power divider with the corresponding input of the divider in half ( shown in section, positions 18, 20, 22, 24, 26, 27 are hidden).

The design of a linear antenna array, consisting of N identical radiators (4), powered by a distribution system (1), is based on a multilayer structure including five odd conductive (19, 21, 23, 25, 27) layers and four even dielectric layers ( 20, 22, 24, 26), which are concentrically mated with a vertical support (6) fixed on a circular support flange (13) and representing a hollow metal cylinder with a metal screen (14) in the upper end part. The distribution system (1) consists of an N-channel power divider (2), the outputs of which are connected to the inputs of N identical power dividers in half (3). In this case, the N-channel divider (2) and dividers in half (3) are implemented on the basis of a conformal symmetric strip line with screens, conductors and dielectric filling in the form of layers (19-27), each of which repeats the shape of the vertical support (6), and has the following purpose:

-layer (19): the outer cylindrical surface of the support (6), which is also the inner screen of the divider (2);

- layer (21): central board with divider topology (2);

- layer (23): a common screen, which is both external for the divider (2) and internal for the dividers (3);

- layer (25): central board with divider topology (3);

- layer (27): outer shield of dividers (3);

- layer (20): dielectric filling between the inner shield (19) and the central plate (21);

- layer (22): dielectric filling between the central plate (21) and the common shield (23);

- layer (24): dielectric filling between the common shield (23) and the central plate (25);

- layer (26): dielectric filling between the center plate (25) and the outer shield (27).

The topology of the central board (21) is a multichannel division scheme based on N-1 ring power dividers (15) with ballast resistors (16), and N stripline unconnected tees form the topology of the central board (25). The connection of the outputs of the divider (2) with the inputs of the dividers (3), located, respectively, on the central boards (21) and (23), is carried out using interlayer junctions in the form of a symmetrical strip line (see view D), limited by a U-shaped screen (12), and jumpers (17). In this case, the U-shaped screen (12) is located between the layers (19) and (27), passing through the layers (20-26), in which the corresponding grooves are provided.

The topology of the slot emitters (5) is organized in the layer (27), which is simultaneously the outer shield of the dividers (3).

Conductive layers (19, 21, 23, 25, 27) are made on the basis of foil-clad lavsan brand LFR-1-35-0.15, TU 2296-009-11436290-98, and dielectric layers (20, 22, 24, 26) - based on polyethylene foam PPE-R (M), TU 2244-001-07521647-96.

The vertical support (6) is additionally used to install the antenna channel (7), consisting of an external active antenna for receiving signals of the GLONASS / GPS standard (8), installed in the upper end of the support on the screen (14), and a radio frequency cable (9), which runs through the inside of the support, connecting the inlet (11) to the antenna inlet (8).

The input (10) of the linear antenna array and the input (11) of the built-in antenna channel (7) are made in the form of coaxial sockets located on the support flange (13) according to A.

To protect against climatic and external mechanical influences, the design of the device is placed under a radio-transparent fairing (18), hermetically mated to the support flange (13).

FIG. 3 shows the design of a conformal slotted emitter (5), excited by a symmetrical strip line operating in idle mode. The topology of the emitter is organized in the layer (27), the topology of the strip line, which is the output of the divider (3), in the layers (23-27). In order to reduce the height of the emitter, the strip line has a coordinated rotation by 90 °, which makes it possible to position its open section in the direction of the parallel slot. In this case, the height of the emitters makes it possible to install them along the centerline of the vertical support with a step of about λ / 4.

Principle of operation.

The linear antenna array works as follows. Excitation of N identical emitters (4) of vertical polarization, placed with a step S along the center line of the support (6), and forming a linear antenna array, is performed from the input (10) through the distribution system (1), consisting of an N-channel power divider (2 ), which implements the amplitude-phase distribution necessary to form the required elevation pattern, and N identical power dividers in half (3), the inputs of which are connected to the outputs of the divider (3). Each emitter (4) consists of two conformal slot emitters (5), rotated 180 ° relative to each other in the horizontal plane, and in-phase excited by a divider in half (3), which makes it possible to form a circular azimuthal pattern. The minimum irregularity of the pattern in the azimuthal plane is ensured with the optimal choice of slit lengths (about λ / 2) of conformal emitters (5). In this case, just as in the prototype, there is no need to adjust the pattern in the azimuthal plane.

A distinctive feature of the linear antenna array design is that the distribution system (1) is located on the outside of the vertical support (6), repeating its shape, which makes it possible to expand the operating frequency range of the distribution system without deteriorating its efficiency and, accordingly, the antenna gain due to the possibility of increasing the transverse size of the N-channel power divider (2) when the lengths of its channels are equalized by more than 3 times in comparison with the similar size of the prototype divider placed inside the support of the same diameter.

In addition, the height of the emitters (5) of the claimed linear antenna array allows them to be installed along the centerline of the vertical support (6) with a step of about λ / 4, which, unlike the prototype, provides the possibility of expanding the working sector in the elevation plane when forming a special shape pattern , including increasing the level of the cosecant pattern in the region of angles close to the center line of the support, without using an additional circular polarization radiator in the upper part of the antenna, which complicates the design.

This construction of a linear antenna array allows the use of the upper and internal parts of the vertical support (6) to accommodate additional elements, in particular, an external active antenna (8) and a radio frequency cable (9) for an embedded antenna channel of the GLONASS / GPS standard (7).

The azimuthal pattern of a linear antenna array consisting of sixteen radiators (4) is shown in FIG. 4. The irregularity of the azimuthal pattern does not exceed 0.25 dB at the center frequency and 0.8 dB in the operating range, which, as in the prototype, is associated with the final level of matching of conformal emitters (5) and, accordingly, the problematic nature of their excitation from divider (3) with the same amplitude and phase in the entire operating frequency band.

The angular antenna pattern of a linear antenna array consisting of sixteen radiators (4) is shown in Fig. 5. In the operating frequency range, the antenna pattern has the following characteristics: width at the level of minus 3 dB - no more than 10.3 °, the maximum level of the side lobes of the pattern - no more than minus 20.4 dB, the level of the pattern towards the horizon - minus 3.1 dB , the gain is at least 8.2 dB.

The reliability of the results shown in FIG. 4 and FIG. 5, is confirmed by electrodynamic calculations of a computer model of a linear antenna array, developed in accordance with the structural diagram (Fig. 1), in an application package using the finite element method in the frequency domain, as well as positive test results of an experimental antenna sample manufactured at the applicant enterprise ...

Thus, the technical result achieved when implementing the proposed invention is to increase the operating frequency range while maintaining a high gain, which allows the antenna array to be used when the radar is operating in request and response modes, to expand the working sector in the elevation plane when forming a special shape radiation pattern, in particular, cosecant (allows you to increase the radar's viewing area in elevation), as well as the presence of a built-in antenna channel of the GLONASS / GPS standard.

Claims (3)

1. Linear antenna array of vertical polarization with a circular azimuth directional pattern, including a vertical support in the form of a hollow metal cylinder, a distribution system, which is an N-channel power divider, the outputs of which are connected to the inputs of N identical power dividers in half, and N identical radiators located along the centerline of the support, each of which consists of two conformal emitters rotated 180 ° relative to each other in the horizontal plane and in-phase excited by a power divider in half, characterized in that the distribution system and emitters are made on the basis of a conformal symmetric strip line in the form of a multilayer structure consisting of five odd conductive layers and four even dielectric layers, which are located on the outer side of the support and are concentrically conjugated to its surface, forming a topology of strip conductors and screens of an N-channel power divider, power in half and conformal emitters, while the connection of the outputs of the N-channel power divider with the corresponding inputs of the dividers in half is made in the form of N conductive jumpers and N conductive U-shaped screens passing through all layers of the structure and jointly forming segments of a symmetrical strip line. 2. Linear antenna array of vertical polarization with a circular azimuthal radiation pattern according to claim 1, characterized in that each conformal emitter is made in the form of a slot excited by a symmetrical strip line. 3. Linear antenna array of vertical polarization with a circular azimuth directional pattern according to claim 1, characterized in that an antenna channel of the GLONASS / GPS standard is installed on the upper and in the inner parts of the vertical support.

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