TW201714348A - Generalized branch coupler capable of regulating output power ratio can be similar to simulated frequency response and can be applied in systems having different frequency bands - Google Patents

Abstract

A generalized branch coupler capable of regulating output power ratio comprises four sectional first transmission wire, second transmission wire, third transmission wire and fourth transmission wire sequentially and vertically surrounding to show rectangle connection, wherein the connection place between the first transmission wire and the second transmission wire, the connection place between the second transmission wire and the third transmission wire, the connection place between the third transmission wire and the fourth transmission wire, and the connection place between the fourth transmission wire and the first transmission wire are respectively disposed with an extension section outwardly and obliquely extended. Moreover, each of the second transmission wire and the fourth transmission wire is electrically connected to a capacitor, wherein each extension section comprises a first triangle section, a second third triangle section and a long rectangle section sequentially and mutually connected. The first triangle section is a right triangle. The second third triangle section is an obtuse triangle. It can be applied in microwave systems having different center frequencies through adjustable structure design.

Description

Adjustable output power ratio generalized branch coupler

The invention relates to a generalized branch coupler with adjustable output power ratio, in particular to a branch coupler technology which is suitable for microwave systems with different center frequencies by adjustable structure design.

The evolution of technology over time, wireless communication has become a trend of modern development in recent years, whether in digital TV systems, global satellite systems, or mobile communication systems, people's lives are inseparable for wireless information transmission, and branch couplers ( As in the reference [1]), it also plays an important role in the above system, so the present invention starts from this component and makes a new circuit improvement. There are many types of couplers, and their functions are nothing more than power distribution (such as reference [2] [3]) or power synthesis, such as branch line coupler, ratrace coupler. , lange coupler... (eg reference [4] [5]). Among them, the branch coupler is most commonly used. The output power ratio of the circuit output 埠|S21| and the coupled 埠|S31| is designed at half power point (-3dB), and the two output signals are 90 degrees out of phase, and |S11| |S41| and two 埠 can reach -15dB or less.

In addition, the geometry of the branch coupler has a high degree of symmetry, since either end can be used as the input port, and the two ends of the output are located on the other side of the input port, the other end on the same side as the input port. It is isolated, and such symmetry can be seen by the scattering coefficient. When all the ends are matched, the power entering the input 会 will be equally divided into the output on the other side, without any Power will pass to the isolation barrier. Although the conventional branch coupler can provide a good input and output impedance matching capability and provide equal power distribution and 90 degree phase difference; however, the conventional branch coupler does not have the function of adjusting the power ratio, so it cannot be applied to different In the microwave system of the center frequency, since the support is low, there is a shortage of the increase in the cost of the construction of the circuit system.

As far as is known, there are no patents or papers that can adjust the output power ratio to be applied to the branch couplers of microwave systems with different center frequencies, plus the urgent need based on the electronics industry, and in response to the needs of different environments. In view of the need, the present invention has developed a generalized branch coupler of adjustable power ratio.

The main object of the present invention is to provide a generalized branching coupler with adjustable output power ratio, which is mainly based on a traditional 2:1 unequal branching coupler, and the T-type equivalent of the transmission lines at both ends is used. And the transmission line at both ends of the coupler is replaced by two sets of transmission lines and a grounded adjustable capacitor. The circuit can adjust the capacitance value to make the original output power ratio more efficient than the output power of the 2:1 coupler. It is confirmed by the electromagnetic simulation software that the output power ratio at the operating frequency can be applied to the microwave system of 1:1 to 2:1, so that the microwave system can be applied to different center frequencies, the circuit is highly supported, and the production is simple and Can significantly reduce the cost of system construction and other characteristics. The technical means for achieving the above-mentioned purpose is to cover the substrate, and comprises four segments of a first transmission line, a second transmission line, a third transmission line and a fourth transmission line which are vertically connected in a rectangular shape. Wherein, the first transmission line and the second transmission line connection, the second transmission line and the third transmission line connection, the third transmission line and the fourth transmission line connection, and the fourth transmission line and the first transmission line connection are respectively provided with an outward oblique direction Extended extension. And electrically connecting a capacitor to the second transmission line and the fourth transmission line, wherein each of the extension segments includes one connected in sequence a first triangular segment, a second triangular segment and a long rectangular segment, the first triangular segment being a right triangle and the second triangular segment being an obtuse triangle.

10‧‧‧Substrate

20‧‧‧ Transmission line group

21‧‧‧First transmission line

22‧‧‧second transmission line

23‧‧‧ third transmission line

25‧‧‧First conductive block

26‧‧‧Second conductive block

24‧‧‧fourth transmission line

30‧‧‧Extension

31a, 31b, 31c, 31d‧‧‧ first triangular segment

32a, 32b, 32c, 32d‧‧‧ second triangular segment

33a, 33b, 33c, 33d‧‧‧ long rectangular segments

40‧‧‧First signal埠

41‧‧‧Second signal埠

42‧‧‧ Third signal埠

43‧‧‧fourth signal埠

C ₁ , C ₂ ‧‧‧ capacitor

1 is a schematic diagram of an equivalent circuit of the circuit structure of the present invention.

Figure 2 is an analysis of the even wave mode of the branch coupler of the present invention ( Schematic diagram of ).

Figure 3 is an analysis of the even wave mode of the branch coupler of the present invention ( )schematic diagram.

4 is a T-type equivalent diagram of the transmission line of the present invention.

Fig. 5 is a schematic view showing the formation of the circuit structure of the present invention.

Figure 6 is a schematic view showing the implementation of the physical circuit structure of the present invention.

Fig. 7(a) is a schematic diagram showing the power ratio adjustment of the present invention to 2:1 simulation and actual measurement.

Fig. 7(b) is a schematic diagram of phase simulation and actual measurement in which the power ratio of the present invention is adjusted to 2:1.

Fig. 8(a) is a schematic diagram showing the adjustment of the power ratio of the present invention to 1:1 simulation and actual measurement.

Fig. 8(b) is a schematic diagram of phase simulation and actual measurement of the power ratio of the present invention adjusted from 2:1 to 1:1.

The invention is mainly a branching coupler with adjustable power ratio. The circuit is based on a traditional 2:1 unequal branching coupler, and combined with a transmission line T-equivalent, the transmission line at both ends of the coupler is composed of two The group transmission line is replaced with a tunable capacitor. By adjusting the value of the capacitor, the circuit can make the original output power ratio more powerful than the output power ratio of the 2:1 coupler. It is confirmed by the electromagnetic simulation software that the output power ratio can be applied to the operating frequency. : 1 to 2:1 system, the circuit is realized by engraving machine, and finally measured by network analyzer, the simulation data and implementation in the working frequency band do have good electrical characteristics. Since the adjustable structure design of the present invention can be applied to microwave systems of different center frequencies, the present invention is highly supportive, easy to manufacture, and can be greatly reduced. Cost of system construction.

Referring to FIGS. 5 and 6, a specific embodiment of the present invention includes a substrate 10 and a transmission line group 20 formed on the substrate 10 by printing or etching. The transmission line group 20 includes four first transmission lines 21, a second transmission line 22, a third transmission line 23, and a fourth transmission line 24 which are sequentially vertically wound in a rectangular connection to respectively generate characteristic impedances. a connection between the first transmission line 21 and the second transmission line 22, a connection between the second transmission line 22 and the third transmission line 23, a connection between the third transmission line 23 and the fourth transmission line 24, and a connection between the fourth transmission line 24 and the first transmission line 21 are respectively An extension 30 extending outwardly (about 45 degrees) is disposed, and a first conductive block 25 is disposed on the outer side of the second transmission line 22 near the middle portion, and is disposed outside the near middle portion of the second transmission line 24. a second conductive block 26, and a second transmission line 22 between the first conductive block 25 electrically connected to a capacitor C _1, and then to the fourth transmission line 24 is connected to a further capacitor 26 is electrically conductive second block C ₂ ; wherein the four extensions 30 comprise a first triangular segment 31a, 31b, 31c, 31d, a second triangular segment 32a, 32b, 32c, 32d and a long rectangular segment 33a, which are sequentially connected to each other. 33b, 33c, 33d, the first triangular segments 31a, 31b, 31c, 31d are right triangles, and the second triangular segments 32a, 32b, 32c, 32d are obtuse triangles.

Referring to FIG. 5 together, the lengths L5 and L6 of the first transmission line and the third transmission line are both 44.2 mm, the widths W5 and W6 are both 4.2 mm, and the second transmission line length L8 is 41.5 mm. The fourth transmission line The length L7 is 41.2 mm, the width W8 of the second transmission line is 0.9 mm, and the width W7 of the fourth transmission line is 1.26 mm. Each of the long rectangular segments has a length L1 to L4 of 10 mm and a width of W1 to W4 of 3.1 mm. Capacitor C ₁ and capacitor C ₂ are both variable capacitors, and the capacitance of the two variable capacitors is between 0.6 and 0.9 pF.

Please cooperate with a pair of sides of the first triangular segment 31a shown in FIG. The first transmission line 21 is connected at one end, and the other pair of sides is connected to one of the second triangular segments 32a, and the bottom edge thereof is connected to one end of the second transmission line 22; the other side of the second triangular segment 32a is opposite thereto One end of a long rectangular section 33a is connected, and a second signal 埠41 is connected to a long rectangular section end 33a.

Referring to the second triangular segment 31b shown in FIG. 5, a bottom edge is connected to the other end of the second transmission line 22, and a pair of edges is connected to one of the two second triangular segments 32b, and the other pair is The edge is connected to one end of the third transmission line 23; the other side of the second triangular segment 32b is connected to one end of the two long rectangular segments 33b, and a third signal 埠 42 is connected to the end of the second rectangular segment 33b.

Referring to the three first triangular segments 31c shown in FIG. 5, a pair of sides are connected to the other end of the third transmission line 23, and the other pair of sides is connected to one of the three second triangular segments 32c. The side is connected to one end of the fourth transmission line 24; the other side of the third second triangular section 32c is connected to one end of the three long rectangular section 33c, and the fourth rectangular section 33c is connected with a fourth signal 埠43 at the end.

Referring to the four first triangular segments 31d shown in FIG. 5, a pair of sides are connected to the other end of the first transmission line 21, and the other pair of sides is connected to one of the four second triangular segments 32d, and the bottom edge thereof is connected. The other end of the four second triangular segments 32d is connected to one end of the four long rectangular segments 33d, and a first signal 埠40 is connected to the end of the four long rectangular segments 33d.

As shown in FIG. 1, the circuit architecture of the present invention is based on a conventional 2:1 branch coupler, and transmits transmission lines of different impedances at both ends of the coupler, first using an even mode transmission matrix such as formula (1):

The even wave mode analysis of the branch coupler is shown in Fig. 2, and then the odd wave mode transfer matrix is used as the formula (2).

The odd-wave mode analysis of the branch coupler is shown in Fig. 3. The odd-even mode analysis result is transferred to the S-matrix. The odd-even mode transfer matrix can be converted into the S-matrix by the formulas (3)-(6).

Where Z _O1 =Z _O2 =Z _O =50Ω is to make the derivation formula more concise, so the impedance is positively normalized to obtain Z _N1 =Z ₁ /Z _O , Z _N2 =Z ₂ /Z _O , Z _N3 =Z ₃ /Z _O , Y _N1 =1/Z _N1 , Y _N2 =1/Z _N2 , Y _N3 =1/Z _N3 , Z _O =Z _O1 =Z _O2 =1, bring equation (1) into equation (3 )-(6) can obtain the even-wave mode S matrix as in equations (7)-(10) where Z _O1 =Z _O2 =Z _O =50Ω to make the derivation formula more concise, then the impedance is normalized to obtain Z _N1 =Z ₁ /Z _O , Z _N2 =Z ₂ /Z _O , Z _N3 =Z ₃ /Z _O , Y _N1 =1/Z _N1 , Y _N2 =1/Z _N2 , Y _N3 =1/Z _N3 , Z _O = Z _O1 = Z _O2 =1, and the equation (1) is brought into the equations (3) - (6) to obtain the even-wave mode S matrix as in the equations (7) - (10).

Bringing equation (2) into equations (3)-(6) yields an odd-wave mode S matrix as in equations (11)-(14):

It can be known from the law of conservation of energy that |S ₁₁ | ² +|S ₂₁ | ² +|S ₃₁ | ² +|S ₄₁ | ² =1, let |S ₁₁ |=0|S ₄₁ |=0, obtain| S ₂₁ | ² +|S ₃₁ | ² =1, assuming |S ₃₁ | ² =C ² then |S ₂₁ | ² =1-C ^{2 The} total S matrix can be known from equations (15)-(18):

By introducing equations (7)-(10) and equations (11)-(14) into equations (15)-(18) and collating them, equations (19)-(22) can be obtained:

From equation (27), equation (28) can be obtained:

It can be known from the formula (28) that if Z ₂ = Z ₃ , the formula (29) can be obtained; if Z _{2 is} not equal to Z ₃ , the formula (30) can be obtained:

Bringing equation (28) back to equation (33) yields equation (31), and simplification (31) yields equation (32):

It can be obtained from equation (30) that when Z3 = 45 Ω, Z2 will be equal to 56.25 Ω. This circuit changes the output power ratio of its output 埠|S21| to the coupled 埠|S31| by the variable capacitance in the T-equivalent. The two sets of transmission lines in the structure are equivalent to T-type, and the equivalent structure is shown in Fig. 4. Therefore, the T-equivalent and transmission line relationship matrix needs to be obtained first, and the relationship is as shown in formula (32):

From the above matrix, the equivalent post-impedance values Zo and B (the admittance of the capacitive reactance) can be obtained as in equation (34) (35):

Given the equivalent electrical length θ o , the original transmission line impedance value Z and the electrical length θ are respectively brought into the equation (34) (35), and the equivalent transmission line impedance value Zo and the capacitance value can be obtained. Bring the obtained parameters into the circuit, through the electromagnetic software IE3D simulation, select the plate as FR4 (3.2mm) and use the tool in the software to convert the corresponding length of the linegauge. The structure is optimized and shown in the figure. 5, the circuit size: L1 = 10mm; W1 = 3.1mm; L2 = 10mm; W2 = 3.1mm; L3 = 10mm; W3 = 3.1mm; L4 = 10mm, W4 = 3.1mm; L5 = 44.2mm; W5 = 4.2mm; L6=44.2mm; W6=4.2mm; L7=41.2mm; W7=1.26mm; L8=41.5mm; W8=0.9mm; capacitance C1=0.7pF, capacitance C2=0.65pF, after the circuit is simulated, In line with the original expected result, the circuit is output to the engraving machine to process the physical circuit and measure the result.

As described above, the structure of the circuit of the present invention processed by the engraving machine is shown in FIG. 5, and is measured by an Anritsu-MS2034A network analyzer, and compared with the simulation result, the frequency response of the IE3D and the physical circuit is as shown in FIG. 7 (a). ), (b), the measurement frequency is from 0 to 2 GHz, the size is from 0 to -40 dB, and the operating frequency band (fo = 0.925 GHz) |S ₁₁ | and |S ₄₁ | are both below -15 dB, both ends The output power ratio |S ₂₁ | and |S ₃₁ | are 2:1, and in Fig. 7(b), the phase difference between |S ₂₁ | and |S ₃₁ | is 90 degrees.

With this good characteristic, the capacitance values of the circuit capacitors C ₁ and C ₂ in Figure 1 are changed from 0.7 pF to 0.9 pF, and from 0.65 pF to 0.7 pF, and the output power ratio is 1:1. The network analyzer measures the frequency response of the IE3D and the physical circuit as shown in Figure 8(a) and (b). The measurement frequency is from 0 to 2 GHz, and the size is from 0 to -40 dB. In the working frequency band, it is |S ₁₁ | and | S ₄₁ | -15dB or less in all the output ends of the power ratio | S ₂₁ | and | S ₃₁ | 1: 1, FIG. 8 (b) as shown in, | S ₂₁ | and | S ₃₁ | of The phase difference is 90 degrees. It can be seen that the above simulation and measurement results are quite close to expectations.

It can be seen that the circuit prepared by the present invention does meet the expected result. The adjustable power ratio of the branch coupler proposed by the present invention is based on a conventional 2:1 unequal branching coupler. The transmission line with different impedance at both ends of the device is equivalent to the T-type added to the transmission line. By changing the capacitance value in the equivalent circuit, the power ratio of the output terminal is controlled to 1:1, which is verified by the electromagnetic simulation software and realized by the engraving machine. The circuit is finally measured by a network analyzer, and its value is similar to the analog frequency response. The result is that the circuit is feasible and can be applied in this design mode. Systems in different frequency bands.

The above is only a possible embodiment of the present invention, and is not intended to limit the scope of the patents of the present invention, and the equivalent implementations of other changes according to the contents, features and spirits of the following claims should be It is included in the patent of the present invention. The invention is specifically defined in the structural features of the request item, is not found in the same kind of articles, and has practicality and progress, has met the requirements of the invention patent, and has filed an application according to law, and invites the bureau to approve the patent according to law to maintain the present invention. The legal rights of the applicant.

references

[1] Reed, J; Wheeler, GJ; "A Method of Analysis of Symmetrical Four-Port Networks", Microwave Theory and Techniques, IRE Transactions on Volume: 4, Issue: 4 , pp.246-252, October 1956

[2] Cohn, Seymour B.; “A Class of Broadband Three-Port TEM-Mode Hybrids,” Microwave Theory and Techniques, IEEE Transactions on Volume: 16, Issue: 2, pp. 110-116, Feb 1968.

[3] EJ Wilkinson; “An N-way hybrid power divider”, IRE Trans. Microwave Theory and Techniques , vol. MTT-8, pp.116-118 1960

[4] Luzzatto, G.; Marconi Italiana SpA; “A General 180-Degree Hybrid Ring”, Broadcasting, IEEE Transactions on Volume: BC-14, Issue: 1 , pp. 41-43, March 1968.

[5] Lange, J.; "Interdigitated Stripline Quadrature Hybrid", Microwave Theory and Techniques, IEEE Transactions on Volume: 17, Issue: 12 , pp.1150-1151, Dec 1969.

[6] Yong-Beom Kim, Hyun-Tai Kim, Kwi-Soo Kim, Jong-Sik Lim, and Dal Ahn; “A Branch line hybrid having arbitrary power division ratio and port impedances”, Microwave Conference, 2006. APMC 2006. Asia-Pacific, pp.1376-1379, 12-15 Dec. 2006.

[7] Tseng, C.-H.; Dept. of Electron. Eng., Nat. Taiwan Univ. of Sci. & Technol., Taipei, Taiwan; Wu, C.-H.; “Design of compact branch-line Couplers using π -equivalent artificial transmission lines", Microwaves, Antennas & Propagation, IET, Volume:6, Issue: 9 , pp. 969-974, June 19 2012.

[8] Arriola, W.; Dept. of Radio Eng., Kyung Hee Univ., Yongin, South Korea; Ihn Seok Kim; “Wideband Branch Line Coupler with Arbitrary Coupling Ratio”, Microwave Conference Proceedings (APMC), 2011 Asia- Pacific, pp. 1758-1761, 5-8 Dec. 2011.

[9] Chun-Han Yu; Inst. of Comput. & Commun. Eng., Nat. Cheng Kung Univ., Tainan, Taiwan; Yi-Hsin Pang; “Dual-Band Unequal-Power Quadrature Branch-Line Coupler With Coupled Lines Microwave and Wireless Components Letters, IEEE Volume: 23, Issue: 1 , pp. 10-12, Jan. 2013.

[10] Tae-Soon Yun; Ki-Byoung Kim; Jong-Chul Le, “Research on Size Reduction of a Branch-line Power Divider Using Shunt-Stub,” Microwave Conference Proceedings, 2005. APMC 2005. Asia-Pacific Conference Proceedings , Vol.1, Feb.2005

20‧‧‧ Transmission line group

21‧‧‧First transmission line

22‧‧‧second transmission line

23‧‧‧ third transmission line

25‧‧‧First conductive block

26‧‧‧Second conductive block

24‧‧‧fourth transmission line

30‧‧‧Extension

31a, 31b, 31c, 31d‧‧‧ first triangular segment

32a, 32b, 32c, 32d‧‧‧ second triangular segment

33a, 33b, 33c, 33d‧‧‧ long rectangular segments

C ₁ , C ₂ ‧‧‧ capacitor

Claims (9)

A generalized branching coupler with adjustable output power ratio, comprising a substrate, and a transmission line group disposed on the substrate, the transmission line group comprising four segments sequentially vertically surrounding and forming a rectangular connection to respectively generate characteristics a first transmission line, a second transmission line, a third transmission line, and a fourth transmission line, the first transmission line and the second transmission line, the second transmission line and the third transmission line, the third transmission line, and the fourth The transmission line and the connection between the fourth transmission line and the first transmission line and the like are respectively provided with an extending portion extending obliquely outwardly. The second transmission line is provided with a first conductive block outside, and a second conductive line is disposed outside the second transmission line. a capacitor, and a capacitor is electrically connected between the second transmission line and the first conductive block, and another capacitor is electrically connected to the second conductive block and the second conductive block, wherein each of the extensions The segment includes a first triangular segment, a second triangular segment and a long rectangular segment which are sequentially connected to each other. The first triangular segment is a right triangle and the second triangular segment is an obtuse triangle. The generalized branch coupler of the adjustable output power ratio according to claim 1, wherein the lengths of the first transmission line and the third transmission line are both 44.2 mm and the width is 4.2 mm, and the length of the second transmission line is The length of the fourth transmission line is 41.2 mm, the width of the second transmission line is 0.9 mm, and the width of the fourth transmission line is 1.26 mm. The tunable output power ratio of the generalized branch coupler according to claim 1, wherein each of the long rectangular segments has a length of 10 mm and a width of 3.1 mm. The modulating output power ratio of the generalized branch coupler according to claim 1, wherein a pair of sides of the first triangular segment are connected to one end of the first transmission line, and the other pair of edges is opposite to the first transmission line One of the two triangular segments is connected to the side, and the bottom edge is connected to one end of the second transmission line; The other pair of sides of the two triangular segments are connected to one end of the long rectangular segment, and a second signal is connected to the end of the long rectangular segment. The generalized branch coupler of the adjustable output power ratio according to claim 1, wherein a bottom edge of the first triangular segment is connected to the other end of the second transmission line, and a pair of edges thereof is opposite to the second One of the two triangular segments is connected to the edge, and the other pair of edges is connected to one end of the third transmission line; the other pair of the second triangular segment is connected to one of the two ends of the long rectangular segment, and the second rectangular segment is A third signal 接 is connected to the end. The tunable output power ratio of the generalized branch coupler according to claim 1, wherein three of the first triangular segments are connected to the other end of the third transmission line, and the other pair of edges is the same as the third One of the second triangular segments is connected to the side, and the bottom edge is connected to one end of the fourth transmission line; the other side of the second triangular segment is connected to one of the three long rectangular segments, and the third end of the long rectangular segment A fourth signal is connected. The tunable output power ratio of the generalized branch coupler according to claim 1, wherein four of the first triangular segments are connected to the other end of the first transmission line, and the other pair of edges is the same as the fourth One of the second triangular segments is connected to the side, and the bottom edge is connected to the other end of the fourth transmission line; the other side of the second triangular segment is connected to one of the four long rectangular segments, and the four rectangular segments are A first signal 接 is connected to the end. The modulating output power ratio of the generalized branch coupler according to claim 1, wherein the first capacitor and the second capacitor are both variable capacitors. The tunable output power ratio of the generalized branch coupler according to claim 8, wherein the capacitance of the two variable capacitors is between 0.6 and 0.9 pF.