24kW high-power synthesizer based on transmission line transformer

Abstract

The invention discloses a 24kW high-power synthesizer based on a transmission line transformer. The 24kW high-power synthesizer mainly solves the problem that kW-level high-power synthesis cannot be transmitted in the prior art. The synthesizer comprises four input ports, an output port, four transmission line transformers, four 50-ohm isolation resistors, eight 100-ohm isolation resistors, a 2.7-meter 50-ohm coaxial line, a matched PCB (Printed Circuit Board) and a matched shielding box. The coaxial line of the combiner uses the outer conductor to transmit signals, can bear high power of more than 6kW, and overcomes the difficulty that the traditional power combiner cannot bear high power. The isolation resistors are connected in series and in parallel to form an isolation resistor with higher power capacity, but the impedance is kept unchanged, so that the isolation resistor can meet the requirement of high power capacity of an input port. The kW-level high-power combiner can be used for kW-level high-power combination and distribution in a communication system with the frequency band of 1-30 MHz.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, and more specifically relates to a 24kW high-power combiner based on a transmission line transformer in the field of radio frequency power supply technology. This invention can be used for power combining and distribution of multiple high-power radio frequency signals. Background Technology

[0002] In shortwave and microwave wireless communications, to achieve sufficiently long transmission distances, signals must be amplified and sent to the transmitting antenna to provide adequate power. Power combiners operating over a wide bandwidth require low insertion loss and frequency combining. Typical power combiners are manufactured using lumped elements, planar structures, or waveguides. Solid-state power combining technology overcomes the power bottleneck of single devices through a multi-source collaborative mechanism, making it valuable in microwave electronic systems. Employing power combining technology can typically increase system transmit power by 1-2 orders of magnitude, effectively extending the effective radius. This characteristic makes it crucial in radar detection, communication, and precision measurement and control. Power combiner / distributor architectures can be categorized into various types, with typical implementations including radial waveguide-based combiners, lumped parameter LCR network combiners, transmission line transformer-coupled combiners, directional coupler structures, and Wilkinson combiners. Transmission line transformers (TRTs) are transformers made by winding transmission lines (including coaxial lines, two-wire lines, three-wire lines, parallel strip lines, etc.) on ferrite cores. Different connections and combinations allow them to perform various functions, such as power distribution / combining, impedance transformation, and directional coupling. TRT-type power combiners, due to their energy conservation characteristics (output power equals the vector sum of the power at each input port) and advantages such as wide bandwidth response, compact structure, and low insertion loss, occupy an important position in microwave power distribution and combining networks. In low-frequency circuits, lumped-element power combiners are assembled. These combiners are small in size and have relatively large bandwidths, but due to manufacturing limitations, they possess distributed parameters such as distributed capacitance and inductance, which restrict their upper frequency limit and prevent them from handling high-power transmission. Wilkinson and Gysel structures can be used for in-phase power combining using planar techniques. These combiners are usable in the UHF to microwave frequency range, but their bandwidth is mostly limited to one octave, and their power capacity is generally no more than 20W, which also limits their applicability. Waveguides are used to construct high-power combiners using spatial power combining technology. This structure has poor isolation between input ports and requires precise fabrication, which is costly.

[0003] Changzhou Ruisijie Electronic Technology Co., Ltd. disclosed a four-in-one HF high-power combiner in its patent application "Four-in-One HF High-Power Combiner" (application number 201220428178.2, authorization announcement number CN 202772253 U). This power combiner includes a first impedance transformer, a second impedance transformer, a third impedance transformer, a fourth impedance transformer, a first two-in-one balun, a second two-in-one balun, and a third two-in-one balun. The output terminals of the first and second impedance transformers are connected to the input terminal of the first two-in-one balun, and the output terminals of the third and fourth impedance transformers are connected to the input terminal of the second two-in-one balun. The output terminals of the first and second two-in-one baluns are both connected to the input terminal of the third two-in-one balun. A drawback of this power combiner is that, based on experience, when transmitting 6kW of high power, a wire diameter of 5mm or more is required, which is very difficult to wind. Furthermore, a single 50-ohm resistor cannot serve as an isolation resistor for a 3kW power capacity. Traditional magnetic core materials are prone to saturation under high power. After the magnetic core is saturated, the common-mode current will affect the power efficiency and generate intermodulation interference. In addition, the insufficient heat dissipation design of the transmission cavity will limit the power capacity. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the prior art by proposing a 24kW high-power combiner based on a transmission line transformer. This invention solves the problems of intermodulation interference generated in the transmission line transformer, insufficient heat dissipation design of the transmission cavity limiting power capacity, and reduced isolation caused by current returning to the input port.

[0005] To achieve the above objectives, the technical approach of this invention addresses the problem that current technologies cannot transmit kW-level high power using traditional components. It proposes using a coaxial cable with an outer conductor as a parallel pair of wires to connect multiple resistors in series and parallel, forming an isolation resistor capable of carrying high power. Since this invention is a four-in-one combined circuit, each port transmits 6kW of power, resulting in a total of 24kW. Typically, transmitting 6kW of high power requires wires with a diameter of 5mm or more, which are very difficult to wind. This invention provides a solution using two coaxial cable outer conductors to form a parallel pair of wires, simultaneously solving both the high power and winding problems. The characteristic impedance of the transmission line constructed in this way is around 50 ohms. Because this invention connects multiple low-power resistors in series and parallel to form an isolation resistor capable of carrying high power, it can withstand isolation impedance power capacity up to 3kW.

[0006] To achieve the above objectives, the present invention provides a high-power synthesizer comprising four transmission line transformers T1, T2, T3, and T4; four input ports P1, P2, P3, and P4; one output port P5; and three high-power isolation resistors R1, R2, and R3. The outputs of transmission line transformers T3 and T4 are connected in parallel to output port 5. The synthesizer uses coaxial cable outer conductors as parallel double lines, and utilizes the matching PCB board and shielding box for isolation and shielding.

[0007] Furthermore, input ports P1 and P2 are connected in parallel with transmission line transformer T1, and a high-power isolation resistor R1 is connected between the two ports of input ports P1 and P2.

[0008] Furthermore, input ports P3 and P4 are connected in parallel with transmission line transformer T2, and a high-power isolation resistor R2 is connected between the two input ports P3 and P4.

[0009] Furthermore, the outputs of transmission line transformers T1 and T2 are connected in parallel with the inputs of transmission line transformers T3 and T4, and a high-power isolation resistor R3 is connected between the two ports of the inputs of transmission line transformers T3 and T4.

[0010] Furthermore, the high-power capacity isolation resistor includes four low-power capacity resistors, wherein the first isolation resistor is connected in series with the second isolation resistor, the third isolation resistor is connected in series with the fourth isolation resistor, and the two series branches are connected in parallel.

[0011] Furthermore, the value of each isolation resistor among the four low-power resistors must be such that it carries half of the power transmitted through each input port.

[0012] Furthermore, the high-power isolation resistors R1, R2, and R3 are twice the input port impedance.

[0013] Furthermore, the coaxial outer conductor has a parallel double-wire structure, which achieves the transmission and transformation function by winding the coaxial outer conductor parallel to the ferrite magnetic ring.

[0014] Furthermore, the outer conductor of the coaxial line is a 2.7m long 50-ohm coaxial line, and each outer conductor of the coaxial line can carry a high power of more than 6kW.

[0015] Furthermore, the outer conductor of the coaxial line is wound with parallel double wires.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] First, because the present invention uses coaxial cable outer conductors as parallel double lines, each coaxial cable can carry a high power of more than 6kW, which broadens the application of traditional transmission lines and overcomes the problem that traditional general power combiners cannot withstand high power, enabling the present invention to complete the kW-level high power combining and distribution in 1-30MHz frequency band communication systems.

[0018] Secondly, because this invention constructs an isolation resistor capable of carrying high power by connecting four low-power resistors in series and parallel, the current is effectively blocked and forced to flow through the isolation resistor during non-in-phase synthesis, overcoming the problem that isolation resistors in the prior art cannot withstand high power. This allows the invention to meet the requirement of handling high power capacity at the input port. Attached Figure Description

[0019] Figure 1 This is the electrical schematic diagram of the present invention;

[0020] Figure 2 This is a schematic diagram of the isolation resistor of the present invention;

[0021] Figure 3 This is a schematic diagram of the coaxial outer conductor of the present invention forming parallel double lines;

[0022] Figure 4 This is a schematic diagram of the working principle of the high-power synthesizer of this invention;

[0023] Figure 5 This is a simulation diagram of the S-parameters of the high-power synthesizer of the present invention. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings.

[0025] Reference Figure 1 The high-power synthesizer of the present invention will be described in further detail below.

[0026] The high-power combiner of this invention includes four input ports P1, P2, P3, and P4, an output port P5, and a power combining and distribution module. The power combining and distribution module includes four transmission line transformers, four 50-ohm isolation resistors, eight 100-ohm isolation resistors, a 2.7-meter-long 50-ohm coaxial cable, a matching PCB board, and a shielding box. Every four low-power isolation resistors are connected in series and parallel to form a high-power isolation resistor, and each high-power isolation resistor is connected between each input stage.

[0027] The high-power combiner of this invention includes four input ports P1, P2, P3, and P4, one output port P5, four transmission line transformers T1, T2, T3, and T4, two high-power 100-ohm isolation resistors R1 and R2, one high-power 50-ohm isolation resistor R3, a 2.7-meter 50-ohm coaxial cable outer conductor, a matching PCB board, and a shielding box. Signals are input in parallel from input ports P1 and P2 to transmission line transformer T1, with a high-power 100-ohm isolation resistor connected between the two ports. Similarly, input ports P3 and P4 are input in parallel to transmission line transformer T2, with a high-power 100-ohm isolation resistor connected between the two ports. The signals then pass through transmission line transformers T1 and T2 and are input in parallel to transmission line transformers T3 and T4, with a high-power 50-ohm isolation resistor connected between the two ports. Finally, the signals are combined through transmission line transformers T3 and T4 and output to port 5.

[0028] The first port of transmission line transformer T1 is connected to input port P1, the second port of transmission line transformer T1 is connected to input port P2, the first port of transmission line transformer T2 is connected to input port P3, the second port of transmission line transformer T2 is connected to input port P4, the third and fourth ports of transmission line transformer T1 are connected to the first port of transmission line transformer T3, the third and fourth ports of transmission line transformer T2 are connected to the first port of transmission line transformer T4, the second port of transmission line transformer T3 is grounded, the second port of transmission line transformer T4 is grounded, the fourth port of transmission line transformer T3 is connected to the first port of transmission line transformer T4, the fourth port of transmission line transformer T4 is connected to the first port of transmission line transformer T3, and the third port of transmission line transformer T3 and the third port of transmission line transformer T4 are both connected to output port P5.

[0029] The isolation resistor for each high-power capacity is connected between each input stage, meaning that the first isolation resistor R1 is connected between input ports P1 and P2, the second isolation resistor R2 is connected between input ports P3 and P4, and the third isolation resistor R3 is connected between input port 1 of transmission line transformer T3 and input port 1 of transmission line transformer T4.

[0030] The values ​​of the three high-power isolation resistors R1, R2, and R3 are not exactly the same. The isolation resistor is twice the impedance of the input port. The impedance of input ports P1 and P2 is 50 ohms, so the impedance of isolation resistor R1 is 100 ohms. The impedance of input ports P3 and P4 is 50 ohms, so the impedance of isolation resistor R2 is 100 ohms. The impedance of port 1 of transmission line transformers T3 and T4 is 25 ohms, so the impedance of isolation resistor R3 is 50 ohms.

[0031] Reference Figure 2 The high-power capacity isolation resistor of the present invention will be described in further detail below.

[0032] Each high-power capacity isolation resistor of the present invention includes four low-power capacity resistors, with the first and second isolation resistors connected in series, and the third and fourth isolation resistors, which are also connected in series, connected in parallel.

[0033] The isolation resistor needs to be able to carry half of the power transmitted by each input port, that is, 3kW power. By using four 800W resistors, we can obtain an isolation resistor with a power capacity of 3.2kW. The impedance does not change after being connected in series and parallel, but the power capacity is increased, so that the present invention can meet the power capacity requirements of each input port.

[0034] Reference Figure 3 The coaxial outer conductor of the present invention is further described in detail as a parallel double line.

[0035] The coaxial outer conductor of the present invention is wound with parallel double wires, and the specific winding steps are as follows:

[0036] Place one end of each of the two coaxial cable outer conductors at designated starting positions on the ferrite core, marked as points 1 and 3. Starting from these positions, the two coaxial cable outer conductors are wound in parallel. After completing the winding along the predetermined path, they converge on the other side of the core, forming a complete winding structure, marked as points 2 and 4 in the diagram. At this point, the ends of the two cables can be appropriately treated, such as by welding or fixing, to ensure the stability and reliability of the winding.

[0037] Reference Figure 4 The working principle of the high-power synthesizer of the present invention will be described in further detail below.

[0038] The high-power synthesizer of the present invention consists of four transmission line transformers T1, T2, T3, and T4, two high-power capacity 100-ohm isolation resistors R1 and R2, one high-power capacity 50-ohm isolation resistor R3, and the coaxial cable outer conductors used in the input port, output port, and transmission line transformers are all 50 ohms.

[0039] The signal enters the first transmission line transformer T1 from input ports P1 and P2, and the second transmission line transformer T2 from input ports P3 and P4. A portion of the signal energy is absorbed by isolation resistors R1 and R2 to ensure signal stability and reduce reflections, while the remaining energy continues to propagate. Inside each transmission line transformer, the signal undergoes impedance reduction transformation. After processing by transmission line transformers T1 and T2, the impedance of the signal becomes 25 ohms. The signal then travels along its respective path to the third transmission line transformer T3 and the fourth transmission line transformer T4. The combined signal energy undergoes impedance increase transformation in transmission line transformers T3 and T4, resulting in an impedance of 50 ohms. A portion of the signal energy is absorbed by isolation resistor R3 to ensure signal stability and reduce reflections, and then the signal is output through output port P5. The impedance of both the input and output ports remains at 50 ohms, eliminating the need for additional impedance transformation equipment during use, thus facilitating debugging and development.

[0040] The effects of the present invention will be further explained below with reference to simulation experiments.

[0041] 1. Simulation conditions.

[0042] The software platform for the simulation experiment of this invention is: Windows 10 operating system and ADS simulation software.

[0043] 2. Analysis of simulation content and simulation results.

[0044] The characteristics of the high-power combiner of the present invention are simulated using S-parameters. The characteristics of the power combining and dividing device of the present invention include reflection coefficient, insertion loss, and isolation. Figure 5 This is a simulation diagram of the S-parameters of the high-power combiner of this invention. Among them, Figure 5 (a) is a simulation diagram of the reflection coefficient of the high-power synthesizer of the present invention; Figure 5 (b) is a simulation diagram of the insertion loss of the high-power combiner of the present invention; Figure 5 (c) is a simulation diagram of the isolation of the high-power synthesizer of the present invention.

[0045] The following is a simulation. Figure 5 The effects of the present invention will be further described.

[0046] Figure 5 In (a), the horizontal axis represents the frequency scanning range, in MHz. Figure 5 The vertical axis in (a) represents the S-parameter value, in dB. Figure 5In (a), the curve labeled S(1,1) represents the simulated reflection coefficient curve of input port P1, the curve labeled S(2,2) represents the simulated reflection coefficient curve of input port P2, the curve labeled S(3,3) represents the simulated reflection coefficient curve of input port P3, and the curve labeled S(4,4) represents the simulated reflection coefficient curve of input port P4.

[0047] from Figure 5 As shown in the S-parameter simulation graph (a), the curves S(1,1), S(2,2), S(3,3), and S(4,4) all remain below -18dB in the 1-30MHz frequency range, indicating that the impedance matching of each input port is good and meets the bandwidth requirements. This proves that the high-power combiner of the present invention has a bandwidth of 1-30MHz. Furthermore, due to the good impedance matching of each input port of the high-power combiner of the present invention, the high-power combiner of the present invention has a low reflection coefficient.

[0048] Figure 5 In (b), the horizontal axis represents the frequency scanning range, in MHz. Figure 5 (b) The vertical axis represents the S-parameter values, in dB. The high-power synthesizer signal of this invention is input from input ports P1, P2, P3, and P4 respectively, and output from output port P5. Figure 5 In (b), the curve labeled S(1,5) represents the insertion loss curve from input port P1 and output port P5, the curve labeled S(2,5) represents the insertion loss curve from input port P2 and output port P5, the curve labeled S(3,5) represents the insertion loss curve from input port P3 and output port P5, and the curve labeled S(4,5) represents the insertion loss curve from input port P4 and output port P5.

[0049] from Figure 5 As can be seen from the simulation graph in (b), curves S(1,5), S(2,5), S(3,5), and S(4,5) all do not exceed 0.47 dB in the 1–30 MHz frequency band. This demonstrates that the power combining and dividing device of this invention, when used as a divider, has a bandwidth of 1–30 MHz and exhibits low insertion loss.

[0050] Figure 5 In (c), the horizontal axis represents the frequency scanning range, in MHz. Figure 5 (c) The vertical axis represents the S-parameter values, in dB. The high-power synthesizer signal of this invention is input from input ports P1, P2, P3, and P4, and output from output port P5. Figure 5In (c), the curve labeled S(1,2) represents the isolation curve from input ports P1 and P2, the curve labeled S(1,3) represents the isolation curve from input ports P1 and P3, the curve labeled S(1,4) represents the isolation curve from input ports P1 and P4, the curve labeled S(2,3) represents the isolation curve from input ports P2 and P3, the curve labeled S(2,4) represents the isolation curve from input ports P2 and P4, and the curve labeled S(3,4) represents the isolation curve from input ports P3 and P4.

[0051] from Figure 5 As can be seen from the simulation graph in (c), curves S(1,2), S(1,3), S(1,4), S(2,3), S(2,4), and S(3,4) all remain below -14dB in the 1-30MHz frequency band. Therefore, the power combining and dividing converter of this invention, when used as a divider, has a bandwidth of 1-30MHz and good isolation.

Claims

1. A 24kW high-power combiner based on a transmission line transformer, characterized in that, The synthesizer includes four transmission line transformers T1, T2, T3, and T4, four input ports P1, P2, P3, and P4, one output port P5, and three high-power isolation resistors R1, R2, and R3. The outputs of transmission line transformers T3 and T4 are connected in parallel to output port 5. The synthesizer uses coaxial cable outer conductors as parallel double lines, and uses the matching PCB board and shielding box for isolation and shielding.

2. The high-power combiner according to claim 1, characterized in that: Input ports P1 and P2 are connected in parallel with transmission line transformer T1, and a high-power isolation resistor R1 is connected between the two ports of input ports P1 and P2.

3. The high-power combiner according to claim 2, characterized in that: Input ports P3 and P4 are connected in parallel with transmission line transformer T2, and a high-power isolation resistor R2 is connected between input ports P3 and P4.

4. The high-power combiner according to claim 3, characterized in that: The outputs of transmission line transformers T1 and T2 are connected in parallel with the inputs of transmission line transformers T3 and T4, and a high-power isolation resistor R3 is connected between the two ports of the inputs of transmission line transformers T3 and T4.

5. The high-power combiner according to claim 1, characterized in that: The high-power capacity isolation resistor includes four low-power capacity resistors, wherein the first isolation resistor is connected in series with the second isolation resistor, the third isolation resistor is connected in series with the fourth isolation resistor, and the two series branches are connected in parallel.

6. The high-power combiner according to claim 5, characterized in that, The value of each isolation resistor among the four low-power resistors must be such that it can carry half of the power transmitted through each input port.

7. The high-power combiner according to claim 1, characterized in that: The high-power isolation resistors R1, R2, and R3 are twice the input port impedance.

8. The high-power combiner according to claim 1, characterized in that: The coaxial outer conductor has a parallel double-wire structure, which achieves the function of transmission and transformation by winding the coaxial outer conductor parallel to the ferrite magnetic ring.

9. The high-power combiner according to claim 8, characterized in that: The outer conductor of the coaxial line is a 2.7m long 50-ohm coaxial line, and each outer conductor of the coaxial line can carry a high power of more than 6kW.

10. The high-power combiner according to claim 8, characterized in that: The outer conductor of the coaxial line is wound with parallel double wires.

Images