Microstrip-microstrip / coaxial / grounding coplanar waveguide interconnection structure

Abstract

The invention belongs to the technical field of microwave devices, and discloses a microstrip-microstrip / coaxial / grounded coplanar waveguide interconnection structure. The structure comprises a metal carrier, a dielectric substrate, a grounding layer on the front surface of the dielectric substrate, a conductor layer on the back surface and an air interlayer, the grounding layer is divided into a wider first metal patch and a narrower second metal patch; the metal carrier and the grounding layer below the first metal patch are slotted to form a suspended microstrip air interlayer, and the first metal patch is used for being connected with the microstrip / coaxial / grounding coplanar waveguide. According to the invention, the air interlayer is arranged to form a suspended microstrip line structure; through an interconnection structure of a microstrip-to-suspended microstrip line, a fine microstrip line which is inconvenient to interconnect originally is converted into a wide suspended microstrip line which is convenient to interconnect with a microstrip / coaxial / grounding coplanar waveguide; meanwhile, the antenna also has the advantages of low loss, ultra wide band, compact structure, easy processing and the like in conversion from a wide conductor to a thin conductor.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave devices, and specifically relates to an ultra-wideband microstrip-microstrip / coaxial / grounded coplanar waveguide interconnection structure, which is used to convert a microstrip line with a narrow line width into a wider suspended microstrip line structure to achieve efficient interconnection between microstrip-microstrip / coaxial / grounded coplanar waveguides. Background Art

[0002] A microstrip line is an important microwave transmission line, which consists of a dielectric substrate, a conductor, and a ground layer. The dielectric substrate is generally a low-loss material, such as common ceramics, polytetrafluoroethylene, etc., which supports the conductor. The microstrip conductor is located on the top of the dielectric substrate, and its width determines the characteristic impedance of the microstrip line; the ground layer is located at the bottom of the dielectric substrate, and the two together form a structure for guiding the propagation of electromagnetic waves. The microstrip line has the advantages of small size, light weight, easy fabrication, planarization, and easy integration, and is widely used in modern microwave circuits.

[0003] With the development of communication radio frequency technology, requirements such as high operating frequency and miniaturization are put forward for the system. The microstrip lines used in the system often need to meet the two characteristics of a thin substrate and a high substrate dielectric constant. Because at high frequencies, a substrate with a high dielectric constant can strengthen the confinement of the electric field, and a thinner substrate is beneficial to the miniaturization of the circuit. At the same time, it can reduce dispersion and the size of equivalent circuit elements, which is beneficial to improving the transmission performance of high-frequency signals. A thinner high-dielectric-constant dielectric substrate usually results in a narrower microstrip line width, while the microstrip / coaxial / grounded coplanar waveguide in the peripheral circuit has certain requirements for the minimum line width of the microstrip line in the interconnection structure to ensure efficient signal transmission. Taking a ceramic material with a dielectric constant of 9.8 as an example, the width of a 50Ω microstrip line using this material as the substrate is only 90um, while the diameter of the solder ball of a gold wire bonding / coaxial probe is generally greater than 350um. If this microstrip line is directly used to interconnect with the microstrip / coaxial / grounded coplanar waveguide in other modules, it will undoubtedly cause a series of problems such as deterioration of the signal standing wave ratio and increase in insertion loss. Therefore, designing an interconnection structure with characteristics such as wideband, low loss, high efficiency, and miniaturization is of great help in improving the performance of microwave circuit systems. Summary of the Invention

[0004] In view of the above deficiencies in the prior art, the present invention proposes a microstrip-microstrip / coaxial / grounded coplanar waveguide interconnection structure. The present invention is based on a suspended microstrip line and has the advantages of ultra-wideband, low loss, gentle structure transition, compact structure, and easy processing.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A microstrip-microstrip / coaxial / grounded coplanar waveguide interconnection structure, characterized by comprising: a metal carrier, a dielectric substrate, a ground layer, a conductor layer, and an air sandwich;

[0007] The metal carrier is used to carry the dielectric substrate;

[0008] The grounding layer is disposed on the back surface of the dielectric substrate, and the conductor layer is disposed on the front surface of the dielectric substrate;

[0009] The conductor layer includes a first metal patch and a second metal patch arranged in sequence along the input / output direction; wherein, the second metal patch is a rectangular metal patch, and the width of the first metal patch is greater than that of the second metal patch, and is used for connecting with a microstrip / coaxial / ground coplanar waveguide;

[0010] A slot is formed in the metal carrier and the grounding layer below the first metal patch to form a suspended microstrip air sandwich.

[0011] Furthermore, the first metal patch is a tapered metal patch, or is composed of a rectangular metal patch and a tapered metal patch.

[0012] Furthermore, the tapered metal patch is an exponential tapered metal patch, a stepped tapered metal patch, or a linear tapered metal patch.

[0013] Furthermore, the thickness of the air sandwich is uniform, and the shape of the top view projection matches the shape of the first metal patch.

[0014] Furthermore, the material of the dielectric substrate is silicon (εr = 11.7) or ceramic (εr = 9.8).

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. In the present invention, the grounding layer and the dielectric substrate corresponding to the connection part (the first metal patch) of the conductor layer are removed to form a suspended microstrip line structure with air as the transmission medium; through the interconnection structure of the microstrip to suspended microstrip line, the originally inconveniently interconnected fine microstrip lines are transformed into wide suspended microstrip lines that are convenient for interconnection with microstrip / coaxial / ground coplanar waveguides. From the perspective of the assembly process, this structure increases the line width of the interconnection section, which is beneficial to wire bonding of gold wires and welding of coaxial probes; from the perspective of microwave transmission, since the dielectric constant of air is low, the line width of the conductor layer of the suspended microstrip line is smaller than that of the conductor layer of the ordinary microstrip line under the same impedance condition. Using the suspended microstrip line can improve problems such as poor voltage standing wave ratio and large insertion loss caused by size differences in the interconnection transmission line, and maintain good transmission characteristics in the broadband range.

[0017] 2. The present invention also has the advantages of low loss, ultra-wideband, compact structure, and easy processing in the conversion from a wide conductor to a thin conductor. Description of the Drawings

[0018] Figure 1This is a schematic diagram of the present invention's suspension microstrip line interconnection structure for microstrip-microstrip.

[0019] Figure 2 This is a schematic diagram of the present invention's suspension microstrip line interconnection structure for microstrip-coaxial.

[0020] Figure 3 This is a schematic diagram of the present invention's suspension microstrip line interconnection structure for microstrip-ground coplanar waveguide.

[0021] Figure 4 This is an overall schematic diagram of the present invention's suspension microstrip line interconnection structure.

[0022] Figure 5 This is a top view of the present invention's suspension microstrip line interconnection structure.

[0023] Figure 6 This is a side view of the present invention's suspension microstrip line interconnection structure.

[0024] Figure 7 This is an S-parameter curve graph of the present invention's suspension microstrip line interconnection structure.

[0025] Explanation of the reference numerals in the attached drawings: 1. First metal patch, 2. Gradient metal patch, 3. Second metal patch, 4. Dielectric substrate, 5. Metal carrier, 6. Ground layer, 7. Air sandwich. Detailed implementation manners

[0026] In order to better illustrate the purpose, advantages and technical ideas of the present invention, the technical solutions in the present invention will be clearly and completely described below in conjunction with the attached drawings and specific examples. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. The components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, it should be noted that the specific examples given below only serve to explain the present invention, and the protection scope of the present invention is not limited to the following description.

[0027] Figure 1 、 Figure 2 And Figure 3 respectively represent the scenarios of the suspension microstrip line interconnection structure for microstrip-microstrip, microstrip-coaxial and microstrip-ground coplanar waveguide.

[0028] Figure 4 This is an overall structure schematic diagram of an embodiment of the present invention. Figure 5 This is a top view of an embodiment of the present invention. Figure 6 This is a side view of an embodiment of the present invention. As shown in the figure, the structure includes: a metal carrier, a dielectric substrate, a ground layer, a conductor layer and an air sandwich.

[0029] The metal carrier is used to carry the dielectric substrate; the dielectric substrate is a ceramic with a relative permittivity εr = 9.8 and a thickness of 0.1 mm.

[0030] The ground layer is disposed on the back surface of the dielectric substrate with a thickness of 0.018 mm; the conductor layer is disposed on the front surface of the dielectric substrate with a thickness of 0.018 mm.

[0031] The conductor layer includes a first metal patch and a second metal patch arranged in sequence along the input / output direction; wherein, the first metal patch is composed of a rectangular metal patch with a length of 1 mm and a width of 0.45 mm and an isosceles trapezoidal tapered metal patch with a height of 0.2 mm, and the second metal patch is a rectangular metal patch with a length of 2 mm and a width of 0.09 mm. The tapered metal patch is used to gradually increase the width of the rectangular part in the second metal patch to the width of the first metal patch for connection with a microstrip / coaxial / ground coplanar waveguide.

[0032] A suspended microstrip air layer is formed by grooving the metal carrier and the ground layer below the first metal patch, so that the impedances of the suspended microstrip line and the second metal patch are both 50 ohms. The depth of the air layer is 0.1 mm; the top-view projection shape of the air layer matches the shape and length of the first metal patch, where the wider part has a width of 0.9 mm and a length of 1 mm, the tapered part has a length of 0.2 mm, and the narrowest part is 0.3 mm.

[0033] In order to verify the effectiveness of the transition structure, the entire simulation model was established in the simulation software, and calculations and verifications were carried out. Figure 7 It is the S-parameter simulation result of the suspended microstrip line to microstrip line transition structure of the present invention. Figure 7 In it, S11 is lower than -20 dB in the range of DC to 60 GHz, indicating that the interconnection structure has good standing wave characteristics; the signal S21 is greater than -0.2 dB in the range of DC to 60 GHz, indicating that the interconnection structure has low transmission loss. This embodiment can cover DC to 60 GHz, is suitable for broadband application scenarios, and can further expand the working bandwidth.

[0034] The results show that a microstrip-microstrip / coaxial / ground coplanar waveguide interconnection structure based on a suspended microstrip line provided by the present invention has the advantages of ultra-wideband, low loss, gentle structure transition, and easy processing. It provides a practical new method for the interconnection of a fine microstrip line structure with a microstrip line / coaxial line / ground coplanar waveguide of other modules.

[0035] The above examples are only for illustrating the technical concept and features of the present invention, and are only used for a specific description of the present invention, so that those skilled in the art can understand the content of the present invention and implement it accordingly. However, it cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the content of the present invention should be covered within the protection scope of the present invention.

Claims

1. A microstrip-microstrip / coaxial / grounded coplanar waveguide interconnection structure, characterized in that: include: Metal carrier, dielectric substrate, ground layer, conductor layer and air interlayer; The metal carrier is used to carry the dielectric substrate; The ground layer is arranged on the back side of the dielectric substrate, and the conductor layer is arranged on the front side of the dielectric substrate; The conductor layer includes a first metal patch and a second metal patch arranged in sequence along the input and output directions; wherein the second metal patch is a rectangular metal patch, the width of the first metal patch is greater than that of the second metal patch, and is used to connect with the microstrip / coaxial / grounded coplanar waveguide; The metal carrier and the ground layer below the first metal patch are grooved to form a suspended microstrip air sandwich.

2. A microstrip-microstrip / coaxial / grounded coplanar waveguide interconnection structure as claimed in claim 1, characterized in that: The first metal patch is a gradient metal patch, or is composed of a rectangular metal patch and a gradient metal patch.

3. A microstrip-microstrip / coaxial / grounded coplanar waveguide interconnection structure as claimed in claim 2, characterized in that: The gradient metal patch is an exponential gradient metal patch, a step gradient metal patch, or a linear gradient metal patch.

4. A microstrip-microstrip / coaxial / grounded coplanar waveguide interconnection structure as claimed in claim 2 or 3, characterized in that: The thickness of the air interlayer is consistent, and its top-view projection shape matches the shape of the first metal patch.

5. A microstrip-microstrip / coaxial / grounded coplanar waveguide interconnection structure as claimed in claim 4, characterized in that: The material used for the dielectric substrate is silicon or ceramic.

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