Miniaturized high-frequency microwave transmission structure for height difference transition

Abstract

The invention relates to a miniaturized high-frequency microwave transmission structure for height difference transition. The miniaturized high-frequency microwave transmission structure comprises a microwave multilayer dielectric substrate. The microwave multilayer dielectric substrate comprises a substrate main body, an upper side metalized conduction band and a lower side metalized conduction band. The substrate body comprises a first conduction band layer, a second conduction band layer, a third conduction band layer, a first dielectric layer and a second dielectric layer. Metalized through holes are formed in the substrate main body; the second conduction band layer comprises a middle layer signal conduction band and two fifth grounding conduction bands; and the metalized through hole passes through the first dielectric layer and the second dielectric layer and is connected with the first conduction band layer, the second conduction band layer and the third conduction band layer. Compared with an existing transition structure, the miniaturized high-frequency microwave transmission structure can effectively solve the problem of transmission transition of various height differences in a radio frequency microsystem module, not only ensures good transmission characteristics, but also can adapt to various height differences, and is convenient for realizing miniaturized integration of the radio frequency microsystem module.

Description

Technical Field

[0001] The invention relates to the technical field of radio frequency microsystems, and in particular to a miniaturized high-frequency microwave transmission structure for height difference transition. Background Art

[0002] With the development of next-generation wireless communication system technology, electronic equipment is moving towards high frequency, integration, and miniaturization. Especially on airborne and satellite-borne application platforms, the conformal coplanarity between electronic equipment and the platform is a hot spot and difficulty in design. RF microsystems rely on the rapid development of three-dimensional interconnection, chip stacking, and advanced packaging technology to become the main solution for high-density integration of electronic equipment and conformal conformity with device platforms.

[0003] In the circuit design of RF microsystem modules, especially when the modules and platforms need to be conformally designed, the module inevitably needs to undergo a three-dimensional structure transmission transition. Therefore, it is necessary to solve various height difference transmission transition problems. In the process of solving the problem, the transmission structure must ensure good transition matching and not deteriorate the transmission characteristics, while also adapting to various height differences and achieving miniaturization.

[0004] There are three main traditional solutions:

[0005] (1) Using coaxial cable

[0006] Use coaxial cable to connect the high-position microstrip board and the low-position microstrip board, and weld the inner core and outer metal to the signal and ground conductors of the two microstrip boards respectively. This transition method has two disadvantages: first, it cannot be used for high frequencies, such as the millimeter wave band, due to the parasitic parameters caused by welding; second, the turning radius required by the coaxial cable is too large and cannot be flexibly adapted to various height difference scenarios; third, the welding process is complicated and the consistency of batch manufacturing is poor.

[0007] (2) Slope structure

[0008] A slope structure is added between the high-position microstrip board and the low-position microstrip board for transition. In this transition mode, due to the requirements of process operations and reliability such as bonding and welding, the slope angle cannot be too large. Therefore, when dealing with a large height difference, a very long slope structure is required, which makes the overall size of the module larger and is not conducive to miniaturization. At the same time, due to the large spatial radiation of the microstrip transmission structure, when the inclination angle is large, mutual interference of electromagnetic field distribution will also occur.

[0009] (3) Use wool button structure

[0010] Combine multiple fur buttons to form a quasi-coaxial transmission structure and install it on the structure that needs transition. This transition method has two disadvantages: first, the fixing method of the fur buttons will increase the size of the transition space, which is not conducive to miniaturization; second, the parasitic parameters of the fur buttons themselves cannot be compensated, and are not suitable for high frequencies, such as the millimeter wave band.

[0011] The above three commonly used methods all have certain limitations in actual use and are not suitable for all application scenarios, especially in high-frequency applications where various height difference transition problems need to be handled flexibly at the same time. Summary of the invention

[0012] In order to address the deficiencies of the prior art, the purpose of the present invention is to provide a miniaturized high-frequency microwave transmission structure for height difference transition. The transmission transition performance of the transmission structure can adapt to various height differences and is also suitable for high-frequency band applications. It can be widely used in miniaturized, high-density RF microsystem modules.

[0013] To achieve the above object, the present invention adopts the following technical solutions:

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

[0015] The microwave multilayer dielectric substrate comprises a substrate body and an upper metallized conductive strip and a lower metallized conductive strip respectively arranged on the upper and lower sides of the substrate body.

[0016] The substrate body includes a first conductive tape layer, a second conductive tape layer and a third conductive tape layer which are arranged in sequence, a first dielectric layer arranged between the first conductive tape layer and the second conductive tape layer, and a second dielectric layer arranged between the second conductive tape layer and the third conductive tape layer; a metallized through hole is opened on the substrate body; the second conductive tape layer includes an intermediate layer signal conductive tape and two fifth ground conductive tapes respectively located on both sides of the intermediate layer signal conductive tape; the metallized through hole passes through the first dielectric layer and the second dielectric layer, and connects the first conductive tape layer, the two fifth ground conductive tapes of the second conductive tape layer and the third conductive tape layer.

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

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

[0019] Preferably according to the present invention, the metallized through holes include two rows, which are located on both sides of the middle layer signal conductive strip.

[0020] Preferably, according to the present invention, the upper side signal conductor strip is connected to the signal conductor strip of the high-position microstrip board in the radio frequency microsystem module by bonding wires; and the two upper side ground conductor strips are connected to the two ground conductor strips of the high-position microstrip board in the radio frequency microsystem module by bonding wires.

[0021] Preferably according to the present invention, the lower side signal conductive strip is connected to the middle layer signal conductive strip of the second conductive strip layer; and the two lower side ground conductive strips are respectively connected to the two fifth ground conductive strips of the second conductive strip layer.

[0022] Preferably, according to the present invention, the lower side signal conductor strip is connected to the signal conductor strip of the low-position microstrip board in the radio frequency microsystem module by welding or bonding; the two lower side ground conductor strips are connected to the two ground conductor strips of the low-position microstrip board in the radio frequency microsystem module by welding or bonding.

[0023] Preferably, according to the present invention, the first conductive tape layer and the third conductive tape layer are respectively provided with notches; the notches are used to prevent the conductive tape layers from being connected to the signal conductive tapes of the side metallized conductive tapes.

[0024] Preferably, according to the present invention, the length and width of the upper side signal conductive strip are designed for impedance compensation and matching according to the parasitic inductance generated by the length, diameter, arch height and number of bonding wires at the operating frequency, so as to achieve optimal transmission performance.

[0025] Preferably, according to the present invention, the bonding wire is a bonding gold wire;

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

[0027]

[0028] In formula (1) and formula (2), L n is the total parasitic inductance of the bonding wire, n is the number of bonding wires, μ0 is the magnetic permeability of the air medium, l 3D is the effective length of a single gold wire, d is the diameter of the gold wire, μ r is the relative magnetic permeability of the gold wire, δ is the skin depth of the gold wire, h is the arch height of the gold wire, and D is the distance between the bonding points of the gold wire.

[0029] The impedance generated by the bonding wire is calculated using formula (3):

[0030] |Z|=2πF0×L n (3)

[0031] In formula (3), |z| represents the impedance of the bonding wire, F0 is the highest frequency of signal transmission, and L n is the total parasitic inductance of the bonding wire.

[0032] Preferably, according to the present invention, the length and width of the upper side signal conductive strip are designed for impedance compensation and matching according to the parasitic inductance generated by the length, diameter, arch height and number of bonding wires at the operating frequency, including:

[0033] The length and width of the upper side signal conductive strip (308) are designed for impedance compensation and matching according to the parasitic inductance generated by the length, diameter, arch height and number of the bonding wires (501) at the operating frequency, including:

[0034] First, according to the calculation formula of the flat plate capacitor, the equivalent capacitance C of the flat plate capacitor formed by the upper side signal conductive band (308) is obtained using formula (4): p :

[0035]

[0036] In formula (4), ε0 is the dielectric constant of vacuum, ε r is the relative dielectric constant of the microwave multilayer dielectric substrate, W up Indicates the width of the upper signal band, L up represents the length of the upper side signal conductor, S is the distance between the upper side signal conductor and the two upper side ground conductors;

[0037] Secondly, according to the calculation formula of LC resonant frequency, the parasitic inductance L generated by the bonding wire (501) is n and the flat plate capacitor C formed by the upper side signal conductive band (308) p , based on formula (5), resonance is formed at the highest operating frequency F0 to achieve low-loss transmission at this frequency:

[0038]

[0039] In formula (5), F0 is the highest frequency of signal transmission, L n is the total parasitic inductance of the bonding wire;

[0040] Finally, the area of ​​the upper side signal conductive strip (308) is calculated using formula (6), and then the length and width of the upper side signal conductive strip (308) are determined:

[0041]

[0042] In formula (6), W up Indicates the width of the upper signal band, L uprepresents the length of the upper side signal conductor, S is the distance between the upper side signal conductor and the two upper side ground conductors, ε0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the microwave multilayer dielectric substrate, F0 is the highest frequency of signal transmission, L n is the total parasitic inductance of the bonding wire.

[0043] From this, the area of ​​the upper signal conduction band can be calculated, and then W can be adjusted according to other conditions in the structure. up and L up to further determine the size.

[0044] Compared with the prior art, the advantages of the present invention are:

[0045] The miniaturized high-frequency microwave transmission structure of the present invention can be manufactured using related microwave multilayer dielectric substrates, with flexible process selection, mature and simple manufacturing methods and low cost; the microwave stripline structure can transmit very high frequencies, and the loss per unit length is relatively low, which can achieve long-distance, low-loss transition transmission; ground vias can be added on both sides of the stripline structure, which can effectively improve the shielding performance of the transmission structure and avoid electromagnetic interference; the transmission structure can be installed and connected using conventional welding and gold wire bonding process means, with high assembly accuracy, which can ensure the consistency of batch production, especially in high-frequency band systems; in applications where high-frequency signals are transmitted, the parasitic effect of the bonding wire will seriously affect the transmission performance. The side metallization of the transmission structure described in the present invention can perform impedance matching compensation for the parasitic inductance generated by the span, diameter, arch height and number of the bonding wires at the operating frequency, and the length and width of the side metallization can be matched and designed, which can effectively improve the transition performance of transmission in different frequency bands. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the miniaturized high-frequency microwave transmission structure of the present invention;

[0047] Figure 2 It is a schematic diagram of the first conducting band layer of the miniaturized high-frequency microwave transmission structure of the present invention;

[0048] Figure 3 It is a schematic diagram of the intermediate layer conduction band of the miniaturized high-frequency microwave transmission structure of the present invention;

[0049] Figure 4 A schematic diagram of the third conduction band layer of the miniaturized high-frequency microwave transmission structure of the present invention;

[0050] Figure 5 A schematic diagram of the upper side metallized conductive strip of the miniaturized high-frequency microwave transmission structure of the present invention;

[0051] Figure 6It is a schematic diagram of the metallized conductive strip at the lower side of the miniaturized high-frequency microwave transmission structure of the present invention;

[0052] Figure 7 It is a characteristic curve diagram of the insertion loss of the miniaturized high-frequency microwave transmission structure under different height differences in the embodiment;

[0053] Figure 8 It is a characteristic curve diagram of the standing wave coefficient of the miniaturized high-frequency microwave transmission structure in the embodiment under different height differences.

[0054] in:

[0055] 101. RF microsystem module, 201. high-position microstrip board, 202. first grounding conductive strip, 203. first signal conductive strip, 204. second grounding conductive strip, 301. miniaturized high-frequency microwave transmission structure, 302. metallized through hole, 303. first conductive strip layer, 304. middle layer signal conductive strip, 305. fifth grounding conductive strip, 306. third conductive strip layer, 307. upper side grounding conductive strip, 308. upper side signal conductive strip, 309. lower side grounding conductive strip, 310. lower side signal conductive strip, 401. low-position microstrip board, 402. third grounding conductive strip, 403. third signal conductive strip, 404. fourth grounding conductive strip, 501. bonding wire. DETAILED DESCRIPTION

[0056] The present invention will be further described below in conjunction with the accompanying drawings:

[0057] This embodiment discloses a Figure 1 The miniaturized high-frequency microwave transmission structure for height difference transition shown in the figure. There are two microstrip boards with height difference and need to be interconnected by high-frequency microwave signals inside the radio frequency microsystem module 101: a high-position microstrip board 201 and a low-position microstrip board 401. The surface conductive strip of the high-position microstrip board 201 includes a first signal conductive strip 203 and two ground conductive strips (a first ground conductive strip 202 and a second ground conductive strip 204). The surface conductive strip of the low-position microstrip board 401 includes a third signal conductive strip 403 and two ground conductive strips (a third ground conductive strip 402 and a fourth ground conductive strip 404).

[0058] In this embodiment, due to the characteristics and requirements of high-frequency microwave signal transmission, the two microstrip boards cannot be directly interconnected by wires, etc. When the height difference is large and the frequency of the transmitted signal is high, the traditional transition method cannot effectively solve such an efficient connection problem.

[0059] In this embodiment, the miniaturized high-frequency microwave transmission structure 301 can be processed using the relevant microwave multilayer dielectric substrate manufacturing process, and the multilayer substrate of the same length can be manufactured according to the required transition height difference. The process means are flexible, mature and low-cost; inside the multilayer substrate, a microwave stripline transmission structure is set to transmit microwave high-frequency signals. The stripline transmission structure has the advantages of low transmission loss, large working bandwidth, and no dispersion, which facilitates the transmission transition of broadband high-frequency signals. At the same time, adding ground vias on both sides of the stripline can increase the shielding performance of the transmission; on the two sides of the multilayer substrate perpendicular to the transmission direction, the side metallization process of the microwave multilayer dielectric substrate is used to respectively manufacture the transition structure of the microwave signal and the ground signal. The transition structure can be designed for compensation and matching of the parasitic inductance caused by the bonding wire at high frequency, and can flexibly realize the transmission transition of higher frequency and larger bandwidth.

[0060] Preferably, the microwave high frequency signal is up to 20 GHz. The height difference between the high microstrip plate 201 and the low microstrip plate 401 is H. To illustrate the universality of the present method, the height of H is set according to actual needs. The microwave characteristic impedance of the first signal conductive strip 203 and the third ground conductive strip 403 are both 50 ohms.

[0061] The miniaturized high-frequency microwave transmission structure 301 includes a microwave multilayer dielectric substrate, which includes two dielectric layers (a first dielectric layer and a second dielectric layer), three conductive tape layers (a first conductive tape layer, a second conductive tape layer and a third conductive tape layer), a metallized through hole 302 and two side metallized conductive tapes (an upper side metallized conductive tape and a lower side metallized conductive tape). The microwave multilayer dielectric substrate can be a substrate obtained by 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 ceramics, wherein the relative dielectric constant of the dielectric layer is 10.2, the thickness of each dielectric layer is 0.381 mm, and the thickness of each of the three conductive tape layers is 0.002 mm, so the total thickness of the microwave multilayer dielectric substrate is 0.768 mm. It can be understood that the thickness of the dielectric layer and the metal conductive tape layer here can be adjusted according to the design of the radio frequency microsystem, and no specific limitation is required.

[0062] Furthermore, the three-layer guide band layer of the miniaturized high-frequency microwave transmission structure 301 includes a first guide band layer, a second guide band layer and a third guide band layer, and the structures of the three guide band layers are as follows: Figure 2 , Figure 3 and Figure 4 The structures of the two side metallized conductive strips, the upper side metallized conductive strip and the lower side metallized conductive strip of the miniaturized high-frequency microwave transmission structure 301 are shown in FIG. Figure 5 and Figure 6 shown.

[0063] Specifically, the pattern of the first conductive layer 303 is as follows: Figure 2 As shown, it is connected to two rows of metallized through holes 302. The pattern of the second conductive layer is as shown in FIG. 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 through holes 302. The pattern 306 of the third conductor layer is as shown in FIG. Figure 4 As shown, it is connected to two rows of metallized through holes 302.

[0064] In this embodiment, preferably, both sides of the first conductive layer 303 and the third conductive layer 306 are left blank to prevent short circuits during substrate preparation and assembly. The width of the blank areas on both sides is Wb = 0.7 mm, Lb = 0.2 mm. The width of the intermediate signal conductive layer 304 is W0 = 0.3 mm.

[0065] The pattern of the metallized conductive strip on the upper side is as follows Figure 5 As shown, it includes an upper side signal conductor 308 and two upper side ground conductors 307, wherein 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 plays the role of interconnection, but also the distribution parameters brought by its external dimensions can also compensate for the parasitic inductance brought by the bonding wire 501 at high frequencies, and can be designed according to actual conditions without limitation. In this embodiment, the maximum operating frequency of the RF microsystem module 101 is 20 GHz.

[0066] The length and width of the upper side signal conductive strip 308 are designed for impedance compensation and matching according to the parasitic inductance generated by the length, diameter, arch height and number of bonding wires at the operating frequency, so as to achieve the best transmission performance.

[0067] Preferably, according to the present invention, the bonding wire is a bonding gold wire;

[0068] The parasitic inductance of the bonding wire is calculated using formula (1) and formula (2):

[0069]

[0070] In formula (1) and formula (2), L n is the total parasitic inductance of the bonding wire, n is the number of bonding wires, μ0 is the magnetic permeability of the air medium, l 3D is the effective length of a single gold wire, d is the diameter of the gold wire, μ r is the relative magnetic permeability of the gold wire, δ is the skin depth of the gold wire, h is the arch height of the gold wire, and D is the distance between the bonding points of the gold wire.

[0071] The impedance generated by the bonding wire is calculated using formula (3):

[0072] |Z|=2πF0×L n (3)

[0073] In formula (3), |z| represents the impedance of the bonding wire, F0 is the highest frequency of signal transmission, and L n is the total parasitic inductance of the bonding wire.

[0074] It can be seen from formula (3) that as the operating frequency increases, the parasitic inductance caused by the gold wire becomes larger and larger, and the impact on the transmission performance also becomes larger and larger.

[0075] Preferably, according to the present invention, the length and width of the upper side signal conductive strip 308 are designed for impedance compensation and matching according to the parasitic inductance generated by the length, diameter, arch height and number of bonding wires at the operating frequency, including:

[0076] In order to compensate for it, the upper side signal conducting strip 308 can be used for compensatory matching. The specific calculation method is as follows:

[0077] Assume that the width of the upper signal conductive strip 308 is W up , length L up , the relative dielectric constant of the microwave multilayer dielectric substrate is ε r , the upper side signal conductive band 308 will form an equivalent capacitance structure similar to a flat plate capacitor during the transmission process.

[0078] First, according to the calculation formula of the flat plate capacitor, the equivalent capacitance C of the flat plate capacitor formed by the upper side signal conductive band (308) is obtained using formula (4): p :

[0079]

[0080] In formula (4), ε0 is the dielectric constant of vacuum, ε r is the relative dielectric constant of the microwave multilayer dielectric substrate, W up Indicates the width of the upper signal band, L up represents the length of the upper side signal conductor, S is the distance between the upper side signal conductor and the two upper side ground conductors;

[0081] Secondly, according to the calculation formula of LC resonant frequency, the parasitic inductance L generated by the bonding wire is n and the flat plate capacitor C formed by the upper signal conductive band p , it is necessary to form resonance at the highest operating frequency F0 to achieve low-loss transmission at this frequency.

[0082] The three parameters should satisfy the formula:

[0083]

[0084] In formula (5), F0 is the highest frequency of signal transmission, L n is the total parasitic inductance of the bonding wire

[0085] Finally, the area of ​​the upper side signal conductor 308 is calculated using formula (6), and then the length and width of the upper side signal conductor 308 are determined:

[0086]

[0087] In formula (6), W up Indicates the width of the upper signal band, L up represents the length of the upper side signal conductor, S is the distance between the upper side signal conductor and the two upper side ground conductors, ε0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the microwave multilayer dielectric substrate, F0 is the highest frequency of signal transmission, L n is the total parasitic inductance of the bonding wire.

[0088] Thus, the area of ​​the upper side signal conductive strip 308 can be calculated, and the width W can be adjusted according to other conditions in the structure. up and length L up to further determine the size.

[0089] The following constraints need to be met during the determination process:

[0090] (1)W up It should be larger than the width of the middle signal conductive strip 304 of the second conductive strip layer, and smaller than the distance between the two upper side ground conductive strips 307 to ensure that there is no short circuit.

[0091] (2)L up It should be smaller than the total thickness of the miniaturized high-frequency microwave transmission structure 301 , and in order to ensure the reliability and convenience of bonding, it should be greater than 0.2 mm.

[0092] When the above two constraints are met, W up and L up The size can be selected arbitrarily without limitation. It is worth mentioning that although the above-mentioned compensation matching calculation process is only for the highest operating frequency F0, as the operating frequency decreases, the parasitic inductance caused by the bonding gold wire and the compensation capacitor introduced by the upper side signal conductive band (308) generate lower and lower impedance at low frequencies, and the impact on the transmission performance of the low frequency band is also getting smaller and smaller, so it is only necessary to perform compensation matching design for the highest frequency. Therefore, the method provided by the present invention also has broadband working capability.

[0093] Preferably, according to the aforementioned design calculation formula, the area Wup×Lup of the upper side signal conductive strip 308 is calculated to be approximately 0.25 square millimeters, and then according to the constraint rules, the width of the upper side signal conductive strip 308 is determined to be 0.5 millimeters and the length Lup is determined to be 0.5 mm.

[0094] The pattern of the metallized conductive strip on the lower side is as follows: Figure 6 As shown, it includes a lower side signal conductive strip 310 and two lower side ground conductive strips 309 , wherein the lower side signal conductive strip 310 is connected to the middle layer signal conductive strip 304 , and the two lower side ground conductive strips 309 are connected to the first conductive strip layer 303 and the third conductive strip layer 306 .

[0095] Furthermore, during installation, the miniaturized high-frequency microwave transmission structure 301 is closely attached to the vertical surface of the metal shell 101 of the radio frequency microsystem module, and the lower side 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 carried out by welding or bonding, without limitation. Among them, the two grounding conductive strips 309 of the lower side 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 side signal conductive strip 310 of the lower side metallized conductive strip is connected to the third signal conductive strip 403 of the low-position microstrip board 401.

[0096] Preferably, the lower side metallized conductive strip mainly plays a connecting role, and during the preparation process, its surface treatment must meet the requirements of welding or bonding process. In order to avoid short circuit, the width Wdown of the lower side signal conductive strip 310 of the lower side metallized conductive strip cannot be greater than the width of the third signal conductive strip 403 of the low-position microstrip plate 401. In this embodiment, Wdown is 0.4 mm and Ldown is 0.5 mm.

[0097] Preferably, the upper side metallized conductive strip is connected to the upper microstrip board 201 by wire bonding, wherein the two ground conductive strips 307 of the upper side metallized conductive strip are respectively connected to the two ground conductive strips (the first ground conductive strip 202 and the second ground conductive strip 204) of the upper microstrip board 201, and the signal conductive strip 309 of the upper side metallized conductive strip is connected to the first signal conductive strip 203 of the upper microstrip board 201. The number and morphology of wire bonding are set according to actual design requirements and are not limited here.

[0098] In order to verify the effectiveness and universality of the miniaturized high-frequency microwave transmission structure, the height difference H between the high-position microstrip plate and the low-position microstrip plate was set to 5 mm, 10 mm, and 15 mm respectively for design. The performance was simulated in the three-dimensional electromagnetic field simulation software, and the transmission and reflection performance were obtained as shown in Figure 2. Figure 7 and Figure 8 As shown. Figure 7 and Figure 8 It can be seen from the results that within the operating frequency of 20GHz, the standing wave coefficient of the miniaturized high-frequency microwave transmission structure is less than 1.5 and the insertion loss is less than 0.5dB. More importantly, the standing wave coefficient and insertion loss performance do not deteriorate significantly due to the increase in height difference, thus proving that the miniaturized high-frequency microwave transmission structure can not only be used for high-frequency operation, but is also very suitable for transitions of various height differences.

[0099] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined 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) comprises a microwave multilayer dielectric substrate; The microwave multilayer dielectric substrate comprises a substrate body and an upper side metallized conductive strip and a lower side metallized conductive strip respectively arranged on the upper and lower sides of the substrate body; The substrate body comprises a first conductive tape layer (303), a second conductive tape layer and a third conductive tape layer (306) which are arranged in sequence, a first dielectric layer arranged between the first conductive tape layer (303) and the second conductive tape layer, and a second dielectric layer arranged between the second conductive tape layer and the third conductive tape layer (306); a metallized through hole (302) is provided on the substrate body; the second conductive tape layer comprises an intermediate signal conductive tape (304) and two fifth ground conductive tapes (305) respectively located on both sides of the intermediate signal conductive tape (304); the metallized through hole (302) passes through the first dielectric layer and the second dielectric layer, and connects the first conductive tape layer (303), the two fifth ground conductive tapes (305) of the second conductive tape layer and the third conductive tape layer (306); The upper side metallized conductive strip comprises an upper side signal conductive strip (308) and two upper side ground conductive strips (307) respectively located on both sides of the upper side signal conductive strip (308); the lower side metallized conductive strip comprises a lower side signal conductive strip (310) and two lower side ground conductive strips (309) respectively located on both sides of the lower side signal conductive strip (310); the upper side signal conductive strip (308) is connected to the middle layer signal conductive strip (304), and the two upper side ground conductive strips (307) are respectively connected to two fifth ground conductive strips (305).

2. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 1, characterized in that: The first dielectric layer and the second dielectric layer are both made of 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 through holes (302) include two rows and are located on both sides of the middle layer signal conductive strip (304).

4. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 1, characterized in that: The upper side signal conductive strip (308) is connected to the signal conductive strip of the high position microstrip board (201) in the radio frequency microsystem module (101) by using a bonding wire (501); The two upper side grounding conductive strips (307) are connected to two grounding conductive strips of a high-position microstrip board (201) in a radio frequency microsystem module (101) using 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 conductive strip (310) is connected to the middle layer signal conductive strip (304) of the second conductive strip layer; The two lower side grounding conductive strips (309) are respectively connected to the two fifth grounding conductive strips (305) of the second conductive strip layer.

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

7. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 1, characterized in that: The first conductive tape layer (303) and the third conductive tape layer (306) are respectively provided with notches; the notches are used to prevent the conductive tape layers from being connected to the signal conductive tapes of the side metallized conductive tapes.

8. 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 conductive strip (308) are designed for impedance compensation and matching based on the parasitic inductance generated by the length, diameter, arch height and number of the bonding wires (501) at the operating frequency, so as to achieve optimal transmission performance.

9. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 8, characterized in that: The bonding wire (501) is a bonding gold wire; The parasitic inductance of the bonding wire is calculated using formula (1) and formula (2): In formula (1) and formula (2), L n is the total parasitic inductance of the bonding wire, n is the number of bonding wires, μ0 is the magnetic permeability of the air medium, l 3D is the effective length of a single gold wire, d is the diameter of the gold wire, μ r is the relative magnetic permeability of the gold wire, δ is the skin depth of the gold wire, h is the arch height of the gold wire, and D is the distance between the bonding points of the gold wire; The impedance generated by the bonding wire is calculated using formula (3): |Z|=2πF0×L n (3) In formula (3), |z| represents the impedance of the bonding wire, F0 is the highest frequency of signal transmission, and L n is the total parasitic inductance of the bonding wire.

10. The miniaturized high-frequency microwave transmission structure for height difference transition according to claim 9, characterized in that: The length and width of the upper side signal conductive strip (308) are designed for impedance compensation and matching according to the parasitic inductance generated by the length, diameter, arch height and number of the bonding wires (501) at the operating frequency, including: First, according to the calculation formula of the flat plate capacitor, the equivalent capacitance C of the flat plate capacitor formed by the upper side signal conductive band (308) is obtained using formula (4): p : In formula (4), ε0 is the dielectric constant of vacuum, ε r is the relative dielectric constant of the microwave multilayer dielectric substrate, W up Indicates the width of the upper signal band, L up represents the length of the upper side signal conductor, S is the distance between the upper side signal conductor and the two upper side ground conductors; Secondly, according to the calculation formula of LC resonant frequency, the parasitic inductance L generated by the bonding wire (501) is n and the flat plate capacitor C formed by the upper side signal conductive band (308) p , based on formula (5), resonance is formed at the highest operating frequency F0 to achieve low-loss transmission at this frequency: In formula (5), F0 is the highest frequency of signal transmission, L n is the total parasitic inductance of the bonding wire; Finally, the area of ​​the upper side signal conductive strip (308) is calculated using formula (6), and then the length and width of the upper side signal conductive strip (308) are determined: In formula (6), W up Indicates the width of the upper signal band, L up represents the length of the upper side signal conductor, S is the distance between the upper side signal conductor and the two upper side ground conductors, ε0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the microwave multilayer dielectric substrate, F0 is the highest frequency of signal transmission, L n is the total parasitic inductance of the bonding wire.

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