Symmetrical layout structure of type I and type II RC polyphase filter
By using a symmetrical layout design, the connection lengths of resistors and capacitors in the RC multiphase filter are kept consistent, which solves the problem of signal orthogonality loss in traditional RC multiphase filters, improves matching accuracy and scalability, and is suitable for multi-stage cascade applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HUOXIN ELECTRONIC TECHNOLOGY (SHANGHAI) CO LTD
- Filing Date
- 2025-06-17
- Publication Date
- 2026-06-16
Smart Images
Figure CN224366427U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of integrated circuit design, specifically to a symmetrical layout structure of a type I and type II RC polyphase filter. Background Technology
[0002] RC polyphase filters are widely used in communication and radar systems due to their simple circuit structure, high robustness, and low cost. Their main applications include, but are not limited to, generating quadrature signals and achieving image suppression. Regarding quadrature signal generation, by inputting a differential signal into the RC polyphase filter, mutually orthogonal differential output signals can be generated, including in-phase and quadrature components.
[0003] like Figure 1 and Figure 2 As shown, in the traditional layout design of Type I and Type II RC polyphase filters, the placement of resistors and capacitors often leads to inconsistent metal interconnect lengths, resulting in compromised orthogonality of the output signals. This problem becomes increasingly severe with increasing frequencies, especially in the millimeter-wave band. Furthermore, due to the interleaved placement of resistors and capacitors in traditional RC polyphase filters, the matching and consistency of these two passive components are difficult to guarantee, particularly in cascaded multi-stage RC polyphase filter applications. Therefore, an optimized layout structure is needed to address these issues. Summary of the Invention
[0004] The purpose of this invention is to provide a symmetrical layout structure that can be applied to both Type I and Type II RC polyphase filters.
[0005] The technical solution of this utility model is: a symmetrical layout structure of a type I and type II RC multiphase filter, the layout structure including: a first resistor R1; a second resistor R2; a third resistor R3; a fourth resistor R4 and a first capacitor C1; a second capacitor C2; a third capacitor C3; and a fourth capacitor C4. The resistors and capacitors are connected in series alternately to form a closed loop, that is, the first resistor R1 is connected to the first capacitor C1, the first capacitor C1 is connected to the second resistor R2, the second resistor R2 is connected to the second capacitor C2, the second capacitor C2 is connected to the third resistor R3, the third resistor R3 is connected to the fourth capacitor C4, and the fourth capacitor C4 is connected to the first resistor R1. Maintaining the connection relationship, the resistor elements are arranged symmetrically vertically about the longitudinal axis, and the center-to-center spacing between adjacent resistor elements is the same. Similarly, the capacitor elements are arranged symmetrically vertically about the longitudinal axis, and the center-to-center spacing between adjacent capacitor elements is the same. The center-to-center spacing between adjacent resistor elements is the same as that between adjacent capacitor elements. The vertical columns of resistors and capacitors are arranged symmetrically about the transverse axis.
[0006] Furthermore, the connection lines between the first resistor R1 and the first capacitor C1, the third resistor R3 and the third capacitor C3, the first capacitor C1 and the second resistor R2, the second capacitor C2 and the third resistor R3, the first resistor R1 and the fourth capacitor C4, the fourth resistor R4 and the third capacitor C3, the fourth resistor R4 and the fourth capacitor C4, and the second resistor R2 and the second capacitor C2 are all of the same length.
[0007] Furthermore, in the Type I RC multivariate filter, the connection port between the first resistor R1 and the first capacitor C1 and the connection port between the third resistor R3 and the third capacitor C3 are differential signal input ports; the connection port between the fourth capacitor C4 and the first resistor R1 and the connection port between the second capacitor C2 and the third resistor R3 are in-phase component differential signal output ports; and the connection port between the third capacitor C3 and the fourth resistor R4 and the connection port between the first capacitor C1 and the second resistor R2 are quadrature component differential signal output ports.
[0008] Furthermore, in the Type II RC multivariate filter, the connection ports of the first resistor R1 and the first capacitor C1, and the connection ports of the second resistor R2 and the second capacitor C2 are combined into one port. The connection ports of the third resistor R3 and the third capacitor C3, and the connection ports of the fourth resistor and the fourth capacitor are combined into one port. The aforementioned two combined ports are differential signal input ports. The connection ports of the fourth capacitor C4 and the first resistor R1, and the connection ports of the second capacitor C2 and the third resistor R3 are in-phase component differential signal output ports. The connection ports of the third capacitor C3 and the fourth resistor R4, and the connection ports of the first capacitor C1 and the second resistor R2 are quadrature component differential signal output ports.
[0009] Furthermore, the resistive and capacitive elements are placed in different regions in the layout, with virtual units of the resistive elements filling the resistive regions and virtual units of the capacitive elements filling the capacitive regions.
[0010] Furthermore, in the cascading of multi-stage RC polyphase filters, the output signal of the preceding RC polyphase filter (hereinafter referred to as the pre-stage) serves as the input signal of the following RC polyphase filter (hereinafter referred to as the post-stage), and the pre-stage and post-stage are symmetrical about the horizontal axis. The in-phase differential signal output by the pre-stage is connected to the connection port of the first resistor R1 and the first capacitor C1 and the connection port of the third resistor R3 and the third capacitor C3 of the post-stage. The quadrature differential signal output by the pre-stage is connected to the connection port of the fourth resistor R4 and the fourth capacitor C4 and the connection port of the second resistor R2 and the second capacitor C2 of the post-stage. In each pair of poles, the connection port of the fourth capacitor C4 and the first resistor R1 and the connection port of the second capacitor C2 and the third resistor R3 of the post-stage are the output ports of the in-phase differential signal, and the connection port of the third capacitor C3 and the fourth resistor R4 and the connection port of the first capacitor C1 and the second resistor R2 of the post-stage are the output ports of the quadrature differential signal. The connection line lengths of the in-phase differential signal and the quadrature differential signal are the same.
[0011] The beneficial effects of this invention are as follows: This invention ensures that the metal connection lines between resistive and capacitive elements in the RC multiphase filter are of consistent length through a specific arrangement and connection method, thereby effectively avoiding the problem of output signal orthogonality loss caused by inconsistent connection line lengths. The design of placing resistive and capacitive elements in separate regions facilitates filling virtual units in their respective regions, which not only improves the matching accuracy of the devices but also balances the electrical characteristics of the layout. Furthermore, in the case of cascading multi-stage RC multiphase filters, this invention can still guarantee that the connection line lengths of in-phase and quadrature component signals between each stage are the same, exhibiting good scalability and compatibility. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of the layout structure of a traditional Type I RC polyphase filter.
[0013] Figure 2 This is a schematic diagram of the layout structure of a traditional Type II RC polyphase filter.
[0014] Figure 3 This is a schematic diagram of the layout structure of a two-stage Type I RC polyphase filter according to Embodiment 1 of this utility model.
[0015] Figure 4 This is the layout of the two-stage Type I RC polyphase filter of Embodiment 1 of this utility model.
[0016] Figure 5 The simulation results are those of the two-stage type I RC polyphase filter of Embodiment 1 of this utility model and the traditional two-stage type I RC polyphase filter.
[0017] Figure 6This is a schematic diagram of the layout structure of a two-stage type II RC polyphase filter according to Embodiment 2 of this utility model.
[0018] Figure 7 This is the layout of the two-stage type II RC polyphase filter of Embodiment 2 of this utility model.
[0019] Figure 8 The simulation results are those of the two-stage type II RC polyphase filter of Embodiment 2 of this utility model and the traditional two-stage type II RC polyphase filter. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this application clearer, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining this application and are not intended to limit this application. Any modifications made based on the technical concept proposed by this utility model shall fall within the protection scope of the claims of this utility model. Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprising of," etc., will be understood to include the stated elements or components, and does not exclude other elements or other components.
[0021] Example 1
[0022] This embodiment provides a layout structure for a two-stage Type I RC polyphase filter, including a first-stage RC polyphase filter and a second-stage RC multi-function filter (hereinafter referred to as the first stage and the second stage). Figure 3 This is a schematic diagram of the layout structure of this embodiment (the schematic diagram does not include virtual cells), including: a first-stage first resistor. Second resistor Third resistor Fourth resistor and the first capacitor Second capacitor Third capacitor Fourth capacitor The first-stage resistor and capacitor are connected in series alternately to form a closed loop, i.e., the first resistor... Connect the first capacitor First capacitor Connect the second resistor Second resistor Connect the second capacitor Second capacitor Connect the third resistor The third resistor Connect the fourth capacitor Fourth capacitor Connect the first resistor Maintaining the connection relationship described in the first stage, the first-stage resistive element about the vertical axis Symmetrical vertical arrangement, with the same center-to-center spacing between adjacent resistive elements, and the first-stage capacitor element about the vertical axis. Symmetrically arranged longitudinally, with the center-to-center spacing between adjacent capacitor elements being the same, and denoted as . Furthermore, the center-to-center spacing between adjacent resistive elements is the same as and equal to the center-to-center spacing between adjacent capacitive elements. .
[0023] Specifically, the first resistor With the first capacitor The connection wire, the third resistor With the third capacitor The connection line, the first capacitor With the second resistor The connecting wire, the second capacitor With the third resistor The connection wire, the first resistor With the fourth capacitor The connection wire, the fourth resistor With the third capacitor The connection wire, the fourth resistor With the fourth capacitor Connecting wires and the second resistor With the second capacitor The connecting lines are all of the same length, denoted as . .
[0024] Specifically, the first resistor With the first capacitor Connection port and third resistor With the third capacitor The connection port is a differential signal input port. Fourth capacitor. With the first resistor Connection port and second capacitor With the third resistor The connection port is the in-phase component differential signal output port, and the third capacitor... With the fourth resistor Connection port and first capacitor With the second resistor The connection port is the quadrature component differential signal output port.
[0025] Second stage, first resistor Second resistor The third resistor Fourth resistor and the first capacitor Second capacitor The third capacitor Fourth capacitor The first-stage resistor and capacitor are connected in series alternately to form a closed loop, i.e., the first resistor... Connect the first capacitor First capacitor Connect the second resistor Second resistor Connect the second capacitor Second capacitor Connect the third resistor The third resistor Connect the fourth capacitor Fourth capacitor Connect the first resistor Maintaining the connection relationship described in the second stage, the second-stage resistive element about the vertical axis The resistors are arranged symmetrically in a vertical direction, with the center-to-center spacing between adjacent resistors being the same. The second-stage capacitors are arranged about the vertical axis. Symmetrical vertical arrangement, with the center-to-center spacing between adjacent capacitor elements being equal to... Furthermore, the center-to-center spacing between adjacent resistive elements is the same as and equal to the center-to-center spacing between adjacent capacitive elements. .
[0026] Specifically, the first resistor With the first capacitor The connection wire, the third resistor With the third capacitor The connection line, the first capacitor With the second resistor The connecting wire, the second capacitor With the third resistor The connection wire, the first resistor With the fourth capacitor The connection wire, the fourth resistor With the third capacitor The connection wire, the fourth resistor With the fourth capacitor Connecting wires and the second resistor With the second capacitor The connecting lines are all of the same length, denoted as . .
[0027] Specifically, the first resistor With the first capacitor Connection port and third resistor With the third capacitor The connection port is a differential signal input port. Fourth capacitor. With the first resistor Connection port and second capacitor With the third resistor The connection port is the in-phase component differential signal output port, and the third capacitor... With the fourth resistor Connection port and first capacitor With the second resistor The connection port is the quadrature component differential signal output port.
[0028] The aforementioned two-stage RC polyphase filter about the horizontal axis The components are arranged symmetrically in a horizontal manner and cascaded, with the output signal of the first stage serving as the input signal of the second stage.
[0029] Specifically, the in-phase differential signal output from the first stage is connected to the in-phase differential input port of the second stage, and the quadrature differential signal output from the first stage is connected to the quadrature differential input port of the second stage. The connection lengths of the in-phase differential signal and the quadrature differential signal are the same, denoted as . .
[0030] Figure 4 For the layout implementation of this embodiment, a 40nm CMOS process is used, with an operating frequency of 77 GHz. Poly resistors are selected, and MOM capacitors are selected. Intersections of the interconnects are bridged using different layers of metal with a consistent metal thickness. Vias are not shown. In each stage, dummy cells for the resistors fill the spaces between the resistors and have the same size as the resistors in that stage. Similarly, dummy cells for the capacitors fill the ends of the capacitor columns in each stage and have the same size as the resistors in that stage. This layout separates the poly and metal elements into distinct regions, effectively improving device matching accuracy and balancing the electrical characteristics of the layout.
[0031] Figure 5 This paper compares the simulation results of the two-stage Type I RC polyphase filter in this embodiment with those of a traditional two-stage Type I RC polyphase filter. The comparison between the layout implementation and simulation results of this embodiment shows that the Type I RC polyphase filter using the layout structure of this invention can effectively maintain the orthogonality of the output signal over a wide bandwidth and is suitable for multi-stage cascaded applications.
[0032] Example 2
[0033] This embodiment provides a layout structure for a two-stage Type II RC polyphase filter, including a first-stage RC polyphase filter and a second-stage RC multi-function filter (hereinafter referred to as the first stage and the second stage). Figure 6 This is a schematic diagram of the layout structure of this embodiment (the schematic diagram does not include virtual cells), including: a first-stage first resistor. Second resistor The third resistor Fourth resistor and the first capacitor Second capacitor The third capacitor Fourth capacitor The first-stage resistor and capacitor are connected in series alternately to form a closed loop, i.e., the first resistor... Connect the first capacitor First capacitor Connect the second resistor Second resistor Connect the second capacitor Second capacitor Connect the third resistor The third resistor Connect the fourth capacitor Fourth capacitor Connect the first resistor Maintaining the connection relationship described in the first stage, the first-stage resistive element about the vertical axis Symmetrical vertical arrangement, with the same center-to-center spacing between adjacent resistive elements, and the first-stage capacitor element about the vertical axis. Symmetrically arranged longitudinally, with the center-to-center spacing between adjacent capacitor elements being the same, and denoted as . Furthermore, the center-to-center spacing between adjacent resistive elements is the same as and equal to the center-to-center spacing between adjacent capacitive elements. .
[0034] Specifically, the first resistor With the first capacitor The connection wire, the third resistor With the third capacitor The connection line, the first capacitor With the second resistor The connecting wire, the second capacitor With the third resistor The connection wire, the first resistor With the fourth capacitor The connection wire, the fourth resistor With the third capacitor The connection wire, the fourth resistor With the fourth capacitor Connecting wires and the second resistor With the second capacitor The connecting lines are all of the same length, denoted as . .
[0035] Specifically, the first resistor With the first capacitor Connection port and second resistor With the second capacitor The connection ports are merged into one port, and the third resistor With the third capacitor Connection port and fourth resistor and the fourth capacitor The connection ports are combined into one port, and the two combined ports are differential signal input ports. Fourth capacitor. With the first resistor Connection port and second capacitor With the third resistor The connection port is the in-phase component differential signal output port, and the third capacitor... With the fourth resistor Connection port and first capacitor With the second resistor The connection port is the quadrature component differential signal output port.
[0036] Second stage, first resistor Second resistor The third resistor Fourth resistor and the first capacitor Second capacitor The third capacitor Fourth capacitor The first-stage resistor and capacitor are connected in series alternately to form a closed loop, i.e., the first resistor... Connect the first capacitor First capacitor Connect the second resistor Second resistor Connect the second capacitor Second capacitor Connect the third resistor The third resistor Connect the fourth capacitor Fourth capacitor Connect the first resistor Maintaining the connection relationship described in the second stage, the second-stage resistive element about the vertical axis The resistors are arranged symmetrically in a vertical direction, with the center-to-center spacing between adjacent resistors being the same. The second-stage capacitors are arranged about the vertical axis. Symmetrical vertical arrangement, with the center-to-center spacing between adjacent capacitor elements being equal to... Furthermore, the center-to-center spacing between adjacent resistive elements is the same as and equal to the center-to-center spacing between adjacent capacitive elements. .
[0037] Specifically, the first resistor With the first capacitor The connection wire, the third resistor With the third capacitor The connection line, the first capacitor With the second resistor The connecting wire, the second capacitor With the third resistor The connection wire, the first resistor With the fourth capacitor The connection wire, the fourth resistor With the third capacitor The connection wire, the fourth resistor With the fourth capacitor Connecting wires and the second resistor With the second capacitor The connecting lines are all of the same length, denoted as . .
[0038] Specifically, the first resistor With the first capacitor Connection port and third resistor With the third capacitor The connection port is a differential signal input port. Fourth capacitor. With the first resistor Connection port and second capacitor With the third resistor The connection port is the in-phase component differential signal output port, and the third capacitor... With the fourth resistor Connection port and first capacitor With the second resistor The connection port is the quadrature component differential signal output port.
[0039] The aforementioned two-stage RC polyphase filter about the horizontal axis The components are symmetrically arranged horizontally and cascaded, with the output signal of the first stage serving as the input signal of the second stage. Specifically, the in-phase differential signal output from the first stage is connected to the in-phase differential input port of the second stage, and the quadrature differential signal output from the first stage is connected to the quadrature differential input port of the second stage. The connection line lengths for the in-phase and quadrature differential signals are the same, denoted as . .
[0040] Figure 7For the layout implementation of this embodiment, a 40nm CMOS process is used, with an operating frequency of 77 GHz. Poly resistors are selected, and MOM capacitors are used. Intersections of interconnects are bridged using different layers of metal with a consistent metal thickness. Vias are not shown. Dummy cells for each resistor element in each stage fill the spaces between the resistor elements and have the same size as the resistor elements in that stage. Dummy cells for each capacitor element in each stage fill the ends of the capacitor columns and have the same size as the resistor elements in that stage. This layout arranges poly and metal elements in separate regions, effectively improving device matching accuracy and balancing the electrical characteristics of the layout.
[0041] Figure 8 This paper compares the simulation results of the two-stage Type II RC polyphase filter in this embodiment with those of a traditional two-stage Type II RC polyphase filter. The comparison between the layout implementation and simulation results of this embodiment shows that the Type II RC polyphase filter using the layout structure of this invention can effectively maintain the orthogonality of the output signal over a wide bandwidth and is suitable for multi-stage cascaded applications.
[0042] In summary, based on the various embodiments and accompanying drawings, it can be seen that the symmetrical layout structure of the Type I and Type II RC polyphase filters provided in this utility model can keep the connection line length between the resistor and capacitor elements consistent, thereby effectively ensuring the orthogonality of the output signal and significantly improving the matching of each component. Moreover, this layout structure is still applicable in the cascaded application of multi-stage RC polyphase filters.
Claims
1. A symmetrical layout structure for Type I and Type II RC polyphase filters, characterized in that, The layout structure includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first capacitor C1, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4. The resistors and capacitors are connected in series alternately to form a closed loop, i.e., the first resistor R1 is connected to the first capacitor C1, the first capacitor C1 is connected to the second resistor R2, the second resistor R2 is connected to the second capacitor C2, the second capacitor C2 is connected to the third resistor R3, the third resistor R3 is connected to the fourth capacitor C4, and the fourth capacitor C4 is connected to the first resistor R1. The resistors are arranged symmetrically about the vertical axis, with the same center-to-center spacing between adjacent resistors. The capacitors are also arranged symmetrically about the vertical axis, with the same center-to-center spacing between adjacent capacitors. The center-to-center spacing between adjacent resistors is the same as the center-to-center spacing between adjacent capacitors. The columns of resistors and capacitors are arranged symmetrically about the horizontal axis.
2. The symmetrical layout structure of the Type I and Type II RC polyphase filters according to claim 1, characterized in that, The connection lines between the first resistor R1 and the first capacitor C1, the third resistor R3 and the third capacitor C3, the first capacitor C1 and the second resistor R2, the second capacitor C2 and the third resistor R3, the first resistor R1 and the fourth capacitor C4, the fourth resistor R4 and the third capacitor C3, the fourth resistor R4 and the fourth capacitor C4, and the connection line between the second resistor R2 and the second capacitor C2 are all the same length.
3. The symmetrical layout structure of the Type I and Type II RC polyphase filters according to claim 1 or 2, characterized in that, In the Type I RC multivariate filter, the connection port between the first resistor R1 and the first capacitor C1 and the connection port between the third resistor R3 and the third capacitor C3 are the differential signal input ports. The connection port between the fourth capacitor C4 and the first resistor R1 and the connection port between the second capacitor C2 and the third resistor R3 are the in-phase component differential signal output ports. The connection port between the third capacitor C3 and the fourth resistor R4 and the connection port between the first capacitor C1 and the second resistor R2 are the quadrature component differential signal output ports.
4. The symmetrical layout structure of the Type I and Type II RC polyphase filters according to claim 1 or 2, characterized in that, In the Type II RC multivariate filter, the connection ports of the first resistor R1 and the first capacitor C1, and the connection ports of the second resistor R2 and the second capacitor C2 are combined into one port. The connection ports of the third resistor R3 and the third capacitor C3, and the connection ports of the fourth resistor R4 and the fourth capacitor C4 are combined into one port. The aforementioned two combined ports are differential signal input ports. The connection ports of the fourth capacitor C4 and the first resistor R1, and the connection ports of the second capacitor C2 and the third resistor R3 are in-phase component differential signal output ports. The connection ports of the third capacitor C3 and the fourth resistor R4, and the connection ports of the first capacitor C1 and the second resistor R2 are quadrature component differential signal output ports.
5. The symmetrical layout structure of the Type I and Type II RC polyphase filters according to claim 1 or 2, characterized in that, Resistive and capacitive elements are placed in separate regions on the layout. Virtual cells for resistors are filled in the resistor region, and virtual cells for capacitors are filled in the capacitor region.
6. The symmetrical layout structure of the Type I and Type II RC polyphase filters according to claim 1 or 2, characterized in that, In the cascading of multi-stage RC polyphase filters, the previous stage RC polyphase filter is referred to as the pre-stage, and the next stage RC polyphase filter is referred to as the post-stage. The output signal of the pre-stage is used as the input signal of the post-stage, and the pre-stage and post-stage are symmetrical about the horizontal axis. The in-phase differential signal output from the preamplifier is connected to the connection port of the first resistor R1 and the first capacitor C1 and the connection port of the third resistor R3 and the third capacitor C3 in the subsequent stage. The quadrature differential signal output from the preamplifier is connected to the connection port of the fourth resistor R4 and the fourth capacitor C4 and the connection port of the second resistor R2 and the second capacitor C2 in the subsequent stage. In each pair of poles, the connection port between the fourth capacitor C4 and the first resistor R1 and the connection port between the second capacitor C2 and the third resistor R3 are the output ports for the in-phase differential signal. The connection port between the third capacitor C3 and the fourth resistor R4 and the connection port between the first capacitor C1 and the second resistor R2 are the output ports for the quadrature differential signal. The connection line lengths for the in-phase differential signal and the quadrature differential signal are the same.