A miniaturized high-frequency microwave transmission structure for height difference transition

Abstract

This invention relates to a miniaturized high-frequency microwave transmission structure for height difference transitions, comprising a microwave multilayer dielectric substrate. The microwave multilayer dielectric substrate includes a substrate body, an upper side metallized conductive strip, and a lower side metallized conductive strip. The substrate body includes a first conductive strip layer, a second conductive strip layer, a third conductive strip layer, a first dielectric layer, and a second dielectric layer. Metallized vias are formed on the substrate body; the second conductive strip layer includes an intermediate signal conductive strip and two fifth ground conductive strips; the metallized vias pass through the first dielectric layer and the second dielectric layer, connecting the first, second, and third conductive strip layers. Compared with existing transition structures, the miniaturized high-frequency microwave transmission structure of this invention effectively solves the problem of various height difference transmission transitions in RF microsystem modules, ensuring good transmission characteristics while adapting to various height differences, facilitating the miniaturized integration of RF microsystem modules.

Description

Technical Field

[0001] This invention relates to the field of radio frequency microsystems technology, and more specifically to a miniaturized high-frequency microwave transmission structure for height difference transition. Background Technology

[0002] With the development of next-generation wireless communication system technologies, electronic devices are moving towards higher frequencies, greater integration, and miniaturization. Especially in airborne and spaceborne applications, achieving conformal integration between electronic devices and the platform is a design hotspot and a significant challenge. Radio frequency microsystems (RF microsystems), relying on the rapid development of 3D interconnects, chip stacking, and advanced packaging technologies, have become the main solution for achieving high-density integration and conformal integration with the device platform.

[0003] In the circuit design of RF microsystem modules, especially when conformal design between the module and the platform is required, three-dimensional transmission transitions are unavoidable within the module. Therefore, it is necessary to solve various challenges related to transmission transitions with varying height differences. In solving these challenges, the transmission structure must ensure good transition matching to avoid degrading transmission characteristics, while also adapting to various height differences and achieving miniaturization.

[0004] There are three main traditional solutions:

[0005] (1) Use coaxial cable

[0006] Using coaxial cables to connect high-level and low-level microstrip boards, the inner core and outer metal layers are soldered to the signal and grounding conductors of the two microstrip boards, respectively. This transition method has two drawbacks: first, the parasitic parameters introduced by the soldering prevent its use at high frequencies, such as millimeter-wave bands; second, the coaxial cable requires a large turning radius, making it unsuitable for various height difference scenarios; and third, the soldering process is complex, resulting in poor consistency in mass production.

[0007] (2) Adopting a sloping structure

[0008] A ramp structure is added between the high-position microstrip board and the low-position microstrip board for transition. In this transition method, due to the requirements of bonding and welding processes and reliability, the slope angle cannot be too large. Therefore, when handling large height differences, a very long ramp structure is required, resulting in a larger overall module size, which is not conducive to miniaturization. At the same time, since the microstrip transmission structure has significant spatial radiation, a large slope angle can also cause mutual interference in the electromagnetic field distribution.

[0009] (3) Adopting a rough button structure

[0010] Multiple hair buttons are combined to form a coaxial-like transmission structure, which is then installed on the structure requiring a transition. This transition method has two drawbacks: first, the way the hair buttons are fixed increases the size of the transition space, which is not conducive to miniaturization; second, the parasitic parameters of the hair buttons themselves cannot be compensated, making it unsuitable for high frequencies, such as the millimeter-wave band.

[0011] The three commonly used methods mentioned above all have certain limitations in actual use and cannot be suitable for all application scenarios. They are especially unsuitable when high-frequency applications require flexible handling of various height difference transition problems. Summary of the Invention

[0012] To address the shortcomings of existing technologies, the present invention aims to provide a miniaturized high-frequency microwave transmission structure for height difference transition. This transmission structure has transmission transition performance adaptable to various height differences and is also suitable for high-frequency applications. It can be widely used in miniaturized, high-density radio frequency microsystem modules.

[0013] To achieve the above objectives, the present invention adopts the following technical solution:

[0014] A miniaturized high-frequency microwave transmission structure for height difference transition, the miniaturized high-frequency microwave transmission structure comprising a microwave multilayer dielectric substrate.

[0015] The microwave multilayer dielectric substrate includes a substrate body and upper side metallized conductive strips and lower side metallized conductive strips respectively disposed on the upper and lower sides of the substrate body.

[0016] The substrate body includes a first conductive layer, a second conductive layer, and a third conductive layer arranged sequentially, a first dielectric layer disposed between the first and second conductive layers, and a second dielectric layer disposed between the second and third conductive layers; a metallized via is formed on the substrate body; the second conductive layer includes an intermediate layer signal conductive strip and two fifth ground conductive strips located on both sides of the intermediate layer signal conductive strip; the metallized via passes through the first dielectric layer and the second dielectric layer, and connects the first conductive layer, the two fifth ground conductive strips of the second conductive layer, and the third conductive layer.

[0017] The upper side metallized conductor includes an upper side signal conductor and two upper side ground conductors located on both sides of the upper side signal conductor; the lower side metallized conductor includes a lower side signal conductor and two lower side ground conductors located on both sides of the lower side signal conductor; the upper side signal conductor is connected to the middle layer signal conductor, and the two upper side ground conductors are respectively connected to two fifth ground conductors.

[0018] According to a preferred embodiment of the present invention, both the first dielectric layer and the second dielectric layer are prepared using any one of a low-temperature co-fired ceramic substrate, a microwave printed circuit board, or a silicon-based substrate.

[0019] According to a preferred embodiment of the present invention, the metallized vias comprise two rows located on both sides of the signal conductor band of the intermediate layer.

[0020] According to a preferred embodiment of the present invention, the upper side signal conductor is connected to the signal conductor of the high-position microstrip board in the radio frequency microsystem module by bonding wire; the two upper side ground conductors are connected to the two ground conductors of the high-position microstrip board in the radio frequency microsystem module by bonding wire.

[0021] According to a preferred embodiment of the present invention, the lower side signal conductor is connected to the middle layer signal conductor of the second conductor layer; the two lower side ground conductors are respectively connected to the two fifth ground conductors of the second conductor layer.

[0022] According to a preferred embodiment of the present invention, the lower side signal conductor is connected to the signal conductor of the low-position microstrip board in the radio frequency microsystem module by welding or bonding; the two lower side ground conductors are connected to the two ground conductors of the low-position microstrip board in the radio frequency microsystem module by welding or bonding.

[0023] According to a preferred embodiment of the present invention, the first conductor layer and the third conductor layer are respectively provided with notches; the notches are used to prevent the conductor layer from connecting with the signal conductor of the side metallized conductor.

[0024] According to a preferred embodiment of the present invention, the length and width of the upper side signal conductor are designed for impedance compensation matching based on the parasitic inductance generated at the operating frequency by the length, diameter, arch height and number of bonding wires, so as to achieve optimal transmission performance.

[0025] According to a preferred embodiment of the present invention, the bonding wire is a bonding alloy wire;

[0026] The parasitic inductance of the bonding wire is calculated using formulas (1) and (2):

[0027] (1)

[0028] (2)

[0029] In equations (1) and (2), L n The total parasitic inductance of the bonding wire. n The number of bonding wires, μ 0 represents the permeability of air. l 3D The effective length of a single gold wire. d The diameter of the gold wire. μ r denoted as , where is the relative permeability of the gold wire. δ To achieve the skin-penetrating depth of the gold thread,h The arch height is for the gold wire. D This represents the distance between the gold wire bonding points.

[0030] The impedance generated by the bonding wire is calculated using equation (3):

[0031] (3)

[0032] In equation (3), | z | represents the impedance of the bonding wire. F 0 represents the highest frequency for signal transmission. L n Let be the total parasitic inductance of the bonding wire.

[0033] According to a preferred embodiment of the present invention, the length and width of the upper side signal conductor are designed for impedance compensation matching based on the parasitic inductance generated at the operating frequency by the length, diameter, arch height, and number of bonding wires, including:

[0034] The length and width of the upper side signal conductor (308) are designed for impedance compensation matching based on the parasitic inductance generated at the operating frequency by the length, diameter, arch height, and number of the bonding wires (501), including:

[0035] First, based on the calculation formula for a parallel plate capacitor, the equivalent capacitance value of the parallel plate capacitor formed by the upper side signal conductor (308) is obtained using equation (4). C p :

[0036] (4)

[0037] In equation (4), ε 0 is the vacuum permittivity. ε r The relative permittivity of the microwave multilayer dielectric substrate is given. W up Indicates the width of the upper side signal conductor. L up Indicates the length of the upper side signal conductor. S The distance between the upper side signal conductor and the two upper side ground conductors;

[0038] Secondly, according to the calculation formula for LC resonant frequency, the parasitic inductance generated by the bonding wire (501) L n The parallel plate capacitor formed by the upper side signal conductor (308) C p Based on formula (5), at the highest operating frequency F 0 forms resonance to achieve at that frequency point FZero-loss transmission:

[0039] (5)

[0040] In equation (5), F 0 represents the highest frequency for signal transmission. L n The total parasitic inductance of the bonding wire;

[0041] Finally, the area of ​​the upper side signal guide (308) is calculated using equation (6), and the length and width of the upper side signal guide (308) are then determined:

[0042] (6)

[0043] In equation (6), W up Indicates the width of the upper side signal conductor. L up Indicates the length of the upper side signal conductor. S The distance between the upper side signal conductor and the two upper side ground conductors. ε 0 is the vacuum permittivity. ε r The relative permittivity of the microwave multilayer dielectric substrate is given. F 0 represents the highest frequency for signal transmission. L n Let be the total parasitic inductance of the bonding wire.

[0044] Therefore, the area of ​​the upper side signal conduction band can be calculated, and then based on other conditions in the structure... W up and L up The dimensions need to be further determined.

[0045] Compared with the prior art, the advantages of the present invention are:

[0046] This invention discloses a miniaturized high-frequency microwave transmission structure that can be manufactured using relevant microwave multilayer dielectric substrates. The manufacturing process is flexible, mature, simple, and low-cost. Utilizing a microwave stripline structure, very high frequencies can be transmitted with relatively low loss per unit length, enabling long-distance, low-loss transition transmission. Grounding vias can be added to both sides of the stripline structure to effectively improve the shielding performance and prevent electromagnetic interference. During installation and connection, conventional welding and wire bonding processes can be employed, resulting in high assembly precision and ensuring consistency in mass production, especially in high-frequency systems. In applications transmitting high-frequency signals, the parasitic effects of the bonding wires can severely impact transmission performance. The side metallization of the transmission structure described in this invention can compensate for impedance matching of the parasitic inductance generated at the operating frequency by the span, diameter, arch height, and number of bonding wires. Matching the length and width of the side metallization effectively improves the transition performance across different frequency bands. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the miniaturized high-frequency microwave transmission structure of the present invention;

[0048] Figure 2 This is a schematic diagram of the first conductor layer of the miniaturized high-frequency microwave transmission structure of the present invention;

[0049] Figure 3 This is a schematic diagram of the middle layer conductor band of the miniaturized high-frequency microwave transmission structure of the present invention;

[0050] Figure 4 This is a schematic diagram of the third conductor layer of the miniaturized high-frequency microwave transmission structure of the present invention;

[0051] Figure 5 This is a schematic diagram of the metallized conductor strip on the upper side of the miniaturized high-frequency microwave transmission structure of the present invention.

[0052] Figure 6 This is a schematic diagram of the lower side metallized conductor strip of the miniaturized high-frequency microwave transmission structure of the present invention;

[0053] Figure 7 The diagram shows the insertion loss characteristic curves of the miniaturized high-frequency microwave transmission structure in the embodiment under different height differences.

[0054] Figure 8 The figure shows the characteristic curves of the standing wave coefficient of the miniaturized high-frequency microwave transmission structure in the embodiment under different height differences.

[0055] in:

[0056] 101. RF microsystem module; 201. High-position microstrip board; 202. First grounding conductor; 203. First signal conductor; 204. Second grounding conductor; 301. Miniaturized high-frequency microwave transmission structure; 302. Metallized via; 303. First conductor layer; 304. Middle layer signal conductor; 305. Fifth grounding conductor; 306. Third conductor layer; 307. Upper side grounding conductor; 308. Upper side signal conductor; 309. Lower side grounding conductor; 310. Lower side signal conductor; 401. Low-position microstrip board; 402. Third grounding conductor; 403. Third signal conductor; 404. Fourth grounding conductor; 501. Bonding wire. Detailed Implementation

[0057] The present invention will be further described below with reference to the accompanying drawings:

[0058] This embodiment discloses a method such as Figure 1 The diagram illustrates a miniaturized high-frequency microwave transmission structure for height difference transitions. Within the RF microsystem module 101 are two microstrip boards with a height difference that require high-frequency microwave signal interconnection: a high-level microstrip board 201 and a low-level microstrip board 401. The surface conductor of the high-level microstrip board 201 includes a first signal conductor 203 and two ground conductors (first ground conductor 202 and second ground conductor 204). The surface conductor of the low-level microstrip board 401 includes a third signal conductor 403 and two ground conductors (third ground conductor 402 and fourth ground conductor 404).

[0059] In this embodiment, due to the characteristics and requirements of high-frequency microwave signal transmission, the two microstrip boards cannot be directly interconnected using wires or other methods. When the height difference is large and the frequency of the transmitted signal is high, traditional transition methods cannot effectively solve such efficient connection problems.

[0060] In this embodiment, the miniaturized high-frequency microwave transmission structure 301 can be fabricated using relevant microwave multilayer dielectric substrate manufacturing processes. Multilayer substrates of the same length can be manufactured according to the required transition height difference, offering flexible, mature, and low-cost processing methods. Inside the multilayer substrate, a microwave stripline transmission structure is used to transmit high-frequency microwave signals. This stripline transmission structure offers advantages such as low transmission loss, large operating bandwidth, and no dispersion, facilitating the transmission transition of broadband high-frequency signals. Simultaneously, adding grounding vias on both sides of the stripline increases the shielding performance. On the two sides of the multilayer substrate perpendicular to the transmission direction, a side metallization process for microwave multilayer dielectric substrates is used to fabricate transition structures for microwave signals and ground signals, respectively. This transition structure can be designed to compensate for and match the parasitic inductance caused by the bonding wires at high frequencies, flexibly enabling transmission transitions at higher frequencies and with greater bandwidth.

[0061] Preferably, the highest microwave high-frequency signal is 20 GHz. The height difference between the high-position microstrip board 201 and the low-position microstrip board 401 is H. To illustrate the universality of this method, the height H is set according to actual needs. The microwave characteristic impedance of both the first signal conductor 203 and the third ground conductor 403 is 50 ohms.

[0062] The miniaturized high-frequency microwave transmission structure 301 includes a microwave multilayer dielectric substrate. The microwave multilayer dielectric substrate comprises two dielectric layers (a first dielectric layer and a second dielectric layer), three conduction layers (a first conduction layer, a second conduction layer, and a third conduction layer), metallized vias 302, and two side metallized conduction strips (an upper side metallized conduction strip and a lower side metallized conduction strip). The microwave multilayer dielectric substrate can be a substrate obtained using conventional processes in the art, and specific examples include, but are not limited to, ceramic substrates, microwave printed circuit boards, or silicon-based substrates. In this embodiment, preferably, both dielectric layers are AlN HTCC ceramic, wherein the relative permittivity of the dielectric layers is 10.2, the thickness of each dielectric layer is 0.381 mm, and the thickness of each of the three conduction layers is 0.002 mm, so the total thickness of the microwave multilayer dielectric substrate is 0.768 mm. It is understood that the thickness of the dielectric layers and the metal conduction strip layers can be adjusted according to the design of the RF microsystem and is not specifically limited.

[0063] Furthermore, the miniaturized high-frequency microwave transmission structure 301 has three conduction band layers, including a first conduction band layer, a second conduction band layer, and a third conduction band layer, the structures of which are as follows: Figure 2 , Figure 3 and Figure 4 As shown. The miniaturized high-frequency microwave transmission structure 301 has two side metallized conduction strips. The structures of the upper and lower side metallized conduction strips are as follows: Figure 5 and Figure 6 As shown.

[0064] Specifically, the pattern of the first conductor layer 303 is as follows: Figure 2 As shown, it connects to two rows of metallized vias 302. The pattern of the second conductor layer is as follows. Figure 3 As shown, it includes an intermediate signal conductor 304 and two fifth ground conductors 305. The two fifth ground conductors 305 are connected to two rows of metallized vias 302. The pattern 306 of the third conductor layer is as follows. Figure 4 As shown, it is connected to two rows of metallized through holes 302.

[0065] In this embodiment, preferably, blank areas are left on both sides of the first conductive layer 303 and the third conductive layer 306 to prevent short circuits during substrate fabrication and assembly. The width of the blank areas on both sides is Wb=0.7mm and Lb=0.2mm. The width of the signal conductive strip 304 in the middle layer is W0=0.3mm.

[0066] The pattern of the upper side metallized conduction band is as follows Figure 5 As shown, it includes an upper side signal conductor 308 and two upper side ground conductors 307. The upper side signal conductor 308 is connected to the middle layer signal conductor 304, and the two upper side ground conductors 307 are connected to the first conductor layer 303 and the third conductor layer 306. The upper side signal conductor 308 not only serves as an interconnect, but its size-related distribution parameters can also compensate for the parasitic inductance of the bonding wire 501 at high frequencies. It can be designed according to actual conditions and is not limited. In this embodiment, the highest operating frequency of the RF microsystem module 101 is 20 GHz.

[0067] The length and width of the upper side signal conductor 308 are designed to compensate for the parasitic inductance generated at the operating frequency based on the length, diameter, arch height and number of the bonding wire, so as to achieve optimal transmission performance.

[0068] According to a preferred embodiment of the present invention, the bonding wire is a bonding alloy wire;

[0069] The parasitic inductance of the bonding wire is calculated using formulas (1) and (2):

[0070] (1)

[0071] (2)

[0072] In equations (1) and (2), L n The total parasitic inductance of the bonding wire. n The number of bonding wires, μ 0 represents the permeability of air. l 3D The effective length of a single gold wire. d The diameter of the gold wire. μ r denoted as , where is the relative permeability of the gold wire. δ To achieve the skin-penetrating depth of the gold thread, h The arch height is for the gold wire. D This represents the distance between the gold wire bonding points.

[0073] The impedance generated by the bonding wire is calculated using equation (3):

[0074] (3)

[0075] In equation (3), | z | represents the impedance of the bonding wire. F 0 represents the highest frequency for signal transmission. L nLet be the total parasitic inductance of the bonding wire.

[0076] As can be seen from equation (3), as the operating frequency increases, the parasitic inductance of the gold wire also increases, which has a greater impact on the transmission performance.

[0077] According to a preferred embodiment of the present invention, the length and width of the upper side signal conductor 308 are designed for impedance compensation matching based on the parasitic inductance generated at the operating frequency by the length, diameter, arch height, and number of bonding wires, including:

[0078] To compensate for this, the upper side signal conductor 308 can be used for compensatory matching. The specific calculation method is as follows:

[0079] Assuming the width of the upper side signal conductor 308 is W up , length is L up The relative permittivity of the microwave multilayer dielectric substrate is ε r The upper side signal conductor 308 will form an equivalent capacitance structure similar to a parallel plate capacitor during transmission.

[0080] First, based on the calculation formula for a parallel plate capacitor, the equivalent capacitance value of the parallel plate capacitor formed by the upper side signal conductor (308) is obtained using equation (4). C p :

[0081] (4)

[0082] In equation (4), ε 0 is the vacuum permittivity. ε r The relative permittivity of the microwave multilayer dielectric substrate is given. W up Indicates the width of the upper side signal conductor. L up Indicates the length of the upper side signal conductor. S The distance between the upper side signal conductor and the two upper side ground conductors;

[0083] Secondly, according to the formula for calculating the LC resonant frequency, the parasitic inductance generated by the bonding wire... L n The parallel plate capacitor formed by the upper side signal conductor band. C p It needs to be at the highest operating frequency F 0 forms resonance to achieve at that frequency point F Zero-loss transmission.

[0084] The three parameters should satisfy the formula:

[0085] (5)

[0086] In equation (5), F 0 represents the highest frequency for signal transmission. L n The total parasitic inductance of the bonding wire

[0087] Finally, the area of ​​the upper side signal guide 308 is calculated using equation (6), and the length and width of the upper side signal guide 308 are then determined:

[0088] (6)

[0089] In equation (6), W up Indicates the width of the upper side signal conductor. L up Indicates the length of the upper side signal conductor. S The distance between the upper side signal conductor and the two upper side ground conductors. ε 0 is the vacuum permittivity. ε r The relative permittivity of the microwave multilayer dielectric substrate is given. F 0 represents the highest frequency for signal transmission. L n Let be the total parasitic inductance of the bonding wire.

[0090] Therefore, the area of ​​the upper side signal conductor 308 can be calculated, and then the width can be determined based on other conditions in the structure. W up and length L up The dimensions need to be further determined.

[0091] The following constraints must be met during the determination process:

[0092] (1) W up It should be greater than the width of the middle layer signal conductor 304 of the second conductor layer, and less than the distance between the two upper side ground conductors 307 to ensure no short circuit.

[0093] (2) L up It should be less than the total thickness of the miniaturized high-frequency microwave transmission structure 301, and at the same time, in order to ensure the reliability and convenience of bonding, it should be greater than 0.2 mm.

[0094] Under the condition that the above two constraints are satisfied Wup and L up The dimensions can be chosen arbitrarily and are not limited. It is worth mentioning that although the above compensation matching calculation process only applies to the highest operating frequency F0, as the operating frequency decreases, the parasitic inductance caused by the bonding wire and the compensation capacitor introduced by the upper side signal conductor (308) generate increasingly lower impedance at low frequencies, thus having a smaller impact on the transmission performance in the low-frequency band. Therefore, compensation matching design only needs to be performed for the highest frequency. Thus, the method provided by this invention also has broadband operating capability.

[0095] Preferably, according to the aforementioned design calculation formula, the area Wup×Lup of the upper side signal guide 308 is calculated to be approximately 0.25 square millimeters. Then, according to the constraint rules, the width of the upper side signal guide 308 is determined to be 0.5 millimeters, and the length Lup is 0.5 millimeters.

[0096] The pattern of the lower side metallized conduction band is as follows Figure 6 As shown, it includes a lower side signal conductor 310 and two lower side ground conductors 309, wherein the lower side signal conductor 310 is connected to the middle layer signal conductor 304, and the two lower side ground conductors 309 are connected to the first conductor layer 303 and the third conductor layer 306.

[0097] Furthermore, during installation, the miniaturized high-frequency microwave transmission structure 301 is placed close to the vertical surface of the metal housing 101 of the RF microsystem module. The lower metallized conductive strip of the miniaturized high-frequency microwave transmission structure 301 is connected to the surface conductive strip of the low-position microstrip board 401, which can be done by welding or bonding, without limitation. Among them, the two grounding conductive strips 309 of the lower metallized conductive strip are respectively connected to the two third grounding conductive strips 402 and the fourth grounding conductive strip 404 of the low-position microstrip board 401, and the lower signal conductive strip 310 of the lower metallized conductive strip is connected to the third signal conductive strip 403 of the low-position microstrip board 401.

[0098] Preferably, the lower side metallized conductor mainly serves a connecting function, and its surface treatment during fabrication must meet the requirements of welding or bonding processes. To avoid short circuits, the width Wdown of the lower side signal conductor 310 of the lower side metallized conductor cannot be greater than the width of the third signal conductor 403 of the low-position microstrip board 401. In this embodiment, Wdown is 0.4 mm and Ldown is 0.5 mm.

[0099] Preferably, the upper metallized conductive strip is connected to the high-position microstrip board 201 by wire bonding. The two grounding conductive strips 307 of the upper metallized conductive strip are respectively connected to the two grounding conductive strips (first grounding conductive strip 202 and second grounding conductive strip 204) of the high-position microstrip board 201, and the signal conductive strip 309 of the upper metallized conductive strip is connected to the first signal conductive strip 203 of the high-position microstrip board 201. The number and morphology of the wire bonds are set according to actual design needs and are not limited here.

[0100] To verify the effectiveness and universality of the miniaturized high-frequency microwave transmission structure, the height difference H between the high-position microstrip board and the low-position microstrip board was set to 5 mm, 10 mm, and 15 mm, respectively. Performance simulations were performed using three-dimensional electromagnetic field simulation software, and the transmission and reflection performance were obtained as follows: Figure 7 and Figure 8 As shown. From Figure 7 and Figure 8 The results show that, within the operating frequency range of 20 GHz, the standing wave ratio (SWR) of the miniaturized high-frequency microwave transmission structure is less than 1.5, and the insertion loss is less than 0.5 dB. More importantly, the SWR and insertion loss performance do not deteriorate significantly with the increase in height difference, thus proving that this miniaturized high-frequency microwave transmission structure is not only suitable for high-frequency operation but also highly suitable for transitions with various height differences.

[0101] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A miniaturized high-frequency microwave transmission structure for height difference transition, characterized in that, The miniaturized high-frequency microwave transmission structure (301) includes a microwave multilayer dielectric substrate; The microwave multilayer dielectric substrate includes a substrate body and upper side metallized conductive strips and lower side metallized conductive strips respectively disposed on the upper and lower sides of the substrate body. The substrate body includes a first conductive layer (303), a second conductive layer, and a third conductive layer (306) arranged sequentially, a first dielectric layer disposed between the first conductive layer (303) and the second conductive layer, and a second dielectric layer disposed between the second conductive layer and the third conductive layer (306); a metallized via (302) is formed on the substrate body; the second conductive layer includes an intermediate layer signal conductor (304) and two fifth ground conductors (305) located on both sides of the intermediate layer signal conductor (304); the metallized via (302) passes through the first dielectric layer and the second dielectric layer, and connects the first conductive layer (303), the two fifth ground conductors (305) of the second conductive layer, and the third conductive layer (306). The upper side metallized conductor includes an upper side signal conductor (308) and two upper side ground conductors (307) located on both sides of the upper side signal conductor (308); the lower side metallized conductor includes a lower side signal conductor (310) and two lower side ground conductors (309) located on both sides of the lower side signal conductor (310); the upper side signal conductor (308) is connected to the middle layer signal conductor (304), and the two upper side ground conductors (307) are connected to two fifth ground conductors (305) respectively. The lower side signal guide (310) is connected to the middle layer signal guide (304) of the second guide layer. The two lower side grounding conductors (309) are respectively connected to the two fifth grounding conductors (305) of the second conductor layer.

2. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 1, characterized in that, Both the first dielectric layer and the second dielectric layer are prepared using any one of a co-fired ceramic substrate, a microwave printed circuit board, or a silicon-based substrate.

3. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 1, characterized in that, The metallized vias (302) comprise two rows located on both sides of the intermediate layer signal conductors (304).

4. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 1, characterized in that, The upper side signal guide strip (308) is connected to the signal guide strip of the high-position microstrip board (201) in the radio frequency microsystem module (101) by bonding wire (501); The two upper side grounding conductors (307) are connected to the two grounding conductors of the high-position microstrip board (201) in the radio frequency microsystem module (101) by bonding wires (501).

5. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 1, characterized in that, The lower side signal guide strip (310) is connected to the signal guide strip of the low-position microstrip board (401) in the radio frequency microsystem module (101) by welding or bonding. The two lower side grounding conductors (309) are connected to the two grounding conductors of the low-position microstrip board (401) in the radio frequency microsystem module (101) by welding or bonding.

6. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 1, characterized in that, The first conductor layer (303) and the third conductor layer (306) are respectively provided with notches; the notches are used to prevent the conductor layer from connecting with the signal conductor of the side metallized conductor.

7. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 4, characterized in that, The length and width of the upper side signal conductor (308) are designed to compensate for the parasitic inductance generated at the operating frequency based on the length, diameter, arch height and number of the bonding wire (501) so as to achieve optimal transmission performance.

8. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 7, characterized in that, The bonding wire (501) is made of bonding alloy wire; The parasitic inductance of the bonding wire is calculated using formulas (1) and (2): （1） （2） In equations (1) and (2), L n The total parasitic inductance of the bonding wire. n The number of bonding wires, μ 0 represents the permeability of air. l 3D The effective length of a single gold wire. d The diameter of the gold wire. μ r denoted as , where is the relative permeability of the gold wire. δ To achieve the skin-penetrating depth of gold threads, h The arch height is for the gold wire. D This represents the distance between the gold wire bonding points; The impedance generated by the bonding wire is calculated using equation (3): （3） In equation (3), | z | represents the impedance of the bonding wire. F 0 represents the highest frequency for signal transmission. L n Let be the total parasitic inductance of the bonding wire.

9. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 8, characterized in that, The length and width of the upper side signal conductor (308) are designed for impedance compensation matching based on the parasitic inductance generated at the operating frequency by the length, diameter, arch height, and number of the bonding wires (501), including: First, based on the calculation formula for a parallel plate capacitor, the equivalent capacitance value of the parallel plate capacitor formed by the upper side signal conductor (308) is obtained using equation (4). C p : （4） In equation (4), ε 0 is the vacuum permittivity. ε r The relative permittivity of the microwave multilayer dielectric substrate is given. W up Indicates the width of the upper side signal conductor. L up Indicates the length of the upper side signal conductor. S The distance between the upper side signal conductor and the two upper side ground conductors; Secondly, according to the calculation formula for LC resonant frequency, the parasitic inductance generated by the bonding wire (501) L n The parallel plate capacitor formed by the upper side signal conductor (308) C p Based on formula (5), at the highest operating frequency F 0 forms resonance to achieve at that frequency point F Zero-loss transmission: （5） In equation (5), F 0 represents the highest frequency for signal transmission. L n The total parasitic inductance of the bonding wire; Finally, the area of ​​the upper side signal guide strip (308) is calculated using equation (6), and the length and width of the upper side signal guide strip (308) are then determined: （6） In equation (6), W up Indicates the width of the upper side signal conductor. L up Indicates the length of the upper side signal conductor. S The distance between the upper side signal conductor and the two upper side ground conductors. ε 0 is the vacuum permittivity. ε r The relative permittivity of the microwave multilayer dielectric substrate is given. F 0 represents the highest frequency for signal transmission. L n Let be the total parasitic inductance of the bonding wire.

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