Substrate integrated waveguide-based magnetic vibrator-photon coupling device and method

Abstract

The invention discloses a substrate integrated waveguide-based magnetic vibrator-photon coupling device and a substrate integrated waveguide-based magnetic vibrator-photon coupling method. A non-metallization window and a through hole penetrating through a substrate are formed in the top layer of a substrate integrated waveguide (SIW) resonant cavity, a magnetic vibrator source is installed in the through hole in an embedded mode and located at the antinode of a magnetic field, and surface current is guided through the window to reconstruct a local magnetic field. The system supports two-dimensional cooperative regulation and control: a window parameter static preset frequency and coupling strength are utilized, and geometric regulation and control freedom degree of coherent coupling strength is given to the system; and the frequency of the magnetic vibrator is dynamically adjusted in combination with the bias magnetic field, so that resonance matching and hybrid state evolution in a preset range are realized. According to the method, the advantages of SIW high-quality factors are reserved, meanwhile, the parasitic mode and radiation loss are restrained, accurate control over the coherent exchange rate and hybrid state evolution is achieved, key physical dimensions are provided for coherent regulation and control of a hybrid quantum system, and the method has important application prospects in the fields of quantum storage, transduction and signal precision processing.

Description

Technical Field

[0001] This invention relates to the interdisciplinary field of microwave integrated circuits and quantum information processing, specifically to a magnetoron-photon coupling device and method based on a substrate integrated waveguide; and more particularly to a strong coupling device that utilizes a surface current reconstruction mechanism to achieve parameterized preset of coherent coupling strength and control of geometric degrees of freedom. Background Technology

[0002] The convergence of quantum physics and microwave technology has propelled leapfrog developments in fields such as quantum information processing, quantum communication, and high-precision sensing. In these cutting-edge fields, single quantum systems often struggle to simultaneously meet the demands of long coherence times and high manipulation rates. Therefore, hybrid quantum systems constructed from different quasiparticles such as photons, magnons, and phonons have emerged. Among these, the magnon-photon coupling (PMC) system based on yttrium iron garnet (YIG) material has become a current research hotspot due to its high spin density, extremely low magnetic damping, and wide-bandwidth tunability. Magnons, as the quantized manifestation of spin waves, can generate strong coherent energy exchange with photons in a microwave resonant cavity. When the coherent exchange rate (i.e., coupling strength g) is much greater than the system loss rate, the system enters a strongly coupled state. This state is not only crucial for improving the performance of traditional microwave devices such as circulators and filters, but also forms the physical basis for realizing quantum state transduction, quantum storage, and hybrid state manipulation.

[0003] In existing strong coupling implementation schemes, traditional three-dimensional metal resonant cavities are fabricated from solid metal, possessing extremely high quality factors (Q values) and excellent electromagnetic shielding effects. However, this approach has revealed significant limitations under modern integration trends: the physical dimensions of the three-dimensional cavity are typically proportional to the operating wavelength. In low-frequency or multi-functional integration scenarios, the device becomes bulky and heavy, making it incompatible with planar integrated circuits (ICs) or printed circuit boards (PCBs) based on semiconductor processes, severely hindering the miniaturization process. Three-dimensional metal cavities are typical rigid structures, and their internal electromagnetic field distribution is difficult to fine-tune non-destructively after fabrication. This means that adapting to different frequency requirements or changing the coupling strength of the ferromagnetic resonator often necessitates redesign and high-precision machining. This "one cavity, one use" approach not only has a long development cycle and high costs but also makes it difficult to achieve precise pre-setting and subsequent correction of coupling parameters.

[0004] To improve integration, researchers have developed coupling schemes based on planar transmission lines such as microstrip lines and coplanar waveguides (CPWs). While these schemes are simple to fabricate and inexpensive, their semi-open structures, such as the "conductor strip + dielectric + ground" structure of microstrip lines, lack closed physical boundaries. In this environment, electromagnetic energy is dispersed in space, resulting in an excessively large effective mode volume. According to the principle of strong coupling, the coupling strength g is inversely proportional to the square root of the mode volume; the dispersion of energy distribution directly leads to a decrease in the magnetic field participation factor. The semi-open structure makes microwave energy easily radiated into free space, which not only reduces the Q value of the system but also makes the device susceptible to interference from the external electromagnetic environment. Furthermore, the proximity of nearby objects can drastically change the local electromagnetic field distribution, leading to resonant frequency drift and decreased quantum state stability. Simultaneously, the small cross-sectional area of ​​the microstrip conductor makes it prone to excessive heat loss or dielectric breakdown under high-power excitation, limiting its power handling capacity.

[0005] Substrate integrated waveguides (SIWs), as quasi-closed waveguide structures realized on dielectric substrates, are considered ideal physical carriers for realizing high-performance integrated magnon-photon coupling (PMC) systems due to their combination of the high quality factor (Q value) of traditional three-dimensional hollow waveguides and the high integration of planar circuits. However, the application of SIWs in the PMC field is still in the early exploratory stage, and existing coupling control schemes face significant technical bottlenecks. Currently, a limited number of studies mainly adjust the coupling strength by changing the spatial coordinate position of the ferromagnetic resonator or mounting vias. This not only leads to deep coupling (entanglement) between coupling strength and frequency, but also disrupts the original degenerate state within the cavity due to asymmetric changes in boundary conditions, inducing mode distortion or parasitic modes. This control method lacks effective parameterized degrees of freedom and cannot achieve static frequency compensation without altering spatial displacement, resulting in inherent defects such as insufficient design flexibility and poor stability when facing complex frequency band requirements.

[0006] To address the aforementioned problems, this invention introduces a non-metallized region into the first metal layer and uses the annular width w as a parametric degree of freedom for frequency adjustment. While maintaining a constant assembly position of the ferromagnetic resonator, the reconstruction effect of the non-metallized region on the surface current distribution establishes a collaborative control mechanism for the synchronous evolution of the resonant frequency and coherent coupling strength with geometric dimensions. This invention not only solves the mode instability problem caused by traditional displacement control but also provides a parameterized and easily integrated collaborative design paradigm for magnon-photon strongly coupled devices. Summary of the Invention

[0007] To address the problems of existing technologies, this invention provides a magnetoresistive-photon coupling device and method based on a substrate integrated waveguide.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A magnetoron-photon coupling device based on a substrate integrated waveguide, comprising:

[0010] A dielectric substrate; a first metal layer and a second metal layer, respectively covering the upper and lower surfaces of the dielectric substrate; a metallized via array, which penetrates the dielectric substrate and electrically connects the first metal layer and the second metal layer, the metallized via array forming a rectangular waveguide resonant cavity inside the dielectric substrate; a non-metallized annular region, formed on the surface of the first metal layer and located at the geometric center of the rectangular waveguide resonant cavity; a mounting via, which penetrates the dielectric substrate, and the central axis of the mounting via coincides with the central axis of the non-metallized annular region; a ferromagnetic resonator (such as a yttrium iron garnet (YIG) sphere), stably disposed within the mounting via by a fastener or adhesive layer; wherein, the geometric center of the ferromagnetic resonator coincides with the antinode of the photonic mode magnetic field of the rectangular waveguide resonant cavity; the non-metallized annular region, by blocking the current continuity of the first metal layer, realizes the topological reconstruction of the surface current distribution, thereby forming a localized magnetic field enhancement region in the vicinity of the mounting via, so that the photonic mode in the rectangular waveguide resonant cavity and the magnon mode in the ferromagnetic resonator are strongly coupled.

[0011] The aforementioned magnetoron-photon coupling device based on a substrate integrated waveguide further includes:

[0012] A microstrip feed line is disposed on the surface of the first metal layer. The microstrip feed line is connected to the rectangular waveguide resonant cavity through a feed coupling structure (such as an impedance transformation line or a coupling window) to realize the excitation, transmission and extraction of microwave signals.

[0013] The ring width w of the non-metallized annular region is a preset parameter used to change the equivalent electromagnetic boundary conditions of the rectangular waveguide resonant cavity by reconstructing the surface current path of the first metal layer, thereby realizing the static parameterization preset of the device reference resonant frequency.

[0014] An external bias magnetic field source is used to apply a constant magnetic field to the ferromagnetic resonator in a direction perpendicular to the plane of the dielectric substrate; the external bias magnetic field is used to dynamically adjust the frequency of the ferromagnetic resonator mode so that it resonates with the photonic mode of the rectangular waveguide resonator.

[0015] In the array of metallized vias, the center-to-center distance b between adjacent metallized vias and the via diameter c satisfy a proportional relationship: b / c < 2.5, so as to form a quasi-closed electromagnetic boundary within the dielectric substrate.

[0016] The ferromagnetic resonator is preferably a yttrium iron garnet (YIG) microsphere with a diameter of 1 mm; the thickness of the first metal layer and the second metal layer ranges from 0.03 mm to 0.04 mm; and the dielectric constant of the dielectric substrate ranges from 9.8 to 10.5.

[0017] The adjustable range of the ring width w is configured to be from 0.7 mm to 3.7 mm. The resonant frequency of the rectangular waveguide resonant cavity system exhibits a monotonically decreasing negative correlation mapping law with the increase of the ring width w; using this mapping law, the precise static locking of the device's operating frequency can be achieved without changing the assembly position by preset geometric parameters w.

[0018] A method for achieving strong magnetoron-photon coupling based on the aforementioned substrate-integrated waveguide-based magnetoron-photon coupling device includes the following steps:

[0019] 1) Static preset steps for frequency and coupling parameters: Based on the target strong coupling frequency band, by determining the annular width w of the non-metallized region (5), under the condition of keeping the spatial coordinate position of the assembly through hole (6) constant, the static parameterization preset of the operating frequency and coherent coupling strength of the resonant cavity is realized by utilizing the reconstruction effect of the surface current of the first metal layer (1) on the annular width w.

[0020] 2) Device fabrication and assembly steps: A substrate integrated waveguide structure containing a metallized via array (2), a non-metallized region (5) and a mounting via (6) is fabricated using printed circuit technology; a ferromagnetic resonator (7) is assembled in the mounting via (6), and the geometric center of the ferromagnetic resonator (7) is positioned in the magnetic field antinode region of the target mode in the rectangular waveguide resonant cavity;

[0021] 3) Dynamic control and characterization steps of strong coupling state: Input microwave excitation signal through microstrip feed line (4) and apply an external bias magnetic field perpendicular to the plane of the dielectric substrate at the ferromagnetic resonator (7); adjust the strength of the external bias magnetic field to make the resonant frequency of the magnetic resonator and the resonant frequency of the cavity photon consistent, thereby obtaining a strong coupling state with anti-crossing characteristics in the transmission spectrum.

[0022] This invention, through the fusion design of YIG microspheres and substrate integrated waveguides (SIW), offers significant technical advantages in enhancing electromagnetic performance and promoting quantum-integrated applications. Firstly, by introducing the geometric width *w* of the non-metallized region as a key control variable, this invention achieves parametric pre-setting of the operating frequency and coupling strength using the surface current reconstruction effect while maintaining a constant ferromagnetic resonator assembly position. This effectively solves the persistent technical problem of highly entangled frequency and coupling range in existing integrated solutions, significantly improving the design determinism and independent control capability of the device in complex quantum circuits. The structure, through the precise localization reconstruction of the electromagnetic field distribution within the SIW cavity using a non-metallized ring, significantly enhances the coherent coupling efficiency between magnons and photons. Combined with the high-quality factor (Q-value) characteristics of SIW, it effectively suppresses energy leakage and radiation loss in traditional planar structures, ensuring efficient and stable information exchange between strongly coupled states. Thanks to the inherent frequency selectivity of SIW and the optimization of the surface current path in this invention, the device can effectively suppress higher-order spurious modes, improving out-of-band suppression performance. Meanwhile, the quasi-closed cavity formed by the metallized through-hole array endows the device with superior electromagnetic self-shielding capabilities, which can block external interference and avoid the impact of signal leakage on surrounding sensitive circuits, greatly improving the environmental robustness of the system. This invention further advances the technological evolution of magnon devices towards a monolithic integrated architecture. Its unique planar geometric parameter control mechanism eliminates the dependence on precision micro-displacement mechanisms in traditional solutions, significantly reducing the physical dimension and manufacturing difficulty of system assembly. This provides a highly reliable and easily standardized underlying technical path for constructing large-scale, scalable on-chip hybrid quantum systems and magnon logic networks. Attached Figure Description

[0023] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0024] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the substrate integrated waveguide in an embodiment of the present invention.

[0025] Figure 2 This is a top view of the substrate integrated waveguide in an embodiment of the present invention, mainly showing the non-metallized annular region on the surface of the first metal layer and the microstrip feeding structure.

[0026] Figure 3 This is a bottom view of the substrate integrated waveguide in an embodiment of the present invention, showing the distribution of the second metal layer and the metallized via array.

[0027] Figure 4 This is a comparison diagram of the transmission spectrum curves (S21) corresponding to the change of the width w of the non-metallic ring in the embodiments of the present invention.

[0028] Figure 5 This is a reference magnetic field distribution diagram of the substrate integrated waveguide in this embodiment of the invention when no non-metallized region is introduced.

[0029] Figure 6 This is a magnetic field distribution diagram of the substrate integrated waveguide in this embodiment of the invention after the introduction of a non-metallized region, which shows the topological reconstruction and modulation effect of the non-metallized region on the field distribution of the cavity resonant mode.

[0030] Figure 7 This is a schematic diagram of the overall assembly three-dimensional structure of the substrate-integrated waveguide magnetoresistive-photon coupling system (including YIG spheres) provided by the present invention.

[0031] Figure 8 This is a mapping cloud diagram of the transmission coefficient (S21) of the coupling system in this embodiment of the invention under the condition of non-metallic ring width w=0mm as a function of bias magnetic field scanning, which shows the mode splitting and energy level collision avoidance characteristics.

[0032] Figure 9 This is a mapping cloud diagram of the transmission coefficient (S21) of the coupling system in this embodiment of the invention under the condition of non-metallic ring width w=3mm as a function of bias magnetic field scanning, which shows the mode splitting and energy level collision avoidance characteristics.

[0033] Figure 10 These are the corresponding coupling strengths extracted from the coupling system in the embodiments of the present invention under the condition that the width of the non-metallic ring is w=0, 1, 2, 3 mm, which are intended to demonstrate the quantitative control law of static geometric parameters on coherent coupling strength. Detailed Implementation

[0034] The present invention will be further described in detail below through embodiments. These embodiments are only used to illustrate the present invention and do not limit the scope of the present invention.

[0035] A magnetoron-photon coupling device based on a substrate integrated waveguide, comprising:

[0036] The dielectric substrate (3) serves as the dielectric carrier of the device; a first metal layer (1) and a second metal layer are respectively covered on the upper and lower surfaces of the dielectric substrate (3); a metallized via array (2) penetrates the dielectric substrate (3) and electrically connects the first metal layer (1) and the second metal layer, and the metallized via array (2) forms a rectangular waveguide resonant cavity inside the dielectric substrate (3); a non-metallized annular region (5) is formed on the surface of the first metal layer 1 and is located in the magnetic field antinode region of the target resonance mode inside the rectangular waveguide resonant cavity; a mounting via (6) is precisely positioned at the center of the non-metallized region (5) and is used to place a ferromagnetic resonator (7) that supports collective spin excitation. The non-metallized region (5) breaks the continuity of the surface current of the first metal layer (1), forces the current path to detour, and thus realizes the local reconstruction of the spatial distribution of the microwave magnetic field at the assembly position. By changing the geometric parameters of the non-metallized region (5), the structure can quantitatively adjust the coherent coupling strength between the photon mode in the cavity and the ferromagnetic resonator (7), realize the parameterized preset of the Rabi splitting amplitude, and give the system geometric control degree of freedom in the quantum coherent state evolution process.

[0037] Magneto-photon coupling devices based on substrate integrated waveguides also include:

[0038] A microstrip feed line (4) is integrated on the surface of the first metal layer. The microstrip feed line (4) is connected to the rectangular waveguide resonant cavity through an electromagnetic coupling interface and is used for microwave signal input and output. The linewidth a of the microstrip feed line (4) is preset so that its characteristic impedance matches the standard impedance of the external system.

[0039] The non-metallized region (5) is a non-metallized annular region, and its annular width w is a preset control parameter; by configuring the annular width w to change the equivalent electromagnetic boundary conditions of the rectangular waveguide resonant cavity, static control or frequency compensation of the device reference operating frequency can be achieved.

[0040] The device further includes an external bias magnetic field for providing a direction perpendicular to the surface of the dielectric substrate (3); the external bias magnetic field acts on the ferromagnetic resonator (7) to dynamically adjust the frequency of the magnetic resonator mode in order to achieve resonance matching and hybrid hybrid state evolution between the magnetic resonator mode and the photonic mode of the resonant cavity.

[0041] In the metallized via array (2), the center-to-center distance b between adjacent metallized vias and the via diameter c satisfy the proportional relationship: b / c < 2.5, so as to form a quasi-closed electromagnetic boundary in the dielectric substrate (3), thereby suppressing the outward radiation leakage of microwave energy in the rectangular waveguide resonant cavity.

[0042] The ferromagnetic resonator (7) is a yttrium iron garnet (YIG) sphere with a radius of 0.5 mm; the thickness of the first metal layer and the second metal layer ranges from 0.03 mm to 0.04 mm; the dielectric constant of the dielectric substrate (3) ranges from 9.8 to 10.5.

[0043] The adjustment range of the ring width w is 0 mm to 3 mm; the reference operating frequency of the rectangular waveguide resonant cavity exhibits a monotonically decreasing negative correlation mapping relationship with the increase of the ring width w.

[0044] This invention provides a method for strong magnetoron-photon coupling based on substrate integrated waveguides, referring to... Figures 1 to 10 Specifically, it includes the following steps:

[0045] 1) Frequency and Coupling Preset Steps: Based on the requirements of the target strong coupling frequency band, the geometric parameters of the non-metallized region (5), i.e., the annular etched region, are first determined. In this embodiment, the inner radius of the non-metallized annular region (5) is equal to the radius of the mounting via. By establishing a mapping model between the annular width w and the system resonant frequency, the value of the annular width w that meets the target (range from 0 mm to 3 mm) is determined. During the design phase, the spatial coordinate position of the mounting via (6) is kept fixed (located at the geometric center of the resonant cavity). The static parameterization preset of the resonant cavity reference operating frequency and coherent coupling strength is achieved by utilizing the reconstruction effect of the annular width w on the surface current of the first metal layer (1).

[0046] 2) Substrate-integrated waveguide structure fabrication steps: The fabrication is carried out using standard PCB printed circuit board processing technology. A dielectric substrate (3) with a length of 60 mm, a width of 35.6 mm, and a thickness of 1.3 mm is selected, and its dielectric constant is 10. The upper and lower surfaces of the substrate are covered with a metal layer with a thickness of 0.035 mm. A metallized via array (2) with a radius of 0.4 mm is fabricated on the dielectric substrate (3). This array forms a rectangular waveguide resonant region inside the waveguide. The upper and lower metal layers are electrically connected to the dielectric substrate through the metallized vias to form a quasi-closed substrate-integrated waveguide transmission structure. The non-metallized annular region (5) is etched at the center of the surface of the first metal layer (1), and a mounting via (6) penetrating the substrate is fabricated.

[0047] 3) Ferromagnetic Resonator Integration and Precision Assembly Steps: Yttrium iron garnet (YIG) microspheres are used as ferromagnetic resonators (7) and precisely assembled into the assembly through-hole (6). Ensure that their geometric center is located at the center of the annular etched area and within the magnetic field antinode region of the target mode in the rectangular waveguide resonant cavity, thereby constructing a substrate-integrated waveguide-YIG microsphere coupling system. In the integration step of the ferromagnetic resonator (7), this embodiment uses a quartz capillary assembly to achieve precision assembly and fixation. The specific operation is as follows:

[0048] A quartz capillary tube (such as high-purity fused silica) with an outer diameter slightly smaller than the diameter of the mounting through-hole (6) and extremely low dielectric loss is selected. A ferromagnetic resonator (7) (YIG ball) with a radius of 0.5 mm is pre-loaded into the internal cavity of the quartz capillary tube, and the ball is positioned in a specific section of the capillary tube using a small amount of low-loss adhesive. The quartz capillary tube carrying the ferromagnetic resonator (7) is vertically passed through the mounting through-hole (6) on the dielectric substrate (3). By adjusting the height of the quartz capillary tube in the vertical direction, it is ensured that the geometric center of the ferromagnetic resonator (7) is completely coincident with the antinode of the magnetic field of the target mode in the rectangular waveguide resonant cavity in three-dimensional space. Subsequently, the two ends of the quartz capillary tube exposed outside the dielectric substrate (3) are fixed to the center of the annulus on the surface of the first metal layer (1) and the corresponding position of the second metal layer, respectively, using adhesive.

[0049] 1) Dynamic control and characterization steps of strong coupling: A microwave excitation signal is input through a microstrip feed line (4), and an external bias magnetic field perpendicular to the plane of the dielectric substrate is applied at the ferromagnetic resonator (7); an adjustable bias magnetic field perpendicular to the plane of the dielectric substrate (3) is applied to the coupling system. By adjusting the strength of the external magnetic field, the resonant frequency of the ferromagnetic resonator (7) is dynamically changed. When the ferromagnetic resonator frequency and the cavity photon resonant frequency tend to be consistent, a continuous switching from weak coupling to strong coupling is achieved. In the transmission spectrum measured by the vector network analyzer, a mode splitting signal with typical anti-crossing characteristics is observed, indicating that the system has entered a strong coupling state.

[0050] This invention, through the fusion design of substrate integrated waveguide (SIW) and ferromagnetic resonators (such as YIG spheres), has significant technical advantages in improving electromagnetic performance and promoting on-chip integrated applications.

[0051] First, addressing the spatial radiation leakage and dielectric loss issues inherent in traditional microstrip line coupling schemes, this invention utilizes a quasi-closed transmission environment composed of a metallized via array and upper and lower metal layers to achieve strong localization of the electromagnetic field within the dielectric substrate. This significantly improves the quality factor (Q value) of the resonant cavity and effectively suppresses energy loss caused by the open structure, providing a high-fidelity photonic environment for efficient coherent exchange between magnons and photons.

[0052] Secondly, addressing the limitations of traditional three-dimensional metal cavity solutions, which are bulky and difficult to integrate, this invention utilizes planar processes such as printed circuit boards (PCBs) or low-temperature co-fired ceramics (LTCCs), significantly reducing the physical size and weight of the device. While significantly reducing manufacturing complexity and cost, it realizes the evolution of magnon devices from a bulk configuration to a monolithic integrated architecture, providing an efficient and feasible technical path for constructing large-scale, scalable on-chip hybrid quantum systems.

[0053] More importantly, this invention innovatively achieves static parameterization of the system's reference operating frequency and coherent coupling strength under the premise of a constant ferromagnetic resonator assembly position through the parameterized design of the key geometric parameter w of the width of the non-metallic annular region. This mechanism fundamentally solves the technical pain points of high entanglement between frequency and coupling parameters and poor experimental reproducibility in traditional displacement control schemes, endowing the device with extremely high design determinism and independent control freedom, and significantly improving performance consistency and environmental robustness in mass production scenarios.

[0054] Example 1: Figure 1 This embodiment illustrates the structure of a magnetoresistive-photon coupling device based on a substrate integrated waveguide. The device employs a standard PCB stack-up configuration, with its physical layers from top to bottom comprising a first metal layer (1) (upper surface metal layer), a dielectric substrate (3), and a second metal layer (lower surface metal layer). The dielectric substrate (3) has a relative permittivity of 10 and a thickness of 1.3 mm; the thicknesses of the upper and lower surface metal layers are both 0.035 mm. Inside the dielectric substrate, a pre-defined array of metallized vias (corresponding to the dark gray circles in the figure, with a radius of 0.4 mm) penetrates the upper and lower surface metal layers, thus physically defining a rectangular substrate integrated waveguide (SIW) resonant cavity. This array utilizes the electromagnetic shielding walls formed by the vias to confine microwave energy within the cavity, effectively reducing spatial crosstalk and insertion loss in the system.

[0055] In this embodiment, as shown... Figure 2 At the geometric center of the rectangular resonant cavity, a non-metallized annular region with an inner radius of 0.7 mm is formed on the first metal layer (1) through selective etching. The width w of the annular region is a key parameter for adjusting the resonant frequency of the resonant cavity and the coupling strength of the device. This annular structure breaks the continuity of the surface current of the first metal layer (1), forcing the current to travel along the edge of the annular region, thereby generating a topological reconstruction effect and achieving fine modulation of the spatial magnetic field distribution of the photon mode in the resonant cavity. Since the coupling strength g between the magnon and the photon depends on the local magnetic field energy density at the location of the ferromagnetic resonator (7), by changing the value of the width w, the coupling strength g can be precisely statically preset while keeping the assembly position of the ferromagnetic resonator (7) constant. This control method gives the device the ability to independently optimize the coupling characteristics during the design stage, making it easier to observe clear anti-crossing strong coupling characteristics in subsequent dynamic magnetic field control.

[0056] In this embodiment, the device excitation and signal pickup are achieved through a microstrip feed line (4): the microstrip feed line (4) is symmetrically distributed on both sides of the rectangular waveguide resonant cavity, forming the microwave signal input port and output port respectively. In the preferred configuration of this embodiment, for a dielectric substrate (3) with a dielectric constant of 10.2 and a thickness of 1.3 mm, the linewidth a of the microstrip feed line (4) is set to 1.1 mm, which aims to ensure that the feed line system has a standard characteristic impedance, thereby minimizing the reflection loss and voltage standing wave ratio (VSWR) of the signal during transmission. Furthermore, a gradient impedance transformation structure is integrated at the physical connection between the microstrip feed line (4) and the rectangular waveguide resonant cavity. This structure uses a gradient metal boundary to achieve a smooth impedance transition, and its core function is to efficiently convert the quasi-TEM mode in the microstrip line into the TE10 resonant mode in the substrate integrated waveguide. This mode field conversion mechanism ensures that microwave energy can be injected into the cavity with extremely low insertion loss and interact strongly with the ferromagnetic resonator (7) located at the center of the cavity.

[0057] Figure 4 illustrates the effect of changing the ring width w on the device's transmission spectrum (S21) under conditions of no external bias magnetic field (H=0 Oe). The test results show that, when other structural parameters remain constant, the central resonant frequency of the device exhibits a significant downward (leftward) shift as the ring width w increases. Physically, increasing the ring width w alters the current distribution path in the SIW's top metal layer, leading to changes in the equivalent electromagnetic parameters of the resonant cavity, thus enabling flexible control of the device's operating frequency band.

[0058] Figure 5 shows the magnetic field vector distribution of a conventional substrate integrated waveguide (SIW) resonant cavity in TE101 mode. In this mode, the induced current path on the surface of the first metal layer remains continuous, and the magnetic field strength exhibits a quasi-cosine distribution from the cavity edge towards the center. The magnetic field vector is relatively uniformly distributed in the central region and is not significantly affected by boundary interference.

[0059] Figure 6 shows the change in magnetic field distribution after introducing a non-metallic ring region (5) under the same excitation conditions. It can be clearly observed that due to the physical interruption of the continuity of the metal layer, the surface induced current is forced to travel around the ring boundary, resulting in a significant topological reconstruction effect in the magnetic field distribution.

[0060] Comparing Figures 5 and 6, it can be seen that the introduction of a non-metallic ring structure disrupts the steady state of the original magnetic field distribution in the cavity. This reconstruction effect allows the spatial overlap integral between the magnetic field at the location of the ferromagnetic resonator (7) and the cavity photon mode to be statically preset based on the ring geometry parameters.

[0061] Example 2: Based on the structure of Example 1, this example further integrates a ferromagnetic resonator (7) (YIG ball) and realizes parameterized control of coupling strength. Figure 7 The diagram shows a schematic of the overall assembly of a substrate-integrated waveguide magnetic resonator-photon coupling system (including YIG spheres). Its core design utilizes the localized magnetic field reconstruction effect generated by the non-metallic annular region (5) to precisely place the ferromagnetic resonator (7) within a region where the magnetic field energy density is controlled, thereby achieving deterministic control of the strong coupling characteristics. The specific implementation process is as follows:

[0062] In this embodiment, a mounting through hole (6) with a radius of 0.7 mm is machined at the geometric center of the rectangular resonant cavity. This hole is concentrically aligned with the non-metallized annular region (5) on the first metal layer (1) on the upper surface. In this embodiment, a YIG ball with a radius of 0.5 mm is selected as the ferromagnetic resonator (7). In order to achieve accurate positioning in three-dimensional space and maintain the high quality factor of the resonant cavity, a quartz capillary assembly is used for assembly: the ferromagnetic resonator (7) is pre-installed in a quartz capillary with a matching outer diameter. By vertically passing through the mounting through hole (6) and adjusting its longitudinal height, it is ensured that the center of the ball completely coincides with the antinode of the magnetic field of the TE101 mode in the cavity.

[0063] The core control of this embodiment lies in the fact that by pre-setting different widths w of the non-metallized annular region (5) (e.g., values ​​ranging from 0 mm to 3 mm), the static pre-setting of the coherent coupling strength g between the magnetic resonator (7) and the photon is achieved while keeping the assembly position of the ferromagnetic resonator (7) completely constant. Referring to the magnetic field distribution results in Figure 6, the change in width w reshapes the induced current path on the surface of the first metal layer (1), thereby modulating the local magnetic field distribution at the location of the ferromagnetic resonator (7). This mechanism makes the optimization of the coupling strength g no longer dependent on complex mechanical displacement adjustments, significantly improving the structural stability and experimental repeatability of the device.

[0064] This embodiment verifies the effectiveness of the system as an independent controllable degree of freedom by comparing the electromagnetic response of the system under different ring widths w. Figures 8 and 9 show two-dimensional mapping cloud diagrams of the system transmission coefficient (S21) as a function of the bias magnetic field.

[0065] Under baseline conditions (w = 0 mm), when the bias magnetic field is scanned in the range of 1000 Oe to 1500 Oe, the magnon mode interacts strongly with the cavity mode at about 5.1 GHz, producing clear anti-crossing fringes, proving that the system has entered a strong coupling mechanism.

[0066] When the ring width increases to w = 3 mm, the system still exhibits robust energy level collision avoidance characteristics at approximately 4.8 GHz, confirming that the system remains in a strongly coupled state during modulation. However, due to the electromagnetic boundary reconstruction induced by the nonmetallized region, the center frequency of strong coupling shifts significantly to lower frequencies.

[0067] Comparing the response characteristics in Figures 8 and 9 reveals that, although both states are in the strongly coupled region, there are significant differences in their Rabi Splitting amplitudes.

[0068] In Figure 8, the frequency spacing (2g) generated by the splitting corresponds to the interaction intensity under the reference state;

[0069] In Figure 9, the increase in width w changes the current distribution on the surface of the first metal layer (1), which in turn reconstructs the local magnetic field energy density at the location of the ferromagnetic resonator (7), causing the spatial overlap integral of the magneton and photon to evolve, ultimately resulting in an observable quantitative change in the Rabi split amplitude.

[0070] To further quantitatively reveal the above-mentioned regulation law, this embodiment extracts data from two-dimensional mapping cloud maps with different non-metallic ring widths w, obtains the coupling strength g value at the resonance point, and plots the quantitative correlation curve shown in Figure 10.

[0071] Specifically, as the width w of the non-metallized ring gradually increases from 0 mm to 3 mm, the extracted coupling strength g corresponds to 110 MHz, 85 MHz, 68 MHz, and 50 MHz, respectively. The data results show a clear monotonically decreasing mapping relationship between the width w of the non-metallized ring and the coupling strength g.

[0072] This result confirms that by presetting the static geometric parameter w on the first metal layer (1), it is possible to achieve two-dimensional parameterization of the operating frequency band (frequency offset) and coupling strength (splitting amplitude) of the magnetic resonator (7) while keeping the physical assembly position of the magnetic resonator (7) constant. This static control mechanism effectively solves the problems of high coupling between frequency and coupling strength and mode instability caused by traditional displacement control in traditional schemes, and provides a reliable physical means for the customized design of high-performance microwave magnetic devices.

[0073] This embodiment demonstrates that, through the combination of the quasi-two-dimensional stacked configuration provided by the present invention and the degree of freedom of the non-metallic ring, precise control and optimization of the microwave photonic coupling strength of the magnon can be effectively achieved within a monolithic integrated framework.

[0074] This embodiment further confirms, through the above experimental data, that the technical solution provided by the present invention achieves the following technical effects through the synergistic effect of the width w of the non-metallic annular region and the external bias magnetic field H:

[0075] First, by statically configuring the width w of the ring, the spatial distribution of the mode magnetic field and the local energy density inside the resonant cavity are statically preset. On this basis, in conjunction with the dynamic tuning of the frequency of the YIG microsphere magnon by the external bias magnetic field, the present invention can induce and maintain a stable strong magnon-photon coupling effect under a planar integrated architecture.

[0076] Second, the coupling strength g of the coupling system exhibits a clear monotonically decreasing mapping relationship with the width w of the non-metallic ring. Experiments have confirmed that by quantitatively adjusting the value of the width w, the mode field distribution and energy localization degree within the rectangular waveguide resonant cavity can be effectively reconstructed. This structured control mechanism further enables precise control and static preset of the Rabi splitting amplitude in the transmission response contour map.

[0077] Third, based on the quasi-closed structure of substrate integrated waveguides (SIW), spatial radiation loss is minimized, which plays a crucial role in maintaining the long coherence time of hybrid quantum systems. This characteristic enables the device to not only have a low insertion loss advantage in classical microwave signal processing, but also to exhibit unique technical competitiveness in hybrid integrated systems of superconducting quantum circuits and magnons. Due to the high designability of the mode splitting characteristics in the anti-crossing response, the device of this invention can achieve precise locking of specific operating frequencies and on-demand switching of coupling strength according to the frequency requirements of the actual electromagnetic environment through the two-dimensional synergy of static presetting of the geometric parameters w of the non-metallic region and dynamic tuning of the external magnetic field H.

[0078] In summary, the structural scheme provided by this invention demonstrates that steady-state strong coupling between magnons and photons can be achieved within a planar integrated architecture. Through the dual-dimensional manipulation of the spatial geometry of the non-metallic ring width *w* and the dynamic physical field of the external bias magnetic field *H*, the system exhibits excellent mode field reconstruction and parameterized customization capabilities for the coupling strength *g*. This provides a solid physical foundation for constructing high-performance, reconfigurable hybrid quantum information systems. This invention opens up an efficient technical path for the subsequent integrated development of on-chip quantum information processing, coherent state transitions, and magnon logic units.

[0079] To further elucidate the mechanism by which the width w of the non-metallic ring affects the strong coupling effect described in this invention, this embodiment establishes the following physical model based on quantum mechanical processing methods:

[0080] The Hamiltonian of this hybrid system can be expressed as:

[0081] (1)

[0082] Under the rotating wave approximation, the corrected Hamiltonian of the system is:

[0083] (2)

[0084] Where g represents the coupling strength between the photon and magnon modes. Considering the dissipation characteristics of the system, the coupling matrix of the system can be derived according to the Langevin equation. :

[0085] (3)

[0086] By solving the eigenvalue equations of this matrix, the complex eigenfrequency of the system can be obtained. :

[0087] (4)

[0088] Based on the above model and input-output theory, the system's transmission coefficient... The expression is derived as follows

[0089] (5)

[0090] The relevant physical parameters are defined as follows:

[0091] This represents the intrinsic coupling loss rate between the resonator and the external port;

[0092] The total energy loss inside the resonator satisfies ,in The intrinsic loss rate inside the resonator;

[0093] The intrinsic damping rate of the magnon mode is represented;

[0094] and These represent the eigenfrequency of the cavity photon and the eigenfrequency of the magnon, respectively.

[0095] when When, coupling strength satisfy .

[0096] This invention utilizes a non-metallized window and a through-hole penetrating the substrate at the center of the top metal layer of a substrate-integrated waveguide (SIW) resonant cavity. A magnon source is embedded within this through-hole and positioned at the antinode of the magnetic field. The window guides surface currents to reconstruct the local magnetic field. The system supports dual-dimensional collaborative control: statically presetting the frequency and coupling strength using window parameters grants geometrical control freedom over the system's coherent coupling strength; and dynamically adjusting the magnon frequency using a bias magnetic field achieves resonance matching and hybrid state evolution within a preset range. This invention effectively solves the technical bottlenecks of traditional metal cavities (large size, difficult integration) and microstrip line schemes (high loss, weak anti-interference). Furthermore, this invention not only addresses the mode instability problem caused by traditional displacement control but also provides a parameterized and easily integrated collaborative design paradigm for magnon-photon strongly coupled devices. This device possesses advantages such as high quality factor, strong self-shielding capability, and high monolithic integration, providing an efficient technical path for constructing large-scale, scalable on-chip hybrid quantum systems and magnon logic networks.

[0097] This invention employs a precise integrated structure design of YIG microspheres and SIW, directly embedding the YIG microspheres into the core transmission region of the SIW, placing them in the region where magnetic field energy is most concentrated, thereby maximizing coupling efficiency, avoiding energy leakage problems, significantly reducing insertion loss, and greatly improving the device quality factor.

[0098] This invention utilizes SIW (Self-Supported Waveguide) characteristics for impedance matching and spurious mode suppression design. Taking advantage of the near-ideal rectangular waveguide nature of the SIW transmission mode, the waveguide dimensions, number and arrangement of YIG beads are optimized through simulation. Higher-order spurious modes are suppressed by leveraging SIW symmetry, while simultaneously adjusting the parameters of the metallized via array to achieve a standard 50Ω impedance matching. This effectively reduces the impact of manufacturing tolerances on impedance characteristics, ensures performance stability during mass production, reduces parasitic passband and signal reflection, and improves the device's out-of-band rejection capability and signal selectivity, overcoming the core shortcomings of traditional solutions.

[0099] This invention constructs a closed integrated structure that combines shielding and high power carrying capacity, forming a natural electromagnetic shielding barrier. Simultaneously, it optimizes the spacing between the YIG spheres and the inner wall of the SIW to reduce local electric field concentration and utilizes the metal boundary for efficient heat dissipation. This design not only effectively isolates external electromagnetic interference, preventing its own signal radiation from affecting surrounding circuits, but also significantly improves the device's power capacity, meeting the requirements of high-power microwave systems and comprehensively compensating for the shortcomings of microstrip lines in terms of interference immunity and power carrying capacity.

[0100] This invention features highly flexible functional expansion and integrated compatibility design. It can adapt to different operating frequencies by adjusting SIW structural parameters (such as via spacing and waveguide width) or the embedding position and number of YIG spheres. Simultaneously, leveraging the planar integration characteristics of SIW, it enables seamless transition with planar circuits such as microstrip lines and coplanar waveguides, supporting mass production using standard processes such as LTCC. This design allows for rapid iteration, enabling the design of multi-band, multi-functional devices, reducing the complexity of processing and assembly and manufacturing costs. It effectively promotes the miniaturization and integration of YIG-based microwave devices, overcoming the inherent limitations of traditional metal cavities.

[0101] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A magnetoron-photon coupling device based on a substrate integrated waveguide, characterized in that, include: A dielectric substrate (3), and a first metal layer (1) and a second metal layer respectively covering the upper and lower surfaces of the dielectric substrate (3); a metallized via array (2) that penetrates the dielectric substrate (3) and electrically connects the first metal layer (1) and the second metal layer, the metallized via array (2) forming a rectangular waveguide resonant cavity inside the dielectric substrate (3); a non-metallized region (5) formed on the surface of the first metal layer (1) and located in the magnetic field antinode region of the target resonant mode inside the rectangular waveguide resonant cavity; and a mounting via (6) precisely positioned at the center of the non-metallized region (5) for placing a ferromagnetic resonator (7) supporting collective spin excitation. The non-metallized region (5) breaks the continuity of the surface current of the first metal layer (1), forces the current path to detour, and thus realizes the local reconstruction of the spatial distribution of the microwave magnetic field at the assembly position. By changing the geometric parameters of the non-metallized region (5), the structure can quantitatively adjust the coherent coupling strength between the photon mode in the cavity and the ferromagnetic resonator (7), realize the parameterized preset of the Rabi splitting amplitude, and give the system geometric control degree of freedom in the quantum coherent state evolution process.

2. The magnetoron-photon coupling device based on a substrate integrated waveguide according to claim 1, characterized in that, Also includes: A microstrip feed line (4) is integrated on the surface of the first metal layer. The microstrip feed line (4) is connected to the rectangular waveguide resonant cavity through an electromagnetic coupling interface and is used for microwave signal input and output. The linewidth a of the microstrip feed line (4) is preset so that its characteristic impedance matches the standard impedance of the external system.

3. The magnetoron-photon coupling device based on a substrate integrated waveguide according to claim 1, characterized in that: The non-metallized region (5) is a non-metallized annular region, and its annular width w is a preset control parameter; by configuring the annular width w to change the equivalent electromagnetic boundary conditions of the rectangular waveguide resonant cavity, static control or frequency compensation of the device reference operating frequency can be achieved.

4. The magnetoron-photon coupling device based on a substrate integrated waveguide according to claim 1, characterized in that, Also includes: A bias magnetic field generating device is used to provide an external bias magnetic field perpendicular to the surface of the dielectric substrate (3); the external bias magnetic field acts on the ferromagnetic resonator (7) to dynamically adjust the frequency of the magnetic resonator mode in order to achieve resonance matching and hybrid hybrid state evolution between the magnetic resonator mode and the photon mode of the resonant cavity.

5. The magnetoron-photon coupling device based on a substrate integrated waveguide according to claim 1, characterized in that: In the metallized via array (2), the center-to-center distance b between adjacent metallized vias and the via diameter c satisfy the proportional relationship: b / c < 2.5, so as to form a quasi-closed electromagnetic boundary in the dielectric substrate (3), thereby suppressing the outward radiation leakage of microwave energy in the rectangular waveguide resonant cavity.

6. The magnetoron-photon coupling device based on a substrate integrated waveguide according to claim 1, characterized in that: The ferromagnetic resonator (7) is a yttrium iron garnet sphere with a diameter of 1 mm; the thickness of the first metal layer and the second metal layer ranges from 0.03 mm to 0.04 mm; the dielectric constant of the dielectric substrate (3) ranges from 9.8 to 10.

5.

7. The magnetoron-photon coupling device based on a substrate integrated waveguide according to claim 3, characterized in that: The adjustment range of the ring width w is from 0.7 mm to 3.7 mm; the reference operating frequency of the rectangular waveguide resonant cavity exhibits a monotonically decreasing negative correlation mapping relationship with the increase of the ring width w.

8. A method for achieving strong magnetoron-photon coupling based on the magnetoron-photon coupling device based on a substrate integrated waveguide as described in any one of claims 1 to 7, characterized in that, Includes the following steps: 1) Frequency and Coupling Preset Steps: Based on the target strong coupling frequency band, by determining the annular width w of the non-metallized region (5), and while keeping the spatial coordinate position of the assembly through hole (6) constant, the static parameterization preset of the operating frequency and coherent coupling strength of the resonant cavity is achieved by utilizing the reconstruction effect of the annular width w on the surface current of the first metal layer (1). 2) Device fabrication and assembly steps: A substrate integrated waveguide structure containing the metallized via array (2), non-metallized region (5) and mounting via (6) is fabricated using printed circuit technology; a ferromagnetic resonator (7) is assembled in the mounting via (6), and the geometric center of the ferromagnetic resonator (7) is positioned in the magnetic field antinode region of the target mode in the rectangular waveguide resonant cavity; 3) Dynamic control and characterization steps: Input microwave excitation signal through microstrip feed line (4) and apply an external bias magnetic field perpendicular to the plane of the dielectric substrate at the ferromagnetic resonator (7); adjust the strength of the external bias magnetic field to make the resonant frequency of the magnetic resonator and the resonant frequency of the cavity photon consistent, thereby obtaining a strongly coupled state with energy level collision avoidance characteristics in the transmission spectrum.

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