KR100886511B1 - QHA feeder using wilkinson power divider with 90 degree shifted phase - Google Patents

Abstract

The present invention provides a QHA feeder using a Wilkinson power divider having a phase difference of 90 degrees, comprising: an input port to which a signal is applied; A first output port for outputting a signal having a zero degree phase difference when a signal of the input port is applied; A second output port for outputting a signal having a 90 degree phase difference by a λ / 4 transmission line when a signal is applied to the input port; A λ / 2 transmission line connected to the first output port and the second output port; A third output port configured to output a signal having a phase difference of 180 degrees by the λ / 2 transmission line when a signal is applied to the input port; And a second output port for outputting a signal having a 270 degree phase difference by the λ / 2 transmission line when a signal is applied to the input port, and is relatively simple to apply the QHA to a portable satellite communication device. It is possible to propose a feeder circuit that can be designed in a small size.

QHA, power supply circuit, quadrature signal, Wilkinson power divider, matching circuit

Description

QHA feeder using wilkinson power divider with 90 degree shifted phase}

1 is a structural diagram of a patch antenna for a conventional satellite communication.

2 is a structural diagram of a conventional helical antenna.

3 is a structural diagram of a conventional QHA antenna.

4 is a schematic diagram of a conventional QHA antenna.

5 is a perspective view showing the configuration of a conventional QHA antenna.

6 is a schematic diagram of a QHA feeder using a Wilkinson power divider having a 90 degree phase difference according to an embodiment of the present invention.

FIG. 7 is a schematic diagram showing an example in which a QHA feeder using a Wilkinson power divider having a 90 degree phase difference of FIG. 6 is applied to compensate a phase characteristic of an orthogonal signal by connecting a λ / 4 shorting stub to an in phase signal output terminal of the Wilkinson power divider. .

In a QHA feeder using a Wilkinson power divider having a 90 degree phase difference of FIG. A schematic diagram showing an example in which a separate matching unit for antenna matching is added between an output terminal of a Wilkinson power divider having a 90 degree phase difference and a portion where an antenna is connected.

FIG. 9 is a graph illustrating power distribution characteristics of orthogonal signals appearing at four output ports in a QHA feeder using a Wilkinson power divider having a 90 degree phase difference of FIG. 7.

FIG. 10 is a graph showing four phase differences according to frequencies of quadrature signals output in a QHA feeder using a Wilkinson power divider having a 90 degree phase difference of FIG. 7.

<Description of Symbols for Main Parts of Drawings>

1: Input port 2: 1st output port (0 degree)

3: second output port (90 degrees) 4: third output port (180 degrees)

5: 4th output port (270 degrees) 6: λ / 2 transmission line

7: lambda / 4 stub 8: first matching portion

9: the second matching portion

[1] Kilgus, C.C, "Multielement Fractional Turn Helices", IEEE Trans. Antennas and Propagation, Vol. AP-16, No. 4, July PP. 400-501 (1968)

[2] Kilgus, C.C, "Resonant Quadrifilar Helix", IEEE Trans. Antennas and Propagation, Vol. AP-17, No. 3, May PP. 349-351 (1969)

[3] Bricker, R. W., "A Shaped Beam Antenna for Satellite Data Communication", IEEE AP-S Int. Symp. Digest, October pp. 121-126 (1976)

[4] Patton, W.T., "The Backfire Bifilar Helical Antenna", Antenna Laboratory Resort 61, AD 289084, Univ. of Illinois, Urbana, IL, September 1962

[5] Kilgus, C.C, "Resonant Quadrifilar Helix Design", Microwave Journal, Vol. 13, No. 12, December pp. 49-54 (1970)

[6] Adam, A.T, R.K. Greenough, R. F. Wallenberg, A. Mendlovics, and C. Lumjiak, "The Quadrifilar Helix Antenna", IEEE Trans. Antennas and Propagation, Vol. Ap-22, no. 2, March pp. 173-178 (1974)

[7] Korean Intellectual Property Office Application No. 20-2006-0003127 (filed February 02, 2006), "Antenna module for satellite communication in mobile wireless communication device"

[8] Korean Intellectual Property Office Application No. 10-2004-0014926 (Application Date: March 05, 2004), "Antenna for Portable Wireless Communication Device"

[9] Korean Intellectual Property Office Application No. 10-2000-7008943 (Application Date: August 16, 2000), "Adaptive Multi-Pillar Antenna"

[10] Korean Intellectual Property Office Application No. 10-2002-7003119 (Application Date: March 08, 2002), "Adaptive Multi-Pillar Antenna"

[11] Korean Intellectual Property Office Application No. 10-2005-0067681 (filed July 26, 2005), "Handset Quadreplier Spiral Antenna Mechanical Structures"

[12] Korean Intellectual Property Office Application No. 10-2005-0022253 (filed March 17, 2005), "Antenna with four spiral radiator structures"

The present invention relates to a QHA (Quadrifilar Helix Antenna, Quadraphil Helical Antenna), and in particular, to apply a QHA to a portable satellite communication device, it is suitable to propose a feed circuit that can be designed relatively simple and small size 90 degrees A QHA feeder using a Wilkinson power divider having a phase difference is provided.

In general, the satellite, broadcasting, telecommunications, and internet industries are exploding, and are becoming the core medium of the information society in the 21st century. The satellite broadcasting receiving equipment industry has already been developed, including satellite antennas, and this is especially noticeable in the recent fields of global positioning system (GPS) and satellite digital multimedia broadcasting (DMB). . In addition, with the development of semiconductors and the development of communication technologies, as the size of the device becomes smaller and lighter, its application range becomes wider, and its use such as GPS and DMB reception functions in vehicles as well as personal portable devices is becoming more common.

1 is a structural diagram of a patch antenna for a conventional satellite communication.

Thus, as a representative example of an antenna for receiving a conventional satellite signal, a patch antenna refers to an antenna having a planar shape, as shown in FIG.

This conventional method is advantageous in that it is small, light, inexpensive, and easy to integrate, but due to the characteristics of the directional antenna, the front of the antenna should always be installed upward to receive satellite signals. There was a disadvantage that there are many installation restrictions, such as to be mounted. This installation limitation has a limitation in design application, and when carrying, there is a problem that the reception level may drop due to friction, accessories, and mounting positions.

What has emerged as an antenna to compensate for this problem is a QHA (Quadrifilar Helix Antenna) using a conventional helix antenna.

2 is a structural diagram of a conventional helical antenna.

As shown, the helical antenna refers to an antenna which is wound around a coil 21 having a spring shape electrically having a length of λ / 4, and connects a spiral conductor to the center conductor of the coaxial feeder and connects the coaxial cable 23 The outer conductor is an antenna connected to the ground plane 25. Helical antenna has the advantage that can be implemented in a much smaller size than the dipole antenna and monopole antenna at the same frequency.

3 is a structural diagram of a conventional QHA antenna.

QHA type antennas are a type of antenna used for satellite communication in mobile wireless communication devices such as mobile terminals or GPS receivers. The antenna provides circularly polarized radiation and can be designed to have a quarter-wave or half-wavelength structure with shorted ends. Referring to the drawings, the QHA forms the ground section 35 to form the feed section 31 and the short circuit section 37 and to electrically connect therebetween. Comprising four radiating elements 33 electrically connected to one side of the feed section and the short circuit section, the feed section is arranged to feed the four radiating elements with a phase difference of 90 degrees to provide a circularly polarized radiation pattern .

1 to 3 are contents described in the prior art document information [7] (hereinafter, only the document number is described).

The quadrupole antenna is an electrical microantenna for providing circular polarization in the broad angular region. The antenna generally consists of four Helices, each Helix placed equally on the circumferential surface of the dielectric cylinder or any dielectric disk support, with four equally applied signals of four phases each Is fed. The quadruple can also be described as two orthogonal bifilars fed in four phases, where the bifilar is a two-element helical antenna.

Quadrupole antennas have been developed by many researchers, and Kilgus has proposed a halt-turn current distribution, and the half-wavelength quadrifilar is shown to be similar to the current distribution of a loop dipole antenna ([1], [2]. From this interpretation, Kilgus derives an equation describing the normalized radiant field and presents circular polarizations that exist outside of the sphere ([2]).

In the QHA, dielectric support pieces are important. Cylindrical foam, hollow dielectric tubes, or periodic dielectric spacers are used to support helical devices. These dielectric materials must have low loss tangent and low permittivity to meet the phase velocity required for radiation ([3]).

Quadruple helix feeds at 1) top and 2) bottom. In case 1), the helix element is fed at the top and these elements are shorted at the bottom above the ground plane. Electromagnetic radiation radiates towards the feed point and this arrangement is called backfire quadrifilar helix. Patton showed that as the backfire bifilar creates a conical beam and the size of the antenna increases, the beam is scanned from the backfire to the broadside and the front-to-back ratio drops to unity when the number of turns decreases to 1 (4). Kilgus provided a design technique for a short backfire quadrifilar helice. [5] When powered from the bottom, the quadruple helical antenna feeds toward the ground plane, radiates in the forward direction and forwards it. Called fire quadrifilar helix. Adam provided design data for this ([6]).

Referring to the technology filed for such a QHA antenna as follows.

FIG. 3 shows the structure of the quadruple helix antenna proposed in the [8] antenna for a portable radio communication device.

Thus comprising four radiating elements 33 for forming a quarter-wave quadruple helix structure, each of the radiating elements 33 being arranged for electrical connection to a wireless circuit of a portable radio communication device. At one end, each of the radiating elements 33 is at a second end facing the first end electrically connected to a corresponding second end of the other three radiating elements, thereby providing four radiating elements 33 An antenna unit for a portable radio communication device which forms a short circuit 37 for an electric field, wherein the quadruple helix structure is arranged between the ground and the short circuit 37 for electrical connection to the portable radio communication device. It characterized in that it comprises a grounding portion 35 is arranged coaxially along the inside of.

4 is a schematic diagram of a conventional QHA antenna, which is described in "Adaptive Multi-Pillar Antenna" of [9] and "Adaptive Multi-Pillar Antenna" of [10].

The QHA thus comprises four helical filaments (10-40) and eight radial filaments (50-120). (Other embodiments may use spiral filaments spacing six angles, and may also use spiral filaments spacing even angles.) The spiral filaments are intertwined as shown in FIG. And are positioned around the longitudinal axis of the antenna at 90 degrees to each other. Four radial filaments 50-80 are disposed at the top and 90-120 are disposed at the bottom of the spiral to connect with the helical filaments and form two bifilar loops. The antenna is fed to a set of radial filaments 90, 110 with a 90 degree phase difference between the two feeds. The radial filaments 50-80 at the top of the antenna for the feed may be a circuit that is partially shorted or open depending on the resonant length of the helical filament and the required response.

Fig. 5 is a perspective view showing the structure of a conventional QHA antenna, which is described in "Handset Quadreplier Spiral Antenna Mechanical Structures" in [11] and "Antenna with Four Spiral Radiator Structures" in [12].

Thus, it includes filler windings 12, 14, 16, and 18 that extend from the lower portion 20 to the upper portion 22 of the QHA 10 having a cylindrical shape. FIG. 5 shows that the fillers 12, 16 arranged in opposite positions are electrically connected by the conductive bridge 23 and the pillars 14, 18 are electrically connected by the conductive bridge 24. QHA is indicated. The signal propagating through the filler 12/16 has a quadrature phase relationship with the signal propagating through the filler 14/18 to produce the desired circular signal polarization. Each of the pillars 12, 14, 16, 18 comprises a conductive element such as a conductor having a circular or rectangular cross section or a wire having conductive lines or lines on the dielectric.

Conductive bridges are used with QHA having a filler length equal to an even multiple of one-quarter wavelength at the operating frequency, but are not generally used when the length of the filler includes an odd multiple of one-fourth wavelength. Each conductive bridge 23, 24 (also referred to as a crossbar) comprises a conductive tape strip.

As such, the conventional QHA has a spotlight in the fields of satellite radio or satellite mobile phone system because it is physically small and light, so that it is easy to apply to a portable satellite communication device and the price is low.

QHA is particularly advantageous for satellite communication systems because it exhibits a radiation pattern with higher antenna gain when the satellite is between the ceiling and the horizon.

In order for QHA to emit excellent circular polarization, a relatively accurate orthogonal signal must be applied, and for this, a feeding network with excellent performance is required.

However, the feeding network required for the operation of the QHA, that is, the feeder circuit, generally uses circuits such as ring hybrids, 90 degree hybrids, and Wilkinson power dividers to reduce insertion loss and return loss and improve isolation between each output port. These conventional circuits have a problem that it is difficult to apply to a portable satellite communication device because it requires a relatively large area.

In addition, when the power ratio between the orthogonal signals output from the conventional power supply circuit is greatly changed in accordance with the change in frequency, there is a problem that the QHA does not emit stable circular polarization.

Accordingly, the present invention has been proposed to solve the conventional problems as described above, and an object of the present invention is to propose a power supply circuit that can be designed with a relatively simple and small size for applying QHA to a portable satellite communication device. To provide a QHA feeder using a Wilkinson power divider having a 90 degree phase difference.

In order to achieve the above object, a QHA feeder using a Wilkinson power divider having a 90 degree phase difference according to an embodiment of the present invention includes an input port to which a signal is applied; A first output port for outputting a signal having a zero degree phase difference when a signal of the input port is applied; A second output port for outputting a signal having a 90 degree phase difference by a λ / 4 transmission line when a signal is applied to the input port; A λ / 2 transmission line connected to the first output port and the second output port; A third output port configured to output a signal having a phase difference of 180 degrees by the λ / 2 transmission line when a signal is applied to the input port; And a fourth output port for outputting a signal having a 270 degree phase difference by the [lambda] / 2 transmission line when a signal is applied to the input port.

Hereinafter, an embodiment according to the present invention, a technical concept of a QHA feeder using a Wilkinson power divider having a phase difference of 90 degrees will be described with reference to the accompanying drawings.
As is well known, the Wilkinson power divider is a circuit proposed by Wilkinson for distributing and outputting an input signal into a plurality of signals having in-phase. In the present invention, the Wilkinson power divider having a phase difference of 90 degrees includes two signals output by connecting a λ / 4 transmission line to one of the two output stages in a conventional Wilkinson power divider having two output stages. It is configured to have a phase difference of 90 degrees.
6 is a schematic diagram of a QHA feeder using a Wilkinson power divider having a 90 degree phase difference according to an embodiment of the present invention, and FIG. 7 is a diagram of a Wilkinson power divider in a QHA feeder using a Wilkinson power divider having a 90 degree phase difference of FIG. 6. Schematic diagram showing an example of applying the λ / 4 shorting stub to the in-phase signal output terminal to compensate the phase characteristics of the orthogonal signal, Figure 8 is a QHA feeder using a Wilkinson power divider having a 90-degree phase difference of FIG. A schematic diagram showing an example in which a separate matching unit for antenna matching is added between an output terminal of a Wilkinson power divider having a 90 degree phase difference and a portion where an antenna is connected.

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As shown therein, an input port 1 to which a signal is applied; A first output port (2) for outputting a signal having a zero degree phase difference when a signal is applied to the input port (1); A second output port (3) for outputting a signal having a phase difference of 90 degrees by a λ / 4 transmission line when a signal is applied to the input port (1); A λ / 2 transmission line (6) connected to the first output port (2) and the second output port (3); A third output port (4) for outputting a signal having a phase difference of 180 degrees by the λ / 2 transmission line (6) when a signal is applied to the input port (1); And a fourth output port 5 for outputting a signal having a 270 degree phase difference by the λ / 2 transmission line 6 when a signal is applied to the input port 1.

The QHA feeder using the Wilkinson power divider having the 90 degree phase difference is configured by connecting the lambda / 4 stub 7 to the in-phase signal output terminal of the Wilkinson power divider.

The QHA feeder using the Wilkinson power divider having a 90 degree phase difference is configured by adding a separate matching unit for antenna matching between the output terminal of the Wilkinson power divider having a 90 degree phase difference and a portion where the antenna is connected.

The QHA feeder using the Wilkinson power divider having the 90 degree phase difference has an impedance

By doing so, the phase error of the output quadrature signal is minimized.

A preferred embodiment of a QHA feeder using a Wilkinson power divider having a 90 degree phase difference according to the present invention configured as described above will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to intention or precedent of a user or an operator, and thus, the meaning of each term should be interpreted based on the contents throughout the present specification. will be.

First, the present invention is to propose a feeder (Feeder) that can be designed in a relatively simple and small size in order to apply the QHA to a portable satellite communication device.

In addition, the present invention has a simple and easy to implement configuration, it is easy to apply to various miniaturized devices.

In addition, it is possible to simply add a λ / 4 stub to obtain a more accurate orthogonal signal over a wide frequency band.

In addition, by inserting a matching part between the output terminal of the Wilkinson power divider having a 90-degree phase difference and the antenna connection, it is also possible to apply the structure to minimize the insertion loss and return loss for any antenna impedance connected.

The feed structure in the present invention uses a Wilkinson power divider having a 90-degree phase difference to make two outputs having a 90-degree phase difference primarily, and additionally 180 degrees by connecting λ / 2 transmission lines to the output terminals, respectively. A signal having a phase difference of 270 degrees is obtained to generate an orthogonal signal having a total of four phases.

FIG. 6 is a diagram schematically illustrating a QHA power supply circuit using a Wilkinson power divider having a 90 degree phase difference according to an embodiment of the present invention.

When a signal is applied to the input port 1, an orthogonal signal having a phase of 0 degrees and 90 degrees appears as an output terminal of a power divider having a phase difference of 90 degrees, and 180 degrees through a λ / 2 transmission line 6 connected to each output terminal. In addition, an orthogonal signal having a phase of 270 degrees is further obtained.

In FIG. 6, four input ports of QHA are connected to the first output port 2, the second output port 3, the third output port 4, and the fourth output port 5, respectively.

If any impedance is seen through the λ / 2 transmission line, it will look the same, so if all four input ports of the antenna have the same input impedance, the same impedance of the two input ports of the antenna at the 90-degree hybrid output stage Are shown in parallel with each other, and half of the actual antenna port impedance is visible.

In another application example of the present invention as shown in FIG. 7, a λ / 4 shorting stub having a predetermined characteristic impedance is connected to an in-phase signal output terminal of a Wilkinson power divider having a 90 degree phase difference, and a signal output from the Wilkinson power divider. This compensates for the phase error of.

In the Wilkinson power divider having a phase difference of 90 degrees, a phase change rate according to frequency in a λ / 4 transmission line added to give a phase difference of 90 degrees is calculated by Equation 1 below.

는 전송선로의 전기적인 길이이고, f₀는 중심주파수이다.here

Is the electrical length of the transmission line and f ₀ is the center frequency.

The other impedance of the Wilkinson power divider should be connected to the λ / 4 short stub to determine the characteristic impedance of the stub so that the rate of phase change with frequency appears to be the same as Equation 1 at the center frequency.

The propagation scattering coefficient S ₂₁ in the λ / 4 shorting stub connected in parallel may be represented by Equation 2 below.

Where Y ₀ is the characteristic admittance seen from the second output stage of the circuit before adding the λ / 4 shorting stub, Y ₁ is the characteristic admittance of the λ / 4 shorting stub added, f ₀ is the center frequency, and f is the actual frequency applied. Indicates.

When the phase change rate according to the frequency of the transfer scattering coefficient by the lambda / 4 short stub is calculated from Equation 2 is expressed by the following equation (3) at the center frequency.

Where Z ₀ is the characteristic impedance seen from the second output terminal of the circuit before adding the λ / 4 shorting stub, Z ₁ is the characteristic impedance of the λ / 4 shorting stub to be added, and f ₀ is the center frequency.

The phase error of the orthogonal signal is minimized when the phase change rate of the Wilkinson power divider with the λ / 4 shorting stub and the λ / 2 transmission line of the Wilkinson power divider having a 90 degree phase difference is the same at the center frequency. From the equation of Equation 3, the same conditions as in Equation 4 below are made.

Thus, it is possible to minimize the phase error of the output quadrature signal.

FIG. 9 is a graph illustrating power distribution characteristics of orthogonal signals appearing at four output ports in a QHA feeder using a Wilkinson power divider having a 90 degree phase difference of FIG. 7.

Therefore, the magnitude error of the orthogonal signal output of less than 1 dB occurs over the 1 GHz range, showing that the stable power distribution characteristics in a very wide frequency band.

FIG. 10 is a graph showing four phase differences according to frequencies of quadrature signals output in a QHA feeder using a Wilkinson power divider having a 90 degree phase difference of FIG. 7.

Therefore, it can be seen that the slope of the phase difference according to the change of frequency is relatively gentle, showing a phase error over a wide frequency band.

As in the configuration of FIG. 8, as another embodiment of the present invention, it is possible to add a matching circuit between the output terminal of the Wilkinson power divider having a 90 degree phase difference and the antenna connection part so that the insertion loss of the power feeding circuit is minimized.

As such, the present invention proposes a feed circuit that can be designed with a relatively simple and small size in order to apply the QHA to a portable satellite communication device.

As described above, the QHA feeder using the Wilkinson power divider having a 90-degree phase difference according to the present invention can propose a feed circuit that can be designed with a relatively simple and small size for applying QHA to a portable satellite communication device. Will be.

In addition, the present invention has a feature that the configuration is simple and easy to implement, it can be implemented in a small area when applied to various miniaturized devices.

In addition, the present invention compensates the output phase characteristic of the Wilkinson power divider by adding a lambda / 4 short stub, it is possible to reduce the phase error of the orthogonal signal according to the frequency to a minimum.

Furthermore, the present invention has an excellent power distribution characteristic of the output orthogonal signal, which is easy to improve the radiation characteristic of the QHA.

Although the above has been described as being limited to the preferred embodiment of the present invention, the present invention is not limited thereto and various changes, modifications, and equivalents may be used. Therefore, the present invention can be applied by appropriately modifying the above embodiments, it will be obvious that such application also belongs to the scope of the present invention based on the technical idea described in the claims below.

Claims (4)

It has a first output terminal and a second output terminal, the second output terminal is connected to one end of the λ / 4 transmission line, the signal output from the other end of the λ / 4 transmission line is 90 degrees of the signal output from the first output terminal A QHA feeder using a Wilkinson power divider with a 90 degree phase difference configured to have a phase difference, An input port connected to an input terminal of the Wilkinson power divider; A first output port connected to a first output terminal of the Wilkinson power divider and outputting a signal having a phase difference of 0 degrees with a signal applied to the input port; A second output port connected to the other end of the λ / 4 transmission line and outputting a signal having a phase difference of 90 degrees with a signal applied to the input port; A third output port connected to the first output port through a λ / 2 transmission line to output a signal having a phase difference of 180 degrees with a signal applied to an input port; A fourth output port connected to the second output port through a λ / 2 transmission line to output a signal having a phase difference of 270 degrees with a signal applied to an input port; QHA feeder using a Wilkinson power divider with a 90 degree phase difference. The method according to claim 1, QHA feeder using the Wilkinson power divider having the 90 degree phase difference, A lambda / 4 short stub, one end of which is connected to the first output port and the other end of which is grounded; QHA feeder using a Wilkinson power divider having a 90-degree phase difference, characterized in that it further comprises. The method according to claim 1 or 2, QHA feeder using the Wilkinson power divider having the 90 degree phase difference, QHA feeder using a Wilkinson power divider having a 90 degree phase difference configured by connecting a separate matching unit for antenna matching between a portion where the first output port and the antenna are connected and a portion where the second output port and the antenna are connected, respectively . delete

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