TWI633702B - Hybrid branch coupler with adjustable output power - Google Patents

Abstract

The invention discloses a hybrid branch coupler with adjustable output power, which comprises a substrate, a transmission line group and two inductors. The transmission line group includes a first transmission line and a second transmission line juxtaposed at a lower edge of the first transmission line; wherein, one end of the second transmission line extends with a first extension section, and the first extension section has a first hypotenuse. A second extension section extends at the other end of the second transmission line, and the second extension section has a second hypotenuse. One end of one of the inductors is electrically connected to a position close to one end of the first transmission line, and the other end is electrically connected to one end of the second transmission line. One end of the second inductor is electrically connected to the other end of the first transmission line, and the other end is electrically connected to the other end of the second transmission line. It can be applied to system circuits with different center frequencies through the adjustable inductor structure design. in.

Description

Hybrid branch coupler with adjustable output power

The invention relates to a hybrid branch coupler with adjustable output power, in particular to a branch coupler technology suitable for system circuits with different center frequencies through the design of an adjustable inductor structure.

With the development of the times, wireless communication systems have developed rapidly. For digital TV systems, global satellite systems, or mobile communication systems, wireless information transmission has become inseparable from life. Its products are gradually moving towards high performance, low cost, and easy production. And light, thin and small improvements, and broadband, multi-band, downsizing, and adjustable structure are the key items for designing couplers. In microwave circuits, the branch coupler is an indispensable and important component as shown in reference [1-6]. It is widely used in power amplifiers as shown in reference [7], and image rejection mixers as in reference [ 8], antenna array as shown in reference [9] and phase shifter as shown in reference [10].

Furthermore, the electrical characteristics of traditional equal-power branch couplers are that the electrical length of the transmission line is a quarter wavelength ( θ = 90 °), the output power ratio between the output port and the coupling port is at the half power point (-3dB), and the two outputs The phase difference of the signal is 90 degrees, and | S ₁₁ | and | S ₄₁ | can reach -15dB or less, in order to increase the flexibility of the circuit in response to different usage requirements. According to the current knowledge, no patent or paper has been proposed for a hybrid branch coupler with any adjustable output power. Based on the urgent needs of the electronics industry, the inventors and others have made continuous efforts to develop Finally, a new circuit architecture of the present invention has been developed with a branch coupler element as a starting point.

The main object of the present invention is to provide a hybrid branch coupler with adjustable output power, which is mainly a coupler that realizes a variety of output ratios by using a circuit. It is quite convenient in system construction and can be applied to a variety of different center frequencies. Not only has a high degree of system support, and can reduce the cost of the entire system construction, so it is highly supportive, easy to produce, small in size, and can greatly reduce the cost of building a communication system. The technical means adopted to achieve the above-mentioned effects include a substrate, a transmission line group and two inductors. The transmission line group includes a first transmission line and a second transmission line juxtaposed at a lower edge of the first transmission line; wherein, one end of the second transmission line extends with a first extension section, and the first extension section has a first hypotenuse. A second extension section extends at the other end of the second transmission line, and the second extension section has a second hypotenuse. One end of one of the inductors is electrically connected to a position close to one end of the first transmission line, and the other end is electrically connected to one end of the second transmission line. One end of the two inductors is electrically connected to a position near the other end of the first transmission line, and the other end is electrically connected to the other end of the second transmission line.

10‧‧‧ substrate

20‧‧‧ Transmission line group

21‧‧‧The first transmission line

22‧‧‧Second transmission line

220‧‧‧First extension

220a‧‧‧First hypotenuse

220b‧‧‧The first trapezoidal section

220c‧‧‧The first rectangular segment

221‧‧‧second extension

221a‧‧‧Second hypotenuse

221b‧‧‧Second trapezoidal section

221c‧‧‧The second rectangular segment

30‧‧‧input port

31‧‧‧Output port

32‧‧‧Coupling Port

33‧‧‧ isolated port

L‧‧‧Inductance

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

Figure 2 is a schematic diagram of a conventional branch coupler circuit structure.

Figure 3 is a schematic diagram of a PI-type equivalent circuit of a conventional transmission line.

FIG. 4 is a schematic diagram of a PI-type equivalent circuit (LC) of a transmission line according to the present invention.

FIG. 5 is a schematic diagram of a circuit forming method according to the present invention.

FIG. 6 is a schematic implementation diagram of a physical circuit of the present invention.

FIG. 7 (a) is a schematic diagram of simulation and measurement data of an output power ratio 4: 1 circuit of the present invention.

FIG. 7 (b) is a schematic diagram of simulation and measurement data of an output power ratio 3: 1 circuit of the present invention.

In order to allow your reviewers to further understand the overall technical features of the present invention and the technical means for achieving the purpose of the present invention, specific embodiments and drawings are described in detail as follows: The present invention is mainly a hybrid type with adjustable output power Branch coupler design. The circuit is based on a traditional branch coupler. Through two different transmission line PI-type equivalent formulas, one pair of transmission lines is replaced by one transmission line and two ground capacitors, and the other pair of transmission lines is replaced by An adjustable inductor and two ground capacitors are substituted, and the adjacent capacitor values are offset, so that the circuit structure is only composed of the inductor and the transmission line, without additional capacitance. By adjusting the size of the inductance value, the original output power can be added to the circuit with more power output options. The invention uses a coupler with an output power ratio of 4: 1 to 3: 1 for implementation, and the circuit characteristics are verified by electromagnetic simulation software It is realized by an engraving machine. The board uses a FR-4 substrate with a thickness of 1.6mm and a relative dielectric coefficient of 4.3. Finally, it is measured by a network analyzer. The simulated data in the working frequency band is consistent with the measured results. The circuit of the invention is designed with an adjustable structure, so it can be applied to systems with different center frequencies, and therefore has the characteristics of high supportability, simple production, small size, and can greatly reduce the cost of building a communication system.

Please refer to FIGS. 5 and 6 for specific embodiments for achieving the main purpose of the present invention. The embodiments include a substrate 10, a transmission line group 20 disposed on the substrate 10, and two inductors L and other technical features. The transmission line group 20 includes a laterally extending first transmission line 21 and a second transmission line 22 juxtaposed on the lower edge of the first transmission line 21 in parallel. One end of the second transmission line 22 is extended with a first extension 220, and the other end of the second transmission line 22 is extended with a second extension 221. The first extension section 220 has a first beveled edge 220a; the second extension section 221 has a second beveled edge 221a. One end of one of the inductors L is electrically connected to a position near one end of the first transmission line 21, and the other end thereof is electrically connected to one end of the second transmission line 22. The other end of the inductor L is electrically connected At a position near the other end of the first transmission line 21, the other end is electrically connected to the other end of the second transmission line 22.

Specifically, the above-mentioned equivalent impedance Z _{3 of the} transmission line group 20 = 50Ω; the electrical length θ _{3 of the} transmission line group 20 = 116.6 °. Please refer to FIGS. 5 and 6, the length L ₁ = L ₂ = 33.74 mm and the width W ₁ = W ₂ = 3.055 mm of the first transmission line 21. The length L ₃ at the top of the second transmission line 22 is 23.14 mm, and the length L ₄ at the bottom of the second transmission line 22 is 21.74 mm.

In addition, please refer to FIGS. 5 and 6 again, the first extension section 220 includes a first trapezoidal section 220b and a first rectangular section 220c. The hypotenuse of the first trapezoidal section 220b is the first hypotenuse 220a, and one side thereof The side is connected to one end of the second transmission line 22, and the bottom side is connected to the first rectangular segment 220c. The length W _{3 of the} first oblique side 220 a is 3.89 mm; the long side W 2 of the first rectangular segment 220 c is W ₄ = W ₅ = 3.95 mm, and the second short side L _{5 is} 3.055 mm. The second extension section 221 includes a second trapezoidal section 221b and a second rectangular section 221c. The hypotenuse of the second trapezoidal section 221b is a second hypotenuse 221a. One side of the second trapezoidal section 221b is connected to the other end of the second transmission line 22. The bottom edge is connected to the second rectangular segment 221c. The length W _{6 of the} second hypotenuse 221a is 3.83 mm; one of the long sides W _{7 of the} second rectangular segment 221 c is 3.95 mm, the other two long sides W ₈ = 3.055 mm, and the two short sides L ₆ = 3.055 mm.

Specifically, the hybrid branch coupler with adjustable output power proposed by the present invention is different from the traditional branch coupler, which is composed of four transmission lines, but is composed of two transmission lines and two adjustable inductors L. The circuit structure is shown in Figures 1 and 6. One end of the first transmission line 21 is Port1 input port 30, the other end of the first transmission line 21 is Port2 output port 31, one end of the second transmission line 22 is Port3 coupling port 32, and the second transmission line 22 is another The terminal is Port4 isolated port 33, Z ₃ is the transmission line impedance, θ ₃ is the electrical length, and L is the adjustable inductor. The output power ratio of the circuit can be adjusted only by changing the inductance value. The circuit of the invention has the advantages of using a circuit to realize a coupler with multiple output ratios, which is very convenient in the system construction, so it can be applied to a variety of different center frequencies, not only has a high degree of system support, but also can reduce the entire system construction Costs.

In the implementation of the circuit analysis and design of the present invention, the branch coupler structure with a traditional output ratio of 4: 1 is shown in Figure 2, Port1 is the input port 30, Port2 is the output port 31, Port3 is the coupling port 32, and Port4 is Isolated port 33, Z ₁ = 44.72Ω, Z ₂ = 100Ω, θ ₁ = θ ₂ = 90 °. Replace the Z ₁ transmission line with a PI-type equivalent structure as shown in Figure 3. Z ₃ and θ ₃ are the equivalent post-resistance and electrical length, C ₁ is the equivalent capacitance, and the PI-type equivalent impedance and capacitance values of the transmission line are formulas ( 1) (2). Then replace the Z _{2 with a} PI-type equivalent structure of the LC transmission line, as shown in FIG. 4, where L is the equivalent inductance L and C ₂ is the equivalent capacitance, which can be obtained by formulas (3) and (4). In order to simplify the circuit configuration, without additional capacitance equivalent to the capacitance value C ₁ Z ₁ and Z ₂ the equivalent capacitance value C ₂ are offset results in Equation (5), the circuit structure shown in Figure 1 Show. After the above formula is simplified, the formulas (6), (7), and (8) of FIG. 1 can be obtained. By adjusting the value of L, the output power of the circuit can be changed.

Z ₃ = Z ₀ (characteristic impedance) (6)

According to the aforementioned formulas (6), (7), and (8) and the output power ratio of 4: 1 branch coupler parameters, Z ₃ = 50Ω, θ ₃ = 116.6 °, and L = 6.5 nH can be obtained through the electromagnetic simulation software (Microwave Office & IE3D) to verify the circuit characteristics, the board is FR4 (thickness 1.6mm), the relative permittivity is 4.3, the structure is optimized and adjusted as shown in Figure 5, the circuit size: L ₁ = 33.74mm, W ₁ = 3.055mm , L ₂ = 33.74mm, W ₂ = 3.055mm, L ₃ = 23.14mm, W ₃ = 3.89mm, L ₄ = 21.74mm, W ₄ = 3.95mm, L ₅ = 3.055mm, W ₅ = 3.95mm, L ₆ = 3.055mm, W ₆ = 3.83mm, W ₇ = 3.95mm, W ₈ = 3.055mm. The finished product processed by the engraving machine is shown in Figure 6. Measured by a network analyzer, and compared with the simulation results, the circuit simulation results and the frequency response of the physical circuit are shown in Figure 7 (a). The measurement frequency is from 0 to 4 GHz, and the size is from 0 to -40 dB. ( f ₀ = 2.45GHz) | S ₁₁ | and | S ₄₁ | are both below -15dB, and the output power ratios | S ₂₁ | and | S ₃₁ | at both ends are 4: 1. The above simulation and measurement results and expectations Quite close.

With this good characteristic, adjust the inductance L to L = 5.63 nH to achieve the output power ratio of 3: 1. The characteristics of the circuit are measured by a network analyzer and compared with the simulation results. The circuit simulation results and the frequency response of the physical circuit are as follows: Figure 7 (b), the measurement frequency is from 0 to 4GHz, and the size is from 0 to -40dB. In the working frequency band ( f ₀ = 2.45GHz) | S ₁₁ | and | S ₄₁ | are both below -15dB, the output at both ends The power ratios | S ₂₁ | and | S ₃₁ | are 3: 1, and the above simulation and measurement results are quite close to expectations.

According to the above specific embodiments, the present invention is indeed a hybrid branch coupler design with adjustable output power. The circuit is based on a traditional branch coupler. The two branches are equivalent to each other to couple the traditional branches. The four transmission lines of the converter are modified into two transmission lines and two adjustable inductors L, which are offset by adjacent capacitor values, so that the circuit does not need to add additional capacitors. The invention implements the circuit design with an output power ratio of 4: 1, and By changing the inductance value and adjusting to an output power ratio of 3: 1, the simulation and actual measurement results of the two are similar, so that the circuit is feasible and applicable. For different operating frequencies.

The above description is only a feasible embodiment of the present invention, and is not intended to limit the patent scope of the present invention. Any equivalent implementation of other changes based on the content, characteristics and spirit of the following claims should be It is included in the patent scope of the present invention. The structural features specifically defined in the present invention are not found in similar items, and are practical and progressive. They have met the requirements for invention patents. They have filed applications in accordance with the law. I would like to request the Bureau to verify the patents in accordance with the law in order to maintain this document. Applicants' legitimate rights and interests.

references

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[3] H. Ghali and TA Moselhy, “Miniaturized fractal rat-race, branch-line, and coupled-line hybrids,” IEEE Trans. Microwave Theory Tech. , Vol. 52, no. 11, pp. 2513-2520, Nov. 2004.

[4] B. Mayer and R. Knochel, "Branchline-couplers with improved design flexibility and broad bandwidth," IEEE MTT-S Microwave Symposium Digest, pp. 391-394, May 1990.

[5] J. Reed and GJ Wheeler, "A Method of Analysis of Symmetrical Four-Port Networks," IRE Trans. Microwave Theory and Techniques , vol. 4, no. 4, pp. 246-252, Oct. 1956.

[6] Jin Shi, Jun Qiang, Kai Xu, and Jian-Xin Chen, “A Balanced Branch-Line Coupler With Arbitrary Power Division Ratio,” IEEE Trans. Microwave Theory Tech. , Vol. PP, no. 99, pp. 1-8, Oct. 2016.

[7] W. Chen et al. , "Design and Linearization of Concurrent Dual-Band Doherty Power Amplifier With Frequency-Dependent Power Ranges," IEEE Trans. Microwave Theory Tech. , Vol. 59, no. 10, pp. 2537- 2546, Oct. 2011.

[8] S.-J. Lee, T.-J. Baek, M. Han, S.-G. Choi, D.-S. Ko, and J.-K. Rhee, "94 GHz MMIC single balanced mixer for FMCW radar sensor application, " in Proc. IEEE 5th Global Symp. Millim. Waves (GSMM) , pp. 351-354, May 2012.

[9] S. Cheng, E. Ojefors, P. Hallbjorner, and A. Rydberg, “Compact reflective microstrip phase shifter for traveling wave antenna applications,” IEEE Microwave and Wireless Components Letters , vol. 16, no. 7, pp. 431-433, Jul. 2006.

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Claims (8)

A hybrid branch coupler with adjustable output power includes a substrate, a transmission line group and two inductors arranged on the substrate; the transmission line group includes a laterally extending first transmission line and a juxtaposition on the first A second transmission line at the lower edge of the transmission line; wherein one end of the second transmission line extends with a first extension, and the other end of the second transmission line extends with a second extension; the first extension has a first beveled edge; the second The extension has a second beveled edge; one end of the inductor is electrically connected to a position near one end of the first transmission line, and the other end is electrically connected to one end of the second transmission line; the other end of the inductor is electrically connected. The other end of the first transmission line is electrically connected to the other end of the second transmission line. The two inductors are adjustable inductors, and the inductance values of the two adjustable inductors are between 5.63 and 6.5. nH. The hybrid branch coupler with adjustable output power according to claim 1, wherein the equivalent post impedance Z _{3 of} the transmission line group is 50 Ω, and the electrical length of the transmission line group θ _{3 is} 116.6 °. The hybrid branch coupler with adjustable output power according to claim 1, wherein the length of the first transmission line is L ₁ = L ₂ = 33.74 mm, and the width W ₁ = W ₂ = 3.055 mm. The hybrid branch coupler with adjustable output power according to claim 1, wherein the length of the long side of the top of the second transmission line L ₃ = 23.14mm, and the length of the long side of the bottom of the second transmission line L ₄ = 21.74mm. The adjustable branch power coupler with adjustable output power according to claim 1, wherein the first extension section includes a first trapezoidal section and a first rectangular section, and the hypotenuse of the first trapezoidal section is the first A hypotenuse is connected to one end of the second transmission line, and a bottom is connected to the first rectangular segment. The hybrid branch coupler with adjustable output power according to claim 5, wherein the length of the first hypotenuse is W ₃ = 3.89 mm; the long side of the first rectangular segment W ₄ = W ₅ = 3.95 mm, and the second short side L ₅ = 3.055 mm. The hybrid branch coupler with adjustable output power according to claim 1, wherein the second extension section includes a second trapezoidal section and a second rectangular section, and the hypotenuse of the second trapezoidal section is the first Two oblique sides, one side of which is connected to the other end of the second transmission line, and the bottom side of which is connected to the second rectangular segment. The hybrid branch coupler with adjustable output power according to claim 7, wherein the length of the second hypotenuse is W ₆ = 3.83 mm; one of the long sides of the second rectangular segment W ₇ = 3.95 mm, The second long side W ₈ = 3.055mm, and the second short side L ₆ = 3.055mm.