RU189384U1 - Broadband aerial based on vibrator with upper capacitive load - Google Patents

Abstract

The utility model relates to antenna technology and can be used as a transmitting and receiving broadband VHF antenna with a radiation pattern that is isotropic in the azimuth plane. The antenna contains a vibrator with a capacitive load and a base counterweight. In addition, the first and second insulators are inserted, between which the additional arm of the vibrator is fixed, while the vibrator and the additional arm of the vibrator are partially placed in the first insulator, and the second insulator is fixed on the counterweight base. The technical result consists in providing high broadband (overlap in frequency of 4.5 and above), in the absence of the need to use additional baluns and matching devices, in the absence of the need for complex tuning. 1 hp f-ly, 2 ill.

Description

The proposed device relates to antenna technology and can be used as a transmitting and receiving broadband antenna VHF range with an isotropic in the azimuthal plane of the radiation pattern.

Known dipole antenna in US Pat. RF 2413344, H01Q 9/18, the broadband which is achieved by the inclusion of additional inductance. The disadvantages of this device are the difficulties associated with the use of such a method of coordination in the microwave range and complex design.

Also known vibrator antenna in US Pat. RF 2589451, H01Q 9/18, containing the inductance, a vibrator, electrically connected to one end of the inductance and representing a bulk conductor located in the magnetic field of the inductance. The disadvantages of this antenna are the complexity of the settings associated with the selection of the inductance value and structural complexity.

The closest analogue to the technical nature of the proposed is the antenna according to the patent of the Russian Federation 2523959, H01Q 9/18, adopted for the prototype.

The layout of the prototype device is shown in FIG. 1, where indicated:

1 - capacitive load;

2 - vibrator;

7 - extension coil;

8 - transformer;

6 - counterweight.

The prototype device consists of a vibrator 2 with a capacitive load 1 made of metal rods, a matching device based on the extension coil 7 and a transformer 8, and a counterweight 6. The capacitive load 1 is electrically connected to the vibrator 2, which is electrically connected to one end of the extension coil 7 , made on the closed core of the magnetic circuit. The second end of the extension coil 7 is electrically connected to one end of the secondary winding of the transformer 8, the other end of the secondary winding of which is electrically connected to the counterweight 6.

The device prototype works as follows.

The antenna is powered through the primary winding of the transformer 8. The impedance of an electrically small antenna formed by a vibrator 2 with a capacitive load 1 and a counterweight 6 consists of radiation resistance, loss resistance and reactance of capacitive nature. Capacitive load 1 contributes to a more uniform distribution of current across the vibrator 2, reducing the capacitive component in the total resistance of the electrically small antenna.

The radiation resistance will be greater, the closer the length of the vibrator to a quarter of the wavelength. The loss resistance will be the smaller, the smaller the ohmic resistance of the vibrator 2 at the radio frequency used, and the closer the counterweight 6 to an ideally conducting infinite plane. The inductance of the extension coil 7 compensates for the capacitive component in the impedance of the electrically small antenna, with additional losses occurring consisting of losses on the ohmic resistance of the winding and losses in the core. Transformer 8 transforms the total resistance, consisting of the radiation resistance of an electrically small antenna, the loss resistance of an electrically small antenna and the loss resistance of an extension coil 7, into a nominal resistance of a receiver, transmitter or transceiver used in conjunction with the antenna.

The disadvantages of the device of the prototype is a significant narrowing of the antenna bandwidth while reducing its linear size due to the need to increase the quality of the matching device to preserve the radiation efficiency.

The objective of the proposed device is to expand the working frequency band while maintaining the antenna compactness.

According to the utility model, the first and second insulators are inserted, between which the additional arm of the vibrator is fixed, while the vibrator and the additional arm of the vibrator are partially placed in the first insulator, and the second The insulator is fixed on the base-counterweight.

FIG. 2 shows the scheme of the proposed device, where indicated:

1 - capacitive load;

2 - vibrator;

2.1 - the point of connection of the center conductor with a vibrator;

3, 5 - the first and second insulators;

4 - additional arm of the vibrator;

4.1 - the connection point of the braid with an additional arm of the vibrator;

5 - the second insulator;

6 - counterweight.

The proposed antenna device contains a capacitive load 1, made in the form of a metal disk, electrically connected to the vibrator 2, the lower part of which is placed in the first insulator 3, in which the additional arm of the vibrator 4 is also mounted on the second insulator 5 mounted on the counterweight 6. Vibrator 2 can be made of any electrically conductive material in an arbitrary shape that provides sufficient structural strength, for example, in the form of a cylinder.

The proposed device works as follows.

The antenna is powered by a coaxial cable (not shown in Fig. 2), the center conductor of which is connected to the vibrator 2 at point 2.1, and the braid is connected to the additional arm of the vibrator 4 at point 4.1. Capacitive load 1 contributes to a more uniform distribution of current in the vibrator 2, reducing the capacitive component in the total impedance of the antenna. The structural strength of the antenna near the points 2.1 or 4.1 provides the first insulator 3, made of a dielectric material. Additional capacitive coupling of the vibrator arm 4 and the counterweight 6 is provided through the second insulator 5, which contributes to a uniform current distribution along the additional arm of the vibrator 4. The second insulator 5 can be made of a low-loss dielectric material, the type of which is selected depending on the required antenna parameters. The matching in the frequency band of interest is achieved mainly by choosing the location of the capacitive load 1 on the surface of the vibrator 2, choosing the material and geometrical parameters of the second insulator 5 and the geometrical dimensions and configuration of the vibrator 2 and the vibrator shoulder 4. Despite the absence of a balancing device, the proposed utility model achieves good matching in band with frequency overlap of about 4.5. However, if necessary, additional expansion of the working frequency band, the antenna design allows you to place additional balancing and matching devices inside the additional arm of the vibrator 4. This solution allows you to expand the possible frequency range of the antenna, keep its linear dimensions and protect additional matching and balancing devices from external influences. As a counterweight 6 can act conductive plane, such as the roof of the car.

Thus, compared with the prototype, the proposed device allows to achieve high bandwidth, since there is no limitation introduced by the quality factor of the matching device; does not require complex configuration, which facilitates the introduction into mass production. In addition, unlike the prototype, there is no need to use balancing and balancing devices due to the introduction of an additional arm of the vibrator 4 and the presence of capacitive coupling between it and the counterweight 6 through the second insulator 5. That is, the antenna can be powered by a coaxial cable directly, but if necessary the expansion of the working frequency band the antenna design easily allows you to place a matching device, for example, inside the additional arm of the vibrator 4.

Claims (2)

1. A broadband antenna based on a vibrator with an upper capacitive load, which contains a vibrator with a capacitive load and a base counterweight, characterized in that the first and second insulators are inserted, between which an additional vibrator arm is fixed, while the vibrator and the additional vibrator arm are partially placed in the first an insulator, and the second insulator is fixed on the base-counterweight. 2. Broadband antenna according to claim 1, characterized in that the upper capacitive load is made in the form of a flat metal disk.

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