RU2738758C1 - Hybrid antenna array power supply system - Google Patents

Abstract

FIELD: antenna equipment.

SUBSTANCE: invention relates to antenna engineering, particularly to planar antenna arrays (AA) with high efficiency and low level of side lobes. In hybrid antenna array supply system, including radiating part made in form of two-dimensional slot structure located on dielectric substrate, in the form of a grid of collinear antennae excited in series-parallel manner by a microstrip line, said microstrip line includes power points with given amplitudes spaced along the microstrip line by distances which are multiples of the electric wavelength, wherein each power point is connected through a microstrip-coaxial-waveguide transition to the waveguide non-equilibrium in-phase divider, the stages of which are connected in series, wherein the topology of the slot-type collinear antenna forms serially arranged radiating slots excited by the slit line.

EFFECT: technical result is high efficiency, control of amplitude distribution with accuracy of not less than ±0,5 dB and improved range properties of multi-element AA for wideband small-size radio systems.

1 cl, 7 dwg

Description

Application area

The invention relates to the field of antenna technology and is intended for constructing planar antenna arrays (AR) with an increased level of efficiency (efficiency) and a low level of side lobes (UBL).

State of the art

Known is a linear microwave antenna (patent RU No. 2279741, IPC H01Q13 / 22, publ. 07.10.2006), which consists of a multichannel power divider, a sequential system of radiators and a coupling element of the radiators with the outputs of the multichannel power divider. The multichannel power divider is made on an asymmetrical strip line and is located on a wide wall inside a rectangular pipe. The periodic system of emitters is made in the form of windows on a narrow wall of a rectangular tube. Coupling elements are made in the form of capacitive or inductive vibrators, spaced from another narrow wall of a rectangular pipe at a distance of one quarter of the average wavelength.

Known flat antenna (patent RU No. 2016444, IPC H01Q13 / 18, publ. 07.15.1994), containing a multilayer structure formed by a shielding layer of an electrically conductive material, a layer with a strip power supply circuit and a layer in the form of a plate with slots, electromagnetically connected with the corresponding strip conductors of the power circuit, an array of volume cells and a transition associated with the shielding layer and strip conductors of the power circuit.

The disadvantage of these technical solutions is the implementation of a power divider on a printed circuit board, which does not allow them to be effectively used for AA apertures with linear dimensions of several tens of wavelengths, especially for two-dimensional arrays of emitters due to the increased level of losses.

Closest to the proposed invention is a flat slotted antenna array (patent RU No. 2024129, IPC H01Q13 / 10, publ. 11.30.1994), which contains parallel strip waveguides placed on the printed circuit board. The metal shield of the printed circuit board forms a common wide wall of strip waveguides, their second wide walls are formed by strips with ridge stubs along the edges. Emitting slots are made in the strips, and communication slots are made in the metal screen, which are connected to the signal forming unit, which consists of supply waveguides and waveguide power distributors located on the back side of the metal screen.

The disadvantage of this device is the difficulty of regulating the amplitude distribution, in particular, the limitation on the magnitude of the connections between the waveguide and the slots, which affect the given amplitude distribution, which with small apertures, for example, for small antennas, may be insufficient for its implementation. In addition, the use of H-tees as branching elements does not allow for channel-to-channel isolation, which can be a critical problem in receiving radio systems.

The essence of the invention

The technical problem is aimed at creating a microwave power system for planar multi-element AAs, the use of which allows achieving high radiation efficiency with a low level of side lobes, also providing high repeatability of electrical parameters without the need for tuning.

The technical result of the proposed solution is to increase the efficiency, control the amplitude distribution with an accuracy of not worse than ± 0.5 dB and improve the range properties of multi-element ARs for broadband small-sized radio systems.

The main technical result is achieved by the fact that

- the hybrid power supply system of antenna arrays includes a radiating part made in the form of a slot structure located on a dielectric substrate;

- the slit structure is made in the form of a two-dimensional array of collinear antennas excited in a series-parallel way by a microstrip line;

- the microstrip line includes power points with specified amplitudes, spaced along the microstrip line by distances that are multiples of the electrical wavelength;

- each feed point is connected through a microstrip-coaxial-waveguide junction with a waveguide non-equilibrium in-phase divider, the stages of which are connected in series;

- the topology of the slit collinear antenna forms sequentially located radiating slits, which are excited by the slit line.

The formation of a printed topology, which sets the standing wave mode, ensures the maximum selection of the input power, for a given law of amplitude distribution, since there is no dissipation at matched loads, in contrast to the traveling wave mode, which increases the AA efficiency, and hence the radiation efficiency.

The collinear arrangement of the emitters in a rectilinear system of series-parallel fission reduces dissipative losses, since the total length of the excitation lines decreases, which increases the AR efficiency, and hence the radiation efficiency.

The implementation of collinear antennas in the form of slits excited by a slit line increases the matching band, since the value of the propagation constant decreases, and as a consequence, the resonant size of such emitters increases, which, at large AA apertures, reduces their total number. The directivity increases in comparison with the microstrip structure due to the narrowing of the directional pattern (DP) not in the plane of the collinear antenna by an additional value of up to 3 dB. In addition, the sensitivity of the electrical characteristics to a change in the relative permittivity of the substrate decreases due to the low effective value.

The use of series-parallel excitation ensures the frequency stability of the directional characteristics of the AA, namely, the direction of the maximum and the directional action coefficient in the band determined by the number of successive emitters with a step d according to the criterion specifying their maximum number N _pp

where: γ is the propagation constant,

k is the wavenumber,

λ is the propagation constant of the radiating slot line,

dθ is the expansion coefficient of the beam pattern.

The introduction of feed points spaced along the microstrip line at distances that are multiples of the electrical wavelength technically provides series-parallel excitation and amplitude distribution control.

The waveguide implementation of the distribution system for dividing the power of parallel apertures sets the value of the amplitude weights of the feed points with minimal dissipative losses, which increases the AA efficiency, and hence the radiation efficiency.

The series connection of the stages of the waveguide divider allows minimizing the nonequilibrium of the amplitudes between the channels of one stage in comparison with the classical method of pairwise connection to each arm of the next stage.

Brief Description of Drawings

FIG. 1 shows a section of the topology of a slit collinear antenna with a graphical explanation of the condition of in-phase of the radiation field of each slit, FIG. 2 shows a section of the topology of a two-dimensional slot structure with a graphical explanation of the condition of in-phase parallel excitation of collinear antennas, FIG. 3 shows a general view of the topology of the AR with a hybrid power supply system, while the circuit highlights the waveguide system of parallel division, located inside the reflector of the AR; FIG. 4 shows the general construction of an AP with a hybrid power system; FIG. 5 shows the mounting of the board and the excitation of the AP with a hybrid power supply system; 6 shows enlarged sections of a printed circuit board of a two-dimensional slotted structure; FIG. 7 is a typical view of the normalized pattern in the E-plane.

Implementation of the invention

The technical implementation of the features of an AP with a hybrid power supply system determines the following design, which can be modified depending on the requirements put forward for the AP. The design of the AR, designed on the basis of a hybrid power system, includes features that combine the features of various types of antennas and the principles of their construction, namely:

- printed topology of the emitting part,

- standing wave mode,

- collinear arrangement of emitters,

- sequential power supply of emitters with division into parallel excited sections of the aperture,

- waveguide distribution system for dividing the power of parallel apertures.

The printed circuit board 1 with a slot topology is located above the reflector 2, inside which there is a waveguide non-equilibrium in-phase divider 3 with decoupling, the steps of which are connected in series one after another, while the height of the waveguide is reduced by up to 50% relative to the standard value for the corresponding frequency range. The supply points 4, located along the microstrip 5 on the printed circuit board 1, are connected through a microstrip-coaxial-waveguide junction with a waveguide non-equilibrium in-phase divider 3.

Antenna with a hybrid power system works as follows. At the input of the waveguide non-equilibrium in-phase divider 3, a microwave signal is fed, dividing in a 1: 1 ratio, and then branched off in a predetermined proportion at each successive stage so as to provide an amplitude distribution that determines the UBL AR. From each output of the waveguide non-equilibrium in-phase divider 3, microwave signals of a given amplitude excite an electric current wave in series-parallel at several supply points 4 through microstrip-coaxial-waveguide junctions spaced multiples of the electrical wavelength and located along the microstrip 5. The propagating wave along the microstrip 5 excites sequentially - in parallel, collinear slot antennas 6, the pitch of which is the electric wavelength, while the printed emitting slot structure operates in a standing or quasi-stationary wave mode, providing maximum power takeoff of the microwave signal without its dissipation on a matched load, in contrast to the traveling wave mode.

. Условие синфазности поля излучения каждой щели задается следующим соотношением (пояснение на фиг. 1)The extreme slots in the collinear antenna operate in idle mode, that is, the load resistance

... The condition of the in-phase of the radiation field of each slit is given by the following relation (explanation in Fig. 1)

,

,

- постоянная распространения щелевой линии питания,Where

- constant propagation of the slotted power line,

- длина щелевой линии питания,

- length of the slotted supply line,

- постоянная распространения излучающей щелевой лини,

- the constant of propagation of the radiating slot line,

- длина излучающей щелевой линии,

- length of the radiating slit line,

- длина волны в диэлектрике.

is the wavelength in the dielectric.

. Условие синфазности поля излучения коллинеарных антенн друг относительно друга при их параллельном возбуждении задается следующим соотношением (пояснение на фиг. 2)The extreme sections of the microstrip line are open and operate in idle mode, that is, the load resistance

... The condition of the in-phase of the radiation field of collinear antennas relative to each other with their parallel excitation is given by the following relationship (explanation in Fig. 2)

,

,

определяет фазовый набег до первого участка последовательной апертуры АР,Where:

determines the phase incursion to the first section of the AR series aperture,

определяет фазовый набег до второго участка последовательной апертуры АР.

determines the phase incursion to the second section of the serial aperture AA.

Partial directional patterns (BP) of each collinear slot antenna 6 in superposition form the antenna array pattern with a hybrid power supply system, while the serial-parallel excitation ensures the frequency stability of the antenna pattern maximum due to the fact that the partial patterns of successive apertures have an opposite slope when the frequency deviates from the central value , and as a consequence, the total radiation occurs strictly along the normal.

Thus, the proposed invention increases the efficiency of the antenna array, and hence the radiation efficiency.

In addition, the use of a printed topology of the emitting part provides simplicity of manufacture, planarity of the structure, which significantly improves the mass and dimensions of the antenna array and simplifies serial production.

Claims (1)

A hybrid power supply system for antenna arrays, including a radiating part made in the form of a two-dimensional slot structure located on a dielectric substrate, in the form of an array of collinear antennas excited in a series-parallel manner by a microstrip line, including power points with specified amplitudes spaced along the microstrip line at distances, multiples of the electrical wavelength, with each power point connected through a microstrip-coaxial-waveguide junction with a waveguide nonequilibrium in-phase divider, the steps of which are connected in series, while the topology of the slotted collinear antenna forms sequentially located radiating slots, excited by the slot line.

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