Low-loss circulator and communication signal suppression method

Abstract

The invention relates to the technical field of circulators, in particular to a low-loss circulator and a communication signal suppression method. The circulator comprises a circulator unit and a filtering unit, the filtering unit comprises a plurality of groups of filtering modules, and each group of filtering modules comprises a short-circuit transmission line, a series transmission line, an input port and a common port; the short-circuit transmission line and the series transmission line are connected in parallel with the common port, and the series transmission line is in signal transmission connection with the input port; wherein the input port of one group of filtering modules is in signal transmission connection with the signal output port of the circulator unit, and the input ports of the other groups of filtering modules are cascaded with the common port of the adjacent group of filtering modules. The input port of each group of filtering modules is cascaded with the common port of the adjacent group of filtering modules, and different impedances are matched according to a plurality of frequencies of communication signals, so that the influence caused by the fact that a plurality of frequency values of the communication signals do not reach specified signal frequencies is eliminated, and the effect of low loss is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of circulators, and in particular to a low-loss circulator and a method for suppressing communication signals. Background Art

[0002] Network circulators are used to shape and process communication signals, such as filtering, modulation and demodulation, to improve network performance.

[0003] In some existing technologies, such as the Chinese patent (publication number: CN114464974B), a low-loss circulator with filtering characteristics is disclosed. The overall circuit consists of a 50-ohm standard microstrip interface, an impedance transformer, and a filtering center junction. The low-loss ferrite circulator based on the microstrip line can achieve reverse isolation between ports. The impedance transformer is composed of a traditional two-stage ladder microstrip line, which can achieve input / output matching from the microstrip port to the center junction. In this solution, since it uses a quarter-wavelength impedance transformer and a two-stage folded hairpin filter, it results in a large insertion loss and is difficult to apply in the conventional frequency bands of the four major telecom operators. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art solutions, an embodiment of the present invention provides a low-loss circulator and a method for suppressing communication signals.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] In a first aspect, an embodiment of the present invention provides a low-loss circulator, the low-loss circulator comprising:

[0007] A circulator unit, wherein the circulator unit is provided with a signal input port and a signal output port;

[0008] A filtering unit, wherein the filtering unit comprises a plurality of groups of filtering modules, each group of the filtering modules comprises a short-circuit transmission line, a series transmission line, an input port, and a common port; the short-circuit transmission line and the series transmission line are both connected in parallel with the common port, and the series transmission line is connected to the input port for signal transmission; the input port of one group of the filtering modules is connected to the signal output port of the circulator unit for signal transmission, and the input ports of the other groups of the filtering modules are cascaded with the common port of an adjacent group of the filtering modules.

[0009] In a second aspect, an embodiment of the present invention further provides a method for suppressing a communication signal, the method for suppressing the communication signal being applied to the circulator of the first aspect, the method for suppressing the communication signal comprising:

[0010] a communication signal received via a signal input port of the circulator unit;

[0011] Acquiring multiple frequency values ​​of the communication signal;

[0012] According to each frequency value of the communication signal, adjusting the electrical length and impedance value of each transmission line through simulation software so that each frequency value of the communication signal is adjusted to a target frequency value;

[0013] The communication signal is output through the signal output port of the circulator unit.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] Through multiple groups of filter modules, the input port of each group of filter modules is cascaded with the common port of an adjacent group of filter modules, and different impedances are matched according to the multiple frequencies of the communication signal to eliminate the influence caused by the multiple frequency values ​​of the communication signal not reaching the specified signal frequency, thereby playing a low-loss role and improving the filtering effect of the communication signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0017] Figure 1 It is a structural diagram of an embodiment of the present invention.

[0018] Figure 2 is a circuit diagram of an embodiment of the present invention.

[0019] Figure 3 4 is a flowchart of the steps of the suppression method according to an embodiment of the present invention.

[0020] Figure 4 It is a simulation diagram of the communication signal frequency parameters of an embodiment of the present invention.

[0021] Numbers in the figure

[0022] 1. Circulator unit; 12. Signal input port; 13. Signal output port;

[0023] 2. Filter module; 21. Short-circuit transmission line; 22. Series transmission line; 23. Input port; 24. Common port. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0025] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0026] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0027] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0028] In order to solve the technical problem in the prior art that the existing filter has a large insertion loss and is difficult to be applied in the conventional frequency bands of the four major telecommunications operators, an embodiment of the present invention provides a low-loss circulator.

[0029] The following describes in detail the specific structure of a low-loss circulator provided by an embodiment of the present invention. Figure 1-2 As shown in , the specific structure of the circulator includes a circulator unit 1 and a filtering unit.

[0030] The circulator unit 1 is provided with a signal input port 2312 and a signal output port 13 .

[0031] Specifically, the communication signal received by the signal input port 2312 of the circulator unit 1,

[0032] When the communication signal passes through the filtering unit, it is used to remove unnecessary frequency components to ensure the purity of the signal. The filtered communication signal is then fed to the core of the circulator unit 1, which is composed of one or more high-speed digital logic circuits and can process high-speed data streams; specifically, the core processes the received signal, including decoding, encryption, modulation and other operations, depending on the type and protocol of the communication signal, and then forwards the processed communication signal inside the circulator according to a predetermined algorithm; after a series of processing and forwarding of the communication signal, the communication signal is transmitted to the output port of the circulator unit 1, and the output port re-encodes the communication signal into the original format to ensure that the signal quality meets the requirements, and finally sends the communication signal to the next node or terminal device, thereby completing the communication process of the entire ring network.

[0033] The filtering unit includes multiple groups of filtering modules 2, each group of filtering modules 2 includes a short-circuit transmission line 21, a series transmission line 22, an input port 23, and a common port 24; the short-circuit transmission line 21 and the series transmission line 22 are both connected in parallel with the common port 24, and the series transmission line 22 is connected to the input port 23 for signal transmission; the input port 23 of one group of filtering modules 2 is connected to the signal output port 13 of the circulator unit 1 for signal transmission, and the input ports 23 of other groups of filtering modules 2 are cascaded with the common port 24 of an adjacent group of filtering modules 2.

[0034] Specifically, assuming that the frequencies of the communication signals of the harmonics, intermodulation and stray components to be suppressed are 3f0 and 4f0 respectively, the impedance of the common end of the short-circuit transmission line 21 and the series transmission line 22 in parallel is set, in the first-stage filter module 2 therein, the impedance of the short-circuit transmission line 21 is set to be larger at the suppression frequency 4f0, and the impedance at the input end of the other end of the series transmission line 22 is set to be short-circuited, and this setting ensures that when the input communication signal passes through the filter module 2 of this level, its impedance can be quickly and effectively matched to the desired impedance value. In the second-stage filter module 2, similar to the first-stage filter module 2, it is also used to adjust the impedance of the input end, so that it is short-circuited at the suppression frequency 3f0, and open-circuited at the desired fundamental signal frequency f0. It can be seen from this that in order to improve the filtering effect, the attenuation slope of the communication signal is stronger than the attenuation slope of the single-stage filter by setting the multi-stage filter module 2, so as to effectively improve the filter to suppress the interference frequency point, thereby improving the overall filtering performance.

[0035] In the above-mentioned embodiment, more specifically, in order to short-circuit the impedance of the input end of the first-stage filter module 2 at the suppression frequency 4f0, so as to prevent the signal of this frequency from being directly transmitted, the characteristic impedance is close to zero at the desired frequency through the short-circuit transmission line 21. Specifically, after the short-circuit transmission line 21 and the series transmission line 22 of the first-stage filter module 2 are connected in parallel to the common port 24, the overall impedance performance can be further improved, so that the impedance of the input port 23 of the first-stage filter module 2 is short-circuited at the suppression frequency. At this time, the values ​​of the short-circuit transmission line 21 and the series transmission line 22 are 1pF and 0.4nH, respectively, so that the communication signal can suppress other frequency components while being transmitted. The impedance of the input end of the second-stage filter module 2 is short-circuited at the suppression frequency 3f0. The technical principle of the second-stage filter module 2 is similar to that of the first-stage filter module 2, that is, the short-circuited transmission line 21 and the series transmission line 22 of the second-stage filter module 2 are connected in parallel to the common port 24, so that the impedance of the input port 23 of the second-stage filter module 2 is short-circuited at the suppression frequency. At this time, the values ​​of the short-circuited transmission line 21 and the series transmission line 22 of the second-stage filter module 2 are 1.16pF and 0.34pF respectively, so that the communication signal can suppress other frequency components while being transmitted; according to this setting, different impedance matching can be achieved at different suppression frequencies through multiple filter modules 2, thereby improving the overall filtering effect.

[0036] It should be noted that when the short-circuited transmission line 21 and the series transmission line 22 are connected in parallel to the common port 24, the entire input impedance can be affected, that is, when a communication signal with a frequency of 3f0 or 4f0 passes through the short-circuited transmission line 21, the communication signal is short-circuited at this frequency, thereby providing a relatively low impedance, while at other frequencies, the series transmission line 22 provides a relatively high impedance, which has a strong inhibitory effect on the communication signal.

[0037] In some optional embodiments, at least three groups of filter modules 2 are provided, and the input port 23 of each group of filter modules 2 is cascaded with the common port 24 of an adjacent group of filter modules 2. By cascading filter modules 2 with different frequency characteristics, effective filtering can be performed on a wider frequency range, providing more comprehensive frequency selectivity and filtering characteristics. For example, the first-stage filter module 2 is used to remove some larger noise or interference, that is, the first-stage filter module 2 filters high-frequency communication signals (such as 4f0), the second-stage filter module 2 filters medium-frequency communication signals (3f0), and finally the third-stage filter module 2 filters low-frequency communication signals (2f0), thereby realizing detailed filtering of signals in different frequency bands.

[0038] Among them, the short-circuit transmission line 21 and the series transmission line 22 of the third-stage filter module 2 are connected in parallel to the common port 24. At this time, the values ​​of the short-circuit transmission line 21 and the series transmission line 22 of the third-stage filter module 2 are 0.36nH and 0.08nH respectively.

[0039] In some specific embodiments, two series transmission lines 22 are provided for each group of filtering modules 2, namely a first series transmission line 22 and a second series transmission line 22; the output end of the first series transmission line 22 is connected to the short-circuit transmission line 21 for signal transmission, and the input end of the first series transmission line 22 is connected in parallel with the common port 24; the output end of the second series transmission line 22 is connected in parallel with the common port 24, and the input end of the second series transmission line 22 is connected to the input port 23 for signal transmission.

[0040] Specifically, the input end of the first series transmission line 22 is connected to the common port 24 for signal transmission. When the signal input from the common port 24 directly enters the first series transmission line 22, it is used to allow the communication signal of the common port 24 to be directly transmitted to the filter module 2 for processing, and at the same time, a low impedance path is realized to ensure that the communication signal can be effectively transmitted: the output end of the first series transmission line 22 is connected to the short-circuit transmission line 21 for signal transmission. Since the short-circuit transmission line 21 can play the role of impedance, it can also divert the unnecessary communication signal through the short circuit, ensuring that only the signal of the target frequency band can be transmitted, thereby reducing the effect of interference and stray signals. The input end of the second series transmission line 22 is connected to the input port 23 for signal transmission, which is used to output the filtered communication signal from the second series transmission line 22 to the common port 24, and the filtered communication signal is transmitted to the input port 23 by the common port 24, and the communication signal is transmitted to the signal output port 13 or the input port 23 of the filter module 2 of another level by the input port 23.

[0041] In some specific embodiments, the ground end of the short-circuit transmission line 21 of each filter module 2 is connected to the ground signal transmission.

[0042] Specifically, the ground end of the short-circuited transmission line 21 serves as a signal saddle point, which can reduce the waveform distortion and reflection of the communication signal. The signal saddle point leads the input signal to the saddle point, so that the communication signal remains the same as the saddle point at any time, thereby improving the stability of the communication signal transmission; since common-mode noise refers to the noise acting on the signal and the ground line at the same time, when both are coupled to the ground line at the same time, the ground end of the short-circuited transmission line 21 is connected to the ground line signal transmission, which can suppress the common-mode noise and offset the common-mode noise, thereby improving the quality of the communication signal and the integrity of the signal.

[0043] In some specific embodiments, the impedance of each input port 23 is short-circuited. Specifically, when the impedance of the input port 23 of each filter module 2 is short-circuited, the communication signal with high-frequency interference can be reflected back to prevent the signal from continuing to be transmitted to the signal output port 13, thereby effectively suppressing electromagnetic interference (EMI), improving the anti-interference ability of the system, effectively eliminating or reducing unnecessary high-frequency noise and harmonic components of the communication signal, and reducing the phase distortion and amplitude attenuation of the signal during the transmission process, thereby improving the quality of the signal.

[0044] In some specific embodiments, each of the short-circuit transmission lines 21 and the series transmission lines 22 is a microstrip line.

[0045] Specifically, the short-circuit transmission line 21 is a microstrip line, which can effectively control the transmission and reflection of the communication signal, that is, by adjusting the length parameters of the microstrip line, it can suppress signals of different frequencies, thereby filtering the frequencies of the communication signal. The series transmission line 22 is a microstrip line, which is used to ensure signal transmission while realizing some specific filtering functions. For example, by adjusting the inductance and capacitance characteristics of the microstrip line, it is possible to attenuate or enhance certain frequencies in the communication signal, thereby achieving a filtering effect.

[0046] The following is a detailed description of the specific steps of a method for suppressing communication signals provided by an embodiment of the present invention. Figure 3-4 As shown in , the communication signal suppression method specifically includes the following steps:

[0047] Step S110 is to receive a communication signal through the signal input port 2312 of the circulator unit 1 .

[0048] Specifically, the signal input port 2312 of the circulator unit 1 is an interface connected to an external device. When the external device generates a communication signal (such as a radio frequency signal, a microwave signal, etc.) and sends it to the circulator, the communication signal is transmitted through the input port 23; it can be understood that the signal input port 2312 is a physical interface to adapt to the physical medium of transmission (such as an antenna, a coaxial cable, an optical fiber, etc.) to ensure that the communication signal can be effectively received and transmitted to the filtering unit.

[0049] The step S120 is to obtain multiple frequency values ​​of the communication signal.

[0050] Specifically, when the signal input port 2312 of the circulator unit 1 receives the communication signal, the spectrum analyzer is used to perform a fast Fourier transform (FFT) algorithm on the communication signal to identify each frequency in the communication signal to obtain multiple frequency values ​​of the communication signal.

[0051] In step S130, according to each frequency value of the communication signal, the electrical length and impedance value of each transmission line are adjusted by simulation software so that each frequency value of the communication signal is adjusted to a target frequency value.

[0052] Specifically, since the electrical length and characteristic impedance of the short-circuit transmission line 21 and the series transmission line 22 will affect the communication signals at different frequencies, that is, when the short-circuit transmission line 21 and the series transmission line 22 are connected in parallel to the common port 24, they play a short-circuit role, so that the impedance of the common port 24 increases (close to infinity), which helps to suppress the transmission of communication signals of different frequencies. It can be seen that by adjusting the electrical length value of each transmission line, the communication signals of different frequencies can be suppressed, and the efficiency and quality of communication signal transmission can be improved.

[0053] The steps include adjusting the electrical length and impedance value of each transmission line by simulation software, and further comprising the following steps:

[0054] Calculate the electrical length values ​​of the short-circuited transmission line 21 and each series transmission line 22; specifically, calculate the ratio of the preset reference frequency value to the suppression frequency; multiply the ratio by the phase difference value to obtain the electrical length values ​​of the short-circuited transmission line 21 and each series transmission line 22.

[0055] Specifically, the following is a method for calculating and obtaining the electrical lengths of the short-circuit transmission line 21 and the series transmission line 22 of each filter module 2, specifically including:

[0056] Electrical length = reference frequency / suppression frequency*90°; where the reference frequency is assumed to be f0.

[0057] For example, assuming that the reference frequency is f0, the frequency of the communication signal that the first-stage filter module 2 needs to suppress is 4f0, which is included in the formula:

[0058] The electrical length of each transmission line = f0 / 4f0×90°=22.5°.

[0059] Therefore, it can be obtained that the electrical lengths of the short-circuit transmission line 21 and the series transmission line 22 of the first-stage communication module are both 22.5°.

[0060] With reference to the above embodiment, the electrical lengths of the short-circuit transmission line 21 and the series transmission line 22 of the second-level communication module are both 30° (the frequency of the communication signal to be suppressed by the second-level filter module 2 is 3f0), and the electrical lengths of the short-circuit transmission line 21 and the series transmission line 22 of the third-level communication module are both 45° (the frequency of the communication signal to be suppressed by the third-level filter module 2 is 2f0). Subsequently, tuning optimization is performed through simulation software. Specifically, simulation software (such as HFSS, CST Microwave Studio, ADS, etc.) is used to model and simulate the filter module 2. By setting different frequency points, the impedance values ​​of the short-circuit transmission line 21 and the series transmission line 22 of each filter module 2 at different frequencies are observed and recorded at the same time. According to the data of each impedance value, the electrical lengths of the short-circuit transmission line 21 and the series transmission line 22 are adjusted, thereby suppressing the communication signal.

[0061] In the above-mentioned embodiment, it should be noted that a corresponding circuit model is established in the simulation software, including modeling of each filter module 2, transmission line, resistor, capacitor, inductor and other components, and simulation analysis is performed on them through the simulation software to calculate the reflection coefficient, transmission coefficient or other related parameters of the input port 23. This parameter is used to reflect the performance of the filter unit at different frequencies. Then, based on the simulation results, it is evaluated whether the frequency value of each communication signal reaches the expected fundamental signal frequency value. If not, the circuit parameters (such as transmission line length and characteristic impedance, etc.) can be adjusted through the simulation software until the frequency value of each communication signal reaches the expected fundamental signal frequency value.

[0062] For example, assuming that the frequencies to be suppressed are 2f0, 3f0 and 4f0, and the desired fundamental signal frequency f0 = 2GHz; after adjusting the circuit parameters through simulation software, it is obtained that the short-circuit transmission line 21 and the series transmission line 22 of the first filtering module 2 are 82.9° and 10° respectively, the short-circuit transmission line 21 and the series transmission line 22 of the second-stage filtering module 2 are 44.9° and 65.6° respectively, the electrical lengths of the short-circuit transmission line 21 and the series transmission line 22 of the third-stage filtering module 2 are 17.9° and 6.3° respectively, the characteristic impedance values ​​of the short-circuit transmission line 21 and the series transmission line 22 of the first filtering module 2 are 34 and 21 respectively, the characteristic impedance values ​​of the short-circuit transmission line 21 and the series transmission line 22 of the second filtering module 2 are 23 and 80 respectively, and the characteristic impedance values ​​of the short-circuit transmission line 21 and the series transmission line 22 of the third filtering module 2 are 20 and 20 respectively.

[0063] According to the attached Figure 3As shown in the figure, after suppression, the communication signals with frequency values ​​of 2f0, 3f0, and 4f0 are -40.8dB, -40.2dB, and -30.2dB respectively. Therefore, the insertion loss at f0 is -1.4E-4. As a result, it has the effect of ultra-low insertion loss and high suppression on the communication signal, which can meet the current new generation of communication frequency widening bandwidth requirements.

[0064] The step is S140, outputting the communication signal through the signal output port 13 of the signal unit.

[0065] Specifically, after the communication signal is suppressed, it can be transmitted to the next node or terminal device, thus completing the communication process of the entire ring network.

[0066] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A low-loss circulator, characterized in that: The circulator comprises: A circulator unit, wherein the circulator unit is provided with a signal input port and a signal output port; A filtering unit, wherein the filtering unit comprises a plurality of groups of filtering modules, each group of the filtering modules comprises a short-circuit transmission line, a series transmission line, an input port, and a common port; the short-circuit transmission line and the series transmission line are both connected in parallel with the common port, and the series transmission line is connected to the input port for signal transmission; the input port of one group of the filtering modules is connected to the signal output port of the circulator unit for signal transmission, and the input ports of the other groups of the filtering modules are cascaded with the common port of an adjacent group of the filtering modules.

2. The low-loss circulator according to claim 1, characterized in that: Each group of the filter modules has two series transmission lines, namely a first series transmission line and a second series transmission line; The output end of the first series transmission line is connected to the short-circuit transmission line for signal transmission, and the input end of the first series transmission line is connected in parallel to the common port; the output end of the second series transmission line is connected to the common port in parallel, and the input end of the second series transmission line is connected to the input port for signal transmission.

3. The low-loss circulator according to claim 1, characterized in that: The grounding end of the short-circuit transmission line of each filter module is connected to the ground signal transmission.

4. The low-loss circulator according to claim 1, characterized in that: The filtering modules are provided in at least three groups.

5. The low-loss circulator according to claim 1, characterized in that: The impedance of each input port is set to short circuit.

6. The low-loss circulator according to any one of claims 1 to 5, characterized in that: Each of the short-circuit transmission lines and the series transmission line is a microstrip line.

7. A method for suppressing a communication signal, characterized in that: The suppression method is applied to the circulator according to any one of claims 1 to 5, and the suppression method comprises: a communication signal received via a signal input port of the circulator unit; Acquiring multiple frequency values ​​of the communication signal; According to each frequency value of the communication signal, adjusting the electrical length and impedance value of each transmission line through simulation software so that each frequency value of the communication signal is adjusted to a target frequency value; The communication signal is output through the signal output port of the circulator unit.

8. The method for suppressing communication signals according to claim 7, characterized in that: Before adjusting the electrical length and impedance value of each transmission line through the simulation software, it also includes: Calculate the electrical length values ​​of the short-circuited transmission line and each series transmission line.

9. The method for suppressing communication signals according to claim 8, characterized in that: Calculate the electrical length of the short-circuited transmission line and each series transmission line, including: Calculate the ratio of the preset reference frequency value to the suppression frequency; The ratio is multiplied by the phase difference value to obtain the electrical length values ​​of the short-circuited transmission line and each of the series transmission lines.

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