RU2553572C1 - Electrical field reproduction device - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: device is implemented on the basis of capacitor 1surrounding the working zone designed as a set of coaxially located five thin-walled, metal lamellar rings 2 fixed on dielectric racks. The rings 2 have the identical height H and located on equals distances h (by height) from each other. Each ring 2 is sectioned in four identical parts separated along the circle by equal intervals L. Parts of rings are located symmetrically one above another with reference to the respective parts of other rings. Each two parts of neighboring rings form a piece of two-wire transmission line to the ends of which the matched loads 3 are connected. High-frequency voltage inputs 4 are gaps between the respective parts of the neighboring rings (in the middle of these parts). For each input the matched transition 5 is provided in a gap between ring elements.

EFFECT: increase of the working zone volume and rise of the top boundary frequency of reproduction of uniform electric field at keeping of relatively small overall dimensions of the device.

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Description

The invention relates to the field of electrical measurements and can be used as an exemplary source of a uniform alternating electric field in a given volume of the working area.

Known installation of reproducing a unit of electric field intensity of industrial frequency type P1-11, P1-12, designed to create a uniform alternating electric field. The installations are used in the verification and calibration of electric field strength meters of industrial frequency placed in the working area of these installations. The principle of operation of the installations is based on the phenomenon of the formation of a uniform electric field in the space between two parallel conductive plates forming a flat capacitor. An alternating voltage is applied to the plates in antiphase; as a result, a uniform electric field is formed in the space between the plates of the capacitor, which can be used as a measure of the electric field strength.

As a prototype (see the appendix), a unit for reproducing a unit of electric field strength based on a ring capacitor is adopted, which is two metal ring electrodes with a diameter of D = 2R = 1 m, located coaxially at a distance of 3D = 3 m. The diameter of the electrodes and the distance between them is determined from the condition of obtaining the greatest uniformity of the electric field in the working area. Moreover, the upper cutoff frequency of the installation is only 200 kHz.

The disadvantage of the above installations is the fact that the dimensions of the plates or rings of the capacitor and the distance between them are determined by the required dimensions of the installation working area (the area with a given inhomogeneity of the electric field and the placement of the antenna under test) and the condition for obtaining the maximum uniformity of the electric field inside the working area.

An increase in the size of the working zone of an annular or flat capacitor leads to a substantial increase in the overall dimensions of the installation itself, a decrease in the upper cutoff frequency of its operation, an increase in field inhomogeneity in the volume of the working zone, and a decrease in the maximum reproducible electric field strength with a constant input power.

The technical objective of the proposed solution is to increase the volume of the working area (with a slight increase in the dimensions of the installation) and increase the upper cutoff frequency of the reproduction of the electric field while maintaining the uniformity of the electric field in the working area of the device.

The essence of the technical solution lies in the fact that in the device for reproducing the electric field, including the capacitor surrounding the working zone, with two metal rings coaxially arranged (ring electrodes) mounted on dielectric racks and coordinated loads, the ring capacitor is made of a set (more than two) coaxially arranged thin-walled (metal) plate rings (electrodes) of the same height with equal gaps (in height) between them, each ring is cut into four equal n parts (segments) located at equal intervals from each other in the diametrical plane, while every two parts (segments) of adjacent rings form with a certain wave impedance a segment of the transmission line, at the ends of which matched loads are included, and the gap between the high-frequency voltage is adjacent rings in the middle of the corresponding parts (segments).

The figure schematically shows: figure 1 - General view of the device; figure 2 is a view directly in figure 1; figure 3 is a top view of figure 1.

A device for reproducing an electric field is a cylindrical structure (Fig. 1) made on the basis of a ring capacitor surrounding a working zone 1 in the form of a set of five thin-walled, metal plate rings (ring electrodes) 2 mounted coaxially on dielectric coaxially (one above the other) racks. The rings 2 are made of the same height H and are located at equal intervals (in height) between them h. Each ring 2 is cut into four equal parts (segments), spaced circumferentially at equal intervals L from each other (in the diametrical plane), and are located one above the other symmetrically relative to the corresponding parts of the other rings, with each two parts (segments) of adjacent rings form (figure 2) a segment of a two-wire transmission line with a wave impedance of 100 Ohms, at the ends of which are matched loads 3 (resistors of 200 Ohms), and the input 4 of the high-frequency voltage is the gap between adjacent rings middle of the relevant parts (segments). At each input, a matching transition 5 is provided in the gap between the ring elements.

All components of the device are conductive. Parts of the rings located one above the other, together with the transitions, can be made on a single printed circuit board made of thin fiberglass. Then, fix the resulting four boards on a dielectric spatial frame (rack) 6, which will provide the required radius of bending of the boards, the distance between them and the structural rigidity.

The operation of the device is to convert a ring capacitor, made in the form of a hollow cut cylinder, of the high-frequency voltage coming from the signal generator (not shown in the figure) between the corresponding parts of adjacent rings into each gap between the rings in the middle of the parts, into the electric field strength.

This design of the device as a result has 16 independent symmetric common-mode inputs and consists of 16 segments of transmission lines that surround the working area and create an electric field of the required uniformity in it (the voltage of which is proportional to the current flowing through the segments, creating a voltage drop across the resistors). The facility is capable of operating at frequencies up to 300 MHz due to excitation along the entire loop of the ring with a current uniform in amplitude. All this allows you to reproduce a uniform electric field inside the capacitor at an acceptable installation size and a sufficiently large working area. The dimensions of the entire device (diameter 1 meter, height about 2 meters) do not significantly exceed the size of the working area (cylinder with a base diameter of 0.6 m and a height of 1.4 m).

The number of ring cuts performed depends on the range of operating frequencies. The results of an experimental study showed that for the frequency range up to 300 MHz, the optimal amount is 4 sections.

A device for reproducing an electric field is used as a working standard in the calibration and verification of working instruments for measuring an alternating electric field.

Claims (1)

An electric field reproducing device comprising an annular capacitor surrounding a working area with two metal rings coaxially mounted on dielectric racks and coordinated loads, characterized in that the annular capacitor is made of a set of thin-walled plate rings of the same height with equal intervals in height between them, each the ring is cut into four equal parts located at equal intervals from each other in the diametrical plane and symmetrically above each other gom relative to corresponding parts of other rings, wherein every two adjacent rings form with a certain characteristic impedance of the transmission line segment, the ends of which are incorporated matched load, and inputs the high frequency voltage are gaps between adjacent rings the middle of the respective parts.

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