High-resistance resonator for improving isolation between metal layers

Abstract

The invention discloses a high-resistance resonator for improving isolation between metal layers, and the resonator comprises a first metal layer which is provided with a first radio frequency signal transmission line; the second metal layer is located above or below the first metal layer, a second radio-frequency signal transmission line is arranged on the second metal layer, and the first radio-frequency signal transmission line and the second radio-frequency signal transmission line have crossed and overlapped parts on overlook projections to be coupled to generate parasitic capacitance; and the parallel inductor is arranged between the first metal layer and the second metal layer, and a high-resistance LC resonant cavity is formed through the parallel inductor and the parasitic capacitor. According to the high-resistance resonator capable of improving the isolation between the metal layers, the resonant frequency points of the high-resistance resonator are tuned by changing the value of the parallel inductor L, high impedance is achieved at the different resonant frequency points, coupling between the signal layers is effectively restrained, and the high isolation requirement under the different frequency points is met.

Description

Technical Field

[0001] The invention relates to the field of monolithic microwave integrated circuits, and in particular to a high-resistance resonator for improving isolation between metal layers. Background Art

[0002] In recent years, with the widespread rise of technologies such as 5G, MIMO, and millimeter-wave phased arrays, modern communication systems are developing towards higher frequencies. The complexity of system integration is increasing, and there is an urgent need to improve isolation techniques to solve the crosstalk problem.

[0003] There are many methods to improve isolation, such as designing isolation rings, microstrip isolators, and reasonable wiring. Among them: isolation rings are used in the layout design stage of monolithic microwave integrated circuit chips. Isolation rings are designed for each chip. This method can ensure the isolation between chips and prevent signals from being crosstalked; microstrip isolators mainly play the role of inter-stage decoupling, impedance matching, unidirectional transmission, and signal debugging and processing in microwave systems, and improve isolation at the connection between chips; reasonable wiring is to plan the direction of RF lines, minimize parallel routing, and increase line spacing to reduce crosstalk. It is a method to improve isolation between circuits on the same plane.

[0004] However, in the design of monolithic microwave integrated circuits, it is difficult to avoid the situation where the signal transmission lines cross up and down. Due to the parasitic capacitance between the crossed signal lines located in the upper and lower metal layers, the signals loaded on the crossed lines will couple with each other through the parasitic capacitance. The higher the frequency, the more obvious the coupling and the worse the isolation, causing the signal transmitted between the two metal layers to be strongly interfered. The above technical means cannot solve the crosstalk problem caused by the coupling of the upper and lower crossed lines, and improvements are needed. Summary of the invention

[0005] The main technical problem solved by the present invention is to provide a high-impedance resonator that improves the isolation between metal layers, suppresses the coupling of inter-layer signals, and improves the isolation between metal layers.

[0006] In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a high-impedance resonator for improving the isolation between metal layers, comprising:

[0007] a first metal layer, on which a first radio frequency signal transmission line is disposed;

[0008] A second metal layer, the second metal layer is located above or below the first metal layer, a second radio frequency signal transmission line is arranged on the second metal layer, and the first radio frequency signal transmission line and the second radio frequency signal transmission line have a cross-overlapping portion in a top view projection to couple and generate a parasitic capacitance;

[0009] The parallel inductor is arranged between the first metal layer and the second metal layer, and a high-resistance LC resonant cavity is formed by the parallel inductor and the parasitic capacitor to suppress the coupling between signal layers.

[0010] In a preferred embodiment of the present invention, a first RF input port and a first RF output port located at two ends of the first RF signal transmission line are provided on the first metal layer.

[0011] In a preferred embodiment of the present invention, a first radio frequency signal passes between the first radio frequency input port and the first radio frequency output port.

[0012] In a preferred embodiment of the present invention, a second RF input port and a second RF output port located at two ends of the second RF signal transmission line are provided on the second metal layer.

[0013] In a preferred embodiment of the present invention, a second radio frequency signal passes between the second radio frequency input port and the second radio frequency output port.

[0014] In a preferred embodiment of the present invention, it further includes a first dielectric layer, wherein the first dielectric layer is located between the first metal layer and the second metal layer.

[0015] In a preferred embodiment of the present invention, it further comprises a second dielectric layer, wherein the second dielectric layer is located on a side of the first metal layer or the second metal layer facing away from the first dielectric layer.

[0016] In a preferred embodiment of the present invention, the first dielectric layer and the second dielectric layer can be air or silicon nitride dielectrics. When silicon nitride dielectrics are used, there is no electrical contact, and when air dielectrics are used, there is no substantial physical connection.

[0017] In a preferred embodiment of the present invention, one end of the parallel inductor is connected to the first radio frequency signal transmission line, and the other end is connected to the second radio frequency signal transmission line.

[0018] The beneficial effects of the present invention are as follows: the present invention points out a high-impedance resonator for improving the isolation between metal layers, which utilizes the parasitic capacitance and parallel inductance of the RF signal transmission lines crossing the upper and lower layers to form a high-impedance LC resonant cavity, and tunes its resonant frequency point by changing the value of the parallel inductor L, thereby achieving high impedance at different resonant frequency points, effectively suppressing the coupling between signal layers, and meeting the high isolation requirements at different frequency points. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. 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 work, among which:

[0020] Figure 1 It is a structural schematic diagram of a preferred embodiment of a high-impedance resonator for improving isolation between metal layers of the present invention;

[0021] Figure 2 yes Figure 1 Schematic diagram;

[0022] Figure 3 It is a schematic diagram of the stacked structure of the first metal layer and the second metal layer in a high-impedance resonator for improving isolation between metal layers according to the present invention;

[0023] Figure 4 It is a resonant cavity principle diagram of a high-impedance resonator for improving isolation between metal layers according to the present invention;

[0024] Figure 5 This is a comparative effect diagram of improving the isolation of a high-impedance resonator for improving the isolation between metal layers of the present invention;

[0025] Figure 6 This is an insertion loss comparison diagram of a high-impedance resonator for improving isolation between metal layers according to the present invention. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. 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.

[0027] See also Figure 1 to Figure 6 , the embodiment of the present invention includes:

[0028] like Figure 1 to Figure 3 The high-impedance resonator shown in the figure for improving the isolation between metal layers includes: a first metal layer MET1, a second metal layer MET2 and a parallel inductor L, and a first RF signal transmission line RF1 is arranged on the first metal layer MET1. In this embodiment, a first RF input port RF1_IN and a first RF output port RF1_OUT located at both ends of the first RF signal transmission line RF1 are arranged on the first metal layer MET1, and a first RF signal passes between the first RF input port RF1_IN and the first RF output port RF1_OUT.

[0029] like Figure 2 As shown, the second metal layer MET2 is located above or below the first metal layer MET1, and a second RF signal transmission line RF2 is arranged on the second metal layer MET2. In this embodiment, a second RF input port RF2_IN and a second RF output port RF2_OUT located at both ends of the second RF signal transmission line RF2 are arranged on the second metal layer MET2, and a second RF signal passes between the second RF input port RF2_IN and the second RF output port RF2_OUT.

[0030] The first RF signal transmission line RF1 and the second RF signal transmission line RF2 have a cross-overlapping portion in a top-down projection to couple and generate a parasitic capacitance C. The parallel inductor is arranged between the first metal layer MET1 and the second metal layer MET2. In the present embodiment, one end of the parallel inductor is connected to the first RF signal transmission line RF1, and the other end is connected to the second RF signal transmission line RF2, so as to realize the parallel connection of the parallel inductor and the parasitic capacitance C.

[0031] like Figure 4 As shown, a high-impedance LC resonant cavity is formed by parallel inductance and parasitic capacitance, and its resonant frequency point is tuned by changing the value of the parallel inductance L, so as to achieve high impedance at different resonant frequencies, effectively suppress the coupling between signal layers, and meet the high isolation requirements at different frequencies.

[0032] The theoretical derivation is as follows:

[0033] The impedance of the parasitic capacitor is:

[0034]

[0035] The impedance of the parasitic capacitor in parallel with the inductor is:

[0036]

[0037] j is the unit of the complex imaginary part, ω is the angular frequency, C is the parasitic capacitance, and L is the parallel inductance.

[0038] From the above formula, it can be seen that when only parasitic capacitance exists, the impedance decreases as the frequency increases, and the signal coupling becomes stronger. After the parallel inductor L and the parasitic capacitance form a resonant cavity, the impedance at the resonant frequency can be effectively increased, the signal coupling at the resonant frequency point and nearby frequency points can be suppressed, and the isolation can be greatly improved.

[0039] like Figure 3As shown, a first interlayer interface is included between the first dielectric layer and other dielectrics above it, and the second metal layer MET2 is located on the first interlayer interface. In this embodiment, a second interlayer interface is provided between the first dielectric layer and the second dielectric layer thereunder, the first metal layer MET1 is located on the second interlayer interface, and a third interlayer interface or an infinite ground plane is included between the second dielectric layer and other dielectrics thereunder.

[0040] In this embodiment, the first dielectric layer and the second dielectric layer are made of silicon nitride dielectric, and there is no electrical contact when the silicon nitride dielectric is used.

[0041] like Figure 5 As shown, in the present embodiment, by changing the inductance of the parallel inductor, resonance points are formed at 25 GHz, 26 GHz and 27 GHz respectively; at the 25 GHz resonance frequency, the isolation is effectively improved by about 20 dB, and the isolation can also be effectively improved in the frequency range of 21.5 GHz to 29.5 GHz near the resonance frequency; at the 26 GHz resonance frequency, the isolation is effectively improved by about 20 dB, and the isolation can also be effectively improved in the frequency range of 22.5 GHz to 31 GHz near the resonance frequency; at the 27 GHz resonance frequency, the isolation is effectively improved by about 17 dB, and the isolation can also be effectively improved in the frequency range of 23.5 GHz to 32.5 GHz near the resonance frequency.

[0042] like Figure 6 As shown in the figure, the insertion loss is not greatly affected after the resonance is formed at 25 GHz, 26 GHz and 27 GHz, and the insertion loss in the low frequency band can also be reduced.

[0043] In summary, the high-impedance resonator for improving the isolation between metal layers pointed out in the present invention effectively suppresses the coupling between signal layers and improves the isolation between metal layers.

[0044] The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A high-impedance resonator for improving isolation between metal layers, characterized in that: include: a first metal layer, on which a first radio frequency signal transmission line is disposed; A second metal layer, the second metal layer is located above or below the first metal layer, a second radio frequency signal transmission line is arranged on the second metal layer, and the first radio frequency signal transmission line and the second radio frequency signal transmission line have a cross-overlapping portion in a top view projection to couple and generate a parasitic capacitance; The parallel inductor is arranged between the first metal layer and the second metal layer, and a high-resistance LC resonant cavity is formed by the parallel inductor and the parasitic capacitor to suppress the coupling between signal layers.

2. The high-impedance resonator for improving metal layer isolation according to claim 1, characterized in that: The first metal layer is provided with a first radio frequency input port and a first radio frequency output port located at two ends of the first radio frequency signal transmission line.

3. The high-impedance resonator for improving metal layer isolation according to claim 2, characterized in that: A first radio frequency signal passes between the first radio frequency input port and the first radio frequency output port.

4. The high-impedance resonator for improving metal layer isolation according to claim 1, characterized in that: The second metal layer is provided with a second RF input port and a second RF output port located at two ends of the second RF signal transmission line.

5. The high-impedance resonator for improving isolation between metal layers according to claim 4, characterized in that: A second radio frequency signal passes between the second radio frequency input port and the second radio frequency output port.

6. The high-impedance resonator for improving isolation between metal layers according to claim 1, characterized in that: The invention also includes a first dielectric layer, wherein the first dielectric layer is located between the first metal layer and the second metal layer.

7. The high-impedance resonator for improving isolation between metal layers according to claim 6, characterized in that: The invention also includes a second dielectric layer, wherein the second dielectric layer is located on a side of the first metal layer or the second metal layer facing away from the first dielectric layer.

8. The high-impedance resonator for improving isolation between metal layers according to claim 7, characterized in that: The first dielectric layer and the second dielectric layer are made of air or silicon nitride.

9. The high-impedance resonator for improving isolation between metal layers according to claim 1, characterized in that: One end of the parallel inductor is connected to the first radio frequency signal transmission line, and the other end is connected to the second radio frequency signal transmission line.

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