A spiral-wound filter

Abstract

The application discloses a spiral-winding filter and belongs to the field of radio frequency filters. The spiral-winding filter comprises spiral-winding resonators, an insulating medium, a reference ground metal layer, input and output ports and a coupling path. The spiral-winding resonators comprise at least two spiral-winding resonators, and all the spiral-winding resonators are vertically and alternately arranged on the winding layer. The input and output ports are electrically connected with the first and last spiral-winding resonators respectively. The coupling path is used for connecting different spiral-winding resonators to realize energy transmission. The defects of loose structure, low space utilization and single process caused by the parallel arrangement of resonators and metal wiring layers in traditional filters are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of radio frequency filters, and more particularly to a spiral wiring filter. Background Technology

[0002] Filters are an important component of modern communication systems. With the rapid development of society, the number of communication frequency bands in the same electronic communication products is increasing, and the product size and weight are decreasing. This places higher demands on existing filters in terms of frequency selectivity and miniaturization.

[0003] The prior art patent document with authorization announcement number CN103647122A discloses "a dual-port vertical spiral bandpass filter". This bandpass filter includes only one input terminal, one output terminal, and two quarter-wavelength spiral resonators. The input terminal of the spiral bandpass filter is connected to one end of a spiral tube L1, and the other end of the spiral tube L1 is open. A metal conductor A1 is inserted into the spiral tube L1. The metal conductor A1 acts on the spiral tube L1 to increase the inductance of the spiral tube, and at the same time, the spiral tube L1 and the metal conductor A1 form a spiral resonator, and the spiral tube L2 and the metal conductor A2 form a spiral resonator. The metal conductors A1 and A2 are connected, and a shielding partition B1 is added between the spiral tubes L1 and L2 to control the resonant coupling of the two spiral resonators. The window of the shielding partition B1 is opened at the lower port of the spiral tube.

[0004] While existing technologies, based on LTCC (Low Temperature Ceramic Coefficient) processes, achieve an equivalent lumped circuit model, employing vertical helical tubes as the lumped circuit inductors and radial patch couplings as the lumped circuit capacitors to form a parallel resonance of equivalent inductance and capacitance, and transferring energy to the resonator through narrow-side multi-coupling, without a grounding port, and eliminating unwanted frequency components through magnetic field coupling, offering advantages such as high cost-effectiveness, high unloaded Q value, small size and light weight, low insertion loss, good frequency response performance, and good noise immunity, and can significantly reduce device size under the same technical specifications, effectively increasing out-of-band rejection, improving cutoff steepness and frequency selectivity, making them suitable for mass production and meeting general civilian requirements, existing technologies still have several drawbacks: First, the distribution direction of the multiple helical resonators constituting the filter is parallel to the metal wiring layer, and the resonators are relatively independent, resulting in a less compact structure; second, the number of turns of the helical lines in the same metal wiring layer is low, usually less than or equal to 1, leading to low space utilization of the resonator, or requiring additional structures to increase inductance and lower the resonant frequency; third, the implementation process is simple and not convenient for integration according to the characteristics of the RF system circuit board process. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a spiral wiring filter that solves the problems mentioned in the background section.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution: a spiral wiring filter, comprising: spiral wiring resonators, an insulating dielectric, a reference ground metal layer, input and output ports, and coupling paths; all spiral wiring resonators are stacked vertically on top of each other perpendicular to the winding layer plane, the input and output ports are electrically connected to the first and last spiral wiring resonators respectively, the coupling paths are used to connect different spiral wiring resonators to achieve energy transfer, each spiral wiring resonator has an open-circuit end and a short-circuit end, the short-circuit end is electrically connected to the reference ground metal layer through a metal wiring layer and a metallized via, the reference ground metal layer is located below all spiral wiring resonators, and the insulating dielectric covers the top and bottom of each metal wiring layer; The spiral wiring resonator is composed of at least one layer of metal spiral wiring, which is connected sequentially through metallized holes, and the spiral winding direction of the same spiral wiring resonator is the same in different metal wiring layers.

[0009] Furthermore, the spiral wire resonators, each composed of multi-layered metal spiral wires, have the same winding direction perpendicular to the winding plane.

[0010] Furthermore, the resonant frequency of the spiral wiring resonator is inversely proportional to the length of the metal wiring and the dielectric constant of the insulating medium.

[0011] Furthermore, the coupling path is achieved through a metal wiring layer and metallized vias. When both ends of the coupling path are directly electrically connected to two spiral wiring resonators, the coupling coefficient is positive. When the two ends of the coupling path form a planar capacitor structure with the two spiral wiring resonators to achieve electric field coupling, the coupling coefficient is negative. The coupling path can be set inside or outside the spiral wiring resonator.

[0012] Furthermore, the metal materials used for the metal wiring layer and metallized holes of the spiral wiring resonator and coupling path can be selected from gold, silver, copper or aluminum according to the processing technology, and the insulating medium can be selected from ceramic, resin or glass according to the processing technology.

[0013] Furthermore, the connection point between the input / output port and the spiral wiring resonator affects the external coupling coefficient. The closer the connection point is to the open end of the spiral wiring resonator, the larger the external coupling coefficient; the closer it is to the short-circuit end, the smaller the external coupling coefficient.

[0014] Beneficial effects: By stacking at least two spiral wiring resonators perpendicular to the winding plane, with each resonator consisting of at least one layer of metal spiral wiring and the multiple layers of wiring connected sequentially through metallized vias, the number of turns of the spiral wire in the same layer can be greater than 1. Combined with a coupling path that allows for flexible adjustment of the coupling coefficient, and multiple process implementation schemes adaptable to metal materials such as gold, silver, copper, and aluminum, and insulating media such as ceramics, resins, and glass, this spiral wiring filter achieves the core advantages of compact structure and flexible design. It can be fabricated as a standalone filter chip or directly wound into the circuit board of an RF system. Furthermore, by adjusting the resonator oscillation frequency and coupling coefficient, ideal signal transmission passbands and stopbands can be formed, exhibiting excellent filtering performance. It can fully meet the requirements of modern communication systems for filter miniaturization, multi-band adaptability, and high integration. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the stacked arrangement of the spiral wiring resonator of the present invention. Figure 1 ; Figure 3 This is a schematic diagram of the stacked arrangement of the spiral wiring resonator of the present invention. Figure 2 ; Figure 4 This is a schematic diagram of the winding direction of the present invention; Figure 5 This is a schematic diagram of the positive coupling path of the present invention; Figure 6 This is a schematic diagram of the negative coupling path of the present invention; Figure 7 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of the structure of Embodiment 2 of the present invention; Figure 9 This is a schematic diagram of the electrical performance curves of Embodiment 1 of the present invention; Figure 10 This is a schematic diagram illustrating the impact of the coupling path on the passband bandwidth in Embodiment 1 of the present invention; Figure 11 This is a schematic diagram of the electrical performance curves of Embodiment 2 of the present invention; Figure 12 This is a schematic diagram illustrating the impact of the coupling path on the passband bandwidth in Embodiment 2 of the present invention.

[0016] In the diagram: 1. Spiral wiring resonator; 2. Insulating medium; 3. Reference ground metal layer; 4. Input / output port; 5. Coupling path; 6. Open circuit terminal; 7. Short circuit terminal. Detailed Implementation

[0017] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figures 1-6 As shown, a spiral wiring filter is provided, including: a spiral wiring resonator 1, an insulating dielectric 2, a reference ground metal layer 3, input and output ports 4, and a coupling path 5; all spiral wiring resonators 1 are stacked vertically perpendicular to the winding layer plane, the input and output ports 4 are electrically connected to the first and last spiral wiring resonators 1 respectively, and the coupling path 5 is used to connect different spiral wiring resonators 1 to achieve energy transfer. Each spiral wiring resonator 1 has an open-circuit terminal 6 and a short-circuit terminal 7. The short-circuit terminal 7 is electrically connected to the reference ground metal layer 3 through a metal wiring layer and a metallized via. The reference ground metal layer 3 is located below all spiral wiring resonators 1, and the insulating dielectric 2 covers the top and bottom of each metal wiring layer; stacking the spiral wiring resonators 1 vertically, compared to traditional... The parallel distribution of resonators on the same layer significantly improves the structural compactness. At the same time, the spiral wiring resonator 1 can achieve more than 1 turn in the same layer, effectively improving the space utilization. The inductance can be guaranteed to adjust the resonant frequency without additional structure. The coupling path 5 can flexibly realize the control of positive and negative coupling coefficients, which is convenient for precise adjustment of the filter's passband and stopband performance. The reliable connection between the reference ground metal layer 3 and the short-circuit terminal 7 of the resonator, as well as the full coverage of the insulating medium 2, ensure the electrical stability of the device. Moreover, the metal and dielectric materials can be adapted to various processes, which can be used to make filter chips separately or directly integrated into the RF system circuit board, realizing dual flexibility in design and application. It can fully meet the requirements of modern communication equipment for filter miniaturization, high performance and high integration. The spiral wiring resonator 1 is composed of at least one layer of metal spiral wiring, which is sequentially connected through metallized vias. Furthermore, the spiral winding direction is the same in different metal wiring layers of the same spiral wiring resonator 1 (e.g., ...). Figure 4 (As shown); multi-layer metal spiral wiring is connected sequentially with metallized vias. This can effectively increase the inductance of the resonator without adding additional auxiliary structures, thereby precisely controlling the resonant frequency. It can also support more than 1 spiral turn in the same metal wiring layer, greatly improving the space utilization of the resonator. At the same time, the same spiral wiring resonator 1 maintains a consistent winding direction in different metal wiring layers, which can ensure the stability of the overall electrical performance of the resonator, reduce interlayer electromagnetic interference, and adapt to various metal wiring processes such as multi-layer substrates and LTCC, further enhancing the design flexibility and process adaptability of the filter.

[0019] Furthermore, the resonant frequency of the spiral wiring resonator 1 is inversely proportional to the length of the metal wiring and the dielectric constant of the insulating medium 2; this provides an intuitive and convenient way to adjust the resonant frequency without the need for additional auxiliary structures. Simply adjusting the length of the metal wiring or selecting insulating media 2 with different dielectric constants can accurately match different RF frequency band requirements. At the same time, it aligns with the design direction of filter miniaturization and high integration, greatly improving the design flexibility and process adaptability of the product.

[0020] Furthermore, coupling path 5 is implemented through a metal wiring layer and metallized vias. When both ends of coupling path 5 are directly electrically connected to the two spiral wiring resonators 1, the coupling coefficient is positive (e.g., Figure 5 As shown), when the coupling path 5 forms a planar capacitor structure with the two spiral wiring resonators 1 at both ends to achieve electric field coupling, the coupling coefficient is negative (as shown). Figure 6 As shown in the figure, the coupling path 5 can be set inside or outside the spiral wiring resonator 1; it can realize flexible switching of positive and negative coupling coefficients, and can be arranged inside and outside the resonator as needed, which facilitates precise control of coupling amount and passband bandwidth, which not only improves the adaptability of filter performance, but also optimizes the overall structural layout, and enhances the compactness and design flexibility of the device.

[0021] Furthermore, the metal wiring layer and metallized vias of the spiral wiring resonator 1 and coupling path 5 can be made of gold, silver, copper or aluminum depending on the processing technology, and the insulating medium 2 can be made of ceramic, resin or glass depending on the processing technology. It can be adapted to different processing technologies such as multilayer substrates and LTCC, and can take into account process accuracy, production cost and device performance according to actual needs. It not only breaks the limitation of the single process of traditional filter, but also improves the integration and compatibility of devices and RF system circuit boards, further enhancing the flexibility and practicality of the overall design.

[0022] Furthermore, the connection point between the input / output port 4 and the spiral wiring resonator 1 affects the external coupling coefficient. The closer the connection point is to the open end 6 of the spiral wiring resonator 1, the larger the external coupling coefficient; the closer it is to the short-circuit end 7, the smaller the external coupling coefficient. Without adding an additional control structure, the external coupling coefficient can be precisely adapted by adjusting the connection point position. This not only meets the performance requirements of filtering in different frequency bands, but also, in conjunction with the coupling coefficient adjustment of the coupling path 5, further optimizes the passband and stopband characteristics of the filter, significantly improving the overall design flexibility and performance adjustability of the device.

[0023] Example 1 like Figure 7 As shown, a spiral wiring filter includes: two spiral wiring resonators 1, two input / output ports 4, a coupling path 5, a reference ground metal layer 3 and an insulating dielectric 2, and is fabricated using a 10-layer substrate process.

[0024] Both spiral wire resonators 1 are composed of three layers of metal spiral wires. Viewed from top to bottom, one spiral wire resonator 1 is wired in the first to third metal layers, with the number of turns of each metal wire layer being 1.75, 1.75, and 1.375, respectively; the other spiral wire resonator 1 is wired in the fifth to seventh metal layers, with the number of turns of each metal wire layer being 1.75, 1.75, and 1.875, respectively. The metal wire layers of both spiral wire resonators 1 are wound counterclockwise, with the winding direction perpendicular to the winding plane pointing downwards.

[0025] Two input / output ports 4 are located at the bottom layer, and each is connected to a spiral wiring resonator 1 through a metal wiring layer and a metallized via. The connection point is 2.125 turns away from the short-circuit end 7 of the two spiral wiring resonators 1. The coupling path 5 is placed inside the two spiral wiring resonators 1, and the coupling coefficient is positive. Its two ends are connected to the two spiral resonators at the 2nd and 6th metal layers respectively. The connection point is 1.125 turns away from the short-circuit end 7 of the two spiral resonators.

[0026] In this embodiment, the metal material of the metal wiring layer and the metallized hole is copper, with a thickness of 15 μm, a wiring width and spacing of 40 μm, and a metallized hole diameter of 60 μm; the insulating medium 2 is resin, with a thickness of 25 μm and a dielectric constant of 4.4 between the metal layers.

[0027] The electrical performance curve of the filter is as follows: Figure 9 As shown, it possesses excellent passband and stopband performance; the impact of the coupling path on the passband bandwidth is as follows. Figure 10 As shown, when the connection point of coupling path 5 and the two spiral resonators moves towards the open end 6, the coupling increases and the passband bandwidth widens towards higher frequencies; when the connection point moves far away from the open end 6, the coupling decreases and the passband bandwidth narrows towards lower frequencies.

[0028] Example 2 like Figure 8 As shown, a spiral wiring filter includes: two spiral wiring resonators 1, two input / output ports 4, a coupling path 5, a reference ground metal layer 3, and an insulating dielectric 2, and is fabricated using a 10-layer LTCC process.

[0029] Both spiral-wired resonators consist of three layers of metal spiral wiring. Viewed from top to bottom, one spiral-wired resonator 1 has wiring on the 1st to 3rd metal layers, with 0.75, 0.875, and 0.625 turns per layer, respectively; the other spiral-wired resonator 1 has wiring on the 6th to 8th metal layers, with 0.875, 0.875, and 0.125 turns per layer, respectively. All metal wiring layers in both spiral-wired resonators 1 are wound counterclockwise, with the winding direction perpendicular to the winding plane pointing upwards.

[0030] Two input / output ports 4 are located on the bottom layer, each connected to a spiral wiring resonator 1 via a metal wiring layer and a metallized via. The connection points are 0.875 turns away from the short-circuit terminal 7 of one spiral wiring resonator 1 and 1.125 turns away from the short-circuit terminal 7 of the other spiral wiring resonator 1, respectively. The coupling path 5 is located outside the two spiral wiring resonators 1, with a negative coupling coefficient. Its upper and lower ends are wired on the 2nd and 5th metal layers, and each is separated from the open-circuit terminal 6 of the two spiral resonators by an insulating dielectric 2 with an area of ​​430*380um. 2 .

[0031] In this embodiment, the metal material of the metal wiring layer and the metallized hole is silver, with a thickness of 10 μm, a wiring width and spacing of 100 μm, and a metallized hole diameter of 100 μm; the insulating medium 2 is ceramic, with a thickness of 50 μm and a dielectric constant of 7.8 between the metal layers.

[0032] The electrical performance curve of the filter is as follows: Figure 11 As shown, it possesses good passband and stopband performance; the impact of coupling path 5 on the passband bandwidth is as follows. Figure 12 As shown, when the area of ​​the coupling path 5 and the open terminals 6 of the two helical resonators increases, the coupling increases and the passband bandwidth widens towards lower frequencies; when the area decreases, the coupling decreases and the passband bandwidth narrows towards higher frequencies.

[0033] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A spiral wiring filter, comprising: Multiple spiral wiring resonators (1), insulating medium (2), reference ground metal layer (3), input / output ports (4), and coupling paths (5); all spiral wiring resonators (1) are stacked vertically above and below the winding layer plane, the input / output ports (4) are electrically connected to the first and last spiral wiring resonators (1) respectively, the coupling paths (5) are used to connect different spiral wiring resonators (1) to achieve energy transmission, the spiral wiring resonators (1) have an open-circuit end (6) and a short-circuit end (7), the short-circuit end (7) is electrically connected to the reference ground metal layer (3) through the metal wiring layer and metallized via, the reference ground metal layer (3) is located below all spiral wiring resonators (1), and the insulating medium (2) covers the top and bottom of each metal wiring layer; The spiral wiring resonator (1) is composed of multiple layers of metal spiral wiring, which are connected sequentially through metallized holes, and the spiral winding direction of the same spiral wiring resonator (1) is the same in different metal wiring layers. The coupling path (5) is implemented through a metal wiring layer and a metallized via. In the coupling path (5) implemented by the metallized via, the two ends of the coupling path (5) are directly electrically connected to two spiral wiring resonators (1), and the coupling coefficient is positive. In the coupling path (5) implemented by the metal wiring layer, at the two ends of the coupling path (5), the two spiral wiring resonators (1) form a planar capacitor structure to achieve electric field coupling, and the coupling coefficient is negative. The coupling path (5) is located inside or outside the spiral wiring resonator (1).

2. A spiral wiring filter according to claim 1, characterized in that: The resonant frequency of the spiral wiring resonator (1) is inversely proportional to the length of the metal wiring and the dielectric constant of the insulating medium (2).

3. A spiral wiring filter according to claim 1, characterized in that: The metal wiring layer and metallized via of the spiral wiring resonator (1) and coupling path (5) are made of gold, silver, copper or aluminum, and the insulating medium (2) is made of ceramic, resin or glass.

4. A spiral wiring filter according to claim 1, characterized in that: The connection point between the input / output port (4) and the spiral wiring resonator (1) affects the external coupling coefficient. The closer the connection point is to the open end (6) of the spiral wiring resonator (1), the larger the external coupling coefficient is, and the closer it is to the short end (7), the smaller the external coupling coefficient is.

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