High-Q-value integrated band elimination filter
By employing multiple band-stop resonant units and a spiral coupling line structure in the band-stop filter, the Q value is improved, the loss is reduced, and the circuit size is minimized, solving the problems of low Q value and large circuit size in the prior art and achieving efficient on-chip integration.
Patent Information
- Application Number
- CN202422704461.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2034-11-06
AI Technical Summary
Existing integrated bandstop filters have low Q values, resulting in slow out-of-band attenuation and making them unsuitable for applications where the passband and stopband are closely spaced. In addition, the circuit size of parallel coupled-line structures is large, making them unsuitable for on-chip integration.
Multiple band-stop resonant units are connected by transmission lines. Parallel first and second coupling lines and capacitors are used in combination with a spiral design to achieve a high Q value. The length of the coupling lines is shortened to reduce the circuit size, and the resonant frequency is adjusted by adjusting the length of the coupling lines and the capacitance value.
It achieves high Q value, low loss and steep out-of-band rejection characteristics, while reducing the circuit size without changing the operating frequency, making it suitable for on-chip integration.
Smart Images
Figure CN223502841U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of band-stop filter technology, and for example to a high-Q integrated band-stop filter. Background Technology
[0002] Band-stop filters, also known as notch filters, are widely used in communication, radar, and other systems. They typically work in conjunction with amplification, control, and frequency conversion circuits to form a microwave signal chain, filtering out signals within a specific frequency range.
[0003] Integrated bandstop filters based on semiconductor technology are typically composed of lumped inductors and capacitors. Due to the low Q-value of on-chip inductors, on-chip filters based on lumped LC elements usually also exhibit low Q-values and low rectangular coefficients. These filters experience slow out-of-band attenuation, making them unsuitable for applications where the passband and stopband are closely spaced.
[0004] Band-stop filter structures based on parallel coupled lines are commonly used to implement planar band-stop filters on ceramic or PTFE microwave substrates. The electrical length of the parallel coupled line corresponds to a quarter wavelength of the stopband center frequency. The mutual inductance of the parallel coupled lines enhances the inductance of the transmission line inductance, while the parasitic resistance is unaffected by coupling; therefore, the Q value of this type of structure is higher than that of planar inductors. Thus, filters based on parallel coupled lines have a higher Q value than filters based on LC networks, resulting in lower losses and steeper out-of-band rejection curves. However, the circuit size of parallel coupled lines is relatively large, leading to higher integration costs and making them unsuitable for on-chip integration.
[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content
[0006] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.
[0007] This disclosure provides a high-Q integrated band-stop filter, including multiple band-stop resonant units. Adjacent band-stop resonant units are connected by a transmission line. Each band-stop resonant unit includes a first coupling line, a second coupling line, and a capacitor. The first and second coupling lines are arranged in parallel. One end of the second coupling line is grounded, and the other end of the second coupling line is connected to one end of the capacitor, which is also grounded.
[0008] In one embodiment, the first coupling line and the second coupling line are spirally coiled.
[0009] The high-Q integrated bandstop filter provided in this disclosure can achieve the following technical effects:
[0010] By employing parallel-coupled resonant units, the Q value is increased, enabling the filter to exhibit low loss and steep out-of-band rejection characteristics. Capacitor loading can lower the operating frequency band of the coupling lines. Therefore, by using capacitor loading, the length of the coupling lines can be shortened without changing the operating frequency, reducing the circuit size and allowing for on-chip integration. By adjusting the lengths of the first and second coupling lines and the capacitance value, the resonant frequency of the resonant units can be adjusted; by adjusting the resonant frequencies of each resonant unit, the stopband frequency range can be adjusted.
[0011] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description
[0012] Figure 1 This is a block diagram illustrating the principle of a band-stop filter provided in an embodiment of this application.
[0013] Figure 2 The circuit topology diagram of the band-stop resonant unit provided in the embodiments of this application is shown.
[0014] Figure 3 This is a circuit example diagram of a band-stop filter provided in an embodiment of this application.
[0015] Figure 4 This is a circuit layout example of a band-stop resonant unit based on a spiral-wound parallel coupling line provided in an embodiment of this application.
[0016] Explanation of reference numerals in the attached diagram: 1. Band-stop resonant unit; 11. First coupling line; 12. Second coupling line; 13. Capacitor; 2. Transmission line. Detailed Implementation
[0017] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.
[0018] This disclosure provides a high-Q integrated band-stop filter, including multiple band-stop resonant units 1. Two adjacent band-stop resonant units 1 are connected by a transmission line 2. Each band-stop resonant unit 1 includes a first coupling line 11, a second coupling line 12, and a capacitor 13. The first coupling line 11 and the second coupling line 12 are arranged in parallel. One end of the second coupling line 12 is grounded, and the other end of the second coupling line 12 is connected to one end of the capacitor 13, and the other end of the capacitor 13 is grounded.
[0019] By employing parallel-coupled resonant units, the Q value is improved, enabling the filter to exhibit low loss and steep out-of-band rejection characteristics. Applying capacitor 13 lowers the operating frequency band of the coupling line. Therefore, by applying capacitor 13, the length of the coupling line can be shortened without changing the operating frequency, reducing the circuit size and allowing for on-chip integration. By adjusting the lengths of the first coupling line 11 and the second coupling line 12, and by adjusting the capacitance of capacitor 13, the resonant frequency of the band-stop resonant unit 1 can be adjusted; by adjusting the resonant frequencies of each band-stop resonant unit 1, the stopband frequency range can be adjusted.
[0020] In one embodiment, refer to Figure 4 The first coupling line 11 and the second coupling line 12 are spirally coiled. By spirally coiling the parallel first coupling line 11 and the second coupling line 12, the circuit area is further reduced and the cost is lowered.
[0021] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A high-Q integrated bandstop filter, comprising multiple bandstop resonant units, wherein adjacent bandstop resonant units are connected via transmission lines, characterized in that: The band-stop resonant unit includes a first coupling line, a second coupling line, and a capacitor. The first coupling line and the second coupling line are arranged in parallel. One end of the second coupling line is grounded, and the other end of the second coupling line is connected to one end of the capacitor, and the other end of the capacitor is grounded.
2. The high-Q integrated bandstop filter according to claim 1, characterized in that, include: The first coupling line and the second coupling line are spirally coiled.