Cascade structure for a microstrip connector and a stripline in the Ka band
By employing a multi-layer circuit board design and electrical connection in the cascaded structure of Ka-band microstrip connectors and striplines, the impedance mismatch problem is solved, achieving impedance matching and size reduction. This design is suitable for multi-layer circuit boards and exhibits excellent signal transmission performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- AEROSPACE STELLAR SPACE TECH APPL CO LTD
- Filing Date
- 2025-07-16
- Publication Date
- 2026-06-16
AI Technical Summary
There is an impedance mismatch problem between the Ka-band microstrip connector and the cascaded structure of the stripline on the circuit board, which is particularly noticeable in the high-frequency band, and existing technologies lack effective solutions.
The system employs a top-to-bottom arrangement of a microstrip connector, a top coplanar waveguide metal structure, a first dielectric substrate, a middle stripline metal structure, a second dielectric substrate, and a bottom metal structure. The connector is fixed by soldering pins, and impedance matching is achieved through electrical connections. Signal transmission and shielding are performed using a metal outer conductor, an insulating dielectric, and an inner conductor metal probe.
It achieves impedance matching between Ka-band microstrip connectors and striplines, reduces circuit board size, simplifies structure, is easy to process, has strong scalability, is suitable for multilayer circuit boards and substrates with different dielectric constants, and has good return loss and insertion loss performance.
Smart Images
Figure CN224367110U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of microwave communication technology, and more specifically, to a cascade structure for a Ka-band microstrip connector and a stripline. Background Technology
[0002] With the rapid development of microwave communication, frequency bands are gradually expanding towards the Ka band. Product sizes are also getting smaller, and traditional single-layer or double-layer circuit boards are no longer sufficient due to their large size. Multilayer circuit boards are becoming increasingly widely used in microwave communication. In traditional single-layer or double-layer circuit boards, RF transmission lines can only be placed on the surface layer, typically using microstrip lines or coplanar waveguides (CPWs). To reduce size, multilayer circuit boards often place RF transmission lines on different circuit layers, employing not only microstrip lines and coplanar waveguides but also stripline structures. This complicates the RF transmission line structure and introduces vias, leading to impedance discontinuities.
[0003] Microstrip connectors are typically used as RF connectors on circuit boards, and are soldered onto the microstrip transmission lines on the surface of the circuit board. However, when using circuit boards, impedance mismatch can occur in the cascaded structure between the microstrip connector and the stripline on the circuit board, which is particularly noticeable in the high-frequency band. Therefore, in the Ka band, the cascaded structure of microstrip connectors and striplines is a common feature in circuits, and its performance directly affects the characteristics of the entire system.
[0004] There are currently few reports on cascaded structures of microstrip connectors and RF transmission lines. Most studies focus on the connection between microstrip connectors and microstrip lines or coplanar waveguides (CPWs), and the main optimization schemes are on the structure of the microstrip connectors and metal probes, with little performance coverage of the Ka band. There are currently no solutions for cascading structures of Ka-band microstrip connectors and striplines.
[0005] Therefore, there is an urgent need to develop a cascaded structure of Ka-band microstrip connector and stripline to solve the impedance mismatch problem that occurs in the cascaded structure between Ka-band microstrip connector and stripline on the circuit board, which has important engineering significance and value. Summary of the Invention
[0006] The technical problem this invention aims to solve is the impedance mismatch issue that exists in the cascaded structure between the Ka-band microstrip connector and the stripline on the circuit board.
[0007] To address the aforementioned technical problems, this utility model provides a cascaded structure for a Ka-band microstrip connector and a stripline, comprising, from top to bottom, a microstrip connector, a top coplanar waveguide (CPW) metal structure, a first dielectric substrate, a middle stripline metal structure, a second dielectric substrate, and a bottom metal structure. The microstrip connector has four downwardly extending solder pins. The top coplanar waveguide metal structure, the first dielectric substrate, the middle stripline metal structure, the second dielectric substrate, and the bottom metal structure are bonded together to form a multilayer circuit board. The multilayer circuit board has pre-set solder holes corresponding to the four solder pins of the microstrip connector. The solder pins of the microstrip connector pass through these solder holes and are soldered onto the multilayer circuit board to reinforce the microstrip connector. The microstrip connector, the top coplanar waveguide metal structure, and the middle stripline metal structure are electrically connected to balance the impedance of the cascaded structure.
[0008] According to an embodiment of this utility model, the microstrip connector may also have a metal outer conductor, an insulating medium, and an inner conductor metal probe. The metal outer conductor serves as the base of the microstrip connector and provides signal shielding and mechanical protection. The insulating medium is a vertical cylindrical shape that wraps around the metal outer conductor and isolates the inner conductor metal probe from the metal outer conductor to prevent short circuits. The inner conductor metal probe is an inverted L-shape and is used to transmit high-frequency signals. One end of the probe is wrapped in the vertical insulating medium, and the other end extends from the groove of the metal outer conductor.
[0009] According to an embodiment of this utility model, the top coplanar waveguide metal structure may include: four pin soldering holes, a coplanar waveguide grounding layer, an inner conductor metal probe soldering area, an intermediate transmission line, an impedance transformation line, a pad extension line, a metal pad, a metallized via, and multiple metallized grounding vias. The inner conductor metal probe soldering area, the intermediate transmission line, the impedance transformation line, the pad extension line, and the metal pad are sequentially electrically connected to form the upper coplanar waveguide transmission line, forming a transmission channel, and a gap is set between it and the coplanar waveguide grounding layer.
[0010] According to an embodiment of the present invention, the inner conductor metal probe of the microstrip connector can be soldered to the inner conductor metal probe soldering area for connection.
[0011] According to an embodiment of this utility model, the impedance of the inner conductor metal probe welding area and the metal probe plus solder of the top coplanar waveguide metal structure can be set to be equal to the impedance of the intermediate transmission line; the impedance of the impedance transformation line, the pad extension line and the metal pad formed by the top coplanar waveguide metal structure can be set to be equal to the impedance of the intermediate transmission line.
[0012] According to an embodiment of this utility model, the first dielectric substrate structure may include: a dielectric substrate, four lead bonding holes, metallized vias, and multiple metallized grounding vias; the intermediate stripline metal structure includes: a stripline ground layer, four lead bonding holes, multiple metallized grounding vias, metallized vias, metal pads, and a stripline transmission line, wherein the metallized grounding vias are evenly distributed on the stripline ground layer on both sides of the stripline transmission line; the second dielectric substrate structure includes: a dielectric substrate, four lead bonding holes, and multiple metallized grounding vias; the bottom metal structure includes: a ground layer, four lead bonding holes, and multiple metallized grounding vias, wherein the lead bonding holes and metallized grounding vias on the top coplanar waveguide metal structure, the first dielectric substrate, the intermediate stripline metal structure, the second dielectric substrate, and the bottom metal structure correspond one-to-one; the metallized vias on the top coplanar waveguide metal structure, the first dielectric substrate, and the intermediate stripline metal structure correspond to each other.
[0013] According to an embodiment of the present invention, the metal pads of the intermediate stripline metal structure can be electrically connected to the stripline transmission line to form a stripline transmission channel. A gap can be set between the stripline transmission channel and the stripline ground layer. The impedance of the stripline transmission channel can be set to be equal to the impedance of the upper coplanar waveguide transmission line.
[0014] According to an embodiment of the present invention, the metallized vias of the intermediate stripline metal structure can connect the upper coplanar waveguide transmission line and the stripline transmission line of this layer for transmitting high-frequency signals.
[0015] According to an embodiment of the present invention, the dielectric substrate may be a substrate with a dielectric constant of 3.3 and a thickness of 0.1 mm.
[0016] According to an embodiment of this utility model, the model number of the microstrip connector can be: SMP-J.
[0017] Compared with the prior art, the technical solution provided by the embodiments of this utility model can achieve at least the following beneficial effects:
[0018] According to the cascade structure of the Ka-band microstrip connector and stripline of this invention, the size of the circuit board can be reduced. Compared with the traditional single-layer or double-layer circuit board, this invention uses a multi-layer circuit board, which greatly reduces the size of the circuit board and thus saves system space.
[0019] The cascade structure of the Ka-band microstrip connector and stripline according to this utility model is simple in structure and easy to process. The cascade structure of the Ka-band microstrip connector and stripline of this utility model does not adopt a complex graphic structure, and the transmission line and via structure can be fully processed using conventional processes.
[0020] The cascade structure for Ka-band microstrip connectors and striplines according to this invention offers strong scalability. This cascade structure is not limited to the multilayer circuit boards and dielectric substrates described herein, but is also applicable to multilayer circuit boards with different numbers of layers and dielectric substrates with different dielectric constants and thicknesses.
[0021] The cascade structure for Ka-band microstrip connectors and striplines according to this invention can solve the problem of impedance mismatch in the cascade structure between Ka-band microstrip connectors and striplines on circuit boards, which has important engineering significance and value. Attached Figure Description
[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below only involve some embodiments of this utility model, and are not intended to limit this utility model.
[0023] Figure 1 This is a three-dimensional exploded view showing the cascaded structure according to an embodiment of the present invention.
[0024] Figure 2 This is a three-dimensional model diagram of a microstrip connector according to an embodiment of the present invention.
[0025] Figure 3 This is a schematic planar diagram of the top coplanar waveguide (CPW) metal structure according to an embodiment of the present invention.
[0026] Figure 4 This is a schematic planar view of the first layer dielectric substrate structure according to an embodiment of the present invention.
[0027] Figure 5 This is a planar schematic diagram of the intermediate layer strip metal structure according to an embodiment of the present invention.
[0028] Figure 6 This is a schematic planar view of the second-layer dielectric substrate structure according to an embodiment of the present invention.
[0029] Figure 7 This is a schematic plan view of the underlying metal structure according to an embodiment of the present invention.
[0030] Figure 8 This is a diagram showing the simulation results of return loss according to an embodiment of the present invention.
[0031] Figure 9 This is a diagram showing the simulation results of insertion loss according to an embodiment of the present invention. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the described embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.
[0033] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a limitation of quantity, but rather indicate the presence of at least one.
[0034] like Figure 1 As shown, this cascaded structure mainly consists of a microstrip connector 1, a top coplanar waveguide (CPW) metal structure 2, a first dielectric substrate 3, an intermediate stripline metal structure 4, a second dielectric substrate 5, and a bottom metal structure 6. The microstrip connector 1 is located on top of the top coplanar waveguide (CPW) metal structure 2, which is situated on the upper surface of the first dielectric substrate 3. The intermediate stripline metal structure 4 is located on the lower surface of the first dielectric substrate 3 and the upper surface of the second dielectric substrate 5. The bottom metal structure 6 is located on the lower surface of the second dielectric substrate 3.
[0035] According to the cascade structure of the Ka-band microstrip connector and stripline of this invention, the size of the circuit board can be reduced. Compared with the traditional single-layer or double-layer circuit board, this invention uses a multi-layer circuit board, which greatly reduces the size of the circuit board and thus saves system space.
[0036] like Figure 2 As shown, the main structure of the microstrip connector 1 is: a metal outer conductor 11, an insulating medium 12, an inner conductor metal probe 13, and four solder pins 14, which can be of model SMP-J.
[0037] The outer metal conductor 11 serves as the base of the microstrip connector, providing signal shielding and mechanical protection. The insulating medium 12, a vertical cylinder, encloses the outer metal conductor, isolating the inner and outer conductors to prevent short circuits. The inverted L-shaped inner conductor metal probe 13 is partially enclosed within the vertical insulating medium 12 and extends from the groove in the outer metal conductor 11, soldering to the coplanar waveguide transmission line to transmit high-frequency signals. Four soldering pins 14 pass through the pin soldering holes of the multilayer board and are soldered to the multilayer board, reinforcing the microstrip connector.
[0038] like Figure 3 As shown, the top coplanar waveguide (CPW) metal structure 2 includes: four pin soldering holes 21, a coplanar waveguide grounding layer 22, an inner conductor metal probe soldering area 23, several metallized grounding vias 24, an intermediate transmission line 25, an impedance transformation line 26, a pad extension line 27, a metal pad 28, and a metallized via 29.
[0039] The four soldering pins 14 of the microstrip connector 1 are soldered through the four soldering holes 21. The inner conductor metal probe 13 of the microstrip connector 1 is soldered to the inner conductor metal probe soldering area 23.
[0040] The inner conductor metal probe soldering area 23, intermediate transmission line 25, impedance transformation line 26, pad extension line 27, and metal pad 28 are electrically connected in sequence to form a coplanar waveguide transmission line. The transmission channel formed is spaced from the coplanar waveguide grounding layer 22.
[0041] Several metallized grounding vias 24 are evenly distributed on the grounding layer 22 on both sides of the coplanar waveguide transmission line. According to one or some embodiments of the present invention, the diameter of the metallized grounding vias 24 is 0.2 mm and the spacing between the vias is 0.5 mm. The spacing can also be adjusted appropriately according to the processing technology.
[0042] According to one or more embodiments of this utility model, the inner conductor metal probe soldering area 23 is 0.6 mm wide and 2 mm long. The inner conductor metal probe soldering area 23 and the metal probe 13, when soldered together, form an impedance approximately equal to the impedance of the intermediate transmission line 25 (50 Ω). The length and width of the inner conductor metal probe soldering area 23 can also be appropriately adjusted according to the length and width of the connector metal probe 13.
[0043] According to one or more embodiments of the present invention, the intermediate transmission line 25 has a width of 0.75 mm and a length of 2.5 mm, and is a standard 50Ω impedance line.
[0044] According to one or more embodiments of this utility model, the impedance transformation line 26 has a width of 0.25 mm and a length of 1.5 mm, the pad extension line 27 has a width of 1.3 mm and a length of 1.7 mm, and the metal pad 28 has a diameter of 1.3 mm. The impedance formed by the impedance transformation line 26, the pad extension line 27, and the metal pad 28 is approximately equal to the impedance of the intermediate transmission line 25, which is 50 Ω.
[0045] Metallized via 29 is a metallized via for transmitting high-frequency signals, not a through-hole. Metallized via 29 connects the coplanar waveguide transmission line of the top layer coplanar waveguide (CPW) metal structure 2 and the stripline transmission line of the middle layer stripline metal structure 4, forming a board-level path for high-frequency signals. According to one or more embodiments of this invention, the aperture of metallized via 29 is 0.4 mm, which can be appropriately adjusted according to the dielectric layer thickness. The via aperture of 29 is related to the dielectric thickness; the thicker the dielectric, the larger the aperture. Specific adjustments need to be made based on simulation results.
[0046] like Figure 4 As shown, the first dielectric substrate structure 3 includes: four lead soldering holes 31, a dielectric substrate 32, metallized vias 34, and several metallized grounding vias 33.
[0047] According to one or more embodiments of the present invention, the dielectric substrate 32 is selected as a substrate with a dielectric constant of 3.3 and a thickness of 0.1 mm.
[0048] like Figure 5 As shown, the intermediate stripline metal structure 4 includes: a stripline grounding layer 41, four pin soldering holes 42, several metallized grounding vias 43, metallized vias 44, metal pads 45, and stripline transmission lines 46.
[0049] The metal pad 45 is electrically connected to the stripline transmission line 46, forming the transmission channel of the stripline, with an impedance equal to that of the upper coplanar waveguide transmission line. There is a gap between the stripline transmission channel and the stripline ground layer 41.
[0050] Metallized via 44 connects the upper coplanar waveguide transmission line to the stripline transmission line of this layer, transmitting high-frequency signals.
[0051] Several metallized grounding vias 43 are evenly distributed on the strip grounding layer 41 on both sides of the strip transmission line.
[0052] like Figure 6 As shown, the second dielectric substrate structure 5 includes: a dielectric substrate 51, four lead soldering holes 52, and several metallized grounding vias 53.
[0053] According to one or more embodiments of the present invention, the dielectric substrate 51 is selected as a substrate with a dielectric constant of 3.3 and a thickness of 0.1 mm.
[0054] like Figure 7 As shown, the bottom metal structure 6 includes: a ground layer 61, four pin welding holes 62, and several metallized grounding through holes 63.
[0055] According to one or more embodiments of the present invention, four pin welding holes 21, four pin welding holes 31, four pin welding holes 42, four pin welding holes 52 and four pin welding holes 62 are aligned vertically, and four welding pins 14 pass through these pin welding holes for welding.
[0056] According to one or more embodiments of the present invention, a plurality of metallized grounding through holes 24, a plurality of metallized grounding through holes 33, a plurality of metallized grounding through holes 43, a plurality of metallized grounding through holes 53 and a plurality of metallized grounding through holes 63 are aligned vertically.
[0057] According to one or more embodiments of the present invention, the metallized vias 29, 34, and 44 are vertically aligned.
[0058] The basic idea of this utility model is as follows: a microstrip connector is fixed together with a multilayer circuit board by welding. The metal probe of the connector is welded to the transmission line on the surface of the multilayer circuit board. The high-frequency signal is transmitted through the metal probe → surface coplanar waveguide transmission line → via → middle layer stripline. The entire cascaded structure can be adjusted by adjusting the length and width of the transmission line and impedance transformation line, and the aperture of the via, thereby optimizing the return loss and insertion loss indicators and achieving a better impedance matching effect.
[0059] The cascade structure for Ka-band microstrip connectors and striplines according to this invention can solve the problem of impedance mismatch in the cascade structure between Ka-band microstrip connectors and striplines on circuit boards, which has important engineering significance and value.
[0060] like Figure 8 , Figure 9 The figure shows the simulation results of the cascaded structure of this utility model. Figure 8 The figure shows the simulation results of return loss. The S(1,1) curve is the return loss curve, representing the impedance matching result. Figure 9 The figure shows the insertion loss simulation results, with curve S(2,1) representing the insertion loss curve and indicating the signal loss during transmission. As can be seen from the figure, the -10dB return loss frequency band in this invention covers 25.0GHz to 33.5GHz, and the insertion loss within this bandwidth is within -1.0dB. Therefore, this invention, a cascaded structure of a Ka-band microstrip connector and stripline, covers Ka-band applications, has advantages such as good matching and low insertion loss, and can meet practical engineering requirements.
[0061] The cascade structure of the Ka-band microstrip connector and stripline according to this utility model is simple in structure and easy to process. The cascade structure of the Ka-band microstrip connector and stripline of this utility model does not adopt a complex graphic structure, and the transmission line and via structure can be fully processed using conventional processes.
[0062] The cascade structure for Ka-band microstrip connectors and striplines according to this invention offers strong scalability. This cascade structure is not limited to the multilayer circuit boards and dielectric substrates described herein, but is also applicable to multilayer circuit boards with different numbers of layers and dielectric substrates with different dielectric constants and thicknesses.
[0063] The above description is merely an exemplary embodiment of the present utility model and is not intended to limit the scope of protection of the present utility model. The scope of protection of the present utility model is determined by the appended claims.
Claims
1. A cascade structure for a Ka-band microstrip connector and a stripline, characterized in that, It includes, from top to bottom, a microstrip connector, a top coplanar waveguide metal structure, a first dielectric substrate, a middle stripline metal structure, a second dielectric substrate, and a bottom metal structure. The microstrip connector has four downwardly extending solder pins; the top coplanar waveguide metal structure, the first dielectric substrate, the middle stripline metal structure, the second dielectric substrate, and the bottom metal structure are bonded together to form a multilayer circuit board. The multilayer circuit board has pre-set pin soldering holes corresponding to the four soldering pins of the microstrip connector. The soldering pins of the microstrip connector pass through the pin soldering holes and are soldered to the multilayer circuit board. The microstrip connector, the top coplanar waveguide metal structure, and the middle stripline metal structure are electrically connected to balance the impedance of the cascaded structure.
2. The cascade structure for Ka-band microstrip connectors and striplines as described in claim 1, characterized in that, The microstrip connector also includes a metal outer conductor, an insulating medium, and an inner conductor metal probe. The outer metal conductor serves as the base of the microstrip connector, providing signal shielding and mechanical protection. The insulating medium is a vertical cylindrical shape that encloses the outer metal conductor, isolating the inner conductor metal probe from the outer metal conductor to prevent short circuits. The inner conductor metal probe is an inverted L-shape, used for transmitting high-frequency signals, with one end enclosed in the vertical insulating medium and the other end extending from the groove in the outer metal conductor.
3. The cascade structure for Ka-band microstrip connectors and striplines as described in claim 2, characterized in that, The top-layer coplanar waveguide metal structure includes: four pin soldering holes, a coplanar waveguide ground layer, an inner conductor metal probe soldering area, an intermediate transmission line, an impedance transformation line, a pad extension line, metal pads, metallized vias, and multiple metallized grounding vias. The inner conductor metal probe welding area, intermediate transmission line, impedance transformation line, pad extension line, and metal pad are electrically connected in sequence to form the upper coplanar waveguide transmission line, forming a transmission channel, and a gap is set between it and the coplanar waveguide grounding layer.
4. The cascade structure for Ka-band microstrip connectors and striplines as described in claim 3, characterized in that, The inner conductor metal probe of the microstrip connector is soldered to the inner conductor metal probe soldering area for connection.
5. The cascade structure for Ka-band microstrip connectors and striplines as described in claim 3, characterized in that, The impedance setting of the inner conductor metal probe welding area and the metal probe plus solder of the top coplanar waveguide metal structure is equal to the impedance of the intermediate transmission line; the impedance setting of the impedance transformation line, the pad extension line and the metal pad of the top coplanar waveguide metal structure is equal to the impedance of the intermediate transmission line.
6. The cascade structure for Ka-band microstrip connectors and striplines as described in claim 3, characterized in that, The first dielectric substrate structure includes: a dielectric substrate, four lead bonding holes, metallized vias, and multiple metallized grounding vias; The intermediate stripline metal structure includes: a stripline grounding layer, four pin soldering holes, multiple metallized grounding vias, metallized through-holes, metal pads, and a stripline transmission line. The metallized grounding vias are evenly distributed on the stripline grounding layer on both sides of the stripline transmission line. The second dielectric substrate structure includes: a dielectric substrate, four lead bonding holes, and multiple metallized grounding vias; The underlying metal structure includes: a ground layer, four pin soldering holes, and multiple metallized grounding vias. The pin bonding holes and metallized grounding vias on the top coplanar waveguide metal structure, the first dielectric substrate, the middle stripline metal structure, the second dielectric substrate, and the bottom metal structure are respectively one-to-one; the metallized vias on the top coplanar waveguide metal structure, the first dielectric substrate, and the middle stripline metal structure are corresponding.
7. The cascade structure for Ka-band microstrip connectors and striplines as described in claim 6, characterized in that, The metal pads of the intermediate stripline metal structure are electrically connected to the stripline transmission line to form a stripline transmission channel. A gap is set between the stripline transmission channel and the stripline ground layer. The impedance of the stripline transmission channel is set to be equal to the impedance of the upper coplanar waveguide transmission line.
8. The cascade structure for Ka-band microstrip connectors and striplines as described in claim 6, characterized in that, The metallized vias of the intermediate stripline metal structure connect the upper coplanar waveguide transmission line and the stripline transmission line of this layer, and are used to transmit high-frequency signals.
9. The cascade structure for Ka-band microstrip connectors and striplines as described in claim 6, characterized in that, The dielectric substrate is selected from substrates with a dielectric constant of 3.3 and a thickness of 0.1 mm.
10. The cascade structure for Ka-band microstrip connectors and striplines as described in claim 1, characterized in that, The microstrip connector is model number SMP-J.