Waveguide excitation device

Abstract

The invention provides a waveguide excitation device which can be applied to the technical field of strip line excitation waveguides of a terahertz frequency band and other frequency bands. The device comprises a first dielectric layer, the first dielectric layer comprises a cavity, a metal structure is arranged on the inner wall of the cavity, and a short circuit surface is arranged in the cavity; the first metal layer is stacked above the first dielectric layer; the second dielectric layer is stacked on the first metal layer, and a plurality of metal holes are formed in the second dielectric layer; the second metal layer is stacked above the second dielectric layer, and a transmission line and a probe structure are configured in the second metal layer; the metal waveguide is stacked above the probe structure; wherein the probe structure comprises a stepped probe and a polygonal probe, the stepped probe is aligned with the cavity in the vertical direction, the first metal layer, the plurality of metal holes and the second metal layer jointly form a grounding coplanar waveguide, and the grounding coplanar waveguide is used for receiving or transmitting an electromagnetic wave signal. The transmission line and the probe structure are used for converting the electromagnetic wave signal to a target mode.

Description

Technical Field

[0001] The present disclosure relates to the technical field of stripline excitation waveguides in millimeter wave frequency bands or terahertz frequency bands, and more specifically, to a waveguide excitation device. Background Art

[0002] A rectangular waveguide is a closed metal pipe for transmitting electromagnetic waves. It has the advantages of excellent durability and low insertion loss. It is widely used in millimeter wave and terahertz frequency band test systems and device interfaces. A grounded coplanar waveguide (GCPW) is a planar transmission line with low radiation loss. When coupling electromagnetic wave signals from a grounded coplanar waveguide to a rectangular waveguide, the excitation is often completed by opening a window on the side of the rectangular waveguide and inserting a circuit substrate including a grounded coplanar waveguide, a microstrip probe, and a high-resistance transmission line.

[0003] In the process of realizing the concept of the present disclosure, the inventors found that the waveguide excitation device of the related technology has at least technical problems such as high integration difficulty and narrow working bandwidth, which makes it difficult to meet the application requirements of millimeter wave bands and terahertz bands. Summary of the invention

[0004] In view of this, the present disclosure provides a waveguide excitation device.

[0005] One aspect of the present disclosure provides a waveguide excitation device, comprising:

[0006] A first dielectric layer, the first dielectric layer includes a cavity, the inner wall of the cavity is provided with a metal structure, and a short-circuit surface is provided in the cavity; a first metal layer is stacked on the first dielectric layer; a second dielectric layer is stacked on the first metal layer, and the second dielectric layer includes a plurality of metal holes; a second metal layer is stacked on the second dielectric layer, and the second metal layer is provided with a transmission line and a probe structure; a metal waveguide is stacked on the probe structure; wherein the probe structure includes a step probe and a polygonal probe, the step probe is vertically aligned with the cavity, the first metal layer, the plurality of metal holes and the second metal layer together constitute a grounded coplanar waveguide, the grounded coplanar waveguide is used to receive or transmit electromagnetic wave signals, and the transmission line and the probe structure are used to convert the electromagnetic wave signal to a target mode so that the converted electromagnetic wave signal is transmitted along the metal waveguide.

[0007] According to an embodiment of the present disclosure, the ratio of the distance from the top surface of the second dielectric layer to the short-circuit surface to the wavelength of the electromagnetic wave signal is a target ratio.

[0008] According to an embodiment of the present disclosure, the target ratio includes: one quarter.

[0009] According to an embodiment of the present disclosure, the step probe includes a first rectangular probe and a second rectangular probe having different sizes, and the polygonal probe is located at a side of the step probe away from the transmission line.

[0010] According to an embodiment of the present disclosure, the frequency of the electromagnetic wave is in the millimeter wave frequency band or the terahertz frequency band.

[0011] According to an embodiment of the present disclosure, the shape of the cavity includes one of the following: rectangle, circle, ellipse, stepped shape, chamfered rectangle; the shape of the polygonal probe includes one of the following: rectangle, trapezoid, triangle.

[0012] According to an embodiment of the present disclosure, the above-mentioned device also includes: a first air cavity and a second air cavity with different heights, the first air cavity and the second air cavity are both located above the second metal layer, and the heights of the first air cavity and the second air cavity are both smaller than the height of the metal waveguide.

[0013] According to an embodiment of the present disclosure, the plurality of metal holes are evenly distributed along the edges of the first air cavity, the second air cavity and the metal waveguide in the vertical direction.

[0014] According to an embodiment of the present disclosure, the metal structure of the inner wall of the cavity is a metal wall or a metal column.

[0015] According to an embodiment of the present disclosure, converting an electromagnetic wave signal to a target mode includes: converting the electromagnetic wave signal from a quasi-TEM mode to a TE mode. 10 mold.

[0016] According to the embodiments of the present disclosure, a cavity is opened in the first dielectric layer, and the inner wall of the cavity is metallized, a short-circuit surface is arranged in the cavity, and an electromagnetic wave signal is fed into a grounded coplanar waveguide formed by the first metal layer, the second dielectric layer and the second metal layer, and converted to a target mode through a step probe, a polygonal probe and a transmission line, so that the electromagnetic wave signal can be coupled to the metal waveguide and transmitted in the metal waveguide. Since the size of the polygonal probe can be set according to demand and the short-circuit surface is directly arranged in the cavity of the first dielectric layer, the transmission path and phase of the electromagnetic wave can be adjusted, thereby improving the conversion efficiency of the electromagnetic wave signal and expanding the bandwidth to meet the working requirements of the terahertz frequency band and the millimeter wave frequency band. At the same time, the entire excitation device can be designed and processed in an integrated manner with the radiating antenna and the front-end circuit, effectively solving the technical problems of high difficulty in assembling and integrating the excitation device and the narrow working bandwidth in the related technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0018] Figure 1a A schematic diagram of an H-plane transition probe excitation device in a related example is schematically shown.

[0019] Figure 1bA schematic diagram of an E-plane transition probe excitation device in a related example is schematically shown.

[0020] Figure 2 A schematic diagram of a waveguide excitation device according to an embodiment of the present disclosure is schematically shown.

[0021] Figure 3 A partial schematic diagram of a waveguide excitation device according to an embodiment of the present disclosure is schematically shown.

[0022] Figure 4 A side view of a waveguide excitation device according to an embodiment of the present disclosure is schematically shown.

[0023] Figure 5 The figure schematically shows the simulation result of the waveguide excitation device according to the embodiment of the present disclosure. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0025] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0026] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0027] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0028] Terahertz (THz) waves are located between microwaves and infrared light waves, so the waveguide technology of microwaves and infrared light waves is currently expanding to the THz band. THz active devices and circuits mainly use planar structures, and the electromagnetic wave planar transmission guide structures such as THz microstrip / coplanar waveguide (CPW) have large losses. THz conduction and power synthesis networks mainly use waveguide structures, so waveguide excitation and its efficient interconnection of microstrip / coplanar waveguides are one of the key technologies for efficient integration of THz front-ends.

[0029] The structure of the grounded coplanar waveguide (GCPW) excited rectangular metal waveguide mainly includes probe / antenna feeding, ridge waveguide transition and slot coupling. The ridge waveguide transition uses the metal ridge in the waveguide, which can provide a wider frequency band and lower insertion loss, but the metal ridge must be installed inside the waveguide. Due to the small size of the waveguide in the high-frequency band, it is difficult to manufacture and integrate. The slot coupling excitation method uses the gap on the ground to couple the electromagnetic waves from the grounded coplanar waveguide to the rectangular waveguide. When the excitation is used for broadband applications, it will cause certain radiation losses.

[0030] Based on this, stripline probe excitation is the most commonly used structure at present. It uses a short resonant cavity to improve bandwidth and transition efficiency. In the related technology, a window is opened at the center of the waveguide side, and a planar circuit substrate is inserted into the window. The circuit substrate includes a microstrip probe, impedance matching (also called a high-resistance transmission line), and a stripline to make the signal transition from the stripline to the waveguide. When energy is transmitted from the probe to the rectangular waveguide, the coupling between them will produce capacitive reactance. Therefore, it is necessary to connect a stripline with high inductive reactance at the end of the stripline with a characteristic impedance of 50 ohms for impedance matching to complete efficient excitation. According to the direction in which the circuit substrate is inserted into the rectangular waveguide, the probe excitation structure can be divided into two types: H-plane transition probe excitation structure and E-plane transition probe excitation structure.

[0031] Figure 1a A schematic diagram of an H-plane transition probe excitation structure in a related example is schematically shown.

[0032] Figure 1b A schematic diagram of an E-plane transition probe excitation structure in a related example is schematically shown.

[0033] like Figure 1a and Figure 1b As shown, the circuit substrate 120 is inserted into the window of the rectangular waveguide 110, and the propagation directions of the electromagnetic waves in the strip line and the waveguide in the H-plane transition probe excitation structure are perpendicular to each other, which is suitable for a three-dimensional structure in which the circuit substrate and the waveguide are perpendicular. The propagation directions of the electromagnetic waves in the strip line and the waveguide in the E-plane transition probe excitation structure are parallel to each other, which is suitable for a three-dimensional structure in which the circuit substrate and the waveguide are parallel.

[0034] The stripline excitation waveguide solution in the related technology has high difficulty in assembly and integration, and the working bandwidth is often narrow, which makes it difficult to meet the application requirements of the millimeter wave terahertz frequency band.

[0035] In view of this, an embodiment of the present disclosure provides a waveguide excitation device, comprising:

[0036] A first dielectric layer, the first dielectric layer includes a cavity, the inner wall of the cavity is provided with a metal structure, and a short-circuit surface is provided in the cavity; a first metal layer is stacked on the first dielectric layer; a second dielectric layer is stacked on the first metal layer, and the second dielectric layer includes a plurality of metal holes; a second metal layer is stacked on the second dielectric layer, and the second metal layer is provided with a transmission line and a probe structure; a metal waveguide is stacked on the probe structure; wherein the probe structure includes a step probe and a polygonal probe, the step probe is aligned with the cavity in a vertical direction, the first metal layer, the plurality of metal holes and the second metal layer together constitute a grounded coplanar waveguide, the grounded coplanar waveguide is used to receive or transmit electromagnetic wave signals, and the transmission line and the probe structure are used to convert the electromagnetic wave signal to a target mode so that the converted electromagnetic wave signal is transmitted along the metal waveguide.

[0037] Figure 2 A schematic diagram of a waveguide excitation device according to an embodiment of the present disclosure is schematically shown.

[0038] like Figure 2 As shown, the device 200 includes a first dielectric layer 210, a first metal layer 220, a second dielectric layer 230, a second metal layer 240, and a metal waveguide 250 located above the second metal layer 240, which are stacked in sequence. The first dielectric layer includes a cavity 211, the short-circuit surface is directly arranged in the cavity of the first dielectric layer, the second dielectric layer 230 includes a plurality of metal holes 231, the second metal layer is configured with a step probe 241, a polygonal probe 242 and a transmission line 243, the step probe 242 is aligned with the cavity 211 in a vertical direction, the first metal layer 220, the second dielectric layer 230 and the second metal layer 240 together constitute a grounded coplanar waveguide, the grounded coplanar waveguide is used to receive or transmit electromagnetic wave signals, and the transmission line 243 and the probe structure are used to convert the electromagnetic wave signal to a target mode, so that the converted electromagnetic wave signal is transmitted along the metal waveguide 250.

[0039] According to an embodiment of the present disclosure, the material of the first dielectric layer may include: silicon, glass, low temperature co-fired ceramic (LTCC) and other materials, the second metal layer is the ground and feed signal routing, the material of the second dielectric layer may be benzocyclobutene (BCB), the first metal layer is the ground layer, the surroundings of the cavity and the surface of the first dielectric layer in contact with the bottom of the cavity need to be metallized, and a cavity of corresponding size is dug out at the corresponding position of the first metal layer without coating metal.

[0040] According to the embodiments of the present disclosure, a cavity is opened in the first dielectric layer, and the inner wall of the cavity is metallized, a short-circuit surface is arranged in the cavity, and an electromagnetic wave signal is fed into a grounded coplanar waveguide formed by the first metal layer, the second dielectric layer and the second metal layer, and converted to a target mode through a step probe, a polygonal probe and a transmission line, so that the electromagnetic wave signal can be coupled to the metal waveguide and transmitted in the metal waveguide. Since the size of the polygonal probe can be set according to demand and the short-circuit surface is directly arranged in the cavity of the first dielectric layer, the transmission path and phase of the electromagnetic wave can be adjusted, thereby improving the conversion efficiency of the electromagnetic wave signal and expanding the bandwidth to meet the working requirements of the terahertz frequency band and the millimeter wave frequency band. At the same time, the entire excitation device can be designed and processed in an integrated manner with the radiating antenna and the front-end circuit, effectively solving the technical problems of high difficulty in assembling and integrating the excitation device and the narrow working bandwidth in the related technology.

[0041] According to an embodiment of the present disclosure, the metal structure of the inner wall of the cavity is a metal wall or a metal column.

[0042] According to the embodiments of the present disclosure, the metallization process can be adjusted according to actual processing accuracy and work requirements to form a metal wall or a metal column on the inner wall of the cavity.

[0043] According to an embodiment of the present disclosure, the frequency of the electromagnetic wave is in the millimeter wave frequency band or the terahertz frequency band.

[0044] According to the embodiments of the present disclosure, a probe structure composed of multiple probes is provided to add interconnected transmission zero points, thereby effectively expanding the working bandwidth of the waveguide excitation device. At the same time, by changing the size of the polygonal probe to increase the resonance point, the mode conversion efficiency is further improved, thereby achieving low-loss, wide-bandwidth waveguide excitation in the millimeter-wave band and the terahertz band.

[0045] According to an embodiment of the present disclosure, converting an electromagnetic wave signal to a target mode includes: converting the electromagnetic wave signal from a quasi-TEM mode to a TE mode. 10 mold.

[0046] According to an embodiment of the present disclosure, the electromagnetic wave signal of the quasi-TEM mode in the grounded coplanar waveguide is converted into a TE wave suitable for the metal waveguide. 10 mode to achieve efficient transmission and integration of electromagnetic wave signals between different waveguide structures, meeting the needs of efficient front-end integration in the millimeter wave and terahertz frequency bands.

[0047] According to an embodiment of the present disclosure, the step probe includes a first rectangular probe and a second rectangular probe having different sizes, and the polygonal probe is located at a side of the step probe away from the transmission line.

[0048] According to an embodiment of the present disclosure, the shape of the cavity includes one of the following: rectangle, circle, ellipse, stepped shape, chamfered rectangle; the shape of the polygonal probe includes one of the following: rectangle, trapezoid, triangle.

[0049] To better understand the relative position relationship between polygon probe and step probe, the following will be Figure 3 Taking the probe structure composed of a trapezoidal probe and a step probe as an example, the relative position relationship, i.e., size, of the polygonal probe and the step probe is illustrated.

[0050] Figure 3 A partial schematic diagram of a waveguide excitation device according to an embodiment of the present disclosure is schematically shown.

[0051] like Figure 3 As shown, the grounded coplanar waveguide signal line 310 is connected to the transmission line 243 , the transmission line 243 is connected to the probe structure, and the polygonal probe 242 is located on a side of the step probe away from the transmission line 243 .

[0052] For example: the length of the trapezoidal polygonal probe L1 = 0.18 mm, the width of the long bottom side of the trapezoidal polygonal probe W1 = 0.17 mm, the width of the short bottom side of the trapezoidal polygonal probe W2 = 0.04 mm, the width of the grounded coplanar waveguide signal line W3 = 0.055 mm, the gap width of the grounded coplanar waveguide W4 = 0.02 mm, the length of the second rectangular probe L2 = 0.075 mm, the width of the second rectangular probe W5 = 0.027 mm, the length of the first rectangular probe L3 = 0.077 mm, the width of the first rectangular probe W6 = 0.022 mm, the length of the transmission line L4 = 0.054 mm; the width of the transmission line W7 = 0.03 mm. According to an embodiment of the present disclosure, the above-mentioned device also includes a first air cavity and a second air cavity of different heights, the first air cavity and the second air cavity are both located above the second metal layer, and the heights of the first air cavity and the second air cavity are both less than the height of the metal waveguide.

[0053] Figure 4 A front view of a waveguide excitation device according to an embodiment of the present disclosure is schematically shown.

[0054] like Figure 4 As shown, the first air cavity 410 and the second air cavity 420 have different heights, the first air cavity 410 and the second air cavity 420 are both located above the second metal layer, the first air cavity 410 is located between the metal waveguide 250 and the second air cavity 420, and the heights of the first air cavity 410 and the second air cavity 420 are both less than the height of the metal waveguide 250.

[0055] Among them, the distance from the first metal layer to the short-circuit surface hWG_Si=0.093 mm; the thickness of the dielectric layer hBCB=0.024 mm.

[0056] According to the embodiments of the present disclosure, the first air cavity and the second air cavity have lower insertion loss compared with cavities filled with other media. Therefore, in the terahertz frequency band or the millimeter wave frequency band, the low loss characteristic can reduce the energy loss of the electromagnetic wave signal during the transmission process, ensure the efficient transmission of the electromagnetic wave in the waveguide, and improve the overall performance of the device.

[0057] According to an embodiment of the present disclosure, the plurality of metal holes are evenly distributed along the edges of the first air cavity, the second air cavity and the metal waveguide in the vertical direction.

[0058] According to an embodiment of the present disclosure, the intervals between adjacent metal holes are the same.

[0059] According to an embodiment of the present disclosure, the ratio of the distance from the top surface of the second dielectric layer to the short-circuit surface to the wavelength of the electromagnetic wave signal is a target ratio, and the target ratio is one quarter.

[0060] According to the embodiment of the present disclosure, when the target ratio is one-quarter, the short-circuit surface is a quarter-wavelength short-circuit surface. At this time, the electromagnetic wave signal is reflected back when it is transmitted to the quarter-wavelength short-circuit surface. The reflection distance of the electromagnetic wave signal is twice the quarter-wavelength, and the phase change is related to the propagation distance. By integrating the quarter-short-circuit surface in the cavity of the first dielectric layer, the length of the signal transmission path is precisely controlled, thereby achieving effective adjustment of the phase, and converting the electromagnetic wave signal from the quasi-TEM mode to the TE mode. 10 mode to create good phase conditions.

[0061] In order to better reflect that the waveguide excitation device of the embodiment of the present disclosure has a lower insertion loss, the following will be Figure 5 The results of simulation of the waveguide excitation device are shown.

[0062] Figure 5 The figure schematically shows the simulation result of the waveguide excitation device according to the embodiment of the present disclosure.

[0063] like Figure 5 As shown, the horizontal axis is frequency, and the vertical axis is S parameters, which include return loss S 11 , return loss S 22 and insertion loss S 21 The bandwidth where the return loss is lower than -15 dB can reach 235.4-203.1=32.3 GHz, which means that within this frequency band, the insertion loss is less than 1.5 dB.

[0064] The structural schematic diagrams and simulation result diagrams in the accompanying drawings illustrate the possible architecture and functions of the devices according to various embodiments of the present disclosure. It will be understood by those skilled in the art that the features recorded in the various embodiments of the present disclosure may be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features recorded in the various embodiments of the present disclosure may be combined and / or combined in various ways. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0065] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A waveguide excitation device, characterized in that: include: A first dielectric layer, wherein the first dielectric layer includes a cavity, an inner wall of the cavity is provided with a metal structure, and a short-circuit path is provided in the cavity; A first metal layer, stacked on the first dielectric layer; A second dielectric layer is stacked on the first metal layer, and the second dielectric layer includes a plurality of metal holes; A second metal layer, stacked on the second dielectric layer, wherein a transmission line and a probe structure are disposed in the second metal layer; A metal waveguide, stacked above the probe structure; The probe structure includes a step probe and a polygonal probe, the step probe is aligned with the cavity in the vertical direction, the first metal layer, the multiple metal holes and the second metal layer together constitute a grounded coplanar waveguide, the grounded coplanar waveguide is used to receive or transmit electromagnetic wave signals, the transmission line and the probe structure are used to convert the electromagnetic wave signal to a target mode so that the converted electromagnetic wave signal is transmitted along the metal waveguide.

2. The device according to claim 1, characterized in that The ratio of the distance from the top surface of the second dielectric layer to the short-circuit surface to the wavelength of the electromagnetic wave signal is a target ratio.

3. The device according to claim 1, characterized in that The target proportions include: one quarter.

4. The device according to claim 1, characterized in that The step probe includes a first rectangular probe and a second rectangular probe having different sizes, and the polygonal probe is located at a side of the step probe away from the transmission line.

5. The device according to claim 1, characterized in that The frequency of the electromagnetic wave is in the millimeter wave frequency band or the terahertz frequency band.

6. The device according to claim 1, characterized in that The shape of the cavity includes one of the following: rectangle, circle, ellipse, stepped shape, chamfered rectangle; the shape of the polygonal probe includes one of the following: rectangle, trapezoid, triangle.

7. The device according to claim 1, characterized in that Also includes: A first air cavity and a second air cavity with different heights, wherein the first air cavity and the second air cavity are both located above the second metal layer, and the heights of the first air cavity and the second air cavity are both smaller than the height of the metal waveguide.

8. The device according to claim 7, characterized in that The plurality of metal holes are evenly distributed along the edges of the first air cavity, the second air cavity and the metal waveguide in a vertical direction.

9. The device according to claim 1, characterized in that The metal structure of the inner wall of the cavity is a metal wall or a metal column.

10. The device according to claim 1, characterized in that The converting the electromagnetic wave signal to a target mode comprises: Convert the electromagnetic wave signal from the quasi-TEM mode to the TE mode 10 mold.

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