KR101463072B1 - coupler - Google Patents

Abstract

A coupler is provided. The coupler according to an embodiment of the present invention comprises a first horizontal branch line which connects an input port and a first output port to each other; a second horizontal branch line which connects an isolation port and a second output port to each other; a first vertical branch line which connects the input port and the isolation port to each other; a second vertical branch line which connects the first output port and the second output port to each other; and a third horizontal branch line which connects the first and second branch lines to each other.

Description

Coupler

The present invention relates to a coupler, and more particularly to a dual-band branch-line coupler. The present invention was derived from a research conducted by the Korea Communications Commission (KCC) of the Korea Communications Commission (KFCC) as part of the broadcasting technology development project of the broadcasting and communication media (Project Number 2011-0016802, Space Polarization Division Multiple Access Development of MASSIVE MIMO technology)

The mm-wave band is a very attractive band for application to a broadband high-speed communication system in that it can provide a vast frequency band ranging from several to several tens of GHz. As the operating speed of Si-based devices such as SiGe HBT and Si CMOS increased sharply in the 2000s, the expectations for low-cost millimeter-wave system implementation increased.

As a result, the possibility of commercialization of the mm-wave system has been greatly increased. Currently, the mmwave circuit based on Si RFCMOS has recently been published by several researchers around the world, and research is proceeding toward higher frequencies.

Among commercial applications of the millimeter wave, imaging system (operating frequency 94 GHz) application has attracted much attention in recent years due to the rapid increase in demand for security system, aviation safety system, and sensing system. The potential for growth is also being analyzed to be quite large.

The millimeter wave system developed so far uses a system on package (SoP) type combined with a chip after manufacturing passive circuits (antenna, coupler, filter) on an external substrate using LTCC process. (System on Chip), which is a system in which the entire system including all of them is fabricated on a single chip.

When passive circuits are fabricated together with other high frequency (RF) circuits in a CMOS process, the entire system manufacturing process can be reduced and interconnection problems between different substrates can be solved. As the operating frequency increases, the wavelength becomes shorter. Therefore, it is expected that the size of the passive circuits becomes smaller and it can be mounted inside the CMOS chip.

However, to date, high-frequency passive circuits still have a problem of wasting or insufficient space when considering coupling with a receiving end (LNA, Mixer, VCO) due to its large size.

As a representative example of the high-frequency passive circuit, there is a branch line coupler. A branch line coupler is a transmission line coupler using direct coupling through a branch line, and is a useful coupler for a very wide range of applications.

The two output powers of the branch line couplers each have a power corresponding to one half of the input, that is, a -3 dB coupler that functions to evenly distribute the input power, The even output signal has a phase difference of 90 °. It is used for the path separation of balanced amplifiers and other power divider. It can be used as a combiner since it is a perfectly symmetrical structure.

An object of the present invention is to provide a coupler capable of setting an arbitrary coupling level.

The problems to be solved by the present invention are not limited to the above-mentioned problems, and the problems not mentioned can be clearly understood by those skilled in the art from the present specification and the accompanying drawings will be.

The present invention provides a coupler.

A coupler according to an embodiment of the present invention includes a first horizontal branch line connecting an input port and a first output port, a second horizontal branch line connecting an isolation port and a second output port, A first vertical branch line connecting between the isolation ports, a second vertical branch line connecting between the first output port and the second output port, and a second vertical branch line connecting between the first vertical branch line and the second vertical branch line And may include a third horizontal branch line.

Wherein the first vertical branch line comprises a first microstrip line disposed between the first horizontal branch line and the third horizontal branch line and a second microstrip line disposed between the second horizontal branch line and the third horizontal branch line, The first microstrip line and the second microstrip line may be provided so as to have the same impedance.

The second vertical branch line includes a third microstrip line disposed between the first horizontal branch line and the third horizontal branch line and a third microstrip line disposed between the second horizontal branch line and the third horizontal branch line, And the third microstrip line and the fourth microstrip line may be provided to have the same impedance.

The first microstrip line, the second microstrip line, the third microstrip line, and the fourth microstrip line may be provided to have the same impedance.

The third horizontal branch line includes a first branch line extending from the first vertical branch line toward the second vertical branch line, a second branch line extending from the second vertical branch line toward the first vertical branch line, And a third branch line connecting the first branch line and the second branch line, wherein the first branch line and the second branch line may be connected out of the horizontal line.

The first horizontal branch line and the second horizontal branch line may be formed parallel to each other.

The first vertical branch line and the second vertical branch line may be formed parallel to each other.

The first horizontal branch line and the first vertical branch line may be formed perpendicular to each other.

The second horizontal branch line and the second vertical branch line may be formed perpendicular to each other.

The third horizontal branch line may be formed parallel to the first horizontal branch line and the second horizontal branch line.

The third horizontal branch line may be formed perpendicular to the first vertical branch line and the second vertical branch line.

The coupler may operate in a dual band.

The present invention also provides a coupler according to another embodiment.

According to another aspect of the present invention, there is provided a coupler including a first horizontal branch line connecting an input port and a first output port, a second horizontal branch line connecting an isolation port and a second output port, A first vertical branch line connecting between the isolation ports, a second vertical branch line connecting between the first output port and the second output port, and a second vertical branch line connecting between the first vertical branch line and the second vertical branch line Wherein the first horizontal branch line and the second vertical branch line are substantially parallel to each other and the first horizontal branch line and the second horizontal branch line are substantially parallel to each other, And the first vertical branch line, the second horizontal branch line, and the second vertical branch line are formed perpendicular to each other, A third horizontal branch line is formed parallel to the first horizontal branch line and the second horizontal branch line and the third horizontal branch line is formed perpendicular to the first vertical branch line and the second vertical branch line .

The coupler may operate in a dual band.

According to an embodiment of the present invention, it is possible to provide a coupler capable of setting any coupling level.

The effects of the present invention are not limited to the above-described effects, and the effects not mentioned can be clearly understood by those skilled in the art from the present specification and the accompanying drawings.

1 is a schematic illustration of a coupler of the present invention. Figure 2 is a view in accordance with one embodiment of the coupler of Figure 1;
FIG. 3 is a view of symmetrically viewing the coupler of FIG. 1 in order to obtain an equivalent admittance value in the even mode and the odd mode.
Figs. 4 to 7 are views showing equivalent circuits in an even mode and an odd mode, respectively.
8 is a diagram showing design parameters according to frequency ratios.
Figure 9 shows a coupler according to one embodiment of Figure 8;
FIGS. 10 and 11 are graphs showing the S-parameters according to the frequency of the coupler of FIG.
Figure 12 shows a coupler according to another embodiment of Figure 8;
13 and 14 are graphs showing S-parameters according to the frequency of the coupler of FIG.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to be illustrative of the present invention and not to limit the scope of the invention. Should be interpreted to include modifications or variations that do not depart from the spirit of the invention. In addition, the terms used in the present specification and the accompanying drawings are for explaining the present invention easily, and thus the present invention is not limited by the terms used in the present specification and the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.

1 is a schematic illustration of a coupler of the present invention. Figure 2 is a view in accordance with one embodiment of the coupler of Figure 1;

Referring to Figure 1, coupler 100 includes a first horizontal branch line 110, a second horizontal branch line 120, a first vertical branch line 130, a second vertical branch line 140, And a horizontal branch line 150.

The first horizontal branch line 110 connects between the input port 1 and the first output port 2. The second horizontal branch line 120 connects between the isolation port 4 and the second output port 3. The first horizontal branch line 110 and the second horizontal branch line 120 may have the same electrical characteristics. For example, the impedance of the first horizontal branch line 110 and the second horizontal branch line 120 is Z1 and the phase difference corresponding to the electrical length of the microstrip line (physical length divided by the wavelength) Can be 2 [theta]. The first horizontal branch line 110 and the second horizontal branch line 120 may be arranged in parallel on the same plane.

The first vertical branch line 130 connects between the input port 1 and the isolation port 4. The second vertical branch line 140 connects between the first output port 2 and the second output port 3. The first vertical branch line 130 and the second vertical branch line 140 may be arranged in parallel on the same plane. The first vertical branch line 130 is perpendicular to the first horizontal branch line 110. In addition, the first vertical branch line 130 may be formed perpendicular to the second horizontal branch line 120. And the second vertical branch line 140 is perpendicular to the second horizontal branch line 120. In addition, the second vertical branch line 140 may be formed perpendicular to the first horizontal branch line 110.

The first vertical branch line 130 includes a first microstrip line 132 and a second microstrip line 134. The first microstrip line 132 is disposed between the first horizontal branch line 110 and the third horizontal branch line 150. The second microstrip line 134 is disposed between the second horizontal branch line 120 and the third horizontal branch line 150. The first microstrip line 132 and the second microstrip line 134 may have the same electrical characteristics. For example, the impedance of the first microstrip line 132 and the second microstrip line 134 is Z2 and the phase difference corresponding to the electrical length (physical length of the microstrip line divided by the wavelength) May be &thetas;

The second vertical branch line 140 includes a third microstrip line 142 and a fourth microstrip line 144. The third microstrip line 142 is disposed between the first horizontal branch line 110 and the third horizontal branch line 150. The fourth microstrip line 144 is disposed between the second horizontal branch line 120 and the third horizontal branch line 150. The third microstrip line 142 and the fourth microstrip line 144 may have the same electrical characteristics. For example, the impedance of the third microstrip line 142 and the fourth microstrip line 144 is Z2, and the phase difference corresponding to the electrical length (physical length of the microstrip line divided by the wavelength) May be &thetas; In this case, the first microstrip line 132, the second microstrip line 134, the third microstrip line 142, and the fourth microstrip line 144 may have the same electrical characteristics. For example, the impedance of the first microstrip line 132, the second microstrip line 134, the third microstrip line 142, and the fourth microstrip line 144 is Z2 and the electrical length of the microstrip line 132 the phase difference corresponding to the electrical length (physical length divided by the wavelength) may be?.

The third horizontal branch line 150 connects between the first vertical branch line 130 and the second vertical branch line 140. At this time, the third horizontal branch line 150 is disposed between the first horizontal branch line 110 and the second horizontal branch line 120. The phase difference of the third horizontal branch line 150 can be made the same as the first horizontal branch line 110 and the second horizontal branch line 120. For example, the phase difference corresponding to the electrical length (the physical length of the microstrip line divided by the wavelength) of the third horizontal branch line 150 may be 2 ?. At this time, the impedance of the third horizontal branch line 150 may be Z3.

Referring to FIG. 2, the third horizontal branch line 150 has a first branch line 152, a second branch line 154, and a third branch line 156. The first branch line 152 extends in the direction from the first vertical branch line 130 toward the second vertical branch line 140. The second branch line 154 extends in the direction from the second vertical branch line 140 toward the first vertical branch line 130. The third branch line 156 connects the first branch line 152 and the second branch line 154. The first branch line 152 and the second branch line 154 are connected in a straight line. As an example, as shown in FIG. 2, the first branch line 152 and the second branch line 154 may be provided in parallel. As shown in FIG. 2, the third branch line 156 may connect the first branch line 152 and the second branch line 154 vertically, but may be connected at an angle other than 90 degrees.

The coupler 100 is operable in the dual band. When the phase difference [theta] is equal to [Equation 1], the same characteristics can be exhibited at frequencies f1 and nf1.

 [Equation 1]

FIG. 3 is a view of the coupler 100 of FIG. 1 symmetrically viewed to obtain an equivalent admittance value in an even mode and an odd mode. Figs. 4 to 7 are views showing equivalent circuits in an even mode and an odd mode, respectively. The admittance Yee of the even-even mode of FIG. 4 is obtained by multiplying the input port 1, the first output port 2, the second output port 3 and the isolation port 4 by V , V, V, and V, respectively. The admittance Yeo of the even-odd mode of FIG. 5 is applied to the input port 1, the first output port 2, the second output port 3, , -V, -V, and V, respectively. The admittance Yoe of the odd-even mode of FIG. 6 is applied to the input port 1, the first output port 2, the second output port 3, and the isolation port 4, , V, -V, and -V, respectively. The admittance Yoo of the odd-odd mode of FIG. 7 is applied to the input port 1, the first output port 2, the second output port 3, , -V, -V, and -V, respectively. Using Equivalent Admissions of Figs. 4 to 7, Equation (2) can be obtained.

&Quot; (2) "

Using the admittance of each mode, the reflection coefficient when a signal is applied in each mode can be obtained by the following equation (3).

&Quot; (3) "

If an S-parameter (S-parameter) is obtained through the reflection coefficient of each mode, it is expressed by Equation (4). At this time, it is assumed that the input port 1 is the first port, the first output port 2 is the second port, the second output port 3 is the third port, and the isolation port 162 is the fourth port .

&Quot; (4) "

&Quot; (5) "

The solutions can be obtained by the following equations (4) and (5). In this case, K denotes a power-split ratio at which power is distributed to the first output port 2 and the second output port 3. At this time, K is provided at an arbitrary value. Thus, it can operate as a dual-band branch line coupler with a desired coupling level.

8 is a diagram showing design parameters according to the silver frequency ratio. FIG. 8 shows the case where k2 = -3, 0, and 3 dB, respectively. At this time, k2 = 10 log (K2) is provided. When k2 = -3, the power ratio divided by the first output port and the second output port is 1: 2. When k2 = 0, it indicates that the power ratio divided by the first output port and the second output port is 1: 1. When k2 = 3, the power ratio divided by the first output port and the second output port is 2: 1. Alternatively, however, for any two frequencies, it can be designed to have various power distribution ratios.

Figure 9 shows a coupler according to one embodiment of Figure 8; FIGS. 10 and 11 are graphs showing the S-parameters according to the frequency of the coupler of FIG. Figure 12 shows a coupler according to another embodiment of Figure 8; 13 and 14 are graphs showing S-parameters according to the frequency of the coupler of FIG. The electrical characteristics of the couplers of Figs. 9 and 12 are provided as shown in the following table.

[Table 1]

Referring to Table 1, in the case of FIG. 9, it can be seen that the difference between S31 and S21 is 3 dB. It can also be seen that the difference between S31 and S21 in Fig. 12 is -3dB. 9 and 12, it can be seen that S11 and S41 are very small.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, The present invention is not limited to the drawings. In addition, the embodiments described herein are not limited to be applied, and all or some of the embodiments may be selectively combined so that various modifications can be made.

100: Coupler
110: first horizontal branch line 120: second horizontal branch line
130: first vertical branch line 140: second vertical branch line
132: first microstrip line
134: second microstrip line
142: third microstrip line
144: fourth microstrip line
150: first horizontal branch line 152: first branch line
154: second branch line 156: third branch line

Claims (14)

A first horizontal branch line connecting the input port and the first output port;
A second horizontal branch line connecting between the isolation port and the second output port;
A first vertical branch line connecting the input port and the isolation port;
A second vertical branch line connecting the first output port and the second output port; And
And a third horizontal branch line connecting the first vertical branch line and the second vertical branch line,
Wherein the third horizontal branch line comprises:
A first branch line extending from the first vertical branch line toward the second vertical branch line;
A second branch line extending in the first vertical branch line direction from the second vertical branch line; And
And a third branch line connecting the first branch line and the second branch line,
Wherein the first branch line and the second branch line are connected in a straight line. The method according to claim 1,
Wherein the first vertical branch line comprises:
A first microstrip line disposed between the first horizontal branch line and the third horizontal branch line; And
And a second microstrip line disposed between the second horizontal branch line and the third horizontal branch line,
Wherein the first microstrip line and the second microstrip line are provided to have the same impedance. 3. The method of claim 2,
Wherein the second vertical branch line comprises:
A third microstrip line disposed between the first horizontal branch line and the third horizontal branch line; And
And a fourth microstrip line disposed between the second horizontal branch line and the third horizontal branch line,
Wherein the third microstrip line and the fourth microstrip line are provided to have the same impedance. The method of claim 3,
Wherein the first microstrip line, the second microstrip line, the third microstrip line, and the fourth microstrip line have the same impedance. delete The method according to claim 1,
Wherein the first horizontal branch line and the second horizontal branch line are formed parallel to each other. The method according to claim 6,
Wherein the first vertical branch line and the second vertical branch line are formed parallel to each other. 8. The method of claim 7,
Wherein the first horizontal branch line and the first vertical branch line are formed perpendicular to each other. 9. The method of claim 8,
Wherein the second horizontal branch line and the second vertical branch line are formed perpendicular to each other. 10. The method of claim 9,
And the third horizontal branch line is formed parallel to the first horizontal branch line and the second horizontal branch line. 11. The method of claim 10,
And the third horizontal branch line is formed perpendicular to the first vertical branch line and the second vertical branch line. The method according to any one of claims 1 to 4, 6 to 11,
Wherein the coupler operates in a dual band. A first horizontal branch line connecting the input port and the first output port;
A second horizontal branch line connecting between the isolation port and the second output port;
A first vertical branch line connecting the input port and the isolation port;
A second vertical branch line connecting the first output port and the second output port; And
And a third horizontal branch line connecting the first vertical branch line and the second vertical branch line,
Wherein the first horizontal branch line, the second horizontal branch line, the first vertical branch line, the second vertical branch line, and the second vertical branch line are parallel to each other, and the first horizontal branch line and the first vertical branch line, The second horizontal branch line and the second vertical branch line are formed perpendicular to each other, the third horizontal branch line is formed parallel to the first horizontal branch line and the second horizontal branch line, A branch line is formed perpendicular to the first vertical branch line and the second vertical branch line,
Wherein the third horizontal branch line comprises:
A first branch line extending from the first vertical branch line toward the second vertical branch line;
A second branch line extending in the first vertical branch line direction from the second vertical branch line; And
And a third branch line connecting the first branch line and the second branch line,
Wherein the first branch line and the second branch line are connected in a straight line. 14. The method of claim 13,
Wherein the coupler operates in a dual band.

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