A thermocouple-based broadband microwave power sensing chip

Abstract

The present invention relates to the technical field of microwave power sensing chips, and specifically, to a thermocouple-type broadband microwave power sensing chip. It includes a chip substrate, a coplanar waveguide transmission line, a load resistor, and a thermocouple pair. The load resistor designed in the present invention is composed of multiple resistors connected in series, which can increase the heat source area, enabling the power sensing chip to place more thermocouples, thereby improving the detection sensitivity of the chip; the inner contour of the coplanar waveguide transmission line ground plane adopts a gradual transition in a combination of a straight line and a power function curve, enabling the characteristic impedance of the coplanar waveguide transmission line to gradually change, thereby reducing microwave reflection and improving the working bandwidth of the microwave power sensing chip; it adopts a structure of multiple resistors connected in series in cooperation with a tapered coplanar waveguide to achieve port matching within a wide frequency band while increasing the number of thermocouples, that is, it can achieve a wider working frequency band while performing high-sensitivity microwave power measurement, thereby meeting the application requirements of broadband power measurement and metrological calibration in the development of microwave technology.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave power sensing chips, and more particularly, to a thermocouple-based broadband microwave power sensing chip. Background Art

[0002] A microwave power sensing chip is the core component of a microwave power meter. A microwave power sensing chip based on a thermocouple has the advantages of a low standing wave ratio and good power linearity, and can be applied to the measurement of the average power of microwave signals and metrological calibration, which is an important direction in the research of microwave power sensing chips.

[0003] However, compared with foreign technologies, domestic research is relatively less. The Chinese Academy of Sciences has studied a microbeam structure thermocouple microwave power sensor chip with a working frequency range of DC to 18 GHz and a chip sensitivity of up to 1.1 mV / mW. Southeast University has studied a through-type thermocouple power sensor with an insertion loss of less than -18.6 dB in the working frequency range of DC - 25 GHz and a sensitivity of 81.68 uV / mW at the working frequency point of 10 GHz.

[0004] Domestic designs for thermocouple power sensing chips mostly adopt the design scheme as Figure 1 shown. A coplanar waveguide is used as the transmission line for the power signal to be measured. A thin film resistor is added as a load between the central signal line and the two ground lines at the end of the coplanar waveguide transmission line. The thermocouple pairs are arranged near the thin film resistor, and the Seebeck effect of the thermocouple pairs is used to achieve thermoelectric conversion, thereby completing the conversion of the microwave power signal to a direct current signal. In order to improve the microwave power detection sensitivity, the number of thermocouple pairs must be increased. In this structure, it is necessary to increase the size of the load resistor. As the working frequency increases, the matching degree decreases, and it is difficult to achieve impedance matching within a wide frequency band.

[0005] Generally speaking, the working frequency range of domestic thermocouple power sensing chips is relatively low. With the continuous development of microwave technology, the market's demand for broadband thermocouple power sensing chips is becoming increasingly urgent. In view of this, we have proposed a thermocouple-based broadband microwave power sensing chip. Summary of the Invention

[0006] The purpose of the present invention is to provide a thermocouple-based broadband microwave power sensing chip to solve the problems raised in the above background art.

[0007] To achieve the solution of the above technical problems, one of the purposes of the present invention is to provide a thermocouple-based broadband microwave power sensing chip, including:

[0008] A chip substrate for serving as the dielectric substrate of the thermocouple-based broadband microwave power sensing chip;

[0009] Coplanar waveguide transmission line, a coplanar waveguide is formed by a coplanar waveguide ground plane provided on a chip substrate, and is used as a transmission line for inspection signals;

[0010] Load resistor, which is divided into several thin film resistors. The several thin film resistors are placed in series at the position of the middle signal line of the coplanar waveguide transmission line, and together with the coplanar waveguide metal strip line, form the coplanar waveguide central metal conduction strip line of the thermocouple type broadband microwave power sensing chip;

[0011] Thermocouple pair, which is composed of several thermocouples. The several thermocouples are densely placed at three sides near the load resistor;

[0012] Wherein, the inner contour of the coplanar waveguide transmission line ground plane between the coplanar waveguide ground plane and the coplanar waveguide metal strip line adopts a combination of a straight line and a power function curve for impedance gradual transition.

[0013] As a further improvement of this technical solution, the area of the coplanar waveguide ground plane is smaller than the area of the chip substrate, and the coplanar waveguide metal strip line has an axisymmetric structure.

[0014] As a further improvement of this technical solution, the inner contour of the coplanar waveguide transmission line ground plane adopts a combination of a straight line and a power function curve for gradual transition, so that the characteristic impedance of the coplanar waveguide transmission line gradually changes, which is used to reduce microwave reflection and improve the working bandwidth of the thermocouple type broadband microwave power sensing chip.

[0015] As a further improvement of this technical solution, the load resistor is composed of a plurality of the thin film resistors connected in series, which is used to increase the heat source area, so that more of the thermocouples can be placed on the thermocouple type broadband microwave power sensing chip.

[0016] As a further improvement of this technical solution, the number of the thin film resistors is at least two, and the resistance values of the several thin film resistors can be the same or different.

[0017] As a further improvement of this technical solution, the thermocouple pair is densely placed at three sides near the load resistor, which is used to improve the detection sensitivity.

[0018] As a further improvement of this technical solution, the several thermocouples are symmetrically distributed according to the symmetry axis of the coplanar waveguide metal strip line.

[0019] The second object of the present invention is to provide a manufacturing method of a thermocouple type broadband microwave power sensing chip, including the following steps:

[0020] S1. First, fix the coplanar waveguide ground plane on the chip substrate. Then, divide the load resistor into multiple thin-film resistors and connect them in series at the position of the middle signal line of the coplanar waveguide transmission line. Next, densely place thermocouple pairs on three sides near the load resistor to initially fabricate a microwave power sensing chip;

[0021] S2. Determine the input impedance of the microwave power sensing chip through measurement and calculation, and record the resistance values of the thin-film resistors that make up the load resistor;

[0022] S3. The intermediate connected transmission line is in the form of a coplanar waveguide, and determine its corresponding impedance values;

[0023] S4. Import the above data into simulation software, and analyze the input port return loss data of the microwave power sensing chip in the range of DC - 70 GHz through software simulation;

[0024] S5. Adjust the performance parameters of the microwave power sensing chip by increasing / decreasing the input impedance of the chip, increasing / decreasing the number of thin-film resistors, increasing / decreasing the resistance values of the thin-film resistors, and increasing / decreasing the number of thermocouples in the thermocouple pair respectively, and repeat steps S2 - S4 until a microwave power sensing chip with an input port return loss better than -19 dB can be achieved through software simulation analysis in the range of DC - 70 GHz, which is the required thermocouple-based broadband microwave power sensing chip.

[0025] The third object of the present invention is to provide an operating platform device for simulation software, including a processor, a memory, and a computer program stored in the memory and running on the processor. The processor is used to implement the software simulation analysis step in the above method for fabricating a thermocouple-based broadband microwave power sensing chip when executing the computer program.

[0026] The fourth object of the present invention is to provide a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the software simulation analysis step in the above method for fabricating a thermocouple-based broadband microwave power sensing chip.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. In this thermocouple-based broadband microwave power sensing chip, the load resistor of the microwave power sensing chip is composed of multiple resistors connected in series, which can increase the heat source area, enabling the power sensing chip to place more thermocouples, thereby improving the detection sensitivity of the sensing chip;

[0029] 2. In this thermocouple-based broadband microwave power sensing chip, the inner contour of the coplanar waveguide transmission line ground plane adopts a gradual transition method combining a straight line and a power function curve, enabling the characteristic impedance of the coplanar waveguide transmission line to change gradually, thereby reducing microwave reflection and increasing the working bandwidth of the microwave power sensing chip, effectively solving the technical problem of the narrow working frequency band of existing thermocouple power sensing chips.

[0030] 3. This thermocouple-based broadband microwave power sensing chip adopts a structure of multiple resistors in series combined with a tapered coplanar waveguide. While increasing the number of thermocouples, it achieves port matching within a wide frequency band, that is, it can achieve a wider working frequency band while performing high-sensitivity microwave power measurement. Its working frequency range can reach DC - 70 GHz, thus meeting the application requirements of broadband power measurement and metrological calibration in the development of microwave technology. Brief Description of the Drawings

[0031] Figure 1 It is a schematic diagram of an exemplary existing thermocouple power sensing chip design in the present invention;

[0032] Figure 2 It is a schematic diagram of an exemplary thermocouple-based broadband microwave power sensing chip design in the present invention;

[0033] Figure 3 It is a schematic diagram of the load matching principle of an exemplary thermocouple-based broadband microwave power sensing chip in the present invention;

[0034] Figure 4 It is a simulation result diagram of the input port return loss of an exemplary thermocouple-based broadband microwave power sensing chip in the present invention;

[0035] Figure 5 It is a flowchart of the manufacturing method of an exemplary thermocouple-based broadband microwave power sensing chip in the present invention;

[0036] Figure 6 It is a structural diagram of an exemplary electronic computer platform device in the present invention.

[0037] In the figure:

[0038] 1. Chip substrate; 11. Coplanar waveguide central metal strip line;

[0039] 2. Coplanar waveguide transmission line; 21. Coplanar waveguide ground plane; 22. Coplanar waveguide metal strip line; 23. Inner contour of the coplanar waveguide transmission line ground plane;

[0040] 3. Load resistor; 31. Thin film resistor;

[0041] 4. Thermocouple pair; 41. Thermocouple. Detailed Embodiments

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0043] Embodiment 1

[0044] As Figure 1 - Figure 2 shown, this embodiment provides a thermocouple-type broadband microwave power sensing chip, including:

[0045] A chip substrate 1, used as a dielectric substrate of the thermocouple-type broadband microwave power sensing chip;

[0046] A coplanar waveguide transmission line 2, which forms a coplanar waveguide through a coplanar waveguide ground plane 21 provided on the chip substrate 1 and is used as a transmission line for inspection signals;

[0047] A load resistor 3, which is divided into several thin film resistors 31. The several thin film resistors 31 are placed in series at the middle signal line position of the coplanar waveguide transmission line 2 and jointly form the coplanar waveguide central metal strip line 11 of the thermocouple-type broadband microwave power sensing chip with the coplanar waveguide metal strip line 22;

[0048] A thermocouple pair 4, which consists of several thermocouples 41. The several thermocouples 41 are densely placed at three sides near the load resistor 3;

[0049] Among them, the inner contour 23 of the coplanar waveguide transmission line ground plane between the coplanar waveguide ground plane 21 and the coplanar waveguide metal strip line 22 adopts a combination of a straight line and a power function curve for impedance gradual transition.

[0050] In this embodiment, the area of the coplanar waveguide ground plane 21 is smaller than the area of the chip substrate 1, and the coplanar waveguide metal strip line 22 has an axisymmetric structure.

[0051] Furthermore, the inner contour 23 of the coplanar waveguide transmission line ground plane adopts a combination of a straight line and a power function curve for gradual transition, so that the characteristic impedance of the coplanar waveguide transmission line 2 gradually changes, which is used to reduce microwave reflection and improve the working bandwidth of the thermocouple-type broadband microwave power sensing chip.

[0052] In this embodiment, the load resistor 3 is composed of multiple thin film resistors 31 connected in series, which is used to increase the heat source area, so that more thermocouples 41 can be placed on the thermocouple-type broadband microwave power sensing chip.

[0053] Specifically, the number of the thin film resistors 31 is at least two, and the resistance values of the several thin film resistors 31 can be the same or different.

[0054] In this embodiment, thermocouple pairs 4 are densely placed on three sides near the load resistor 3 to improve the detection sensitivity.

[0055] Furthermore, a number of thermocouples 41 are symmetrically distributed along the symmetry axis of the coplanar waveguide metal strip line 22.

[0056] It should be noted that the coplanar waveguide metal strip line 22, the thin-film resistor 31, and the thermocouple 41 are regularly clamped and arranged between the chip substrate 1 and the coplanar waveguide ground plane 21.

[0057] As Figure 3 shown, this embodiment also provides a manufacturing method of a thermocouple-type broadband microwave power sensing chip, including the following steps:

[0058] S1. First, fix the coplanar waveguide ground plane 21 on the chip substrate 1, then divide the load resistor 3 into multiple thin-film resistors 31 connected in series at the middle signal line position of the coplanar waveguide transmission line 2, and then densely place thermocouple pairs 4 on three sides near the load resistor 3 to initially fabricate a microwave power sensing chip;

[0059] S2. Determine the input impedance of the microwave power sensing chip through measurement and calculation, and record the resistance values of the thin-film resistors 31 that make up the load resistor 3;

[0060] S3. The intermediate connecting transmission line is in the form of a coplanar waveguide, and determine its corresponding impedance values;

[0061] S4. Import the above data into simulation software, and analyze the input port return loss data of the microwave power sensing chip in the range of DC - 70 GHz through software simulation;

[0062] S5. Adjust the performance parameters of the microwave power sensing chip by increasing / decreasing the input impedance of the chip, increasing / decreasing the number of thin-film resistors 31, increasing / decreasing the resistance values of the thin-film resistors 31, and increasing / decreasing the number of thermocouples 41 in the thermocouple pair 4 respectively, and repeat steps S2 - S4 until a microwave power sensing chip that can achieve an input port return loss better than -19 dB in the range of DC - 70 GHz through software simulation analysis is obtained, which is the required thermocouple-type broadband microwave power sensing chip.

[0063] To verify the performance of the thermocouple-type broadband microwave power sensing chip fabricated by the above method, this embodiment also provides a set of simulation experiment data, specifically:

[0064] Figure 4 is the load matching schematic diagram of an exemplary thermocouple-type broadband microwave power sensing chip, where:

[0065] The input impedance of the thermocouple-based broadband microwave power sensing chip is 50 ohms; the load resistor 3 is composed of 4 thin-film resistors 31 connected in series, and the resistance values of the thin-film resistors 31 are 10 ohms, 10 ohms, 10 ohms, and 20 ohms respectively; the intermediate connecting transmission line is in the form of a coplanar waveguide, and its characteristic impedances are 40 ohms, 30 ohms, and 20 ohms respectively;

[0066] Then, through software simulation and analysis, in the range of DC - 70 GHz, the thermocouple-based broadband microwave power sensing chip can achieve an input port return loss better than -19 dB, refer to Figure 5 .

[0067] As Figure 6 shown, this embodiment also provides an operating platform device for simulation software, and this device includes a processor, a memory, and a computer program stored in the memory and running on the processor.

[0068] The processor includes one or more processing cores. The processor is connected to the memory through a bus. The memory is used to store program instructions. When the processor executes the program instructions in the memory, it realizes the software simulation and analysis steps in the above-mentioned method for manufacturing a thermocouple-based broadband microwave power sensing chip.

[0069] Optionally, the memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0070] In addition, the present invention also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, it realizes the software simulation and analysis steps in the above-mentioned method for manufacturing a thermocouple-based broadband microwave power sensing chip.

[0071] Optionally, the present invention also provides a computer program product containing instructions. When it runs on a computer, it enables the computer to execute the software simulation and analysis steps in the above-mentioned methods for manufacturing a thermocouple-based broadband microwave power sensing chip in various aspects.

[0072] Those of ordinary skill in the art can understand that the process of implementing all or part of the steps of the above embodiments can be completed by hardware, or can be completed by a program instructing relevant hardware. The program can be stored in a computer-readable storage medium, and the above-mentioned storage medium can be a read-only memory, magnetic disk or optical disk, etc.

[0073] The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A thermocouple-based broadband microwave power sensing chip, characterized in that: Comprising: A chip substrate (1) for serving as a dielectric substrate of a thermocouple-type broadband microwave power sensing chip; A coplanar waveguide transmission line (2) which forms a coplanar waveguide through a coplanar waveguide ground plane (21) provided on the chip substrate (1) and is used as a transmission line for inspection signals; A load resistor (3) which is divided into a plurality of thin film resistors (31). The plurality of thin film resistors (31) are placed in series at the position of the middle signal line of the coplanar waveguide transmission line (2) and together with the coplanar waveguide metal strip line (22) form a coplanar waveguide central metal strip line (11) of the thermocouple-type broadband microwave power sensing chip; A thermocouple pair (4) which is composed of a plurality of thermocouples (41). The plurality of thermocouples (41) are densely placed at three sides near the load resistor (3); Wherein, an inner contour (23) of the coplanar waveguide transmission line ground plane between the coplanar waveguide ground plane (21) and the coplanar waveguide metal strip line (22) adopts a combination of a straight line and a power function curve for impedance gradual transition; The manufacturing method of the thermocouple-type broadband microwave power sensing chip comprises the following steps: S1. First, fix the coplanar waveguide ground plane (21) on the chip substrate (1), then divide the load resistor (3) into a plurality of thin film resistors (31) in series at the position of the middle signal line of the coplanar waveguide transmission line (2), and then densely place the thermocouple pair (4) at three sides near the load resistor (3) to initially manufacture a microwave power sensing chip; S2. Determine the input impedance of the microwave power sensing chip through measurement and calculation, and record the resistance values of the respective thin film resistors (31) constituting the load resistor (3); S3. The intermediate connecting transmission line is in the form of a coplanar waveguide, and determine its corresponding impedance values; S4. Import the above data into simulation software, and analyze the input port return loss data of the microwave power sensing chip in the range of DC - 70 GHz through software simulation; S5. Adjust the performance parameters of the microwave power sensing chip respectively by increasing / decreasing the input impedance of the chip, increasing / decreasing the number of thin film resistors (31), increasing / decreasing the resistance values of the respective thin film resistors (31), and increasing / decreasing the number of thermocouples (41) in the thermocouple pair (4), and repeat steps S2 to S4 until a microwave power sensing chip that can achieve an input port return loss better than -19 dB in the range of DC - 70 GHz through software simulation analysis is obtained, which is the required thermocouple-type broadband microwave power sensing chip.

2. The thermocouple type broadband microwave power sensing chip according to claim 1, characterized in that: The area of the coplanar waveguide ground plane (21) is smaller than the area of the chip substrate (1), and the coplanar waveguide metal strip line (22) has an axisymmetric structure.

3. The thermocouple type broadband microwave power sensing chip according to claim 1, wherein: The inner contour (23) of the coplanar waveguide transmission line ground plane adopts a combination of a straight line and a power function curve for gradual transition, so that the characteristic impedance of the coplanar waveguide transmission line (2) gradually changes, which is used to reduce microwave reflection and improve the working bandwidth of the thermocouple-type broadband microwave power sensing chip.

4. The thermocouple-type broadband microwave power sensing chip according to claim 1, wherein: The load resistor (3) is composed of a plurality of the thin film resistors (31) in series, which is used to increase the heat source area, so that more of the thermocouples (41) can be placed on the thermocouple-type broadband microwave power sensing chip.

5. The thermocouple-based broadband microwave power sensing chip according to claim 1, wherein: The number of the thin film resistors (31) is at least two, and the resistance values of several of the thin film resistors (31) may be the same or different.

6. The thermocouple type broadband microwave power sensing chip according to claim 1, wherein: The thermocouple pairs (4) are densely arranged on three sides near the load resistor (3) to improve the detection sensitivity.

7. The thermocouple type broadband microwave power sensing chip according to claim 1, characterized in that: Several of the thermocouples (41) are symmetrically distributed according to the symmetry axis of the coplanar waveguide metal strip line (22).

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