Low-loss circulator

Abstract

The utility model relates to the technical field of circulators, in particular to a low-loss circulator. 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 utility model relates to the technical field of circulators, and particularly relates to a low-loss circulator. BACKGROUND

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

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

[0004] To overcome the deficiencies of the prior art, the embodiments of the utility model provide a low-loss circulator.

[0005] The technical scheme adopted by the utility model to solve its technical problems is:

[0006] In a first aspect, the embodiments of the utility model provide a low-loss circulator, which includes:

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

[0008] A filter unit includes multiple groups of filter modules, each group of filter modules includes 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 connected in signal transmission with the input port; the input port of one group of filter modules is connected in signal transmission with the signal output port of the circulator unit, and the input ports of the other groups of filter modules are cascaded with the common ports of the adjacent groups of filter modules.

[0009] Compared with the prior art, the utility model has the beneficial effects that:

[0010] The input port of each filter module is connected with the common port of the adjacent filter module in series, and different impedances are matched according to the multiple frequencies of the communication signal, so as 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 on the communication signal. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical scheme in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the premise of not deviating from the concept of the present application.

[0012] Figure 1 is a structural diagram of the embodiment of the present application.

[0013] Figure 2 is a circuit diagram of the embodiment of the present application.

[0014] Figure 3 is a step flow chart of the suppression method of the embodiment of the present application.

[0015] Figure 4 is a simulation diagram of the communication signal frequency parameter of the embodiment of the present application.

[0016] Reference numerals in the drawings

[0017] 1, circulator unit; 12, signal input port; 13, signal output port;

[0018] 2, filter module; 21, short-circuit transmission line; 22, series transmission line; 23, input port; 24, common port. DETAILED DESCRIPTION

[0019] The technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] It should be understood that when used in the specification and the appended claims, the terms "comprise" and "include" indicate the presence of the 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 groups thereof.

[0021] It should also be understood that the terms used in the present utility model specification are only for the purpose of describing specific embodiments and are not intended to limit the present utility model. As used in the present utility model specification and the appended claims, unless otherwise clear from context, the singular forms "a," "an," and "the" are intended to include the plural forms as well.

[0022] It should be further understood that the term "and / or" as used in the present utility model specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0023] In order to solve the technical problem that the insertion loss of the existing filter is large and it is difficult to be applied in the conventional four telecom operator frequency bands in the prior art, embodiments of the present utility model provide a low-loss circulator.

[0024] The specific structure of the low-loss circulator provided by the embodiments of the present utility model will be described in detail below, according to the specific structure of the low-loss circulator provided by the embodiments of the present utility model shown in the accompanying drawings, Figures 1-2 The specific structure of the circulator includes a circulator unit 1 and a filter unit.

[0025] The circulator unit 1 is provided with a signal input port 2312 and a signal output port 13.

[0026] Specifically, the communication signal received through the signal input port 2312 of the circulator unit 1,

[0027] When the communication signal passes through the filter unit, unnecessary frequency components are removed to ensure the purity of the signal, and 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, etc. operations, depending on the type and protocol of the communication signal, and then forwards the processed communication signal according to a predetermined algorithm inside the circulator; 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, the communication signal is re-encoded into the original format by the output port to ensure that the signal quality meets the requirements, and finally the communication signal is sent to the next node or terminal device, thereby completing the entire communication process of the circulator network.

[0028] The filter unit comprises a plurality of filter modules 2, each of which comprises 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 connected in parallel to the common port 24, and the series transmission line 22 is connected in signal transmission to the input port 23; the input port 23 of one of the filter modules 2 is connected in signal transmission to the signal output port 13 of the circulator unit 1, and the input ports 23 of the other filter modules 2 are connected in cascade to the common ports 24 of the adjacent filter modules 2.

[0029] Specifically, assuming that the frequencies of the communication signals of the harmonic, intermodulation and spurious components to be suppressed are 3f0 and 4f0 respectively, by setting the impedance of the short-circuit transmission line 21 and the series transmission line 22 in parallel to the common port, in the first-stage filter module 2, the impedance of the short-circuit transmission line 21 at the suppression frequency 4f0 is set to be large, and the impedance at the other end of the series transmission line 22 is set to be short-circuit, which ensures that when the input communication signal passes through the filter module 2, its impedance can be quickly and effectively matched to the desired impedance value. In the second-stage filter module 2, similarly to the first-stage filter module 2, the impedance of the input end is also adjusted to be short-circuit at the suppression frequency 3f0 and open-circuit at the desired fundamental signal frequency f0. Thus, in order to improve the filtering effect, the attenuation slope of the communication signal by the multi-stage filter module 2 is stronger than that of the single-stage filter, thereby effectively improving the filter's suppression of the interference frequency point, and thus improving the overall filtering performance.

[0030] In the above embodiment, more specifically, in order to achieve short circuit of the input impedance of the first filter module 2 at the suppression frequency 4f0, the signal at this frequency is prevented from being transmitted directly, and thus the characteristic impedance of the short circuit transmission line 21 is close to zero at the required frequency. Specifically, the short circuit transmission line 21 and the series transmission line 22 of the first filter module 2 are connected in parallel to the common port 24, and the impedance of the input port 23 of the first filter module 2 is short-circuited at the suppression frequency, and the values of the short circuit transmission line 21 and the series transmission line 22 are 1 pF and 0.4 nH respectively, so that the communication signal can be transmitted while suppressing other frequency components. The input impedance of the second filter module 2 is short-circuited at the suppression frequency 3f0, and the second filter module 2 has the same technical principle as the first filter module 2, that is, the short circuit transmission line 21 and the series transmission line 22 of the second filter module 2 are connected in parallel to the common port 24, so that the impedance of the input port 23 of the second filter module 2 is short-circuited at the suppression frequency, and the values of the short circuit transmission line 21 and the series transmission line 22 of the second filter module 2 are 1.16 pF and 0.34 pF respectively, so that the communication signal can be transmitted while suppressing other frequency components. In this way, by using multiple filter modules 2, different impedance matching can be achieved at different suppression frequencies, thereby improving the overall filtering effect.

[0031] It should be noted that when the short circuit transmission line 21 and the series transmission line 22 are connected in parallel to the common port 24, the overall input impedance can be affected, that is, when the communication signal with a frequency of 3f0 or 4f0 passes through the short circuit transmission line 21, the communication signal is short-circuited at this frequency, thereby providing a relatively low impedance, and at other frequencies, the series transmission line 22 provides a relatively high impedance, thereby strongly suppressing the communication signal.

[0032] In some optional embodiments, the filter module 2 is provided in at least three groups, and the input port 23 of each group of filter modules 2 is connected in cascade with the common port 24 of an adjacent group of filter modules 2. By cascading filter modules 2 with different frequency characteristics, a wider frequency range can be effectively filtered, and more comprehensive frequency selectivity and filtering characteristics can be provided. For example, the first filter module 2 is used to remove some large noise or interference, that is, the first filter module 2 is used to filter high-frequency communication signals (such as 4f0), the second filter module 2 is used to filter medium-frequency communication signals (3f0), and the third filter module 2 is used to filter low-frequency communication signals (2f0), thereby achieving detailed filtering of signals in different frequency bands.

[0033] Wherein, the short-circuit transmission line 21 and the series transmission line 22 of the third filter module 2 are connected in parallel after the common port 24, and the values of the short-circuit transmission line 21 and the series transmission line 22 of the third filter module 2 are 0.36nH and 0.08nH respectively at this time.

[0034] In some specific embodiments, the series transmission line 22 of each filter module 2 is provided with two, which are the first series transmission line 22 and the second series transmission line 22; the output end of the first series transmission line 22 is connected in signal transmission with the short-circuit transmission line 21, 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 in signal transmission with the input port 23.

[0035] Specifically, the input end of the first series transmission line 22 is connected in signal transmission with the common port 24, so that the signal input from the common port 24 will directly enter the first series transmission line 22, allowing the communication signal of the common port 24 to be directly transmitted to the filter module 2 for processing, while realizing a low-impedance path to ensure that the communication signal can be effectively transmitted; the output end of the first series transmission line 22 is connected in signal transmission with the short-circuit transmission line 21, which can play a role in impedance, that is, it can drain unnecessary communication signals through short-circuiting, ensuring that only signals of the target frequency band can be transmitted, thereby reducing the effects of interference and stray signals; the input end of the second series transmission line 22 is connected in signal transmission with the input port 23, for outputting the filtered communication signal from the second series transmission line 22 to the common port 24, and transmitting the filtered communication signal from the common port 24 to the input port 23, and transmitting the communication signal from the input port 23 to the signal output port 13 or the input port 23 of another filter module 2.

[0036] In some specific embodiments, the ground end of the short-circuit transmission line 21 of each filter module 2 is connected in signal transmission with the ground wire.

[0037] Specifically, the ground end of the short-circuit transmission line 21 acts as a signal saddle point, which can reduce the waveform distortion and reflection of the communication signal, and the signal saddle point can keep the communication signal the same as the saddle point at any time by leading the input signal to the saddle point, thereby improving the stability of the communication signal transmission; since common-mode noise refers to noise acting on the signal and ground wire at the same time, when both are coupled to the ground wire, connecting the ground end of the short-circuit transmission line 21 in signal transmission with the ground wire can suppress the common-mode noise, which is used to cancel the common-mode noise, thereby improving the quality and integrity of the communication signal.

[0038] In some specific embodiments, the impedance of each input port 23 is set as short circuit. Specifically, when the impedance of the input port 23 of each filter module 2 is set as short circuit, the communication signal of high frequency interference can be reflected back to prevent the signal from continuing to transmit to the signal output port 13, thereby effectively suppressing electromagnetic interference (EMI) and improving the anti-interference ability of the system. The communication signal can effectively eliminate or reduce unnecessary high-frequency noise and harmonic components, while reducing the phase distortion and amplitude attenuation of the signal during transmission, thereby improving the quality of the signal.

[0039] In some specific embodiments, each short-circuit transmission line 21 and series transmission line 22 is a microstrip line.

[0040] 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 parameter of the microstrip line, the suppression of different frequency signals can be realized, thereby realizing the filtering of each frequency 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, some frequencies in the communication signal can be attenuated or enhanced, thereby achieving the effect of filtering.

[0041] The specific steps of the communication signal suppression method provided by the embodiment of the utility model are described in detail below, according to the communication signal suppression method provided by the embodiment of the utility model, the specific steps of the communication signal suppression method are as follows: Figures 3-4 The specific steps of the communication signal suppression method provided by the embodiment of the utility model are described in detail below, according to the communication signal suppression method provided by the embodiment of the utility model, the specific steps of the communication signal suppression method are as follows:

[0042] Step S110 receives the communication signal through the signal input port 2312 of the circulator unit 1.

[0043] Specifically, the signal input port 2312 of the circulator unit 1 is connected to the interface of the 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 (such as an antenna, a coaxial cable, an optical fiber, etc.) for transmission, to ensure that the communication signal can be effectively received and transmitted to the filter unit.

[0044] Step S120 obtains a plurality of frequency values of the communication signal.

[0045] Specifically, after the communication signal is received by the signal input port 2312 of the circulator unit 1, the algorithm of the spectrum analyzer for fast Fourier transform (FFT) of the communication signal is used to identify each frequency in the communication signal to obtain a plurality of frequency values of the communication signal.

[0046] S130, according to the frequency value of the communication signal, adjusting the electrical length and impedance value of each transmission line by simulation software, so that the frequency value of the communication signal is adjusted to the target frequency value.

[0047] 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 signal 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, due to the role of short-circuit, the impedance of the common port 24 is increased (close to infinity), thereby helping to suppress the transmission of communication signals at different frequencies. Therefore, by adjusting the electrical length value of each transmission line, the effect of suppressing communication signals at different frequencies can be achieved, thereby improving the efficiency and quality of communication signal transmission.

[0048] Before the step of adjusting the electrical length and impedance value of each transmission line by simulation software, the following steps are further included:

[0049] Calculate the electrical length value of the short-circuit 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 value of the short-circuit transmission line 21 and each series transmission line 22.

[0050] Specifically, the following is the calculation and acquisition method of the electrical length of the short-circuit transmission line 21 and the series transmission line 22 of each filter module 2, specifically including:

[0051] Electrical length = reference frequency / suppression frequency * 90°; wherein the reference frequency is assumed to be f0.

[0052] For example, assuming that the reference frequency is f0, the first-stage filter module 2 needs to suppress the frequency of the communication signal at 4f0, and is included in the formula:

[0053] The electrical length of each transmission line = f0 / 4f0*90° = 22.5°.

[0054] Therefore, the electrical length of the short-circuit transmission line 21 and the series transmission line 22 of the first-stage communication module can be obtained as 22.5°.

[0055] 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 filter module 2 are both 30° (the filter module 2 needs to suppress the frequency of the communication signal 3f0), and the electrical lengths of the short-circuit transmission line 21 and the series transmission line 22 of the third filter module 2 are both 45° (the filter module 2 needs to suppress the frequency of the communication signal 2f0). Subsequently, tuning optimization is performed by using simulation software. Specifically, the filter module 2 is modeled and simulated by using simulation software (such as HFSS, CST Microwave Studio, ADS, etc.), different frequency points are set, and 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. According to the impedance value data, the electrical lengths of the short-circuit transmission line 21 and the series transmission line 22 are adjusted, so that the communication signal is suppressed.

[0056] In the above embodiment, it should be noted that a corresponding circuit model is established in the simulation software, including modeling of each filter module 2, transmission lines, resistors, capacitors, inductors, etc. The simulation software is used for simulation analysis to calculate the reflection coefficient, transmission coefficient or other related parameters of the input port 23. This parameter reflects the performance of the filter unit at different frequencies. Subsequently, according to the simulation results, it is evaluated whether the frequency values of the communication signals reach the desired fundamental signal frequency value. If not, the circuit parameters (such as transmission line length and characteristic impedance, etc.) can be adjusted by the simulation software until the frequency values of the communication signals reach the desired fundamental signal frequency value.

[0057] For example, it is assumed that the frequencies to be suppressed are 2f0, 3f0 and 4f0, and the desired fundamental signal frequency f0 = 2 GHz. After adjusting the circuit parameters by using the simulation software, the electrical lengths of the short-circuit transmission line 21 and the series transmission line 22 of the first filter module 2 are 82.9° and 10° respectively, the electrical lengths of the short-circuit transmission line 21 and the series transmission line 22 of the second filter module 2 are 44.9° and 65.6° respectively, and the electrical lengths of the short-circuit transmission line 21 and the series transmission line 22 of the third filter 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 filter 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 filter 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 filter module 2 are 20 and 20 respectively.

[0058] According to the attached Figure 3As shown in the figure, after the communication signals with frequency values of 2f0, 3f0 and 4f0 are suppressed, the values are -40.8dB, -40.2dB and -30.2dB respectively, so the insertion loss at f0 is -1.4E-4, thus the communication signals are subjected to ultra-low insertion loss and high suppression, and the demand of current new generation of communication frequency bandwidth can be met.

[0059] The step S140 is outputting the communication signal through the signal output port 13 of the signal unit.

[0060] Specifically, after the communication signal is subjected to suppression, the communication signal can be transmitted to the next node or terminal device, so as to complete the communication process of the whole ring network.

[0061] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited to this, any skilled person in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A low-loss circulator, characterized by, The circulator comprises: a circulator unit provided with a signal input port and a signal output port; a filter unit comprising a plurality of filter modules, each of the filter modules comprising 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 connected in signal transmission with the input port; the input port of one of the filter modules is connected in signal transmission with the signal output port of the circulator unit, and the input port of each of the other filter modules is connected in cascade with the common port of an adjacent one of the filter modules.

2. The low-loss circulator of claim 1, wherein, The series transmission line of each of the filter modules is provided with two, which are a first series transmission line and a second series transmission line. The output end of the first series transmission line is connected in signal transmission with the short-circuit transmission line, and the input end of the first series transmission line is connected in parallel with the common port; the output end of the second series transmission line is connected in parallel with the common port, and the input end of the second series transmission line is connected in signal transmission with the input port.

3. The low-loss circulator of claim 1, wherein, The ground end of the short-circuit transmission line of each of the filter modules is connected in signal transmission with a ground wire.

4. The low-loss circulator of claim 1, wherein, The filter modules are provided with at least three groups.

5. The low-loss circulator of claim 1, wherein, The impedance of each of the input ports is set as short circuit.

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

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