RU2792403C1 - Circular compact vertical antenna array based on split wave vibrators - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: method is used for signal transmission/reception systems when it is necessary to increase coverage areas. The proposed circular CVAA consists of a bearing support in the form of a pipe, on which N vertical split vibrators are located one above the other, with upper and lower levers with an electrical length of half a wavelength, and N coaxial feeders pass inside, wherein the bearing support is made of a dielectric material, while the outer diameter of the support corresponds to the inner diameter of the metal tubes from which the vibrators are made, each coaxial feeder is connected to one of the vibrators through a device for balancing and matching the wave impedance of the feeder and the input impedance of the vibrator, which is a modified U-bend in the form of a half-wave loop of a coaxial cable coiled in the form of a spiral and placed between the levers of the vibrator on a bearing support.

EFFECT: development of a circular compact vertical antenna array (CVAA), having high gain, small weight and dimensions, manufacturability.

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Description

The invention relates to the field of radio engineering and can be applied in signal transmission / reception systems, if it is necessary to increase coverage (service) areas by increasing the radiation power of the transmitting device or the sensitivity over the field of the receiving device, including in cellular, trunking communication systems, as part of basic and dispatching stations, for building repeaters (repeaters) of medium and greater range, as well as in systems for other purposes.

To provide large coverage (service) areas, antenna arrays are often used that provide high gain.

Known compact vertical antenna array (CVAR) [1], containing a bearing metal support in the form of a pipe, on which are located N vertical vibrators; the upper and lower arms of each vibrator are made in the form of metal cylinders coaxial to the support, electrically connected to the support in the upper parts and forming vibrator arms with their outer surfaces, and coaxial resonators together with the support with their inner surfaces.

In [1], several variants of QVAR with different lengths of vibrators are presented - from half-wave to wave. Of all the options, wave vibrators have the greatest amplification, which predetermines the preference for their use when it is necessary to increase the service areas (range) in communication systems or systems for other purposes. Each of the wave vibrators consists of an upper and lower arm with a length close to half the wavelength. To separate adjacent vibrators, isolate feed points and vibrator arms from the metal support at high frequency, a jumper is installed in the middle part of each metal cylinder, made in the form of a metal ring or washer. The excitation of such a vibrator is carried out by a bicoaxial feeder, which is a pair of antiphase excited coaxial feeders.

This constructive solution of CVAR from wave vibrators has the following disadvantages:

- metal cylinders coaxial to the support have sufficiently large transverse dimensions - their diameter is at least twice the diameter of the support;

- the use of jumpers in the design, the introduction of additional unpowered coaxial resonators to improve the decoupling effect with a high-frequency support, as well as compensation for the end capacitance of the resonators leads to a complication of the manufacturing technology, an increase in the longitudinal (vertical) dimensions of the QAR and an increase in its mass;

- the need to use additional technological equipment in the process of manufacturing KVAR to ensure the strength of the structure and the rigidity of the connection of metal cylinders that form the upper and lower arms of the vibrators, with a bearing metal support and metal jumpers;

- the need to create special drainage holes in the jumpers to remove the condensate formed in the bowl-like resonators, which increases the complexity of manufacturing;

- the use of bicoaxial feeders to excite wave vibrators and their placement inside a metal support pipe - the KVAR supporting structure - requires an increase in its diameter or a limitation in the number of vibrators compared to the option of using conventional coaxial feeders.

The aim of the invention is the development of a compact vertical antenna array of circular orientation, providing high gain and having small dimensions and weight, manufacturable in manufacture.

The technical solution consists in the fact that a compact vertical antenna array of circular orientation based on wave split vibrators contains a bearing support in the form of a pipe, on which N vertical vibrators are located one above the other, having upper and lower arms with an electric length of half a wavelength, and inside N coaxial feeders are passed, while the carrier support is made of a dielectric material, N vertical split vibrators are placed directly on the carrier support one above the other, while the outer diameter of the support corresponds to the inner diameter of the metal tubes from which the vibrators are made, each coaxial feeder is connected to one of vibrators through a device for balancing and matching the wave impedance of the feeder and the input impedance of the vibrator, which is a modified U-elbow in the form of a half-wave loop of a coaxial cable coiled and placed between the arms.

The use of a pipe made of a dielectric material as a bearing support provides decoupling of the vibrators from each other.

The small end surface of the tubes from which the vibrators are made minimizes the effect of end capacitance.

A balancing and matching device for a wave vibrator in the form of a half-wave loop provides symmetrical excitation of such a vibrator when powered from an unbalanced coaxial feeder. In addition, the half-wave loop has the property of resistance transformation and provides a decrease in the high input impedance of the wave vibrator by a factor of 4 [2, 3] to values close to the values of the wave impedances of the most common coaxial cables. As a result, losses are minimized and a high efficiency of the vibrator is ensured.

Parallel power supply of wave split vibrators, which are part of the KVAR, provides high gain in a circular pattern.

The spatial alignment of the vibrators with the bearing support and the compactness of the balancing and matching devices ensure the small dimensions of the QVAR based on wave split vibrators and eliminate the need to remove condensate, which is important for cup-like resonators used in the design [1].

The essence of the invention and the design features of the KVAR based on wave split vibrators are illustrated by figures.

In FIG. 1 shows a diagram of the general design of the KVAR based on wave split vibrators (highlighted by a dashed line in the form of a rectangle), Fig. 2 shows a diagram of a device for balancing and matching (USS) of a wave vibrator, in Fig. Figure 3 shows the theoretically calculated radiation patterns in the vertical plane, characterizing the amplification of the QVAR based on wave split vibrators (in decibels relative to an isotropic radiator).

A compact vertical antenna array of circular orientation based on wave split vibrators consists of the following elements (Fig. 1):

- bearing support 1, which is a pipe made of a dielectric material, for example, a PVC pipe or, to increase structural strength, a PVC pipe reinforced with fiberglass;

- wave split vibrators 2.1, 2.2, ..., 2.N (where N is the number of vibrators) made of metal tubes (copper, brass, etc.) with an inner diameter corresponding to the outer diameter of the bearing support 1; vibrators 2.1, 2.2, ..., 2.N are identical to each other, the geometric length of each of them corresponds to the wavelength, taking into account the shortening factor of the wave vibrator;

- identical balancing and matching devices 3.1, 3.2, ..., 3.N, placed on a bearing support between the arms of wave vibrators 2.1, 2.2, ..., 2.N.

Each wave split vibrator 2.n (n=1, 2, ..., N) has two arms 2.n.1 and 2.n.2 of the same length, proportional to half the wavelength and determined taking into account the shortening factor of the wave vibrator.

Coaxial feeder lines 4.1, 4.2, ..., 4.N pass inside the bearing support, each of which is connected on the one hand to one of the wave vibrators, and on the other hand to the corresponding signal generation / reception channel 5.1, 5.2, ... 5.N.

The device for balancing and matching 3.n of the wave split vibrator 2.n (Fig. 2) is a modified U-elbow in the form of a half-wave loop - a piece of coaxial cable 3.n.1 with an electrical length of half a wavelength, coiled and placed between the shoulders 2.n.1 and 2.n.2 on the bearing support 1.

The central conductor of the half-wave loop 3.n.1 on one side is connected to the shoulder 2.n.1 of the wave split vibrator 2.n; on the other hand, the central conductor of the half-wave loop 3.n.1 is connected to the second arm 2.n.2 of this vibrator and the central conductor of the feeder line 4.n, passing inside the bearing support 1 and going out through the hole in its wall. The ends of the outer conductor of the coaxial cable, from which the half-wave loop 3.n.1 is made, are connected to each other and to the outer conductor of the feeder 4.n by a jumper 3.n.2.

For the manufacture of USS in the transmitting antenna, it is advisable to use radio-frequency coaxial cables of the types RK 50-2-25, RK 50-1.5-22 and the like, the outer conductor of which is made in the form of a seamless tube. Such cables provide a small bending radius during installation (up to 4 - 5 mm) with a permissible input power in the decimeter range up to 80 - 250 W. For receiving antennas, cheaper radio-frequency coaxial cables of small cross section with an outer conductor in the form of a braid of wires, etc., which have a small bending radius during installation, can be used.

The described design of the USS is compact, has a low weight, and is technologically advanced in manufacture. From the standpoint of balancing and matching, it has the same properties as a conventional U-bend: due to the inversion of the signal phase, it provides connection of an asymmetric feed line to a symmetrical wave split vibrator and matching the wave impedance of the feed line and the input impedance of the wave split vibrator with a minimum of insertion losses, for thereby achieving a high efficiency.

With an increase in the number N of wave split vibrators in the CVAR and their in-phase excitation, the radiation pattern in the vertical plane narrows, thereby increasing the directivity of the antenna and increasing the gain. In the azimuthal plane, the radiation pattern remains circular for any number of split wave vibrators in its composition.

In FIG. Figure 3 shows theoretically calculated for CVAR from wave split vibrators designed to operate in the 900 MHz band, directivity patterns in the vertical plane, characterizing the CVAR gain in decibels relative to an isotropic antenna:

- the dashed line corresponds to a two-element KVAR containing two split wave vibrators;

- dash-dotted line - four-element KVAR containing four wave split vibrators.

For comparison, in Fig. 3 in the form of a solid line shows the radiation pattern in the vertical plane of a single wave vibrator.

The dimensions of the proposed design of the KVAR are smaller than the dimensions of the structure [1]. The transverse dimensions of the KVAR based on wave split vibrators exceed the diameter of the bearing support 1 by no more than 10–15%, while in the design [1] this excess is at least 100%. Replacing the metal bearing support in the design [1] with a bearing support made of a dielectric material in the proposed design provides decoupling between the vibrators without the use of additional unpowered resonators or jumpers used in the design [1].

To protect against climatic and mechanical influences, the proposed design of the KVAR based on wave split vibrators is placed in a sealed housing, which is a pipe made of a dielectric material with a plug in the upper part (the pipe and the plug are not shown in Fig. 1).

The smaller transverse dimensions of the proposed KVAR make it possible to use an insulating dielectric pipe of a smaller diameter for such protection than in the design [1], which also reduces the weight and size characteristics, as well as the impact of wind loads.

Instead of an insulating dielectric pipe to protect KVAR based on wave split vibrators from adverse mechanical and climatic influences, heat-shrinkable tubes can be used to isolate the components of KVAR - vibrators and USS, placed between their arms on a bearing support. In this case, the transverse dimensions of the KVAR become even smaller.

The described design features of the KVAR based on wave split vibrators provide its protection from adverse external influences and eliminate the problem of condensate accumulation.

QVAR based on wave split vibrators is devoid of the disadvantages inherent in the prototype [1], has small weight and size characteristics, is structurally simple and manufacturable, implements a large gain with a circular orientation in the azimuthal plane and vertical polarization of the wave.

Information sources

1. Patent No. 2573224 RF, IPC H01Q 21/20, H01Q 9/18. Compact vertical antenna array of vertical vibrators spatially combined with a support / D.V. Luchin (RF) and others; FSUE NIIR (RF). - No. 2013144786/08; announced 04.10.2013, publ. 01/20/2016, bul. No. 2. - 21 p., 10 ill.

2. Belotserkovsky G.B. Fundamentals of radio engineering and antennas. In 2 hours. Part II. Antennas. - M.: Radio and communication, 1983. - 296 p.

3. Goshin G.G. Microwave devices and antennas. In 2 hours. Part 2. Antennas. - Tomsk: Tomsk Interuniversity Center for Distance Education, 2003. - 130 p.

Claims (1)

A compact vertical antenna array of circular orientation based on wave split vibrators, containing a bearing support in the form of a pipe, on which N vertical vibrators are located one above the other, having upper and lower arms with an electrical length of half a wavelength, and N coaxial feeders pass inside, differing by the fact that the supporting support in the form of a pipe is made of a dielectric material, N vertical split vibrators are placed directly on the supporting support one above the other, while the outer diameter of the support corresponds to the inner diameter of the metal tubes from which the vibrators are made, each coaxial feeder is connected to one of the vibrators through a device for balancing and matching the wave impedance of the feeder and the input impedance of the vibrator, which is a modified U-elbow in the form of a half-wave loop of coaxial cable coiled and placed between the arms of the vibrator on a bearing support.

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