A double-sideband silicon-based filter with improved interpolation loss in the passband

Abstract

This invention discloses a double-sideband silicon-based filter with improved insertion loss in the passband, comprising: at least one silicon cavity resonator and at least one slot-line dual stopband resonator. The silicon cavity resonator includes a bottom metal layer, a high-resistivity silicon dielectric layer, and a top metal layer stacked sequentially from bottom to top. Each silicon cavity resonator has multiple vias spaced at its edges. These vias penetrate the corresponding bottom metal layer, high-resistivity silicon dielectric layer, and top metal layer vertically. A metal deposition layer is formed on the inner surface of each via. The slot-line dual stopband resonator includes a first slot line and a second slot line formed on the top metal layer. One end of the second slot line is connected to the midpoint of the first slot line. The other end of the second slot line is looped to form a closed-loop structure. Through this method, the double-sideband silicon-based filter with improved insertion loss in the passband of this invention improves out-of-band suppression and reduces insertion loss in the passband.

Description

Technical Field

[0001] This invention relates to the field of filters, and in particular to a double-band silicon-based filter with improved insertion loss within the passband. Background Technology

[0002] Filters play a crucial role in frequency selection and filtering in radio frequency and microwave systems. Specifically, a filter allows electrical signals of a certain frequency to pass through while blocking electrical signals of other frequencies. The main performance indicators of a filter include insertion loss, bandwidth, out-of-band selectivity, and circuit size. Reducing insertion loss and miniaturizing the circuit have always been key design challenges for filters.

[0003] To achieve sufficiently steep out-of-band rejection, conventional multi-cavity silicon-based filters require an increased number of cavity resonators, typically six or more, resulting in a relatively large size. Double-sideband silicon-based filters increase out-of-band rejection by etching slots on the metal surface, thus reducing the number of cavity resonators and achieving miniaturization of the filter chip. However, this also introduces increased passband losses, causing some electromagnetic energy to leak out through the slots, hindering the application and widespread adoption of silicon-based filters in RF and microwave systems, necessitating improvements. Summary of the Invention

[0004] The main technical problem solved by this invention is to provide a double-sideband silicon-based filter with improved in-passband insertion loss, which improves out-of-band rejection and reduces in-passband loss.

[0005] To solve the above-mentioned technical problems, the present invention provides a double-sideband silicon-based filter with improved insertion loss in the passband, comprising: at least one silicon cavity resonator and at least one slot-line dual stopband resonator. The silicon cavity resonator comprises a bottom metal layer, a high-resistivity silicon dielectric layer, and a top metal layer stacked sequentially from bottom to top. Each silicon cavity resonator has multiple vias spaced at its edges. The vias penetrate the corresponding bottom metal layer, high-resistivity silicon dielectric layer, and top metal layer vertically. A metal deposition layer is disposed on the inner surface of each via. The slot-line dual stopband resonator comprises a first slot line and a second slot line formed on the top metal layer. One end of the second slot line is connected to the midpoint of the first slot line. The other end of the second slot line is looped to form a closed-loop structure, which retracts the electromagnetic field emitted from the slot line end into the slot line, reducing electromagnetic energy loss and improving the insertion loss in the passband of the double-sideband silicon-based filter.

[0006] In a preferred embodiment of the present invention, when there are multiple silicon cavity resonator units, they are arranged in a matrix, and two adjacent silicon cavity resonator units in the same row share a slot-line dual stopband resonator.

[0007] In a preferred embodiment of the present invention, the passband-intercalation loss-improved double-sideband silicon-based filter further includes: an input feed slot, an output feed slot, a first defect coupling slot, and a second defect coupling slot. The input feed slot and the first defect coupling slot are formed on the top metal layer of a single silicon cavity resonator or the first silicon cavity resonator in any row of silicon cavity resonators. The output feed slot and the second defect coupling slot are formed on the top metal layer of a single silicon cavity resonator or the last silicon cavity resonator in any row of silicon cavity resonators. The input feed slot is connected to the first defect coupling slot and is used for inputting the signal to be filtered. The output feed slot is connected to the second defect coupling slot and is used for outputting the filtered signal formed after filtering the signal to be filtered. The depths of the input feed slot, the first defect coupling slot, the output feed slot, and the second defect coupling slot are all equal to the thickness of the top metal layer.

[0008] In a preferred embodiment of the present invention, the closed-loop structure is square or circular.

[0009] In a preferred embodiment of the present invention, the first groove line and the second groove line penetrate the corresponding top metal layer in the depth direction.

[0010] In a preferred embodiment of the present invention, the thickness of the bottom metal layer is D1, the thickness of the top metal layer is D2, and the thickness of the high-resistivity silicon dielectric layer is D3, wherein D1≤10um, D2≤10um, and 200um≤D3≤500um.

[0011] In a preferred embodiment of the present invention, the first groove is a U-shaped groove, and the second groove is any one of a straight groove, an arc groove, and a wavy groove.

[0012] In a preferred embodiment of the present invention, the second groove line is located in the inner region of the first groove line of the U-shaped structure.

[0013] In a preferred embodiment of the present invention, the resistivity of the high-resistivity silicon dielectric layer is R1, wherein R1≥3000Ω / cm.

[0014] In a preferred embodiment of the present invention, the through hole is a full through hole or an open semi-through hole.

[0015] The beneficial effects of this invention are as follows: The double-sideband silicon-based filter with improved insertion loss in the passband, as pointed out in this invention, introduces transmission zeros on both sides of the filter's passband by connecting one end of the second slot line to the midpoint of the first slot line, thereby improving the out-of-band suppression on both sides of the filter without increasing the filter size. The closed-loop structure obtained by looping the other end of the second slot line recovers a large amount of electromagnetic field emitted from the slot line end into the slot line, reducing electromagnetic energy loss and lowering the insertion loss in the passband of the double-sideband silicon-based filter. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0017] Figure 1 This is a schematic diagram of a preferred embodiment of a double-band silicon-based filter with improved insertion loss in the passband according to the present invention;

[0018] Figure 2 yes Figure 1 aa ’ A sectional view. Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figures 1-2 The embodiments of the present invention include:

[0021] like Figure 1 The double-sideband silicon-based filter with improved insertion loss in the passband shown includes: at least one silicon cavity resonator 11, at least one slot-line dual stopband resonator 13, input feed slot 14, output feed slot 16, first defect coupling slot 15, and second defect coupling slot 17. When there are multiple silicon cavity resonator units 11, they are arranged in a matrix, and two adjacent silicon cavity resonator units in the same row share one slot-line dual stopband resonator. In this embodiment, a row employs three silicon cavity resonator units and two slot-line dual-stopband resonators 13. The three silicon cavity resonator units are a first silicon cavity resonator unit 111, a second silicon cavity resonator unit 112, and a third silicon cavity resonator unit 113 arranged sequentially. The two slot-line dual-stopband resonators 13 are a first slot-line dual-stopband resonator 134 and a second slot-line dual-stopband resonator 135. The first slot-line dual-stopband resonator 134 spans the first silicon cavity resonator unit 111 and the second silicon cavity resonator unit 112, and the second slot-line dual-stopband resonator 135 spans the second silicon cavity resonator unit 112 and the third silicon cavity resonator unit 113.

[0022] like Figure 2As shown, the silicon cavity resonant unit 11 includes a bottom metal layer 23, a high-resistivity silicon dielectric layer 22, and a top metal layer 21 stacked sequentially from bottom to top. In this embodiment, the thickness of the bottom metal layer 23 is D1, the thickness of the top metal layer 21 is D2, and the thickness of the high-resistivity silicon dielectric layer 22 is D3, wherein D1≤10um, D2≤10um, 200um≤D3≤500um, and the resistivity of the high-resistivity silicon dielectric layer is R1, wherein R1≥3000Ω / cm. The top metal layer 23 and the bottom metal layer 21 can be copper or gold, which has lower metal loss and further reduces the insertion loss of the filter.

[0023] The filtering frequency of the silicon cavity resonator 11 can be determined by controlling its shape and size. In this embodiment, a bottom metal layer 23 and a top metal layer 21 with a thickness of 10 μm can be used, along with a high-resistivity silicon dielectric layer 22 with a thickness of 400 μm. The silicon cavity resonator 11 can be rectangular, with a length of 3 mm and a width of 1.54 mm. Alternatively, the silicon cavity resonator 11 can be square, circular, or other polygonal. By designing a suitable shape and size for the silicon cavity resonator 11, a filter with the desired filtering frequency can be obtained.

[0024] The double-sideband silicon-based filter with improved insertion loss in the passband can be fabricated using microelectromechanical processing technology. Its three-dimensional stacked structure and circuit structure make it extremely small in size and easy to integrate with semiconductor integrated circuit technology, which is conducive to the miniaturization and chip-based fabrication of filters and expands the application range of filters.

[0025] Each silicon cavity resonator unit 11 has multiple through holes 12 spaced at its edge, such as... Figure 1 As shown, the via 12 is either a full through-hole 122 or an open semi-through-hole 121, and the semi-through-holes 121 of adjacent silicon cavity resonator units are connected to form a full through-hole 122. For example... Figure 2 As shown, the via 12 penetrates the corresponding bottom metal layer 23, high-resistivity silicon dielectric layer 22 and top metal layer 21 from top to bottom. Moreover, a metal deposition layer is provided on the inner surface of the via 12 to form a silicon cavity for resonance, so that electromagnetic waves cannot leak out of the silicon cavity, resulting in low energy transmission loss and giving the filter the advantage of low insertion loss.

[0026] The slot-line dual stopband resonator 13 includes a first slot line 131 and a second slot line 132 formed on the top metal layer 21. The first slot line 131 and the second slot line 132 penetrate the corresponding top metal layer 21 in the depth direction. In this embodiment, one end of the second slot line 132 is connected to the midpoint of the first slot line 131, so that the slot-line dual stopband resonator 13 introduces transmission zeros on both sides of the filter passband, generating two transmission zeros, thereby improving the out-of-band suppression on both sides of the filter without increasing the filter size. The width and length of the first slot line 131 determine the out-of-band suppression at high frequencies in the passband, and the width and length of the second slot line 132 determine the out-of-band suppression at low frequencies in the passband, making the two transmission zeros adjustable.

[0027] The other end of the second slot line 132 is coiled into a closed-loop structure 133. The closed-loop structure 133 can be square or circular, which brings the electromagnetic field emitted from the end of the slot line back into the slot line, reducing the loss of electromagnetic energy and improving the insertion loss in the passband of the double-side band silicon-based filter.

[0028] like Figure 1 As shown, in this embodiment, the first groove line 131 is a U-shaped groove line, and the second groove line 132 is located in the inner region of the first groove line 131 of the U-shaped structure. The second groove line 132 can be any one of a straight groove line, an arc groove line, and a wavy groove line.

[0029] The input feed slot 14 and the first defect coupling slot 15 are formed on the top metal layer 21 of a single silicon cavity resonant unit or the first silicon cavity resonant unit in any row of silicon cavity resonant units, such as Figure 2 As shown, the depths of the input feed slot 14, the first defect coupling slot 15, the output feed slot 16, and the second defect coupling slot 17 are equal to the thickness of the top metal layer 21.

[0030] like Figure 1 As shown, the two input feed slots 14 extend from the edge of the top metal layer 21 of the first silicon cavity resonator unit towards the last silicon cavity resonator unit. The input feed slots 14 are connected to the first defect coupling slot 15 and are used for the input of the signal to be filtered. In this embodiment, the first defect coupling slot 15 corresponds one-to-one with the input feed slots 14 and is vertically connected.

[0031] The output feed slot 16 and the second defect coupling slot 17 are formed on the top metal layer 21 of a single silicon cavity resonator unit or the last silicon cavity resonator unit in any row of silicon cavity resonators. The output feed slot 16 and the second defect coupling slot 17 are connected and used to output the filtered signal formed after the signal to be filtered is filtered. In this embodiment, the output feed slot 16 extends to the edge of the top metal layer 21, and the output feed slot 16 and the second defect coupling slot 17 are vertically connected. The impedance of the output feed slot 16 and the input feed slot 14 can be 50Ω.

[0032] The size of the first defect coupling slot 15 determines the coupling strength between the input feed slot 14 and the first silicon cavity resonant unit 111, and the size of the second defect coupling slot 17 determines the coupling strength between the output feed slot 16 and the third silicon cavity resonant unit 113. Specifically, the larger the size of the first defect coupling slot 15 and the second defect coupling slot 17, the greater the coupling strength between the input feed slot 14 and the first silicon cavity resonant unit 111, and the greater the coupling strength between the output feed slot 16 and the third silicon cavity resonant unit 113.

[0033] The first silicon cavity resonant unit 111 and the second silicon cavity resonant unit 112 are coupled through the spacing of the upper and lower through holes 12 of the first slotted double stopband resonator 134. The larger the spacing, the smaller the coupling. The second silicon cavity resonant unit 112 and the silicon cavity resonant unit 113 are coupled through the spacing of the upper and lower through holes 12 of the second slotted double stopband resonator 135. The larger the spacing, the smaller the coupling. Optionally, the slot width of the input feed slot 14 and the output feed slot 16 can be 88 μm, the gap between the two input feed slots 14 can be 70 μm, and the length of the first defect coupling slot 15 and the second defect coupling slot 17 can both be 1.1 mm and the width can both be 0.22 mm.

[0034] In summary, the double-sideband silicon-based filter with improved insertion loss in the passband as described in this invention has a compact structure, improved out-of-band suppression, reduced insertion loss in the passband, and a wide range of applications.

[0035] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A double sideband silicon-based filter with improved passband insertion loss, characterized in that, The application relates to a double-sideband silicon-based filter with improved passband insertion loss. The application relates to a double-sideband silicon-based filter with improved passband insertion loss. The application relates to a double-sideband silicon-based filter with improved passband insertion loss.

2. The in-band interpolation loss improved double sideband silicon-based filter of claim 1, wherein, The application relates to a double-sideband silicon-based filter with improved passband insertion loss.

3. The in-band interpolation loss improved double sideband silicon-based filter of claim 1, wherein, The application relates to a double-sideband silicon-based filter with improved passband insertion loss.

4. The in-band interpolation loss improved double sideband silicon-based filter of claim 1, wherein, The application relates to a double-sideband silicon-based filter with improved passband insertion loss.

5. The in-band interpolation loss improved double sideband silicon-based filter of claim 1, wherein, The application relates to a double-sideband silicon-based filter with improved passband insertion loss.

6. The in-band interpolation loss improved double sideband silicon-based filter of claim 1, wherein, The application relates to a double-sideband silicon-based filter with improved passband insertion loss.

7. The in-band interpolation loss improved double sideband silicon-based filter according to claim 6, wherein, The application relates to a double-sideband silicon-based filter with improved passband insertion loss.

8. The in-band interpolation loss improved double sideband silicon-based filter of claim 1, wherein, The application relates to a double-sideband silicon-based filter with improved passband insertion loss.

9. The in-band interpolation loss improved double sideband silicon-based filter of claim 1, wherein, The application relates to a double-sideband silicon-based filter with improved passband insertion loss. The application relates to a double-sideband silicon-based filter with improved passband insertion loss. The application relates to a double-sideband silicon-based filter with improved passband insertion loss. The application relates to a double-sideband silicon-based filter with improved passband insertion loss. The application relates to a double-sideband silicon-based filter with improved passband insertion loss. The application relates to a double-sideband silicon-based filter with improved passband insertion loss. The application relates to a double-sideband silicon-based filter with improved passband insertion loss. The application relates to a double-sideband silicon-based filter with improved passband insertion loss. 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