Microwave nonreciprocal band-pass or band-stop filter with adjustable frequency band

Abstract

The invention discloses a frequency-band-adjustable microwave nonreciprocal band-pass or band-stop filter, which relates to the technical field of filters and comprises a magnet, a T-shaped microwave resonant cavity, a YIG small ball and a microwave antenna, the T-shaped microwave resonant cavity is positioned above the microwave antenna; the YIG small ball is positioned above a central node of the T-shaped microwave resonant cavity; the magnet is positioned above the YIG small ball; the magnetic field direction of the magnet is vertical to the T-shaped microwave resonant cavity and is downward; and the microwave antenna is used for receiving a pumping signal and inputting the pumping signal into the YIG small ball. According to the invention, a strong coupling effect between a cavity photon mode generated by a microwave resonant cavity and a Whark mode generated by a YIG small ball placed at a node of the microwave resonant cavity is utilized to construct a continuous domain bound state mode with a microwave nonreciprocity characteristic, and a light-induced magneton state in the YIG small ball is excited through a pumping signal; the isolation area of the continuous domain bound state with the non-reciprocity characteristic is changed, and flexible switching of the band-pass state and the band-stop isolated state with the adjustable bandwidth is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of filters, and in particular to a frequency-band-adjustable microwave non-reciprocal bandpass or bandstop filter. Background Art

[0002] A filter is a device used for signal processing. It can extract specific frequency components from the input signal or suppress other frequency components. It is widely used in fields such as communication, audio processing, image processing and control systems. Filters are mainly divided into the following categories: low-pass filter, high-pass filter, all-pass filter, band-pass filter and band-stop filter. Among them, the band-pass filter allows signals between two specific frequency ranges to pass through and suppresses signals of other frequencies. The band-stop filter allows signals of other frequencies to pass through by suppressing signals within a certain frequency band. Filters in the microwave band (usually electromagnetic wave signals in the range of 300MHz to 300GHz) are widely used in wireless communications, radar systems, satellite communications and radio frequency circuits. Current microwave filters mainly include traditional types such as transmission line filters and resonator filters. However, these traditional filtering schemes are difficult to achieve flexible tuning of bandwidth and difficult to meet requirements such as fast response and adjustable frequency band. Summary of the invention

[0003] The purpose of the present application is to provide a band-adjustable microwave non-reciprocal bandpass or bandstop filter, which realizes flexible switching of bandwidth-adjustable bandpass and bandstop isolation states.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] In a first aspect, the present application provides a band-tunable microwave non-reciprocal bandpass or band-stop filter, the band-tunable microwave non-reciprocal bandpass or band-stop filter comprising: a magnet, a T-shaped microwave resonant cavity, a YIG ball and a microwave antenna;

[0006] The T-shaped microwave resonant cavity is located above the microwave antenna;

[0007] The central node of the T-shaped microwave resonant cavity is respectively connected to a first port and a second port on both sides;

[0008] The YIG ball is located above the central node of the T-shaped microwave resonant cavity;

[0009] The magnet is located above the YIG ball; the magnetic field direction of the magnet is perpendicular to the T-shaped microwave resonant cavity and points downward;

[0010] The microwave antenna is used to receive a pump signal and input the pump signal into the YIG ball; when the microwave antenna receives n pump signals with the same frequency interval and a preset frequency as the center frequency under the same power condition, a band stop function is realized between the first port and the second port; when the power of the pump signal and the frequency interval are changed, the bandwidth of the band stop isolation band between the first port and the second port can be adjusted;

[0011] When the microwave antenna receives a strong pump signal, m weak pump signals with frequencies higher than the strong pump signal, and m weak pump signals with frequencies lower than the strong pump signal, a bandpass function is realized between the first port and the second port; the power of the strong pump signal is greater than the power of the weak pump signal; the powers of the weak pump signals are the same; the frequency of the strong pump signal is the preset frequency; the frequencies of the weak pump signals are symmetrically distributed with the preset frequency as the center frequency; the frequency interval between the weak pump signal whose frequency is in the middle value among the m weak pump signals with frequencies higher than the strong pump signal and the preset frequency is the preset frequency interval; wherein m and n are both odd numbers.

[0012] Optionally, the preset frequency is a continuous domain bound state frequency.

[0013] Optionally, when the microwave antenna receives five pump signals with a center frequency of 2.573 GHz and a frequency interval of 2 MHz under a power condition of 1 mW, the bandwidth of the band-stop isolation band between the first port and the second port is 14 MHz.

[0014] Optionally, when the microwave antenna receives a strong pump signal with a power of 60 mW, three weak pump signals with frequencies higher than the strong pump signal, and three weak pump signals with frequencies higher than the strong pump signal, a bandpass filtering area with a bandwidth of 14 MHz is formed between the first port and the second port; the power of the weak pump signal is 1 mW; the frequencies of the weak pump signals are symmetrically distributed with 2.573 GHz as the center frequency; the weak pump signal with an intermediate frequency among the three weak pump signals with frequencies higher than the strong pump signal is spaced 7 MHz from 2.573 GHz.

[0015] Optionally, when a band-stop function is implemented between the first port and the second port, the bandwidth of the band-stop isolation band between the first port and the second port can be adjusted between 1-14 MHz by changing the power of the pump signal and the frequency interval.

[0016] Optionally, the T-shaped microwave resonant cavity and the microwave antenna are processed and generated on a high-frequency dielectric plate;

[0017] The high-frequency dielectric board comprises an upper layer, a middle layer and a lower layer; the upper layer and the lower layer are both copper layers; the middle layer is a dielectric layer;

[0018] The T-shaped microwave resonant cavity and the microwave antenna are processed and generated on the upper layer; and the lower layer is used for grounding.

[0019] Optionally, the magnet is a permanent magnet; the frequency of the T-type microwave resonant cavity is 2.93 GHz; and the diameter of the YIG ball is 1 mm.

[0020] Optionally, both the first port and the second port are SMA connectors.

[0021] Optionally, the frequency-band-adjustable microwave non-reciprocal bandpass or bandstop filter further comprises: a magnet fixing device;

[0022] The magnet fixing device is used to fix the magnet above the YIG ball.

[0023] Optionally, the microwave antenna is connected to a third port, and the third port is an SMA connector.

[0024] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0025] The present application provides a band-adjustable microwave non-reciprocal bandpass or band-stop filter, comprising: a magnet, a T-shaped microwave resonant cavity, a YIG ball and a microwave antenna; the T-shaped microwave resonant cavity is located above the microwave antenna; the central node of the T-shaped microwave resonant cavity is respectively connected to a first port and a second port; the YIG ball is located above the central node of the T-shaped microwave resonant cavity; the magnet is located above the YIG ball; the magnetic field direction of the magnet is perpendicular to the T-shaped microwave resonant cavity and downward; the microwave antenna is used to receive a pump signal and input the pump signal into the YIG ball; when the microwave antenna receives n pump signals with the same frequency interval and a preset frequency as the center frequency under the same power condition, a band-stop function is realized between the first port and the second port; when the pump signal is changed, the first port and the second port are connected to the first port and the second port; when the pump signal is changed, the first port and the second port are connected to the first port and the second port; when the pump signal is changed, the first port and the second port are connected to the first port and the second port; when the first port and the second port are connected to the first port and the second port, the band-stop function is realized between ... When the power of the pump signal and the frequency interval are adjusted, the bandwidth of the band-stop isolation band between the first port and the second port can be adjusted; when the microwave antenna receives a strong pump signal, m weak pump signals with frequencies higher than the strong pump signal, and m weak pump signals with frequencies lower than the strong pump signal, a bandpass function is realized between the first port and the second port; the power of the strong pump signal is greater than the power of the weak pump signal; the powers of the weak pump signals are the same; the frequency of the strong pump signal is the preset frequency; the frequency of the weak pump signal is symmetrically distributed with the preset frequency as the center frequency; the frequency interval between the weak pump signal and the preset frequency, whose frequency is in the middle value among the m weak pump signals with frequencies higher than the strong pump signal, is the preset frequency interval; wherein m and n are both odd numbers. The present application utilizes the strong coupling effect between the cavity photon mode generated by the microwave resonant cavity and the Walker mode generated in the YIG sphere placed at the node of the microwave resonant cavity to construct a continuous domain bound state mode with microwave non-reciprocal characteristics, and then stimulates the light-induced magnon state in the YIG sphere through a pump signal to change the isolation region of the continuous domain bound state with non-reciprocal characteristics, that is, the controllable frequency band, thereby realizing flexible switching of bandwidth-adjustable bandpass and bandstop isolation states. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic structural diagram of a frequency-band-adjustable microwave non-reciprocal bandpass or bandstop filter provided in one embodiment of the present application;

[0028] Figure 2A schematic diagram of strong coupling between PIM and BIC provided in one embodiment of the present application;

[0029] Figure 3 The time domain and frequency domain diagrams of the microwave pump signal input by the high-frequency arbitrary wave generator provided in one embodiment of the present application;

[0030] Figure 4 A schematic diagram of the control effect of multiple microwave (light) pumps provided in one embodiment of the present application;

[0031] Figure 5 A schematic diagram of passband and stopband bandwidth adjustment provided in an embodiment of the present application;

[0032] Figure 6 A schematic diagram of the preparation and use process of a band-tunable microwave non-reciprocal bandpass or bandstop filter provided in one embodiment of the present application. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0034] The current technical problems faced are: In view of the fact that traditional microwave filters are limited by geometric dimensions and physical mechanisms in frequency band regulation, and the existing field of cavity magnon electronics only relies on magnetic field tuning to achieve microwave non-reciprocal regulation, which is difficult to meet the needs of fast response signal filtering, this application proposes a band-adjustable microwave non-reciprocal bandpass and bandstop filter with fast response capability. It mainly utilizes the strong coupling effect between the cavity photon mode generated by the planar resonant cavity and the Walker mode generated in the yttrium iron garnet (YIG) sphere placed at the node of the resonant cavity to construct a continuous domain bound state (BIC) mode with microwave non-reciprocal characteristics. Then, the photoinduced magnon state (PIM) in the yttrium iron garnet sphere is stimulated by the pump signal input by the microwave antenna to change the isolation area of ​​the continuous domain bound state (BIC) with non-reciprocal characteristics, that is, the adjustable frequency band. By changing the number, frequency and power of the input pump signal, the isolation bandwidth of the frequency band and the properties of switching the passband and bandstop can be flexibly changed.

[0035] Simply put, "band-tunable microwave non-reciprocity" means that first of all, the characteristics of the cavity magnetic subsystem are used to build a non-reciprocal transmission system. Then, the input pump signal is used to adjust the transmission and isolation characteristics of this system. This regulation process is always under the condition of non-reciprocal transmission, which means that the non-reciprocal characteristics have always existed when the system is built, and then a new effect is used to adjust its transmission characteristics and isolation bandwidth and switch its passband and bandstop properties.

[0036] The present application relates to a method of directly regulating microwave non-reciprocal frequency bands by microwave (light) pumping in strong coupling to realize multi-dimensionally tuned non-reciprocal bandpass and band-stop filters, and belongs to the fields of information technology and spin electronics. The present invention combines high-frequency ferrite material-yttrium iron garnet (YIG) with a microwave resonant cavity, and utilizes the strong coupling of the Walker mode in YIG and the cavity photon mode to realize unidirectional transmission of microwave non-reciprocity. The microwave pump signal is sent into the patch antenna on the microwave resonant cavity to excite the photoinduced magneton mode (PIM) in YIG to realize the regulation of the microwave non-reciprocal frequency band. By regulating the number, frequency and power combination of the input microwave pump signal, the non-reciprocal bandpass and band-stop filtering functions with adjustable frequency band can be realized.

[0037] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0038] In an exemplary embodiment, Figure 1 As shown, a band-adjustable microwave non-reciprocal bandpass or bandstop filter is provided, including: a magnet, a T-shaped microwave resonant cavity, a YIG ball and a microwave antenna.

[0039] The T-shaped microwave resonant cavity is located above the microwave antenna and contacts the microwave antenna; the first port and the second port are connected to the two sides of the central node of the T-shaped microwave resonant cavity respectively; the YIG ball is located above the central node of the T-shaped microwave resonant cavity; the magnet is located above the YIG ball; the magnetic field direction of the magnet is perpendicular to the T-shaped microwave resonant cavity and faces downward.

[0040] The microwave antenna is connected to a third port, and the third port is an SMA connector. The frequency-adjustable microwave non-reciprocal bandpass or bandstop filter further comprises: a magnet fixing device; the magnet fixing device is used to fix the magnet above the YIG ball.

[0041] Among them, the planar structure of the microwave resonant cavity and the microwave antenna can be modeled and simulated by CST software, and the three ports all achieve 50 ohm impedance matching. The microwave resonant cavity frequency is designed to be 2.93 GHz, the microwave resonant cavity length is 15 mm, and the transmission line and microwave resonant cavity width between the first port (also referred to as port 1 in this embodiment) and the second port (also referred to as port 2 in this embodiment) are 2.33 mm. The microwave antenna at the third port (also referred to as port 3 in this embodiment) is designed to be a symmetrical resonant structure with a gap width of 0.2 mm in the middle and a symmetrical structure width of 2.33 mm on both sides, which are respectively connected to the center pin and ground pin of the SMA connector. The above structures can all be machined on the copper layer on the Rogers 5880 high-frequency dielectric sheet using a circuit board engraving machine (such as Figure 1 As shown in the figure, the processing depth needs to penetrate the upper copper layer (35um), and the redundant structure needs to be removed. The high-frequency dielectric board is composed of a double-sided copper layer with a thickness of 35um sandwiched by a dielectric layer with a thickness of 1.5mm, and the dielectric constant of the dielectric layer is 2.2. Finally, a copper ring with an inner diameter of 2mm and an outer diameter of 2.5mm (i.e., the third interface) is welded to the symmetrical resonant structure of the microwave antenna using a welding pen to form a passage for inputting pump signals. The central axis of the copper ring is parallel to the plane of the microwave resonant cavity.

[0042] The connection relationship between the various structures is as follows: the microwave resonant cavity is a T-shaped structure, which is connected by SMA connectors at the left and right ports. The center pin of the SMA connector is connected to the center of the transmission line, and the grounding pin at the bottom is connected to the copper clad layer on the back to achieve grounding. The YIG ball is placed at the central node of the T-shaped microwave resonant cavity. The third port is connected to the microwave antenna through an SMA connector, and the microwave antenna is located below the microwave resonant cavity. The center pin of the SMA connector is connected to the microstrip line on the right side of the antenna, the left grounding pin above the connector is connected to the microstrip line on the left side of the antenna, and the grounding pin at the bottom is connected to the copper clad layer on the back. The permanent magnet is placed directly above the microwave resonant cavity, and the direction of the magnetic field generated is perpendicular to the resonant cavity and downward. The bottom is a structure that supports the resonant cavity.

[0043] In layman's terms, in this embodiment, the lower copper layer of the high-frequency dielectric board is used for grounding, and the upper copper layer is used for etching a microwave antenna and a microwave resonant cavity, and the microwave antenna is located at the lower part of the microwave resonant cavity. It can be simply understood that the lower half of the thickness of a copper layer is used as a microwave antenna, and then the upper half is etched to form a microwave resonant cavity.

[0044] The microwave antenna is used to receive a pump signal and input the pump signal into a YIG ball; when the microwave antenna receives n pump signals with the same frequency interval and a preset frequency as the center frequency under the same power condition, a band stop function is realized between the first port and the second port; when the power of the pump signal and the frequency interval are changed, the bandwidth of the band stop isolation band between the first port and the second port can be adjusted. The preset frequency is the continuous domain bound state frequency.

[0045] In layman's terms, the band-stop function is achieved when the input pump signal has equal power and the frequency interval is equal to the center frequency of the continuous domain bound state.

[0046] When the microwave antenna receives a strong pump signal, m weak pump signals with frequencies higher than the strong pump signal, and m weak pump signals with frequencies lower than the strong pump signal, a bandpass function is realized between the first port and the second port; the power of the strong pump signal is greater than the power of the weak pump signal; the powers of the weak pump signals are the same; the frequency of the strong pump signal is the preset frequency; the frequencies of the weak pump signals are symmetrically distributed with the preset frequency as the center frequency; the frequency interval between the weak pump signal whose frequency is in the middle value among the m weak pump signals with frequencies higher than the strong pump signal and the preset frequency is the preset frequency interval; wherein m and n are both odd numbers.

[0047] In layman's terms, two types of signals are received, one is a strong pump signal and the other is a weak pump signal. The weak pump signal is symmetrically distributed in frequency with the strong pump signal as the center. There are a batch of weak pump signals at both ends of the strong pump signal. The center frequency of each batch of weak pump signals is spaced at a preset frequency interval from the frequency of the strong pump signal, and the bandpass function is realized at this time.

[0048] When the microwave antenna receives five pump signals with a center frequency of 2.573 GHz and a frequency interval of 2 MHz under a power condition of 1 mW, the bandwidth of the band-stop isolation band between the first port and the second port is 14 MHz. The center of the bandwidth of the band-stop isolation band is 2.573 GHz, and the two sides are 7 MHz.

[0049] When the microwave antenna receives a strong pump signal with a power of 60mW, three weak pump signals with frequencies higher than the strong pump signal, and three weak pump signals with frequencies lower than the strong pump signal, a bandpass filter area with a bandwidth of 14MHz is formed between the first port and the second port; the power of the weak pump signal is 1mW; the frequency of the weak pump signal is symmetrically distributed with 2.573GHz as the center frequency; the weak pump signal with a frequency at the middle value among the three weak pump signals with frequencies higher than the strong pump signal has a frequency interval of 7MHz from 2.573GHz. It can also be understood that when the bandpass isolation bandwidth is greater than 10MHz, three frequency components can be encoded in the corresponding separated non-reciprocal regions at the same time, so that the bandwidth of its stop band is increased, and the stability of the filtering is improved.

[0050] When a band-stop function is implemented between the first port and the second port, the bandwidth of the band-stop isolation band between the first port and the second port can be adjusted between 1-14 MHz by changing the power of the pump signal and the frequency interval.

[0051] The following analyzes from the perspective of principle why a band-tunable microwave non-reciprocal bandpass or bandstop filter can be realized, and introduces several specific implementation methods and specific adjustment methods:

[0052] The permanent magnet can be controlled by a stepping screw, that is, the magnet fixing device has a stepping screw control function.

[0053] The permanent magnet is connected to a Z-axis displacement device, which consists of a small micrometer with an adjustment range of 30mm and a 3D printed bracket. The bracket is used to fix the micrometer and connect the magnet to the end of the micrometer. By rotating the micrometer, the magnet at the end will accurately adjust the magnetic field strength applied to the YIG ball with a step accuracy of 1 / 360mm. Figure 1 The square structure with four M6 threaded holes at the bottom is used to support the microwave resonant cavity and the permanent magnet adjustment device.

[0054] Ports 1 and 2 of the microwave resonant cavity are connected to ports 1 and 2 of the vector network analyzer respectively, and the output detection signal power is set to -20dBm. The scanning frequency range is set to 50MHz and the number of scanning points is set to 10001 points, with the frequency of the continuous domain bound state (BIC) at 2.573GHz as the center. When measuring S21, a low-power detection signal with a frequency sweep will be sent from port 1 of the vector network analyzer and sent into the microwave resonant cavity through port 1. When the detection signal passes through the yttrium iron garnet (YIG) ball, the bias magnetic field is adjusted at this time so that the precession frequency of the Walker mode is within the frequency scanning range of the vector network analyzer. The microwave magnetic field orthogonal to the bias magnetic field will excite the Walker mode in the YIG ball. By detecting the transmission signal at port 2, the transmission information of the YIG ball in the Walker mode can be obtained. The excited Walker mode can reflect the collective precession frequency of the magnons in the yttrium iron garnet (YIG) ball at this time, providing a frequency reference for the subsequent regulation of the non-reciprocal isolation band and acting as a medium for strong coupling regulation. Port 3 is connected to a high-frequency arbitrary wave generator and radiates the generated microwave signal into the YIG sphere through a microwave antenna. The microwave signal radiated into the YIG sphere will excite the unsaturated spins in the YIG sphere to produce photoinduced magnon states. The photoinduced magnon states can be strongly coupled with the Walker mode. The specific form is that the distribution of the Walker mode in the frequency domain is changed. Finally, the strong coupling with the Walker mode is adjusted by regulating the number, frequency and power of the photoinduced magnon states, thereby realizing flexible regulation of the non-reciprocal frequency band.

[0055] Figure 2 It is demonstrated that by adjusting the height of the permanent magnet in the constructed cavity magnetic subsystem, the continuous domain bound state (BIC) condition is achieved when the vector network analyzer measures the S21 transmission spectrum. In the process of adjusting the external magnetic field, the precession frequency of the Walker mode is mainly affected. At the same time, the Walker mode and the cavity photon mode are in strong coupling. When the frequency of the Walker mode is adjusted to a certain value, due to the coherent and dissipative coupling between the two, a special case of zero dissipation will be formed, that is, the continuous domain bound state (such as Figure 2(a)), the frequency center is 2.573 GHz, and its transmittance is only -82 dB at this time. In addition, the transmission spectrum of S12 was also measured at this time, and it can be seen that there is an obvious non-reciprocal transmission characteristic between S21 and S12, where S21 refers to the signal transmission characteristic from port 1 (input end) to port 2 (output end). S12 refers to the signal transmission characteristic from port 2 (input end) to port 1 (output end), and the measurement method is as above. First, in the absence of a pump signal, the height of the magnet is adjusted by a permanent magnet device to precisely control the magnetic field applied to the YIG sphere so that the Walker mode and the cavity photon mode generated by the microwave resonant cavity reach the BIC condition with microwave non-reciprocal characteristics. Subsequently, a high-frequency arbitrary wave generator is used to send a pump signal through port 3 via a microwave antenna to excite the unsaturated spins in the YIG sphere to produce a photoinduced magnon state (PIM). Figure 2 In (b), a single-frequency pump signal is applied, and the pump frequency is at the BIC. Rabi splitting formed by the strong coupling of the Walker mode and the PIM mode is observed, splitting the original single continuous domain bound state mode into two absorption peaks. These two absorption peaks reflect the hybrid mode formed by the strong coupling of the Walker mode and the light-induced magnon state mode. This hybrid mode also has the characteristics of non-reciprocal transmission, and its frequency distribution can be adjusted by the frequency and power of the input pump signal. Its frequency distribution is the filtering bandwidth that we want to use.

[0056] Using a single pump signal sent by a high-frequency arbitrary wave generator, the pump frequency was in the continuous domain bound state, and the control effect under different pump powers was tested. When the pump power was gradually increased, when the input power was 0.28mW, the splitting of the hybrid mode began to appear. By adjusting the size of the pump power, the size of the hybrid mode splitting can be changed. The input power and the splitting spacing are proportional to P. 1 / 4 Relationship (such as Figure 5 (b)). The relationship between power and regulation bandwidth is one-fourth of the relationship between spacing and input power. When the input pump power is 100mW, the microwave non-reciprocal regulation bandwidth of the system can reach 16MHz.

[0057] Subsequently, multiple modulated pump signals are encoded by a high-frequency arbitrary wave generator and also sent in through a microwave antenna. By encoding the frequencies and powers of multiple pumps respectively, each individual pump signal can excite the unsaturated spins in the YIG spheres to produce photoinduced magnon states, which are strongly coupled with the bound states in the continuous domain, so as to achieve the purpose of flexibly regulating the microwave non-reciprocal isolation band.

[0058] Figure 3 The specific application of coding control using multi-pump signals is demonstrated. Figure 3 (a) and Figure 3(b) is the time domain and frequency domain image of the multi-pump signal that needs to be input when switching to band-stop isolation. The pump signal input in the frequency domain is 5 frequency signals with equal intervals (2MHz) and equal power (1mW) and centered on the continuous domain bound state (2.573GHz). When such a pump signal is input into the system, a Figure 4 The bandwidth of the band-stop isolation band in the middle part is 14MHz. By changing the frequency interval and power of the multi-pump, the bandwidth of the band-stop isolation band can be flexibly adjusted within 1-14MHz. The relationship between the bandwidth of the band-stop isolation and the number of pump signals is shown in the figure. Figure 5 (a) shown.

[0059] When it is necessary to switch the bandpass isolation centered on the continuum bound state, the input pump signal is adjusted to Figure 3 (c) and Figure 3 The time domain and frequency domain images in (d) are sufficient. Among them, at the frequency domain continuous domain bound state frequency is a strong pump signal with a power of 60mW, and there are three weaker sideband signals (with a power of 1mW) on the left and right sides. The frequency center of the three sideband signals is 7MHz away from the strong signal in the middle. The position of the left and right sideband signals from the center frequency depends on the input power of the center frequency. The greater the input power, the farther the sideband signal is from the center frequency. The specific physical relationship can refer to the adjustment of the bandwidth in the single pump case, such as Figure 5 (b) When such a frequency signal is input into the system, Figure 4 A bandpass filter region with a bandwidth of 14MHz is formed.

[0060] In this embodiment, a strong pump signal is sent at BIC (2.573GHz) to separate the non-reciprocal region in the middle and form a wider passband; when the pump signal input power is in the range of 0.28mW to 100mW, the passband isolation bandwidth can be adjusted to 1-16MHz. When the passband isolation bandwidth is greater than 10MHz, three frequency components can be encoded in the corresponding separated non-reciprocal regions at the same time, so that the bandwidth of the stopband is increased and the stability of the filtering is improved.

[0061] Finally, by inputting two different multi-pump signals, flexible switching between bandwidth-adjustable bandpass and bandstop isolation states was achieved.

[0062] This embodiment also provides a simple process for preparing and using a frequency-adjustable microwave non-reciprocal bandpass or bandstop filter, such as Figure 6 shown.

[0063] The required microwave resonant cavity and microwave antenna are prepared using high-frequency dielectric sheets by using circuit board engraving machines, laser marking machines combined with chemical etching and other methods. The YIG balls are placed at the nodes of the T-shaped microwave resonant cavity. The high-frequency dielectric sheets are selected from but not limited to Rogers 5880, FR-4, and CEM-1. The SMA connectors are welded to the three ports, and the antenna ring structure is welded to the microstrip structure of the microwave antenna to form a loop.

[0064] The intensity of the magnetic field applied to the YIG ball is adjusted by a micrometer so that the Walker mode in the YIG ball and the resonant cavity reach the condition of a continuous domain bound state (BIC).

[0065] The pump signal is sent in through the microwave antenna, and the strong coupling effect between the photoinduced magnon mode (PIM) and the Walker mode is used from the physical mechanism to change the constructed continuous domain bound state with non-reciprocal transmission, forming a new hybrid mode. The distribution of this hybrid mode is also a non-reciprocal region that can be controlled. By adjusting the magnetic field, the center frequency of the continuous domain bound state can be controlled, and the bandwidth-adjustable bandpass and bandstop isolation of 1-14MHz can be achieved by inputting the microwave pump frequency, power and number. For example, when 5 equally spaced and equal-power pump frequencies centered on the continuous domain bound state are input, a 14MHz bandstop isolation characteristic can be achieved; when 7 modulated pump signals are input, a strong signal centered on the continuous domain bound state frequency (2.573GHz) and the sideband signals on the left and right sides can achieve a 14MHz bandpass isolation characteristic.

[0066] This embodiment integrates the key components of the excitation cavity photons, magnons and light-induced magnon modes into a single device, showing the advantages of portability, easy operation and fast response. By directly regulating the microwave non-reciprocal frequency band through a single microwave (optical) pump, precise regulation of the hybrid mode can be achieved, which will help to achieve high-precision frequency tuning. In the case of a single pump, when the input pump power is 100mW, the non-reciprocal bandwidth of optical regulation can reach 16MHz, and the non-reciprocal isolation of the signal reaches 40dB. When multiple pump signals are input, the strong coupling of the pump-induced light-induced magnon state and the continuous domain bound state can be used to achieve bandwidth-adjustable bandpass and bandstop isolation. By inputting different pump signals, the isolation characteristics of the bandpass and bandstop can be switched.

[0067] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0068] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A band-tunable microwave non-reciprocal bandpass or bandstop filter, characterized in that: The frequency-band-adjustable microwave non-reciprocal bandpass or bandstop filter comprises: a magnet, a T-shaped microwave resonant cavity, a YIG ball and a microwave antenna; The T-shaped microwave resonant cavity is located above the microwave antenna; The central node of the T-shaped microwave resonant cavity is respectively connected to a first port and a second port; The YIG ball is located above the central node of the T-shaped microwave resonant cavity; The magnet is located above the YIG ball; the magnetic field direction of the magnet is perpendicular to the T-shaped microwave resonant cavity and points downward; The microwave antenna is used to receive a pump signal and input the pump signal into the YIG ball; when the microwave antenna receives n pump signals with the same frequency interval and a preset frequency as the center frequency under the same power condition, a band stop function is realized between the first port and the second port; when the power of the pump signal and the frequency interval are changed, the bandwidth of the band stop isolation band between the first port and the second port can be adjusted; When the microwave antenna receives a strong pump signal, m weak pump signals with frequencies higher than the strong pump signal, and m weak pump signals with frequencies lower than the strong pump signal, a bandpass function is realized between the first port and the second port; the power of the strong pump signal is greater than the power of the weak pump signal; the powers of the weak pump signals are the same; the frequency of the strong pump signal is the preset frequency; the frequencies of the weak pump signals are symmetrically distributed with the preset frequency as the center frequency; the frequency interval between the weak pump signal whose frequency is in the middle value among the m weak pump signals with frequencies higher than the strong pump signal and the preset frequency is the preset frequency interval; wherein m and n are both odd numbers.

2. The band-tunable microwave non-reciprocal bandpass or bandstop filter according to claim 1, characterized in that: The preset frequency is the continuous domain bound state frequency.

3. The band-tunable microwave non-reciprocal bandpass or bandstop filter according to claim 1, characterized in that: When the microwave antenna receives five pump signals with a center frequency of 2.573 GHz and a frequency interval of 2 MHz under a power condition of 1 mW, the bandwidth of the band-stop isolation band between the first port and the second port is 14 MHz.

4. The frequency-adjustable microwave non-reciprocal bandpass or bandstop filter according to claim 1, characterized in that: When the microwave antenna receives a strong pump signal with a power of 60 mW, three weak pump signals with frequencies higher than the strong pump signal, and three weak pump signals with frequencies higher than the strong pump signal, a bandpass filtering area with a bandwidth of 14 MHz is formed between the first port and the second port; the power of the weak pump signal is 1 mW; the frequencies of the weak pump signals are symmetrically distributed with 2.573 GHz as the center frequency; the weak pump signal with an intermediate frequency among the three weak pump signals with frequencies higher than the strong pump signal has a frequency interval of 7 MHz from 2.573 GHz.

5. The band-tunable microwave non-reciprocal bandpass or bandstop filter according to claim 1, characterized in that: When a band-stop function is implemented between the first port and the second port, the bandwidth of the band-stop isolation band between the first port and the second port can be adjusted between 1-14 MHz by changing the power of the pump signal and the frequency interval.

6. The frequency-tunable microwave non-reciprocal bandpass or bandstop filter according to claim 1, characterized in that: The T-shaped microwave resonant cavity and the microwave antenna are processed and generated on a high-frequency dielectric plate; The high-frequency dielectric board comprises an upper layer, a middle layer and a lower layer; the upper layer and the lower layer are both copper layers; the middle layer is a dielectric layer; The T-shaped microwave resonant cavity and the microwave antenna are processed and generated on the upper layer; and the lower layer is used for grounding.

7. The frequency-tunable microwave non-reciprocal bandpass or bandstop filter according to claim 1, characterized in that: The magnet is a permanent magnet; the frequency of the T-shaped microwave resonant cavity is 2.93 GHz; and the diameter of the YIG ball is 1 mm.

8. The frequency-tunable microwave non-reciprocal bandpass or bandstop filter according to claim 1, characterized in that: The first port and the second port are both SMA connectors.

9. The frequency-tunable microwave non-reciprocal bandpass or bandstop filter according to claim 1, characterized in that: The frequency-band-adjustable microwave non-reciprocal bandpass or bandstop filter further comprises: a magnet fixing device; The magnet fixing device is used to fix the magnet above the YIG ball.

10. The frequency-tunable microwave non-reciprocal bandpass or bandstop filter according to claim 1, characterized in that: The microwave antenna is connected to a third port, and the third port is an SMA connector.

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