RU2850153C1 - Logo-periodic vibration-spiral antenna - Google Patents

Abstract

FIELD: antenna technology.

SUBSTANCE: invention relates to log-periodic antennas. The result is achieved by proposing a log-periodic vibrator-coil antenna consisting of a log-periodic structure with wire vibrators fixed on a rigid frame, characterised in that the vibrators are made of two wire segments with opposing coils, in the form of compressed-flattened spirals around a supporting flat frame made in the form of a truncated isosceles triangle made of dielectric material, with the beginnings of the turns on the axis of symmetry on different sides of the frame, with the wire transitions of the turns fixed on the opposite side of the frame on the sides of the triangle, in the fastening recesses, at the ends of the vibrators, with the ends of the wires short-circuited to each other at the end of the antenna, and the beginnings of the wire turns connected to a symmetrical matching device located on the antenna's axis, to which a coaxial feed cable is connected, laid to the end of the antenna along the axis, inside the spirals.

EFFECT: simplified design with increased manufacturability while maintaining the basic parameters of log-periodic antennas with linear polarisation.

1 cl, 5 dwg

Description

The invention relates to the design of wireless transceiver devices, and more specifically, to compact broadband traveling-wave antennas. The device is based on a compromise implementation of a log-periodic wire structure consisting of compressed conical spirals wound counter-clockwise on a flat dielectric core. Power is supplied to the wire dipole turns forming the log-periodic structure at the beginning of the winding via a symmetrizing and matching device, which are then shorted together at the end of the winding. Simplification of the design preserves the key electrical parameters inherent in traveling-wave dipole antennas, while improving the matching coefficient across the operating frequency range.

The design of directional antennas with increased electromagnetic accessibility and enhanced compatibility with various types of electronic equipment, over a wide frequency band, while simultaneously reducing the material consumption and dimensions of such antennas in simplified versions has always been relevant.

A simple single-wire traveling-wave antenna (US Patent No. 1,381,089, 1920) is widely used for operation in the low-frequency ranges of the electromagnetic spectrum. The Beverage antenna is a long wire line, shorted to a load resistor, stretched at a low altitude above a conducting surface.

A disadvantage of the known antenna is that, for effective operation, it requires a wire length exceeding the length of the radio waves used, significantly increasing the dimensions.

The Delta CONTACT 2.0 transceiver antenna (http://delta3g.ru/CONTACT20.php) is known to operate in 2G, 3G, 4G networks of the GPRS, EDGE, UMTS, HSDPA, HSUPA, WCDMA, Wi-Fi, WiMax, HSPA+, LTE communication standards to enhance signal strength and increase data transfer speeds in conditions of unstable Internet access. The known antenna contains a feeding symmetrical line made of two tubes with a short-circuited section, with ten pairs of vibrators attached to them. Each of the ten pairs of vibrators is made of wire segments bent at an angle, having a rounded top. The vibrators are secured to the tubes by contact welding. Ten half-vibrators, attached to their tubes, are made of a single zigzag-bent piece of wire. Moreover, the coaxial cable laid in one of the tubes, with a section of switching the braid to the laying tube and the central core to the other tube at the beginning of the antenna, is the balancing unit at the beginning of the antenna.

The disadvantages of the known antenna are the technology, which requires complex equipment, significant dimensions, and increased metal consumption for the microwave range.

The closest to the proposed technical solution is the prototype, a well-known bispiral antenna with linear polarization (RU patent No. 2013830 dated May 30, 1994), containing two identical cylindrical spirals with opposite windings on the axis. The spirals are installed perpendicular to the metal screen with the distance between the axes of the cylindrical spirals D, their number of turns N, winding angle α and diameters d selected from the ratios D ≥ 1.2 λ; N ≥ 2; α ≥ 14°; 0.35 λ ≥ d ≥ 0.25 λ, where λ is the operating wavelength.

The disadvantages of a bispiral antenna are the increased complexity and significantly increased dimensions of the structure, material consumption and manufacturing complexity.

The aim of the invention is a log-periodic dipole-turn antenna with linear polarization of a simplified design and improved manufacturing technology while simultaneously maintaining the basic parameters of log-periodic antennas.

This goal is achieved by a log-periodic dipole-turn antenna consisting of a log-periodic structure with wire dipoles attached to a rigid frame. The dipoles are made of two lengths of wire wound in opposite turns, in the form of compressed-flattened spirals, around a supporting flat frame. The frame is shaped like a truncated isosceles triangle made of a dielectric material. The origins of the turns are located on the axis of symmetry on opposite sides of the frame plane. When the transitions of the wire turns to the opposite side of the frame are secured to the sides of the triangle, they are secured in mounting recesses at the ends of the dipoles. In this case, the ends of the wires are short-circuited with each other at the end of the antenna, and the beginnings of the wire turns are connected to a symmetrizing-matching device located on the centerline of the antenna, to which a supply coaxial cable is connected, laid to the end of the antenna along the centerline, inside the spirals.

The technical result of the proposed log-periodic dipole-turn antenna is a simplified design with increased manufacturing efficiency while simultaneously maintaining the basic parameters of log-periodic antennas with linear polarization.

The appearance of the proposed antenna is illustrated by the sketch in Fig. 1 and graphic materials:

Fig. 2 - computer model of a log-periodic vibrator-turn antenna;

Fig. 3 - radiation patterns in the horizontal and vertical planes in the frequency range under study;

Fig. 4 - graph of the change in the matching coefficient in the frequency range under study;

Fig. 5 - graph of the change in the gain and protective action coefficient in the studied frequency range.

The log-periodic vibrator-turn antenna (Fig. 1) consists of a log-periodic structure with wire vibrators 1, 2, fixed on a rigid frame 3, wherein the vibrators 1, 2 are made from two pieces of wire with opposite turns, in the form of compressed-flattened spirals, around a supporting flat frame 3. Frame 3 is made in the form of a truncated isosceles triangle made of a dielectric material. The beginnings of the turns are located on the axis of symmetry of the antenna 4 on different sides of the plane of the frame 3, when fastening the transitions of the wire turns to the opposite side of the frame 3 on the sides of the triangle, in the fastening recesses 5, in the places of the ends of the vibrators 6. In this case, the ends of the wires are short-circuited among themselves at the end of the antenna 7, and the beginnings of the turns 1, 2 of the wires are connected to the symmetrizing-matching device 8 located on the axial line of the antenna, to which the supply coaxial cable (not shown in the figure) is connected, laid to the end of the antenna along the axial line 4, inside the spirals.

A log-periodic dipole-turn antenna provides reception and transmission of linearly polarized radio waves. Unlike the prototype, in which the combined operation of two identical cylindrical helices with opposite windings compensates for the effects of opposing currents and adds parallel currents, in the proposed device, conductors 1 and 2, in the form of compressed helices, only realize the effects of parallel currents. Minimal orthogonal polarization occurs only due to the separation of conductors 1 and 2 by the thickness of core 3 and its permittivity. At the same time, the minimal reactive component of the antenna impedance, inherent in helical systems, is preserved. Additionally, the ends of the wires, shorted together at the end of antenna 7 without the use of a shielding element, simplify the design of the device, reducing the metal consumption and the antenna's dimensions.

Computer simulation of a log-periodic dipole-turn antenna (computer model in Fig. 2) fully confirms the theoretical assumptions, which is confirmed by studying the antenna version in the range of 1700-2800 MHz, with winding of copper wire with a diameter of 0.6 mm on a truncated triangle with bases of 8 and 2.5 cm at a height along the axis of symmetry of 7.5 cm (Fig. 1). The results of the computer simulation show a unilateral directivity of the antenna in the entire studied frequency range (Fig. 3), a smoothly changing matching coefficient with a value characteristic of use in the receive and transmit mode (Fig. 4), gain and protective action (Fig. 5).

Thus, the proposed log-periodic vibrator-turn antenna has found a direction for the design of log-periodic antennas of a simplified design using a different operating principle.

Claims (1)

A log-periodic vibrator-turn antenna consisting of a log-periodic structure with wire vibrators secured to a rigid frame, characterized in that the vibrators are made from two sections of wire with counter turns, in the form of compressed-flattened spirals, around a supporting flat frame made in the form of a truncated isosceles triangle made of a dielectric material, with the beginnings of the turns on the axis of symmetry on different sides of the frame, with the transitions of the wire turns secured to the opposite side of the frame on the sides of the triangle, in fastening recesses, at the ends of the vibrators, wherein the ends of the wires are short-circuited with each other at the end of the antenna, and the beginnings of the turns of the wires are connected to a symmetrizing-matching device located on the centerline of the antenna, to which a power coaxial cable is connected, laid to the end of the antenna along the centerline, inside the spirals.