A high airtight rectangular waveguide-coplanar waveguide transition structure based on HTCC

Abstract

The present invention belongs to the technical field of microwave millimeter wave devices, and provides a high-airtightness rectangular waveguide-coplanar waveguide transition structure based on HTCC, including a multilayer ceramic medium, wherein the upper and lower ends of the multilayer ceramic medium are respectively connected with a coplanar waveguide and a rectangular waveguide; the multilayer ceramic medium includes a substrate integrated waveguide and a plurality of dielectric substrates arranged sequentially from bottom to top, a metal layer is arranged between two adjacent dielectric substrates and between the substrate integrated waveguide and the dielectric substrate, wave conduction is performed between the coplanar waveguide and the dielectric substrate at the top through a second coupling gap, and wave conduction is performed between the rectangular waveguide and the substrate integrated waveguide through a first coupling gap. The present invention can make W-band radio frequency devices have high airtightness and prevent energy leakage.

Description

Technical Field

[0001] The invention belongs to the technical field of microwave and millimeter wave devices, and in particular relates to a high-airtightness rectangular waveguide-coplanar waveguide transition structure based on HTCC. Background Art

[0002] With the continuous development of wireless communication technology, the radio spectrum of modern communication systems has become increasingly crowded. Among them, the W band (75GHz-110GHz), as an important radio frequency band, although located at the edge of the terahertz band, has the advantages of long transmission distance and strong penetration, so it is still an important window frequency in the millimeter wave and terahertz bands.

[0003] In the microwave field, electromagnetic signals in multi-layer circuit boards are transmitted and converted between transmission lines on different layers. The transition structure is a key component connecting different waveguides or transmission lines to achieve effective signal transmission and matching. Therefore, the design of the transition structure is crucial to improving the performance of RF devices. In the design and manufacture of transition structures, airtightness is a crucial consideration. Airtightness refers to the barrier performance of materials or structures to gases. Especially in high-frequency RF environments, maintaining airtightness inside the device is crucial to preventing signal loss, reducing interference, and improving device stability. Achieving airtight packaging of microwave devices can ensure that the die is isolated from the external environment, avoid the invasion of harmful gases from the outside, limit the water vapor content in the packaging cavity, and control free particles.

[0004] The high temperature co-fired ceramic (HTCC) process is an advanced microelectronic packaging technology, which is characterized by the ability to co-fire multi-layer ceramic components in a high temperature environment. This process uses a multi-layer ceramic substrate, which is stacked and sintered layer by layer. It has excellent mechanical properties and high temperature stability, and can be etched with various patterns like a PCB board, and has a large current carrying capacity. The HTCC process is widely used in microwave and radio frequency devices, sensors, micro antennas and other fields, providing a reliable packaging and integration platform for electronic components.

[0005] Current technologies have some limitations in the design and manufacture of W-band RF devices, which affect the performance and reliability of the devices in high-frequency RF environments. For example, the transition structure may lead to insufficient airtightness during the vertical transition between waveguides, which will not only cause signal leakage and performance degradation, but may also affect the long-term stability and reliability of the device. Therefore, it is necessary to study how to apply the high-temperature co-fired ceramic (HTCC) process to the high-airtightness transition structure of W-band RF devices. Summary of the invention

[0006] The object of the present invention is to provide a high airtight rectangular waveguide-coplanar waveguide transition structure based on HTCC to solve the above problems and achieve the purpose of making W-band RF devices have high airtightness and preventing energy leakage.

[0007] To achieve the above object, the present invention provides the following solution: a high airtight rectangular waveguide-coplanar waveguide transition structure based on HTCC, comprising:

[0008] A multilayer ceramic medium, wherein the upper and lower ends of the multilayer ceramic medium are respectively connected with a coplanar waveguide and a rectangular waveguide;

[0009] The multilayer ceramic medium includes a substrate integrated waveguide and a plurality of dielectric substrates arranged in sequence from bottom to top, a metal layer is arranged between two adjacent dielectric substrates and between the substrate integrated waveguide and the dielectric substrate, wave conduction is performed between the coplanar waveguide and the dielectric substrate at the top through a second coupling gap, and wave conduction is performed between the rectangular waveguide and the substrate integrated waveguide through a first coupling gap.

[0010] Preferably, the first coupling slot is arranged between the substrate integrated waveguide and the rectangular waveguide, and the second coupling slot is arranged between the dielectric substrate and the coplanar waveguide, the electromagnetic waves in the rectangular waveguide enter the substrate integrated waveguide and the dielectric substrate through the first coupling slot, and the electromagnetic valve in the dielectric substrate enters the coplanar waveguide through the second coupling slot.

[0011] Preferably, a metal-filled through-hole array is provided between the substrate integrated waveguide and the plurality of dielectric substrates.

[0012] Preferably, the metal-filled through-hole array includes a plurality of outer metal-filled through-holes and a plurality of middle metal-filled through-holes, and the plurality of outer metal-filled through-holes and the plurality of middle metal-filled through-holes are vertically and uniformly distributed between the substrate integrated waveguide and a plurality of dielectric substrates.

[0013] Preferably, two ends of the outer metal-filled through hole respectively penetrate the bottom surface of the substrate integrated waveguide and the top surface of the dielectric substrate located on the top layer, and two ends of the middle metal-filled through hole respectively penetrate the top surface and bottom surface of the substrate integrated waveguide.

[0014] Preferably, a plurality of inner metal-filled through holes are vertically arranged between the plurality of dielectric substrates, the plurality of inner metal-filled through holes are evenly distributed inside the plurality of middle metal-filled through holes, and two ends of the plurality of inner metal-filled through holes respectively penetrate the top surface of the dielectric substrate located at the top layer and the bottom surface of the dielectric substrate located at the bottom layer.

[0015] Preferably, the metal layer is composed of metal tungsten.

[0016] Preferably, the substrate integrated waveguide and the plurality of dielectric substrates are made of high temperature co-fired ceramics.

[0017] Preferably, surfaces of the substrate integrated waveguide and the plurality of dielectric substrates are all metal surfaces.

[0018] Compared with the prior art, the present invention has the following advantages and technical effects: The present invention successfully realizes the energy transfer between different waveguides through the vertical transition structure from rectangular waveguide to coplanar waveguide. The substrate integrated waveguide plays the role of a quarter-wavelength impedance converter, successfully achieving impedance matching between the rectangular waveguide and the coplanar waveguide. The present invention can be applied to the transmission of different signals in multi-layer circuit boards in the microwave and millimeter wave fields, and has the characteristics of low loss, wide bandwidth, simple structure, high airtightness, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic diagram of a back-to-back structure of a rectangular waveguide-coplanar waveguide transition structure of the present invention;

[0021] Figure 2 A top view of a back-to-back structure of a rectangular waveguide-coplanar waveguide transition structure of the present invention;

[0022] Figure 3 A side view of a rectangular waveguide-coplanar waveguide transition structure of the present invention;

[0023] Figure 4 It is a diagram of the simulation results of S11 and S21 when the embodiment of the present invention is applied to the W band;

[0024] Among them, 1. rectangular waveguide; 2. multilayer ceramic dielectric; 21. metal-filled through-hole array; 211. outer metal-filled through-hole; 212. middle metal-filled through-hole; 213. inner metal-filled through-hole; 221. first coupling gap; 222. second coupling gap; 23. metal layer; 24. substrate integrated waveguide; 25. dielectric substrate; 3. coplanar waveguide. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Reference Figure 1-Figure 4 The present invention provides a high airtightness rectangular waveguide-coplanar waveguide transition structure based on HTCC, comprising:

[0028] A multilayer ceramic medium 2, wherein the upper and lower ends of the multilayer ceramic medium 2 are respectively connected with a coplanar waveguide 3 and a rectangular waveguide 1;

[0029] The multilayer ceramic medium 2 includes a substrate integrated waveguide 24 and a plurality of dielectric substrates 25 arranged in sequence from bottom to top, a metal layer 23 is arranged between two adjacent dielectric substrates 25 and between the substrate integrated waveguide 24 and the dielectric substrate 25, wave conduction is performed between the coplanar waveguide 3 and the top dielectric substrate 25 via a second coupling slot 222, and wave conduction is performed between the rectangular waveguide 1 and the substrate integrated waveguide 24 via a first coupling slot 221.

[0030] The main function of the rectangular waveguide 1 is to receive electromagnetic waves and input electromagnetic waves from the bottom of the rectangular waveguide 1; the main function of the coplanar waveguide 3 is to transmit electromagnetic waves; the substrate integrated waveguide 24 mainly plays the role of a quarter-wavelength impedance converter for impedance matching; the main function of the dielectric substrate 25 is to improve the transition effect. Overall, the present invention can be applied to the transmission of different signals in a multilayer circuit board in the microwave and millimeter wave fields, and has the characteristics of low loss, wide bandwidth, simple structure, high airtightness, etc.

[0031] like Figure 1 As shown, in this embodiment, the rectangular waveguide 1 is a standard rectangular waveguide WR-10 with a size of 2.54 mm×1.27 mm, a height of the rectangular waveguide 1 is 2 mm, a size of the substrate integrated waveguide 24 is 3.5 mm×2 mm, and in the coplanar waveguide 3, the width of the signal line is 0.16 mm, and the waveguide gap is 0.15 mm.

[0032] A further optimized solution is that the first coupling slot 221 is set between the substrate integrated waveguide 24 and the rectangular waveguide 1, and the second coupling slot 222 is set between the dielectric substrate 25 and the coplanar waveguide 3. The electromagnetic waves in the rectangular waveguide 1 enter the substrate integrated waveguide 24 and the dielectric substrate 25 through the first coupling slot 221, and the electromagnetic valve in the dielectric substrate 25 enters the coplanar waveguide 3 through the second coupling slot 222.

[0033] like Figure 2 As shown, the size of the first coupling slot 221 is optimized to 2.08 mm×0.81 mm, and the size of the second coupling slot 222 is optimized to 1.32 mm×0.38 mm.

[0034] In a further optimized solution, a metal-filled through-hole array 21 is provided between the substrate integrated waveguide 24 and the plurality of dielectric substrates 25 .

[0035] According to a further optimized solution, the metal-filled through-hole array 21 includes a plurality of outer metal-filled through-holes 211 and a plurality of middle metal-filled through-holes 212 , and the plurality of outer metal-filled through-holes 211 and the plurality of middle metal-filled through-holes 212 are evenly distributed vertically between the substrate integrated waveguide 24 and the plurality of dielectric substrates 25 .

[0036] As a further optimized solution, both ends of the outer metal-filled through hole 211 respectively penetrate the bottom surface of the substrate integrated waveguide 24 and the top surface of the dielectric substrate 25 located on the top layer, and both ends of the middle metal-filled through hole 212 respectively penetrate the top and bottom surfaces of the substrate integrated waveguide 24.

[0037] like Figure 1 and Figure 2 As shown, the diameter of the outer metal-filled through-hole 211 and the middle metal-filled through-hole 212 are both 0.05 mm. Among them, the number of the outer metal-filled through-holes 211 is 34, which are mainly used for support and positioning during assembly and to prevent energy from overflowing from the sides. The number of the middle metal-filled through-holes 212 is 10, which work together with the outer metal-filled through-holes 211 to ensure that the electromagnetic energy flows in the substrate integrated waveguide 24 without overflowing from the sides, and finally achieve good airtightness during the electromagnetic energy transmission process.

[0038] In a further optimized solution, a plurality of inner metal-filled through holes 213 are vertically arranged between the plurality of dielectric substrates 25, the plurality of inner metal-filled through holes 213 are evenly distributed inside the plurality of middle metal-filled through holes 212, and two ends of the plurality of inner metal-filled through holes 213 respectively penetrate the top surface of the dielectric substrate 25 located at the top layer and the bottom surface of the dielectric substrate 25 located at the bottom layer.

[0039] like Figure 1 and Figure 2As shown, the radius of the inner metal-filled through hole 213 is set to 0.03 mm, and is arranged in three groups of dielectric substrates 25 to prevent energy from overflowing from the coplanar waveguide 3 and the second coupling slot 222 .

[0040] According to the structural optimization of this embodiment, the following is obtained: Figure 4 The simulation results show that within the frequency range of 91.43 to 97.6 GHz, the insertion loss is better than 1.97 dB and the return loss is better than 10 dB, indicating that the present invention can be applied to the field of W-band microwave and millimeter wave devices.

[0041] In a further optimized solution, the metal layer 23 is composed of metal tungsten.

[0042] Metal tungsten has a high melting point and is suitable for the firing process of the multilayer ceramic medium 2. Specifically, the high temperature co-fired ceramic (HTCC) process is used to print the metal layer 23 on the aluminum nitride ceramic green body, and then the multiple layers are stacked and co-fired at a high temperature of 1650-1850° C. The thickness of the metal layer 23 is set to 0.01 mm.

[0043] According to a further optimization scheme, the substrate integrated waveguide 24 and the plurality of dielectric substrates 25 are made of high temperature co-fired ceramics.

[0044] According to a further optimized solution, the surfaces of the substrate integrated waveguide 24 and the plurality of dielectric substrates 25 are all metal surfaces.

[0045] By setting the surfaces of the substrate integrated waveguide 24 and several dielectric substrates 25 as metal surfaces, the multilayer ceramic dielectric 2 is metallized, and its bottom surface, surface and spaces between different layers are all metal surfaces, so that electromagnetic waves are confined to propagate in the rectangular cavity formed by the metal layer and the metal-filled through-hole array, effectively preventing energy overflow and improving airtightness.

[0046] The working process of this embodiment is as follows: electromagnetic waves are input from the bottom of the rectangular waveguide 1 and enter the substrate integrated waveguide 24 through the first coupling slot 221, thereby realizing the role of a quarter-wavelength impedance transformer and achieving impedance matching between the rectangular waveguide and the coplanar waveguide. The outer metal-filled through-hole 211 and the middle metal-filled through-hole 212 ensure that the electromagnetic energy flows in the substrate integrated waveguide without overflowing from the side. The electromagnetic wave enters the coplanar waveguide 3 from the substrate integrated waveguide 24 through the three-layer dielectric substrate 25 and the second coupling slot 222 in sequence. The inner metal-filled through-holes 213 prevent the energy from overflowing during the transmission of the electromagnetic energy from the second coupling slot 222 to the coplanar waveguide 3 and the subsequent transmission process, and finally complete the transmission of the energy of the vertical transition structure.

[0047] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0048] The embodiments described above are only descriptions of the preferred modes 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 high airtight rectangular waveguide-coplanar waveguide transition structure based on HTCC, characterized in that: include: A multilayer ceramic medium (2), wherein the upper and lower ends of the multilayer ceramic medium (2) are respectively connected to a coplanar waveguide (3) and a rectangular waveguide (1); The multilayer ceramic medium (2) comprises a substrate integrated waveguide (24) and a plurality of dielectric substrates (25) arranged in sequence from bottom to top, a metal layer (23) is arranged between two adjacent dielectric substrates (25) and between the substrate integrated waveguide (24) and the dielectric substrate (25), wave conduction is performed between the coplanar waveguide (3) and the dielectric substrate (25) at the top via a second coupling slot (222), and wave conduction is performed between the rectangular waveguide (1) and the substrate integrated waveguide (24) via a first coupling slot (221); The first coupling slot (221) is arranged between the substrate integrated waveguide (24) and the rectangular waveguide (1), and the second coupling slot (222) is arranged between the dielectric substrate (25) and the coplanar waveguide (3); the electromagnetic wave in the rectangular waveguide (1) enters the substrate integrated waveguide (24) and the dielectric substrate (25) through the first coupling slot (221), and the electromagnetic valve in the dielectric substrate (25) enters the coplanar waveguide (3) through the second coupling slot (222); A metal-filled through-hole array (21) is provided between the substrate integrated waveguide (24) and the plurality of dielectric substrates (25); The metal-filled through-hole array (21) comprises a plurality of outer metal-filled through-holes (211) and a plurality of middle metal-filled through-holes (212), wherein the plurality of outer metal-filled through-holes (211) and the plurality of middle metal-filled through-holes (212) are evenly distributed vertically between the substrate integrated waveguide (24) and a plurality of dielectric substrates (25); The two ends of the outer metal-filled through hole (211) respectively penetrate the bottom surface of the substrate integrated waveguide (24) and the top surface of the dielectric substrate (25) located at the top layer, and the two ends of the middle metal-filled through hole (212) respectively penetrate the top surface and the bottom surface of the substrate integrated waveguide (24); A plurality of inner metal-filled through holes (213) are also vertically arranged between the plurality of dielectric substrates (25); the plurality of inner metal-filled through holes (213) are evenly distributed inside the plurality of middle metal-filled through holes (212); and two ends of the plurality of inner metal-filled through holes (213) respectively penetrate the top surface of the dielectric substrate (25) located at the top layer and the bottom surface of the dielectric substrate (25) located at the bottom layer.

2. The HTCC-based high airtight rectangular waveguide-coplanar waveguide transition structure according to claim 1, characterized in that: The metal layer (23) is composed of metal tungsten.

3. The HTCC-based high airtight rectangular waveguide-coplanar waveguide transition structure according to claim 1, characterized in that: The substrate integrated waveguide (24) and the plurality of dielectric substrates (25) are made of high temperature co-fired ceramics.

4. The HTCC-based high airtight rectangular waveguide-coplanar waveguide transition structure according to claim 1, characterized in that: The surfaces of the substrate integrated waveguide (24) and the plurality of dielectric substrates (25) are all metal surfaces.

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