KR101482533B1 - 90-degree phase shifter - Google Patents

Abstract

The present invention relates to a 90 degree phase shifter comprising: an input port having a circular cross-section shape; a first circular waveguide unit which is connected to the input port and has a circular cross-section shape; a first rectangular waveguide unit which is connected to the first circular waveguide unit and has a rectangular cross-section shape; a phase shifting unit which is connected to the first rectangular waveguide unit, has a rectangular cross-section shape, and allows a phase difference of a horizontal polarization signal and a vertical polarization signal included in an inputted circular polarization signal to have a set value; a second rectangular waveguide unit which is connected to the phase shifting unit and has a rectangular cross-section shape; a second circular waveguide unit which is connected to the second rectangular waveguide unit and has a circular cross-section shape; and an output port which has a circular cross-section shape. Therefore, the 90 degree phase shifter can be easily manufactured by separating the horizontal polarization signal and the vertical polarization signal which are orthogonal to each other in the circular polarization signal using protrusion units having different sizes in only two of four internal surfaces. Furthermore, the 90 degree phase shifter adds the circular waveguides and input and output ports which act as circular waveguides to easily perform an connection operation with another device having a circular waveguide, thereby reducing signal losses and improving transmission efficiency of a signal.

Description

90-degree phase shifter {90-DEGREE PHASE SHIFTER}

The present invention relates to a 90 degree phase shifter.

A satellite-based communication system is a satellite-based communication system for communicating between a satellite and a ground station in space orbit. It must be robust and light in weight to be mounted on a satellite. As a result, the satellite-based communication system must have a simple and compact structure.

On the other hand, a satellite-based communication system uses a circularly polarized signal to facilitate signal transmission to the ground.

In particular, very long baseline interferometry (VLBI) observations are intended to measure the physical quantities of asterisks by receiving circularly polarized signals originating from a celestial body. At this time, since the intensity of the radio wave signal as the circularly polarized signal is weak, the radio receiver is cryogenically cooled to have a very low noise temperature. Circular polarizers used in millimeter wave receivers use either a septum polarizer or a 90 degree phase shifter and an orthomode transducer (OMT).

At this time, the septum polarizer has a simple manufacturing method and is widely used in satellite communication and low frequency VLBI radio receiver.

However, when wide-band dual-circular polarization observation is required due to the wide band characteristic, a circular polarizer of a combination of a 90-degree phase shifter and an orthogonal mode converter is employed.

In general, the orthogonal mode converter operates in a wide band, so it is important to develop a 90-degree phase shifter in order to fabricate a broadband circular polarizer.

In this case, the simplest 90-degree phase shifter using a waveguide uses a method of inserting a dielectric into a circular waveguide.

However, this method is disadvantageous in that it is a narrow band, and dielectric resonance occurs because most of the radio wave receivers for observing the millimeter waveband VLBI are cooled at a very low temperature.

To overcome this disadvantage, a 90-degree phase shifter having a wide band characteristic made of a metal material has been developed. The 90-degree phase shifter has a rectangular cross-sectional shape, and a square waveguide is formed at both ends of the 90- It is connected.

However, the input side and the output side of the 90-degree phase shifter are respectively connected to feed horns for transmitting signals received from an antenna (for example, horn antenna) of the satellite communication system, An orthomode transducer (OMT), which is a device for separating two electromagnetic wave components polarized by the horizontal polarization signal and the vertical polarization signal, is connected.

However, these feed horns and orthogonal mode transducers are connected to a circular waveguide rather than a rectangular waveguide.

For this reason, a separate waveguide adapter (ie, a structure for coupling with a circular waveguide) is required for connection between a 90-degree phase shifter having a rectangular waveguide and a feed horn having a circular waveguide and an orthogonal mode transducer There arises a problem that the other side requires a waveguide adapter having a structure for coupling with a rectangular waveguide.

Also, since the waveguides used in the 90-degree phase shifter and the wave horns used in the feed horn and the orthogonal mode transducer connected to the waveguide are different from each other, the impedance matching of the signals is poor, and the signal transmission is adversely affected.

Korean Unexamined Patent Publication No. 10-2009-0132422 (published on Dec. 30, 2009, inventor: Jung Jin Il et al. 2)

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to simplify a connection structure of a 90-degree phase shifter.

Another aspect of the present invention is to reduce signal transmission efficiency and signal loss using a 90-degree phase shifter.

According to an aspect of the present invention, a 90-degree phase shifter includes an input port having a circular cross-sectional shape, a first circular waveguide portion connected to the input port and having a circular cross-sectional shape, a second circular waveguide portion connected to the first circular waveguide portion A phase difference between a horizontal polarization signal and a vertical polarization signal constituting an input circular polarization signal is set to a predetermined value. The first rectangular waveguide section has a rectangular cross section and is connected to the first rectangular waveguide section. A second circular waveguide section connected to the second rectangular waveguide section and having a circular sectional shape, and a second circular waveguide section connected to the phase shifting section and having a rectangular cross section, Sectional shape of the output port.

It is preferable that the phase shifter has four inner surfaces, and the two inner surfaces facing each other include a plurality of first and second wrinkles having different depths.

The phase shifter may have a structure of an inner surface symmetrical about a center line in the longitudinal direction.

Wherein the depth of the first corrugation is 0.156 mm and the width is 0.291 mm, the depth of the second corrugation is 0.216 mm and the width is 0.251 mm, and the interval between two adjacent corrugations in the phase transition portion is 0.14 mm .

Wherein each of the first and second rectangular waveguide portions has a width of 0.248 mm and an inner diameter of 2.54 mm and each of the first and second circular waveguide portions has a width of 0.35 mm and an inner diameter of 2.84 mm, Each of the output ports may have a width of 0.75 mm and an inner diameter of 2.931 mm.

The set value may be 90 +/- 3.3 degrees, and the operating frequency of the phase shifter may be 85 GHz to 115 GHz.

According to this feature, the 90-degree phase shifter separates the circularly polarized signal into a horizontal polarized signal and a vertical polarized signal orthogonal to each other by using protrusions having different sizes on only two inner surfaces of four inner surfaces, It is easy to manufacture.

Also, since the 90-degree phase shifter adds a circular waveguide serving as a circular waveguide and an input and an output port, connection operation with other devices having a win- dow waveguide is easily performed, and signal transmission efficiency is improved do.

1 is a partial perspective view of a 90 degree phase shifter in accordance with one embodiment of the present invention.
FIG. 2 is a cross-sectional view of the 90-degree phase shifter shown in FIG. 1 taken along the line II-II in FIG.
FIG. 3 is a view showing a structure in which an input flange and an output flange are combined with each other in a 90-degree phase shifter shown in FIG.
FIG. 4 is a graph showing a phase difference measured in the 90-degree phase shifter shown in FIG.
FIG. 5 is a graph illustrating return loss measured in the 90-degree phase shifter shown in FIG.
FIG. 6 is a graph illustrating insertion loss measured in the 90-degree phase shifter shown in FIG.
FIG. 7 is a graph illustrating the axial ratio of the 90-degree phase shifter shown in FIG.
8 is a view showing a part of a rectangular waveguide for calculating initial values for dimensions of a circular waveguide, a rectangular waveguide, and input and output ports in a 90-degree phase shifter according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

A 90-degree phase shifter according to an embodiment of the present invention will now be described with reference to the accompanying drawings.

First, the structure of a 90-degree phase shifter according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG.

1 and 2, a 90-degree phase shifter 100 according to an embodiment of the present invention includes an input port 111 to which a circularly polarized signal, which is a radio wave signal applied from the outside, A first circular waveguide section 121 connected to the input port 111 and an input side rectangular waveguide section connected to the first circular waveguide section 121 A phase shifter 14 connected to the first rectangular waveguide section 131 and an output side rectangular waveguide section connected to the phase shifter 14 (Hereinafter, referred to as a second circular waveguide part) 122 connected to the second rectangular waveguide part 132 and a second circular waveguide part 122 connected to the second rectangular waveguide part 132, And an output port 112 connected to the output port 122.

3, the 90-degree phase shifter 100 according to the present embodiment includes an input flange (hereinafter, referred to as 'first flange') disposed at the input port 111 and the output port 112, ) 151 and an output flange (hereinafter referred to as a "second flange"

1 and 2, the outer surface of the 90-degree phase shifter 100 has an uneven surface the same as the inner surface. Alternatively, as shown in FIG. 3, the outer surface of the 90- And the inner surface of the 90-degree phase shifter 100 has an uneven surface, as shown in Figs. 1 and 2, in this case as well.

A 90-degree phase shifter 100 having such a structure is a waveguide having waveguides having different structures. The 90-degree phase shifter 100 receives a radio wave signal and outputs a polarized signal of two quadrature components having a phase difference of about 90 degrees . Therefore, the input and ports 111 and 112, the first and second circular waveguide sections 121 and 122, the first and second rectangular waveguide sections 131 and 132, and the phase shift The inside of the portion 14 is empty for transmission of the radio wave signal.

The input port 111 is connected to a receiver, for example, a feed horn (not shown) that receives and transmits a circularly polarized signal from a front end device coupled through a first flange 151 And receives a circular polarization signal applied from the feed horn.

As shown in FIGS. 1 and 2, the input port 111 has a circular cross-sectional shape similar to that of the first circular waveguide portion 121 positioned at the rear end, and has the same shape as the first circular waveguide portion 121 I have.

Accordingly, the circularly polarized signal is applied to the input port 111 through the input horn 111 via the feed horn.

As already described, since the input port 111 has the same shape as the first circular waveguide portion 121, the input port 111 also functions as a circular waveguide.

The first circular waveguide section 121 is connected to the input port 111 and has a circular cross-sectional shape as described above.

The first rectangular waveguide section 131 is located at the rear end of the first circular waveguide section 131 and is connected to the first circular waveguide section 121 and has a rectangular shape, for example, a square sectional shape.

The first circular waveguide portion 121 and the first rectangular waveguide portion 131 are portions for performing impedance matching with the phase shifter 14 and are formed by changing the reactance to form circular and rectangular waveguide portions Impedance matching is performed so as to reduce the transmission loss of the radio wave signal.

Since the first circular waveguide section 121 is provided on the input side as described above, when the first circular waveguide section 121 is connected to a receiver (for example, a feed horn) having a circular waveguide, A waveguide adapter is not required.

Although the radio wave signal received by the first circular waveguide 121 is incident on the first rectangular waveguide section 131 having a different structure from that of the first circular waveguide section 121, Since the first rectangular waveguide section 131 is in the state where the impedance matching is performed, the propagation signals are transmitted from the first circular waveguide section 121 having a different structure to the first rectangular waveguide section 131, do.

The phase shifter 14 has a rectangular (e.g., square) cross-sectional shape in the same manner as the first rectangular waveguide 131, and has a hollow space therein.

At this time, the phase transition portion 14 has two inner surfaces of four inner surfaces, that is, two corrugated surfaces having different depths on opposite inner surfaces (e.g., upper and lower surfaces) That is, protrusions 141 and 142, respectively.

These corrugations 141 and 142 change the boundary condition of the inner surface of the phase shifter 14 serving as a waveguide.

Accordingly, a horizontal polarization signal that is incident through the input port 111 and constitutes a circular polarization signal incident on the phase shifter 14 via the first circular waveguide section 121 and the first rectangular waveguide section 131, A difference occurs in the propagation constant of the polarized signal, and when the two polarized signals of the horizontal polarization signal and the vertical polarization signal, which are orthogonal components to each other, pass through the phase shifter 14, do.

At this time, the phase difference between the horizontal polarization signal and the vertical polarization signal generated by the phase shifter 14 varies depending on the difference of the propagation constant and the length of the phase shifter 100.

Therefore, the length of the phase shifter 100, the number of the corrugations 141 and 142 formed on the two inner surfaces, the shape and the dimensions, and the like are fabricated such that the horizontal polarization signal and the vertical polarization signal have a phase difference of about 90 degrees from each other.

The depth D1 of the first corrugation 141 is greater than the depth D2 of the second corrugation 142 so that the first diameter 141 is greater than the depth D1 of the second corrugation 142, The inner diameter? 11 of the portion where the second diameter 142 is located is also larger than the inner diameter? 21 of the portion where the second diameter 142 is located.

As described above, the phase shifter 14 having the uneven surface provided with the first and second corrugations 141 and 142 on the two inner surfaces has the phase shift portion 14 in the longitudinal direction (that is, the extending direction) The structure of the inner surface of the phase shifter 14 around the center line C1 has a symmetrical structure.

The left side portion 41 located on the left side with respect to the center line C1 and the right side portion 42 positioned on the right side with respect to the center line C1 extend from the center line C1 to the first wrinkle 141 and the second wrinkle 142 ) Are alternately located. As a result, the two first wrinkles 141 are positioned with the center line C1 therebetween.

In this example, the left side portion 41 and the right side portion 42 each have six first wrinkles 141 and five second wrinkles 142, and a total of twelve first wrinkles 141 are formed on one inner side, And ten second wrinkles 142. [0031]

Each of the first and second corrugations 141 and 142 has a rectangular cross-sectional shape and is a rectangular protrusion extending in the width direction of the phase shifter 14 (i.e., the direction intersecting the longitudinal direction). At this time, each of the first and second wrinkles 141 and 142 is formed by extending the entire width of the corresponding inner surface in a straight line.

The width W1 of the first corrugation 141 and the width W2 of the second corrugation 142 are equal to each other and may be 0.29 mm, for example.

In addition, the interval I1 between the two pleats 141 and 142 (or 141 and 141) positioned adjacent to each other in the longitudinal direction (i.e., extending direction) of the phase shift portion 14 may be about 0.140 mm.

The shape of the inner surface of the phase shifter 14 (that is, the condition of the inner surface) is changed by using the first and second wrinkles 141 and 142 so that the phase difference between the horizontal polarization signal and the vertical polarization signal is And a wrinkle shape is designed on only two inner surfaces of the four inner surfaces, so that the phase shifter 14 can be easily manufactured.

Further, since the two wrinkles 141 and 142 of different shapes are used to generate a 90-degree phase difference with respect to the two polarized signals, a 90-degree phase shifter having a broadband characteristic is fabricated.

The second rectangular waveguide section 132 and the second circular waveguide section 122 are identical to the first rectangular waveguide section 131 and the first circular waveguide section 121 described above and have the same structure and function.

The propagation signals passing through the phase shifter 14 serving as a square waveguide are transmitted to the second square waveguide section 132 which is the same square waveguide and impedance matching with the second rectangular waveguide section 132 is performed And outputted to the first circular waveguide section 122 that has been performed.

Therefore, even though the waveguide sections 132 and 122 having different shapes are already subjected to impedance matching, the loss of the propagation signal due to the impedance mismatching is prevented.

In this example, the dimensions of the corresponding parts of the circular waveguide sections 121 and 122, the rectangular waveguide sections 131 and 132, and the input and output ports 111 and 112 for impedance matching are as follows.

First, as shown in FIG. 8, an initial value for calculating the dimension of each part is calculated by using a case where the shape of protrusions formed as wrinkles formed on the inner surface of the waveguide is uniformly formed.

The initial value is calculated based on the following.

7, when a protruding portion 31 having the same shape on the inner surface in the Y-axis direction is present in a rectangular waveguide having an inner size of a × b, the TE 10 mode transcendental equation Equation (1) is as follows.

이고,

이다. In Equation (1)

ego,

to be.

Here, λ is the wavelength of the polarized signal, β _y is the propagation constant of the TE10 mode, and p, h, and ω denote the interval, depth, and width of the protrusion 31, respectively.

The propagation constant (? _Y ) of the TE10 mode is calculated by using a numerical analysis method of the equation of Equation (1).

에 의해 산출된다.On the other hand, since the propagation constant (? _X ) in the TE01 mode, which is an orthogonal polarization component, is the direction in which the protruding portion 31 is absent,

Lt; / RTI >

Therefore, since the propagation coefficients (? _X ,? _Y ) for the two polarized signals orthogonal to each other are calculated, the length (1) of the waveguide is adjusted as shown in the following formula (2) An initial value for the dimension of each corresponding portion formed on the inner surfaces of the circular waveguide portions 121 and 122, the rectangular waveguide portions 131 and 132 and the input and output ports 111 and 112 is calculated.

However, since the initial value is calculated under the assumption that the protruding portions 31 are uniform, as described above, since the perimeter of each corresponding portion is not uniform as in the present example, the three-dimensional electromagnetic field software is used based on this initial value, The dimensions of the corresponding portions formed on the inner surfaces of the circular waveguide portions 121 and 122, the rectangular waveguide portions 131 and 132 and the input and output ports 111 and 112 are calculated.

The inner diameter PHI 3 of the first and second rectangular waveguide parts 131 and 132 is 2.54 mm and the width W3 thereof is 0.248 mm and the inner diameter of the first and second circular waveguide parts 121 and 122 The inner diameter? 1 of the input port 111 and the output port 112 may be 2.931 mm and the width W1 may be 0.75 mm, .

The length L11 from the center line C1 to the input port 111 and the length L12 from the center line C1 to the output port 112 are equal to 6.35 mm, And the total length L1 to the center line 112 is 12.7 mm.

1 and 2, the depths of the corrugations 143 formed in the portions adjacent to the first and second rectangular waveguides 131 and 132 are equal to the depths of the first and second rectangular waveguides 131 and 132, And the inner diameter of the phase shifter 14 increases toward the first and second rectangular waveguides 131 132.

Since the inner diameter of the phase shifter 14 linearly decreases in this way, the impedance matching between the phase shifter 14 and the first and second rectangular waveguides 131 and 132 can be performed efficiently, .

The phase difference between the horizontal polarization signal and the vertical polarization signal that has passed through the phase shifter 14 at the operating frequency of 85 GHz to 115 GHz band is 90 +/- 3.3 degrees to be.

The output port 112 also has the same structure as the input port 111 and outputs two polarized wave signals having a phase difference of 90 degrees in the phase shifter 14 to a subsequent stage device (for example, an orthogonal mode transducer). Accordingly, the output port 112 also functions as a waveguide outputting a radio wave signal to the rear end.

As described above, since the first and second circular waveguide sections 121 and 122 are provided on the input side and the output side of the phase shifter 14, the input side device (e.g., feed horn) having the circular waveguide and the output side device (For example, an orthogonal mode transducer), a separate waveguide adapter having both ends of different structures (circular shape and square shape) is unnecessary.

That is, in the 90-degree phase shifter 100 of this embodiment, the input flange 151 is engaged with the corresponding flange attached to the output side of the feed horn, and the output flange 152 and the input side of the orthogonal mode converter And the coupling operation between the device and the 90-degree phase shifter 100 is performed.

The first and second flanges 151 and 152 are formed to surround the input port 111 and the output port 112 in the outer surface of the input port 111 and the output port 112, And holes of the input port 111 and the output port 112 are exposed at approximately the center.

The planar shape of each of the flanges 151 and 12 is a donut shape having an input port 111 and an output port 112 at the center and a plurality of flanges 151 and 12 for coupling with fastening means such as screws There is an engaging hole 51 of the engaging portion 51.

Next, the performance of the 90-degree phase shifter 100 according to the present example will be described with reference to FIGS.

First, FIG. 4 shows a graph G11 obtained by measuring the phase difference between the horizontal polarization signal and the vertical polarization signal generated in the 90-degree phase shifter 100 according to the present example.

The phase difference in the 90-degree phase shifter 100 according to this example was measured using a VNA (vector network analyzer). In order to measure the phase difference of the polarized signals orthogonal to each other, a 90-degree phase shifter 100, The S-parameter was measured while rotating the circular waveguide sections 121 and 122 connected to the output ports 111 and 121 by 90 degrees.

Since the operating frequency (85 GHz to 115 GHz) according to this example is outside the W-band, the 110 GHz to 115 GHz band was measured using a D-band VNA.

As shown in FIG. 4, the phase difference G11 measured in the 85 GHz to 115 GHz band, which is the operating frequency of the 90-degree phase shifter 100, was 90 +/- 3.3 degrees. This phase difference is compared with the simulation graph G12 , There was no significant difference.

The graph shown in FIG. 5 is a graph (G21) that measures return loss for determining the degree of impedance matching. It is known that the reflection loss of the 90-degree phase shifter 100 according to the present example is about -20 dB or less , And these values are similar to the simulation graph (G22).

A graph (G21) that measures the actual reflection loss includes a reflection loss of the waveguide adapter used for measuring the reflection loss. However, since the reflection loss for the waveguide adapter is generally 20 dB or less, It is considered that the measurement of the reflection loss of the optical waveguide will not significantly affect the measurement.

FIG. 6 shows a graph G31 in which the insertion loss of the 90-degree phase shifter 100 according to the present embodiment is measured. At this time, the other graph (G32) in Fig. 6 is a simulation graph. The interval where the measured insertion loss is near 0dB is estimated as the interval including the measurement error of the VNA in the process of subtracting the insertion loss of the waveguide adapter used to measure the insertion loss.

Lastly, FIG. 7 is a graph (G41) in which the axial ratio of the 90-degree phase shifter 100 according to the present example is measured. At this time, the graph (G42) in FIG. 7 is the graph measured in the simulation.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

100: 90 degree phase shifter 111: Input port
112: output port 121, 122: circular waveguide section
131, 132: square waveguide part 14: phase shifter
151: input flange 152: output flange

Claims (6)

An input port having a circular cross-sectional shape,
A first circular waveguide connected to the input port and having a circular cross-sectional shape,
A first rectangular waveguide section connected to the first circular waveguide section and having a rectangular sectional shape,
A phase shifter connected to the first rectangular waveguide and having a rectangular sectional shape and having a phase difference between a horizontal polarization signal and a vertical plane signal constituting an input circular polarization signal,
A second rectangular waveguide connected to the phase shifter and having a rectangular cross section,
A second circular waveguide connected to the second rectangular waveguide and having a circular cross-sectional shape, and
An output port having a circular cross-
Lt; / RTI >
Wherein the phase transition portion has four inner surfaces, and the two inner surfaces facing each other on the opposite sides include a plurality of first and second wrinkles having different depths
90 degree phase shifter. delete The method of claim 1,
Wherein the phase shifter has a structure of an inner surface symmetrical about a center line in the longitudinal direction. The method according to claim 1 or 3,
The depth of the first corrugation is 0.156 mm, the width is 0.291 mm,
The depth of the second corrugation is 0.216 mm and the width is 0.251 mm,
The interval between two adjacent corrugations in the direction of the grain of the phase transition portion is 0.14 mm
90 degree phase shifter. 5. The method of claim 4,
Wherein each of the first and second rectangular waveguide portions has a width of 0.248 mm and an inner diameter of 2.54 mm,
Each of the first and second circular waveguide portions has a width of 0.35 mm and an inner diameter of 2.84 mm,
The input port and the output port each have a width of 0.75 mm and an inner diameter of 2.931 mm
90 degree phase shifter. The method of claim 1,
Wherein the set value is 90 +/- 3.3 degrees and the operating frequency of the phase shifter is 85 to 115 GHz.

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