KR20100097923A - Wideband circular polarized turnstile antenna - Google Patents

Abstract

PURPOSE: A broadband circular polarization turnstile antenna is provided to be optimally applied to a satellite control communication system by maintaining a high axial ratio on the overall frequency band. CONSTITUTION: A phase difference power divider(1) comprises a power divider(12), first and second feeding vias(13,14) and a phase transition line(15). The power divider divides the signal transmitted through a coaxial cable to two signals. The first and second feeding vias supply two signals divided by the power divider to an antenna unit. The phase transition line gives the phase difference of 90 degrees to the first and second feeding vias. The antenna unit radiates a phase difference branch signal outputted from the phase difference power divider.

Description

Wideband circular polarized turnstile antenna

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a broadband circular polarization turn style antenna with improved gain and ratio for optimally generating circular polarized signals in a communication system using circular polarized signals including satellite communications.

Satellite-controlled communication systems such as tracking, telemetry and command (TT & C) use circularly polarized signals with good signal transmission characteristics to communicate between satellites in space orbit and ground stations. In addition, since the communication system must be able to communicate even if the attitude of the satellite changes due to the characteristics of the control system, the control antenna should use an antenna having a large beam width and a front direction characteristic and a wide frequency bandwidth.

On the other hand, the communication system using circular polarization has been applied in various fields such as mobile communication, RFID, as well as satellite communication because of the signal separation characteristics of the left and right polarization in addition to the good signal transmission characteristics to the surrounding environment. Because of this trend, circularly polarized antennas are in high demand.

An antenna used in a conventional circular polarization communication system for exhibiting the above characteristics is Korean Patent Office Publication No. 10-0750850 (registered on August 14, 2007) (name of the invention: a small high gain circle for an RFID reader) Polarized antenna and clamp therein) (hereinafter referred to as "prior art 1") and Patent Publication No. 10-0672967 (registered on January 16, 2007) (name of the invention: circular polarized antenna) (hereinafter, " Abbreviated 2 ".

The antenna for the circular polarization communication system of the prior art 1 described above is implemented as a circularly polarized antenna using two vertical folded dipoles as antenna radiators and giving a 90 ° phase difference. In order to implement a single circularly polarized antenna using a device, a phase difference applied to each linearly polarized radiating element is used to realize a consistent antenna radiation pattern in a wider frequency band than a circularly polarized antenna using a single radiating element. It is to.

However, the antenna applied to the conventional circular polarization communication system, although it is possible to implement a wide frequency bandwidth of a wide beam width characteristics, there is a disadvantage that it is difficult to maintain a good ratio in the entire band.

In addition, there is a problem that the gain is reduced when the antenna is made small.

Accordingly, the present invention has been proposed in order to solve various problems occurring in the antenna applied to the conventional circular polarization communication system as described above.

SUMMARY OF THE INVENTION The problem to be solved by the present invention is a broadband turn-style with small gain, wide beam width, wide band characteristics, high gain, and improved ratio in all frequency bands for use in a communication system using a circularly polarized signal including satellite controlled communication. To provide an antenna.

"Wideband circular polarization turn style antenna" according to the present invention for solving the above problems,

A phase difference power distribution unit for branching a signal received through a coaxial cable in a circular polarization communication system and outputting a phase difference branch signal to which a phase difference is imparted;

And an antenna unit for synthesizing the phase difference branch signals output from the phase difference power distribution unit and radiating circularly polarized waves in the space.

In addition, the phase difference power divider,

It characterized in that it comprises a short stub for giving a uniform phase difference over the broadband, the width and length of the short stub is characterized in that it changes according to the frequency band.

In addition, the antenna unit,

A turn-style dipole positioned perpendicular to each other to radiate the retardation branch signal into the air;

A reflector for increasing forward gain characteristics of the circularly polarized wave emitted by the turn-style dipole;

And a feed line and a balance for transmitting the phase difference branch signal to the turn style dipole and supporting the turn style dipole to the reflector.

In addition, the turn-style dipole,

Two elements are arranged in order to increase the gain, and a phase difference branch signal branched from the phase difference power divider is manufactured in the form of a PCB substrate to smoothly supply a dipole radiator.

In addition, the turn-style dipole,

A parasitic element is further provided near the dipole radiator to give a wide band characteristic of the antenna, and the parasitic element is characterized in that the width and length are varied to determine the bandwidth.

According to the present invention, since a circularly polarized signal having high gain and broadband characteristics can be optimally generated, there is an advantage that can be used in a communication system using a circularly polarized signal including satellite control communication.

Further, according to the present invention, there is an advantage in that a circularly polarized antenna having a small but high gain can be provided in a circularly polarized communication system.

In addition, according to the present invention, while having a wide beam width and a wide frequency bandwidth, high gain, good axial ratio over the entire band can be obtained, there is an advantage that can be optimally applied to the system for satellite control communication.

Hereinafter, described in detail with reference to the accompanying drawings a preferred embodiment of the present invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

1A and 1B are structural diagrams showing a configuration of a broadband circular polarized turn style antenna with improved gain and shaft ratio according to the present invention, FIG. 2 is a diagram illustrating a turn style dipole made of a PCB substrate, and FIG. 3 is a PCB substrate form. Figure 4 is a flow chart of the power supply cross section and the signal of the main portion of the signal is supplied to the turn-style dipole of Fig. 4 is a connection diagram of the phase difference power distribution unit and antenna for each polarization, Figure 5 is a graph of the standing wave ratio (VSWR) result of the turn-style antenna 6 is an axial ratio result graph of the turn style antenna, and FIGS. 7A and 7B are graphs of a radiation pattern of the turn style antenna.

As shown in the drawing, the wideband circular polarization turn style antenna with improved gain and axis ratio is composed of a phase difference power distribution unit 1 and an antenna unit 2.

First, in the phase difference power distributor 1, a power divider 12 for distributing a signal transmitted from an external coaxial cable 11 into two signals, and a first feed via for supplying two branched signals to the antenna unit 2. (13) and second feed vias (14) and two feed vias (13, 14) are provided with a phase shift line (15) for giving a 90 ° phase difference, and a shorting stub for giving a flatter phase difference in frequency broadband. (16) is added.

The antenna unit 2 has a first feed line 21 and a second feed line 22 having a coaxial cable connected to the first feed via 13 and the second feed via 14, respectively, and a PCB substrate form. The turn-style dipole 23 receives the phase difference divergence signal through two lines, the first balun 24 and the second balun 25 in the form of a metal column, and the reflector 26 to obtain high front gain. Equipped. The turn-style dipole 23 has a two-element array 27 in which two elements are arranged in order to obtain additional gain of the antenna. In addition, a parasitic element 28 may be added near the dipole for frequency wideband characteristics.

Looking at the operation of the broadband circular polarization turn-style antenna with improved gain and ratio according to the present invention having such a structure in detail as follows.

The signal transmitted from the external coaxial cable 11 is distributed through the power divider 12 with the same power ratio. At this time, the phase shift line 15 is provided on one line to give a 90 ° phase difference to the two signals. That is, in the first feed via 13 and the second feed via 14 that have passed through the phase shift line 15, the phase difference is mutually different, and the phase difference depends on the operating frequency and its length. In this case, in order to generate circular polarization, a phase difference of about 90 ° is required.

In general, the phase difference power divider provides a fixed phase difference only in a predetermined band within an operating frequency, and the phase difference gradually decreases as it moves out of the operating frequency. However, in order to provide good axial ratio circular polarization for frequency broadband, a constant phase difference must be supplied over the entire band. In the present invention, the shorting stub 16 is connected in parallel to the second feed via 14, which is another feed that does not have the phase shift line 15, so that a constant phase difference is supplied even in the frequency broadband. As can be seen in Figure 6, it can be seen that a turnstyle antenna with a short stub 16 has a good axial ratio over a wider frequency band range than a conventional turnstyle antenna. Here, the length of the short stub 16 is basically designed to have a quarter wavelength length in the operating frequency band so that the impedance of the second feed via 14 is not changed. Here, the length and width of the shorting stub can be adjusted accordingly depending on the operating frequency band or to obtain a better axial ratio.

The divided phase difference signals supplied from the phase difference power divider 1 are supplied to the first feed line 21 and the second feed line 22, respectively. These two lines are made of hard coaxial cable that is hard to bend to serve to fix the antenna along with the balances 24 and 25. That is, the first feed line 21 is connected to the vertical dipole 31 and the second feed line 22 is connected to the horizontal dipole 32.

Referring to the turn-style dipole 23 in the form of a PCB in FIG. 2, the horizontal dipole 32 is printed on the front surface 33 of the PCB substrate, and the horizontal dipole via 35 connected to the second feed line 22. The branched signal is supplied through. In addition, the horizontal dipole signal line 36 is connected to the horizontal dipole balance via 37 to transmit a signal to the horizontal dipole 32 and the second balance 25. Similarly, the vertical dipole 31 is printed on the back surface 34 of the PCB substrate and receives a branched signal through the vertical dipole via 38 connected to the first feed line 21. In addition, the vertical dipole signal line 39 is connected to the vertical dipole balance via 40 and transmits a signal to the vertical dipole 31 and the first balance 24.

At this time, each signal line, dipole, line, and balun are separated with a certain interval, and the interval determines the antenna impedance and the isolation between the two dipoles.

On the other hand, the parasitic element 28 can be placed to obtain the broadband characteristics of the antenna, and its length and width and the distance to the dipole can be adjusted appropriately because they determine the operating frequency and bandwidth.

Figure 3 shows a feed cross-sectional view of the turn-style dipole manufactured in the form of a PCB substrate and the flow of signals flowing through each major part. The signal line signal 100 applied to the vertical dipole 31 flows to the inner core of the first feed line 21 made of a coaxial cable, and is transmitted to the first balance 24 made of the vertical dipole 31 and the metal pillar. do. In addition, the ground signal 101 flows to the outer core of the first feed line 21 and has a typical dipole current flow. On the other hand, the horizontal dipole 32 has a form similar to the vertical dipole 31, but has a form in which the outer core of the connection portion of the second feed line 22 and the horizontal dipole via 35 is partially removed. To be separated.

The principle of generating circular polarization in the present invention is due to the 90 ° phase difference input of the dipoles perpendicular to each other. At this time, if the phase difference is + 90 °, the left polarization (LHCP) is shown, and if the phase difference is -90 °, the superior polarization (RHCP) is shown. As shown in FIG. 4, the first feed via connected to the first feed line 21 is shown. When the phase shift line 15 is connected to (13), left polarization (LHCP) is generated, and the phase shift line 15 is connected to the second feed via 14 connected to the second feed line 22. When connected, good polarization (RHCP) occurs. In other words, desired left or even polarized waves can be generated according to the requirements of the communication system.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

FIG. 1A is a bottom structural diagram of a broadband circular polarization turn style antenna with improved gain and axis ratio according to the present invention, and FIG. 1B is a top structural diagram.

Figure 2 is a structural diagram of a turn-style dipole made of a PCB substrate.

Figure 3 is a signal flow diagram of the power supply section and the main part of the signal is supplied to the radiator in the form of a PCB substrate.

4 is a connection diagram of a polarization phase difference power distribution unit and an antenna unit.

5 is a graph of standing wave ratio results of a wideband circular polarization turn style antenna with improved gain and axis ratio according to the present invention;

6 is a graph of the axis ratio results of a wideband circular polarization turn style antenna with improved gain and axis ratio according to the present invention;

7A and 7B are graphs of the radiation pattern results of a wideband circular polarization turn style antenna with improved gain and axis ratios according to the present invention;

<Explanation of symbols for the main parts of the drawings>

One… Phase difference power divider

2… Antenna part

16... Short circuit stub

27... 2-element array dipole

Claims (15)

In a broadband circular polarized turn style antenna, A phase difference power distribution unit for branching a signal received through a coaxial cable in a circular polarization communication system and outputting a phase difference branch signal to which a phase difference is imparted; And Broadband circularly polarized turn-style antenna characterized by increasing the gain of the phase difference branch signal output from the phase difference power distribution unit, and maintaining an optimal axis ratio in all bands to radiate circularly polarized waves in space . The power supply unit of claim 1, wherein the phase difference power divider comprises: A power distributor for distributing the signal transmitted from the external coaxial cable into two signals; A first feed via and a second feed via for supplying two signals branched by the power divider to the antenna unit; And a phase shift line for giving a 90 ° phase difference to the first and second feed vias. According to claim 2, The phase difference power divider, And a short circuit stub for providing a uniform phase difference over the broadband. 4. The wideband circular polarization turn style antenna of claim 3, wherein the width and length of the short stub are variable according to a frequency band. The method of claim 1, wherein the antenna unit, A turn-style dipole positioned perpendicular to each other to radiate the retardation branch signal into the air; A reflector for increasing forward gain characteristics of the circularly polarized wave emitted by the turn-style dipole; And a feed line and a balance therein for transmitting the phase difference branch signal to the turn style dipole and supporting the turn style dipole to the reflector. The method of claim 5, wherein the turn-style dipole, Broadband circularly polarized turn-style antenna, characterized in that two elements are arranged for increasing gain. The method of claim 6, wherein the turn-style dipole, Broadband circularly polarized turn style antenna, characterized in that it is manufactured in the form of a PCB board for smooth signal transmission. The method of claim 5, wherein the antenna unit, And a parasitic element near the dipole radiator to give the broadband characteristics of the antenna. 10. The wideband circularly polarized turn style antenna of claim 8, wherein the parasitic element is variable in width and length to determine a bandwidth. The method of claim 6, wherein the turn-style dipole consists of a horizontal dipole and a vertical dipole, the horizontal dipole is printed on the front surface of the PCB substrate, connected to the second feed line through a horizontal dipole via and branched from the phase difference power distribution unit Broadband circularly polarized turn-style antenna, characterized in that the supplied signal. 12. The wideband circularly polarized turn style antenna of claim 10, wherein the horizontal dipole includes a horizontal dipole signal line and is connected to a horizontal dipole balance via via the horizontal dipole signal line to transmit a signal to a second balance. The broadband circular circle of claim 10, wherein the vertical dipole is printed on a rear surface of the PCB substrate and receives a branched signal from the phase difference power distribution unit through a vertical dipole via connected to a first feed line. Polarized Turnstile Antenna. 13. The wideband circular polarization turn style antenna of claim 12, wherein the vertical dipole includes a vertical dipole signal line and is connected to a vertical dipole balun via via the vertical dipole signal line to transmit a signal to a first balun. 12. The method of claim 11, wherein the horizontal dipole, the horizontal dipole signal line, the second feed line and the second balance are separated from each other at a predetermined interval to determine the isolation between the antenna impedance and the horizontal and vertical dipoles. Broadband Circular Polarized Turnstile Antenna. The broadband of claim 13, wherein the vertical dipole, the vertical dipole signal line, the first feed line, and the first balun are separated from each other at a predetermined interval to determine the isolation between the antenna impedance and the horizontal and vertical dipoles. Circularly polarized turnstyle antenna.

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