TGV-based ultrawideband millimeter-wave filter

Abstract

An ultra-wideband millimeter-wave filter based on TGV belongs to the field of filters. It includes an input conversion port, a tapered microstrip line structure, an input tap, an output tap, and an output conversion port located on the front side of a glass substrate, and a ground metal layer located on the back side of the glass substrate. The tapered microstrip line structure is connected to the ground metal layer through a metallized via penetrating the glass substrate. The input conversion port is connected to one end of the tapered microstrip line structure via the input tap, and the output conversion port is connected to the other end of the tapered microstrip line structure via the output tap. This invention uses a glass substrate instead of a traditional silicon semiconductor substrate, resulting in higher surface smoothness, lower loss performance, and superior high-frequency response in the millimeter-wave band, significantly improving microwave performance. The use of a tapered line resonator offers greater design freedom, smaller size, and higher integration compared to a uniform impedance resonator, and reduces the impact of discontinuities at the step junction compared to a step impedance resonator.

Description

Technical Field

[0001] This invention belongs to the field of filters, and particularly relates to an ultra-wideband millimeter-wave filter based on TGV. Background Technology

[0002] In recent years, with the rapid development of wireless communication, Internet of Things (IoT) and Artificial Intelligence (AI), the demand for miniaturization and low loss of radio frequency components has become particularly urgent. In the radio frequency (RF) and millimeter wave (mmW) bands, the size and loss of traditional interdigital bandpass filters (IBPF) are too large to meet the requirements of recent circuit miniaturization and high performance. Therefore, it is necessary to design more compact, low-loss, and ultra-wideband filters.

[0003] Vertical interconnect technologies mainly include through-silicon vias (TSVs), through-ceramic vias (TCVs), and through-glass vias (TGVs). In the radio frequency (RF) band, especially the millimeter-wave band, passive devices manufactured using TSVs suffer from significant leakage losses, poor signal isolation, and crosstalk between adjacent vias, severely impacting filter performance. Furthermore, silicon presents higher processing difficulty and manufacturing costs. TCVs, on the other hand, struggle to meet the requirements for integrated devices in terms of processing precision and efficiency, resulting in unsatisfactory integration density and manufacturing accuracy. Thick substrates and large feature sizes are their two major limitations. In contrast, TGVs offer advantages such as low loss and high quality factor, and their process technology is fully compatible with mature semiconductor processes. They also have lower processing difficulty and manufacturing costs, and have been widely used in the design and manufacture of RF devices, showing promise for providing better integrated solutions in the millimeter-wave field. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the background technology by proposing an ultra-wideband millimeter-wave filter based on TGV.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An ultra-wideband millimeter-wave filter based on TGV includes an input conversion port, a tapered microstrip line structure, an input tap, an output tap, and an output conversion port located on the front side of a glass substrate, and a ground metal layer located on the back side of the glass substrate; wherein the tapered microstrip line structure is connected to the ground metal layer through a metallized via penetrating the glass substrate, the input conversion port is connected to one end of the tapered microstrip line structure through the input tap, and the output conversion port is connected to the other end of the tapered microstrip line structure through the output tap; The tapered microstrip line structure includes a first tapered microstrip line and a second tapered microstrip line, which form an interdigitated structure. Both the first and second tapered microstrip lines include multiple tapered structures, and the narrow ends of the tapered structures are connected to the ground metal layer through metallized vias. Both the input conversion port and the output conversion port consist of a middle signal terminal and two ground terminals on both sides. The two ground terminals are connected to the ground metal layer through metallized through-holes penetrating the glass substrate.

[0006] Furthermore, in the first tapered microstrip line, the length of the tapered structure connected to the input tap and the output tap is greater than the length of the other tapered structures.

[0007] Furthermore, the first tapered microstrip line includes at least two tapered structures, and the second tapered microstrip line includes at least one tapered structure.

[0008] Furthermore, in the first and second tapered microstrip lines, the narrow and wide ends of adjacent tapered structures are opposite.

[0009] Furthermore, the intermediate signal terminals of the input conversion port and the output conversion port gradually narrow in the direction of the tapered microstrip line structure until they are the same width as the input tap and the output tap; the ground terminals on both sides of the input conversion port and the output conversion port gradually narrow.

[0010] Furthermore, the glass substrate is a quartz wafer, a high borosilicate wafer, or an aluminum borosilicate wafer with a dielectric constant of 3 to 6 and a thickness of 100 to 800 μm.

[0011] Furthermore, the tapered microstrip structure is one of the following: gold layer, silver layer, copper layer, aluminum layer, nickel layer, titanium layer, and platinum layer, and can be obtained by processes such as sputtering, evaporation, or electroplating, with a thickness ≥0.1μm.

[0012] Furthermore, the diameter of the metallized via is 10~80μm.

[0013] Furthermore, the metal filled in the metallized through-hole is one of gold, silver, copper, and titanium.

[0014] Furthermore, the grounding metal layer is one of the following: gold layer, silver layer, copper layer, aluminum layer, nickel layer, titanium layer, and platinum layer.

[0015] Furthermore, the thickness of the grounding metal layer is ≥0.1μm.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses a glass substrate instead of a traditional silicon semiconductor substrate, resulting in a smoother surface and lower electrical losses. It achieves superior high-frequency response in the millimeter-wave band, significantly improving microwave performance. The use of a tapered line resonator (LTLR) offers greater design freedom, smaller size, and higher integration compared to a uniform impedance resonator, while reducing the impact of discontinuities at the step junction compared to a step impedance resonator. Furthermore, considering the small microstrip line size of the filter designed for the millimeter-wave V-band, which hinders probe testing with a vector network analyzer, a tapered input / output conversion port is added. This facilitates impedance matching and subsequent physical testing while reducing additional losses at the conversion port. Moreover, the final size of the filter in this invention can be less than 2 mm. 2 It demonstrates the advantage of high integration. Attached Figure Description

[0017] Figure 1 A schematic diagram of the structure of an ultra-wideband millimeter-wave filter based on TGV provided by the present invention; Figure 2 The image shows the S-parameter performance of the filter according to an embodiment of the present invention.

[0018] Figure label: 1-Glass substrate; 2-Input conversion port; 3-Output conversion port; 4-First tapered microstrip line; 5-Second tapered microstrip line; 6-Metallized via; 7-Input tap; 8-Output tap; 9-Ground metal layer. Detailed Implementation

[0019] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0020] like Figure 1 The diagram shows a schematic of the TGV-based ultra-wideband millimeter-wave filter of the present invention. It includes a glass substrate 1. The front side of the glass substrate 1 is provided with an input conversion port 2, an output conversion port 3, an input tap 7, an output tap 8, and a tapered microstrip line structure. The back side of the glass substrate 1 is provided with a ground metal layer 9. The tapered microstrip line structure is connected to the ground metal layer 9 through a metallized through-hole 6 penetrating the glass substrate. The input conversion port is connected to one end of the tapered microstrip line structure through an input tap, and the output conversion port is connected to the other end of the tapered microstrip line structure through an output tap.

[0021] The tapered microstrip line structure includes a first tapered microstrip line 4 and a second tapered microstrip line 5, which form an interdigitated structure. Both the first and second tapered microstrip lines include multiple tapered structures, and the narrow ends of the tapered structures are connected to the ground metal layer through metallized vias. Both the input conversion port and the output conversion port consist of a middle signal terminal and two ground terminals on both sides. The two ground terminals are connected to the ground metal layer through metallized through-holes penetrating the glass substrate.

[0022] TGV, or Through Glass Via, refers to integrated circuits that utilize glass as an adapter. It offers excellent high-frequency electrical performance, low cost, simple fabrication process, and strong mechanical stability. In this embodiment, the glass substrate 1 is a quartz wafer with a dielectric constant of 3-6 and a thickness of 300 μm. The glass substrate 1 has very low surface roughness, resulting in low-loss electrical performance, superior high-frequency performance, and even better microwave performance. Metallized vias 6 are used to connect the tapered microstrip line and the ground metal layer 9. The diameter of the metallized vias 6 is 40 μm, and the metal material within them is copper. To ensure reliable connection, multiple metallized vias 6 are provided at one end of each tapered microstrip line. The tapered microstrip line is a copper layer, obtained through sputtering, with a thickness of 0.2 μm. The ground metal layer 9 is a copper layer with a thickness of 1 μm.

[0023] The manufacturing process of the TGV-based ultra-wideband millimeter-wave filter in this embodiment is as follows: A glass substrate 1 of a certain size is cut. First, the glass substrate 1 is subjected to laser-induced treatment to form a 2-5 μm micropore structure. Then, wet etching is used to form a 10-80 μm through-hole structure. Next, the through-holes are metallized to obtain metallized through-holes 6. Then, a metal layer, which is a copper layer with a thickness of 1 μm, is formed on the surface of the glass substrate 1 through one or more processes, including sputtering, evaporation, and electroplating. One side of the glass substrate 1 is used as the back side, and the other side as the front side. The metal layer on the back side of the glass substrate 1 is patterned to obtain a grounding metal layer 9. The front side of the glass substrate 1 is patterned to obtain a first tapered microstrip line 4, a second tapered microstrip line 5, an input tap 7, an output tap 8, an input conversion port 2, and an output conversion port 3. The patterning processes include electroplating, sputtering, evaporation, photolithography, development, and etching.

[0024] The feasibility of the TGV-based ultra-wideband millimeter-wave filter of this invention was demonstrated through theoretical modeling and simulation. Subsequently, parameter adjustments were performed, and optimal performance parameters were determined in conjunction with the fabrication process. The employed fabrication process is compatible with traditional silicon semiconductor processes, the stability and reliability of the substrate are easily controlled, it offers superior economic benefits, and has market prospects for mass production. The final size of the fabricated microstrip filter is less than 2 mm. 2 It exhibits advantages in high integration. In addition, its high-frequency microwave performance is superior compared to silicon-based devices.

[0025] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ultra-wideband millimeter-wave filter based on TGV, characterized in that, It includes an input conversion port, a tapered microstrip line structure, an input tap, an output tap, and an output conversion port located on the front side of the glass substrate, and a ground metal layer located on the back side of the glass substrate; wherein the tapered microstrip line structure is connected to the ground metal layer through a metallized via penetrating the glass substrate, the input conversion port is connected to one end of the tapered microstrip line structure through an input tap, and the output conversion port is connected to the other end of the tapered microstrip line structure through an output tap; The tapered microstrip line structure includes a first tapered microstrip line and a second tapered microstrip line, which form an interdigitated structure. Both the first and second tapered microstrip lines include multiple tapered structures, and the narrow ends of the tapered structures are connected to the ground metal layer through metallized vias. Both the input conversion port and the output conversion port consist of a middle signal terminal and two ground terminals on both sides. The two ground terminals are connected to the ground metal layer through metallized through-holes penetrating the glass substrate.

2. The ultra-wideband millimeter-wave filter based on TGV according to claim 1, characterized in that, In the first tapered microstrip line, the length of the tapered structure connected to the input tap and the output tap is greater than the length of the other tapered structures.

3. The ultra-wideband millimeter-wave filter based on TGV according to claim 1, characterized in that, The first tapered microstrip line includes at least two tapered structures, and the second tapered microstrip line includes at least one tapered structure.

4. The ultra-wideband millimeter-wave filter based on TGV according to claim 1, characterized in that, In the first and second tapered microstrip lines, the narrow and wide ends of two adjacent tapered structures are opposite.

5. The ultra-wideband millimeter-wave filter based on TGV according to claim 1, characterized in that, The intermediate signal terminals of the input conversion port and the output conversion port gradually narrow in the direction of the tapered microstrip line structure until they are the same width as the input tap and the output tap; the ground terminals on both sides of the input conversion port and the output conversion port gradually narrow.

6. The ultra-wideband millimeter-wave filter based on TGV according to claim 1, characterized in that, The glass substrate is a quartz wafer, a high borosilicate wafer, or an aluminum borosilicate wafer with a dielectric constant of 3 to 6 and a thickness of 100 to 800 μm.

7. The ultra-wideband millimeter-wave filter based on TGV according to claim 1, characterized in that, The tapered microstrip structure is one of the following: gold layer, silver layer, copper layer, aluminum layer, nickel layer, titanium layer, and platinum layer. It is obtained by sputtering, evaporation, or electroplating, and has a thickness ≥0.1μm.

8. The ultra-wideband millimeter-wave filter based on TGV according to claim 1, characterized in that, The metallized through-hole is filled with one of the following metals: gold, silver, copper, and titanium, and the pore size is 10~80μm.

9. The ultra-wideband millimeter-wave filter based on TGV according to claim 1, characterized in that, The grounding metal layer is one of the following: gold, silver, copper, aluminum, nickel, titanium, and platinum, with a thickness ≥ 0.1 μm.

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