Ultra-wideband balancer applied to high-power microwave measurement

Abstract

The invention discloses an ultra-wideband balancer applied to high-power microwave measurement and a manufacturing method and device. The ultra-wideband balancer comprises a thick slot line layer, a microstrip line dielectric plate and a microstrip line layer, wherein the microstrip line dielectric plate and the microstrip line layer are stacked on one side of the thick slot line layer in the second direction, and the microstrip line layer is provided with an output port; the first input port and the second input port are respectively connected with an SMA connector, the phase difference of input signals of the two SMA connectors is 180 degrees, and the output port is connected with an SMA connector; a resonant cavity and a thick slot line resonator are formed between the first thick slot line structure and the second thick slot line structure, and the thick slot line resonator and the microstrip line layer form electromagnetic coupling, so that an input signal which is input by the first input port and the second input port and has a phase difference of 180 degrees is output from the output interface as an anti-phase microwave synthesis signal; the ultra-wideband balancer has larger power capacity, the problem that the power capacity is limited due to the fact that the slot line is too thin is solved, and the ultra-wideband balancer applied to high-power microwave measurement has larger power capacity.

Description

Technical Field

[0001] This application relates to the field of electronic device design, and particularly to an ultra-wideband balun, a manufacturing method and a device applied to high-power microwave measurement. Background Art

[0002] With the rapid development of wireless communication technology, broadband communication systems have received extensive attention and applications in many fields due to their unique advantages, such as high transmission rate, low power consumption, strong anti-multipath fading ability, and high-precision positioning. In a broadband communication system, a balun, as a key passive device, undertakes the important task of realizing efficient conversion between a balanced transmission line and an unbalanced transmission line, and its performance directly affects the stability and reliability of the entire communication line system.

[0003] Currently, the Marchand balun is one of the mainstream ways to implement a balun. It consists of a coupled line with an open / short circuit at the end and two cascaded balanced output lines to obtain a balanced signal at the output end. However, for the T-shaped coupling junction formed by a slot line and a microstrip line, the characteristic impedance of the traditional slot line is quite high (usually >80Ω), which is not conducive to the transition to many transmission lines. In addition, the transition is also used as an impedance transformer, and its size is usually compared with a quarter wavelength, so it has a large volume, and when the slot line is 50Ω, it has a very narrow slot width (usually <0.050mm), which not only has requirements for the general printed circuit board (PCB) manufacturing process, but also seriously limits its power capacity and is not suitable for high-power microwave applications. Summary of the Invention

[0004] The main purpose of this application is to provide an ultra-wideband balun, a manufacturing method and a device applied to high-power microwave measurement, aiming to solve the technical problem that the slot line is too thin to limit the power capacity when the microstrip line is coupled with the slot line in the traditional Marchand balun.

[0005] To achieve the above object, the present application provides an ultra-wideband balun applied to high-power microwave measurement, including: a thick slot line layer, including a first thick slot line structure and a second thick slot line structure arranged in sequence along a first direction, a resonant cavity is formed between the first thick slot line structure and the second thick slot line structure, a first input port is provided on a first side of the first thick slot line structure, a second input port is provided on a second side of the second thick slot line structure, the first input port and the second input port are diagonally arranged and are both close to the adjacent other thick slot line; and a microstrip line dielectric plate and a microstrip line layer stacked on one side of the thick slot line layer along a second direction, the microstrip line layer has an output port; the first input port and the second input port are respectively connected to an SMA connector, and the phase difference between the input signals of the two SMA connectors is 180 degrees, and the output port is connected to an SMA connector; wherein, in the balanced output mode, a resonant cavity and a thick slot line resonator are formed between the first thick slot line structure and the second thick slot line structure, and the thick slot line resonator forms electromagnetic coupling with the microstrip line layer to output the input signals with a phase difference of 180 degrees input from the first input port and the second input port as an in-phase microwave composite signal from the output interface.

[0006] Optionally, both the first thick slot line structure and the second thick slot line structure include: a first metal plate and a second metal plate stacked along a second direction, there are a plurality of metal connectors arranged along the first direction between the first metal plate and the second metal plate, and the plurality of metal connectors are close to the other thick slot line structure; and a thick slot line dielectric plate located between the first metal plate and the second metal plate and sleeved on the outer side walls of the respective metal connectors.

[0007] Optionally, the projection of the second metal plate on the first metal plate along the second direction coincides with the contour of the first metal plate.

[0008] Optionally, the microstrip line layer includes: an output microstrip line and an open-circuit microstrip resonator vertically connected along the first direction; wherein, the combination of the output microstrip line and the open-circuit microstrip resonator is used to match a preset frequency band.

[0009] Optionally, the length of the open-circuit microstrip resonator is equal to one-quarter of the operating wavelength

[0010] Optionally, in the unbalanced output mode, the output interface is used as the input interface, and the first input port and the second input port are used as two output interfaces to obtain an unbalanced microwave signal with an output phase difference of 180 degrees.

[0011] Optionally, the metal connector is a metal via or a metal post.

[0012] In addition, to achieve the above object, the present application further provides a method for manufacturing an ultra-wideband balun applied to high-power microwave measurement, including:

[0013] Processing the metal connector provided in the previous embodiment through PCB technology;

[0014] Adopting a two-step etching process to form a microstrip line layer and a thick slot line layer respectively.

[0015] In addition, to achieve the above object, the present application further provides an electronic device including the ultra-wideband balun according to any one of claims 1-7.

[0016] An ultra-wideband balun, manufacturing method and device applied to high-power microwave measurement proposed in the embodiments of the present application, through a first thick slot line structure and a second thick slot line structure arranged in sequence along a first direction, a resonant cavity is formed between the first thick slot line structure and the second thick slot line structure, a first input port is provided on a first side of the first thick slot line structure, a second input port is provided on a second side of the second thick slot line structure, the first input port and the second input port are diagonally arranged and are both close to the adjacent other thick slot line; and, a microstrip line dielectric board and a microstrip line layer stacked on one side of the thick slot line layer along a second direction, the microstrip line layer has an output port; the first input port and the second input port are respectively connected to an SMA connector, and the phase difference between the input signals of the two SMA connectors is 180 degrees, and the output port is connected to an SMA connector; wherein, in the balanced output mode, a resonant cavity and a thick slot line resonator are formed between the first thick slot line structure and the second thick slot line structure, and the thick slot line resonator forms electromagnetic coupling with the microstrip line layer to output the input signals with a phase difference of 180 degrees input from the first input port and the second input port as an in-phase microwave composite signal from the output interface. The thick slot line is wider than the traditional slot line and has a larger power capacity, solving the problem that the slot line is too thin and restricting the power capacity, and realizing that the ultra-wideband balun applied to high-power microwave measurement has a larger power capacity. Description of the Drawings

[0017] Figure 1 It is a top view of the structure provided by an embodiment of the present invention;

[0018] Figure 2 It is a side view of the structure provided by an embodiment of the present invention;

[0019] Figure 3(a) is a cross-sectional view of the metal connector in the figure provided by an embodiment of the present invention;

[0020] Figure 3(b) is a cross-sectional view of the through hole in Figure 3(a) provided by an embodiment of the present invention;

[0021] Figure 4 It is an equivalent circuit diagram of the transmission line network provided by an embodiment of the present invention;

[0022] Figure 5 It is a diagram showing the test results of the structural ports provided by an embodiment of the present invention;

[0023] Figure 6 It is a diagram showing the test results of the port phase difference provided by an embodiment of the present invention;

[0024] Figure 7 It is a diagram showing the electric field distribution of the balancer during operation provided by an embodiment of the present invention.

[0025] The realization of the purpose of this application, its functional characteristics and advantages will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0026] It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0027] This application provides an ultra-wideband balancer applied to high-power microwave measurement, including: a thick slot line layer 12, which includes a first thick slot line structure 10 and a second thick slot line structure 11 arranged in sequence along a first direction. A resonant cavity is formed between the first thick slot line structure 10 and the second thick slot line structure 11. A first input port 51 is provided on a first side of the first thick slot line structure 10, and a second input port 52 is provided on a second side of the second thick slot line structure 11. The first input port 51 and the second input port 52 are diagonally arranged and are both close to the adjacent other thick slot line; and a microstrip line dielectric plate 8 and a microstrip line layer 13 stacked on one side of the thick slot line layer 12 along a second direction. The microstrip line layer 13 has an output port; the first input port 51 and the second input port 52 are respectively connected to an SMA connector, and the phase difference between the input signals of the two SMA connectors is 180 degrees. The output port is connected to an SMA connector; wherein, in the balanced output mode, a resonant cavity and a thick slot line resonator are formed between the first thick slot line structure 10 and the second thick slot line structure 11, and the thick slot line resonator forms electromagnetic coupling with the microstrip line layer 13 to output the input signals with a phase difference of 180 degrees input from the first input port 51 and the second input port 52 as an anti-phase microwave synthesis signal from the output interface.

[0028] It should be noted that since the slot line is too thin to limit the power capacity when the microstrip line couples with the slot line in the traditional Marchand balancer, the present invention aims to solve the application problem of the broadband balancer in the high-power microwave measurement system and improve the power capacity.

[0029] Refer to Figure 1 - Fig. 3, where the yellow area is the conductive metal area and the gray area is the dielectric area.

[0030] Specifically, the balancer is composed of a microstrip line layer 13, a microstrip line dielectric plate 8, and a thick slot line layer 12. The microstrip line layer 13 includes an output microstrip line 1 and an open microstrip resonator 2, and there is a coupling port 4 between the output microstrip line 1 and the open microstrip resonator in the microstrip line layer 13. The thick slot line input ports in the thick slot line layer 12 can be a first input port 51 and a second input port 52. The slot line in the middle layer can be a second metal plate 6, and the slot line in the bottom layer can be a first metal plate 7. There is a thick slot line dielectric plate 9 between the second metal plate 6 and the first metal plate 7.

[0031] It should be noted that for such a multi-layer circuit, the open microstrip resonator 2 on the top layer, the slot line resonator in the middle layer, and the slot line resonator in the bottom layer are all 50Ω and can be directly connected to the SMA interface.

[0032] Since the second metal plate 6 in the middle layer and the first metal plate 7 in the bottom layer propagate in-phase electromagnetic waves to both ends, the input ports on both sides of the thick slot line layer 12 should be fed on different sides to achieve the synthesis of 180° out-of-phase microwaves with a phase difference.

[0033] In an embodiment of the present application, both the first thick slot line structure 10 and the second thick slot line structure 11 include: a first metal plate 7 and a second metal plate 6 stacked along the second direction, and a plurality of metal connectors 3 arranged along the first direction between the first metal plate 7 and the second metal plate 6 and close to the other thick slot line side; and, a thick slot line dielectric plate 9 located between the first metal plate 7 and the second metal plate 6 and sleeved on the outer side walls of the metal connectors 3.

[0034] Exemplarily, in the thick slot line structure, the thick slot line width is 0.35mm, the thickness of the dielectric plate in the slot line is 1.05mm, metal columns are arranged side by side thereon, and the metal columns can also be realized by metal vias. The via diameter is 0.3mm, the horizontal pitch of the vias is 0.87mm, and the vertical pitch is 0.78mm.

[0035] In an embodiment of the present application, the projection of the second metal plate 6 on the first metal plate 7 along the second direction coincides with the contour of the first metal plate 7. It can be understood that passing through the thick slot line dielectric plate 9, the upper and lower flat plates of the first metal plate 7 and the second metal plate 6 are aligned.

[0036] In an embodiment of the present application, the microstrip line layer 13 includes: an output microstrip line 1 and an open microstrip resonator 2 vertically connected along the first direction; wherein, the combination of the output microstrip line 1 and the open microstrip resonator 2 is used to match a preset frequency band. Specifically, the presence of the output microstrip line 1 and the open microstrip resonator 2 can completely match a certain frequency band, thereby introducing a small insertion loss to the high-power microwave system.

[0037] In an embodiment of the present application, the length of the open microstrip resonator 2 is equal to one-quarter of the operating wavelength.

[0038] Typically, in an example of the present invention, the length of the 50Ω open microstrip resonator 2 located on the top layer is 21.5 mm, where the length is equal to one-quarter of the operating wavelength, the width is 1.8 mm, and the thickness is 0.08 mm.

[0039] In an embodiment of the present application, in the unbalanced output mode, the output interface is used as the input interface, and the first input port and the second input port are used as two output interfaces to obtain an unbalanced microwave signal with an output phase difference of 180 degrees.

[0040] In an embodiment of the present application, the metal connector 3 is a metal via or a metal post.

[0041] It should be noted that for the second thick slot line structure 11, it has a metal connector 32. The metallized vias and the slot line array form a thick slot line resonator, and the entire structure can be realized by traditional PCB or LTCC processes.

[0042] Based on the above embodiments, the present application further provides a method for manufacturing an ultra-wideband balun applied to high-power microwave measurement, including: processing the metal connector provided in the previous embodiments by PCB technology; respectively forming a microstrip line layer 13 and a thick slot line layer 12 by a two-step etching process.

[0043] It is worth noting that the entire balun is processed using a double-layer PCB board, and the process requirements are not high. The high-power microwave balun realized by PCB technology is used as the test object.

[0044] A balun for high-power microwave measurement refers to combining two signals with the same amplitude and a phase difference of 180° into one signal, controlling the ultra-wideband high-power microwave phase synchronization through transmission line technology, and realizing the high-efficiency in-phase superposition of broadband high-power microwaves.

[0045] Exemplarily, the structural diagram of the balun for broadband high-power microwave measurement is as Figure 1 and Figure 2 shown. In an example of the present invention, the broadband balun is analyzed and fabricated on a dielectric substrate with a thickness of 0.8 mm, and its material is Rogers4003C, with a relative dielectric constant ε r = 3.55 and a loss tangent tanδ = 0.0027. The center frequency of the balun is selected as 2.1 GHz, and the port characteristic impedance is 50Ω.

[0046] Typically, in the embodiments of the present invention, a plate with a length of 54 mm and a width of 69 mm is selected. That is, the unbalanced port is the input port. Correspondingly, the length of the 50Ω microstrip line on the top layer is 27 mm, the width is 1.8 mm, and the thickness is 0.08 mm; the width is 1.8 mm and the thickness is 0.08 mm. The top-layer microstrip line and the resonator use a vertical coupling structure to transmit electromagnetic waves into the lower thick slot line. The thick slot line layer is shown in Figure 3(a). The width of the thick slot line is 0.35 mm, and the thickness of the slot line dielectric plate is 1.05 mm. Metal columns are arranged side by side on the slot line dielectric plate. The metal columns can also be realized by metal vias, as shown in Figure 3(b). The diameter of the metal via is 0.3 mm, the horizontal spacing of the metal vias is 0.87 mm, and the vertical spacing is 0.78 mm. The upper and lower flat plates of the thick slot line passing through the thick slot line dielectric plate are aligned. The coaxial feed ports of the thick slot line, that is, the first input port 51 and the second input port 52, are used to connect to one side of the SMA axis with a line width of 0.57 mm and a length of 4 mm. The entire balancer is processed using a double-layer PCB board. The double-layer PCB board has low process requirements, and the PCB technology is used to realize the test of the high-power microwave balancer.

[0047] Reference Figure 4 , in order to analyze the frequency response, the three-port equivalent transmission line network of the present application is deduced. The three-port equivalent transmission line network has 2 transformers for simulating the physical layout. The open-circuit microstrip resonator and the slot line resonator are respectively represented by a series open-circuit stub and a parallel short-circuit stub. The cascaded thick slot line resonator at the bottom layer is replaced by two transmission line segments. The electrical lengths of the open-circuit stub and the two cascaded thick slot line segments are θ1 and θ2 respectively, and their characteristic impedances are respectively defined as Z m and Z S , and Z0 is the characteristic impedance of the 50Ω feeder at each port. In addition, in order to quantitatively determine the impedance changes caused by the existing coupling, parasitic radiation, and dispersion effects of the vertical coupling microstrip and the slot line resonator in the EM simulation, two transformers N1 and N2 with different turns ratios are adopted in our design.

[0048] Specifically, in order to achieve good matching at the center frequency f0, first determine the characteristic impedance of the cascaded thick slot line at the bottom layer. Assume Figure 4 is a lossless transmission line network, where N = 1, θ1 = θ2 = 90°, and the open-circuit stub in Figure 2 can be ignored. In order to achieve the perfect matching impedance of this odd-mode equivalent circuit, it can be deduced that the impedance value of the cascaded thick slot line can be completely matched at this time.

[0049] Compared with the prior art, the present invention has the following advantages: 1. The entire transducer mainly consists of metallized vias, metal patches and slot lines. The metallized vias and the slot line array form a thick slot line resonator, and the entire structure can be realized by traditional PCB or LTCC processes. 2. The thick slot line is wider than the traditional slot line and has a larger power capacity. At the same time, the low impedance characteristic of the thick slot line makes the present invention small in size and light in weight. 3. The presence of the microstrip line and the stub resonator can perfectly match a certain frequency band, thereby introducing a small insertion loss to the high-power microwave system. 4. The circuit impedance is small, and a 50Ω coaxial cable can be directly fed into the circuit board. 5. Since the input port axes on both sides of the bottom layer should be fed into different sides, an in-phase microwave synthesis with a phase difference of 180° can be achieved.

[0050] Typically, when the unbalanced port of the present invention example inputs a 1W 0-5GHz broadband signal, the induced voltage of the dielectric substrate is shown in Figure 7 , and the electric field strength at the microstrip line to slot line coupling interface is 6000V / m. At this time, the power capacity of the transducer is 250kW, which can meet the power capacity application requirements of general high-power microwave systems. The test results of the present invention show that the transducer has good working characteristics, such as Figure 5 , Figure 6 As shown, the reflection loss is less than -15dB and the insertion loss is better than -5dB in the range of 1.6GHz to 2.7GHz. The signal phase difference at the balanced port, that is, the microstrip line output interface, is 180°. The total length of the transducer board for high-power microwave measurement is 54mm, the width is 69mm, and the thickness is 2.09mm. The transmission line is made of metal, the copper foil thickness of the copper clad laminate is 0.08mm, and the metal surface is tinned.

[0051] In summary, the design and manufacturing method of the transducer for high-power microwave measurement can be proven.

[0052] The present application also provides an electronic device, including the ultra-wideband transducer provided in the previous embodiment.

[0053] The above are only the preferred embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present application by the same token.

Claims

1. An ultra-wideband transducer applied to high-power microwave measurement, characterized in that Comprising: A thick slot line layer, including a first thick slot line structure and a second thick slot line structure arranged in sequence along a first direction. A resonant cavity is formed between the first thick slot line structure and the second thick slot line structure. A first input port is provided on a first side of the first thick slot line structure, and a second input port is provided on a second side of the second thick slot line structure. The first input port and the second input port are diagonally arranged and are both close to the adjacent other thick slot line structure; And a microstrip line dielectric plate and a microstrip line layer stacked on one side of the thick slot line layer along a second direction. The microstrip line layer has an output port; The first input port and the second input port are respectively connected to an SMA connector. The phase difference between the input signals of the two SMA connectors is 180 degrees, and the output port is connected to an SMA connector; Wherein, in the balanced output mode, a resonant cavity and a thick slot line resonator are formed between the first thick slot line structure and the second thick slot line structure. The thick slot line resonator forms an electromagnetic coupling with the microstrip line layer to output the input signals with a phase difference of 180 degrees input from the first input port and the second input port as an in-phase microwave composite signal from the output interface.

2. The ultra-wideband transducer applied to high-power microwave measurement according to claim 1, characterized in that Both the first thick slot line structure and the second thick slot line structure include: A first metal plate and a second metal plate stacked along a second direction. There are a plurality of metal connectors arranged along the first direction between the first metal plate and the second metal plate. The plurality of metal connectors are close to the other thick slot line structure; And a thick slot line dielectric plate located between the first metal plate and the second metal plate and sleeved on the outer sidewalls of the respective metal connectors.

3. The ultra-wideband transducer applied to high-power microwave measurement according to claim 2, wherein The projection of the second metal plate on the first metal plate along the second direction coincides with the contour of the first metal plate.

4. The ultra-wideband transducer applied to high-power microwave measurement according to claim 1, characterized in that The microstrip line layer includes: An output microstrip line and an open-circuit microstrip resonator vertically connected along the first direction; Wherein, the combination of the output microstrip line and the open-circuit microstrip resonator is used to match a preset frequency band.

5. The ultra-wideband transducer applied to high-power microwave measurement according to claim 4, wherein The length of the open-circuit microstrip resonator is equal to one-quarter of the operating wavelength.

6. The ultra-wideband transducer applied to high-power microwave measurement according to claim 1, characterized in that, In the unbalanced output mode, the output interface is used as the input interface, and the first input port and the second input port are used as two output interfaces to obtain an unbalanced microwave signal with an output phase difference of 180 degrees.

7. The ultra-wideband transducer applied to high-power microwave measurement according to claim 2, characterized in that, The metal connector is a metal via or a metal post.

8. A manufacturing method of an ultra-wideband transducer applied to high-power microwave measurement, characterized in that, Comprising: The metal connector applied to the ultra-wideband conversion balun for high-power microwave measurement as claimed in claim 7 processed by PCB technology; Adopting a two-step etching process to respectively form the microstrip line layer and the thick slot line layer.

9. An electronic device, characterized in that, Including the ultra-wideband conversion balun as claimed in any one of claims 1-7.

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