A 6G Reconfigurable Multi-Band Modulation and Filtering Device for SSPP

Abstract

This solution provides a 6G reconfigurable multi-passband modulation and filtering device for SSPP. The top-level design structure includes a first CPW structure, a first conversion structure, an active SSPP waveguide unit structure, a second conversion structure, and a second CPW structure arranged along the propagation direction of electromagnetic waves. The first conversion structure and the second conversion structure are sawtooth transition band structures with multiple sawteeth arranged at intervals, and the depths of the multiple sawteeth in the sawtooth transition band structure gradually increase in the direction towards the active SSPP waveguide unit structure. The active SSPP waveguide unit structure includes multiple serially connected active SSPP units. Each active SSPP unit includes an H-shaped waveguide and two resonant units disposed in the upper and lower directions of the H-shaped waveguide. Each resonant unit is obtained by connecting two split rings through a variable capacitance diode. The dual-passband and triple-passband regulation can be achieved by changing the capacitance value of the variable capacitance diode, and the 2FSK modulation signal function can be realized in the coded state by introducing digital coding.

Description

Technical Field

[0001] The present invention relates to the field of 6G communication, and particularly to a 6G reconfigurable multi-band modulation and filtering device based on spoof surface plasmon polaritons (SSPP). Background Art

[0002] With the rapid development of 6G communication technology, communication systems have put forward higher requirements for the processing ability of high-frequency signals. As a core component in modern communication systems and integrated circuits, the performance of filters has a decisive impact on the operating efficiency of the system. In order to extract specific frequency components from complex frequency signals and improve the selectivity and anti-interference ability of communication channels, the design and optimization of filters are particularly important.

[0003] Spoof Surface Plasmon Polaritons (SSPP) technology is a new type of electromagnetic wave transmission mechanism, which excites pseudo surface plasmon waves by constructing an artificial surface in a sub-wavelength structure. SSPP technology can effectively break through the traditional optical wave diffraction limit and exhibit superior performance in the microwave and terahertz frequency bands. By adjusting the parameters of the artificial surface structure, the SSPP device can achieve flexible adjustment of the transmission frequency.

[0004] However, most of the existing SSPP devices are passive structures, and their functions are fixed after manufacturing, making it difficult to achieve dynamic adjustment, which limits their application in complex communication environments. Specifically, due to the limitations of the structure design, traditional multi-band filters usually can only support a fixed number of passbands and frequency ranges, and lack reconfigurability. For example, the patent with the publication number CN115911795A discloses a substrate integrated artificial surface plasmon multi-band filter, which realizes two band-pass effects of 7.4 - 9.05 GHz and 10.01 - 12.5 GHz through a number of interdigital metal slotted structures arranged symmetrically at intervals on both sides. However, due to the limitation of the cut-off frequency of the dispersion curve of the slotted structure, the band-pass is relatively narrow, and it is a passive device that cannot achieve a reconfigurable effect, which limits the flexibility of the filter. In addition, the fixed performance of traditional filters leads to insufficient adaptability when facing the processing requirements of multi-frequency signals. Moreover, there is often a high transmission loss during the frequency regulation process, making it difficult to meet the requirements of 6G communication systems for high performance and high flexibility at the same time.

[0005] In other words, the functions of current multi-band filters on the market are fixed and lack flexibility. Most existing multi-band filters are of passive structure, and the number of passbands and frequency range are solidified after manufacturing, making it difficult to achieve dynamic adjustment according to actual needs. This design limits their ability to flexibly handle multi-frequency signal processing in a changing communication environment. Although some research has introduced active components such as varactor diodes to achieve frequency regulation, the frequency reconfiguration ability of existing technologies is still limited. For example, multi-band filters have weak capabilities in expanding the number of passbands and dynamically regulating bandwidth, and it is difficult to meet the requirements of 6G communication systems for multi-functionality and high adaptability.

[0006] Therefore, developing a multi-band filtering device capable of dynamic reconfiguration has become an important topic in the development of 6G communication technology. Summary of the Invention

[0007] The purpose of the present invention is to provide a 6G reconfigurable multi-band modulation filtering device based on SSPP, which introduces a digital coding state and uses the varactor diode state to adjust the SSPP dispersion characteristics, capable of achieving multi-band filtering function and realizing the 2FSK modulation signal function in the coding state.

[0008] To achieve the above object, the present technical solution provides a 6G reconfigurable multi-band modulation filtering device based on SSPP, including:

[0009] A dielectric substrate layer;

[0010] A top-layer design structure disposed on the top surface of the dielectric substrate layer, including a first CPW structure, a first conversion structure, an active SSPP waveguide unit structure, a second conversion structure, and a second CPW structure arranged along the propagation direction of electromagnetic waves. The first conversion structure and the second conversion structure are sawtooth transition band structures with multiple sawteeth arranged at intervals, and the depths of the multiple sawteeth in the sawtooth transition band structure gradually increase in the direction towards the active SSPP waveguide unit structure. The active SSPP waveguide unit structure includes a plurality of serially connected active SSPP units, and each active SSPP unit includes an H-shaped waveguide and two resonant units disposed in the up and down directions of the H-shaped waveguide. Each resonant unit is obtained by connecting two split rings through a varactor diode;

[0011] A feeding structure disposed on the back surface of the dielectric substrate layer, where the feeding structure is connected to each varactor diode through a via hole.

[0012] Moreover, the 6G reconfigurable multi-band modulation filtering device based on SSPP provided by this solution can achieve the regulation of dual-band and triple-band by changing the capacitance value of the varactor diode, and can realize the 2FSK modulation signal function in the coding state by introducing digital coding.

[0013] Compared with the prior art, the technical solution has the following features and beneficial effects:

[0014] This solution proposes a 6G reconfigurable multi-band modulation and filtering device for SSPP. The 6G reconfigurable multi-band modulation and filtering device for SSPP introduces a digital coding state and uses varactor diodes to adjust the SSPP dispersion characteristics. It can achieve multi-band filtering functions and realize the 2FSK modulation signal function in the coding state. This device can flexibly select dual-band and triple-band, with a transmission loss lower than 2.68 dB and a stopband rejection ability above -20 dB. It has a low transmission coefficient and good stopband rejection performance, can effectively separate signals and select frequencies, and is suitable for complex signal environments.

[0015] In addition, after introducing the coding function, various function switches of the device can be flexibly controlled by preset digital codes or external input voltages, enabling flexible switching of 2FSK modulation signals and meeting the application requirements of multi-channel communication systems or applications that need to process multi-frequency signals. This technology solves the high-frequency modulation problem in microwave communication and provides a basis for realizing an artificial surface communication system. Brief Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the SSPP unit structure of a 6G reconfigurable multi-band modulation and filtering device for SSPP designed by the present invention.

[0017] Figure 2 It is a schematic diagram of the equivalent circuit of the SSPP unit of a 6G reconfigurable multi-band modulation and filtering device for SSPP designed by the present invention.

[0018] Figure 3 It is a dispersion curve diagram of the SSPP unit of a 6G reconfigurable multi-band modulation and filtering device for SSPP designed by the present invention.

[0019] Figure 4 It is a schematic diagram of the structure of a 6G reconfigurable multi-band modulation and filtering device for SSPP designed by the present invention.

[0020] Figure 5 It is the S of the dual-band filtering of a 6G reconfigurable multi-band modulation and filtering device for SSPP designed by the present invention 21 Parameter simulation diagram.

[0021] Figure 6 It is a 6G reconfigurable multi-band modulation and filtering device for SSPP designed by the present invention at C v The electric field distribution diagrams at 11.8 GHz, 13.9 GHz, and 16.8 GHz when = 0.12 pF.

[0022] Figure 7S three - band filtering of a 6G reconfigurable multi - passband modulation and filtering device of SSPP designed by the present invention 21 Parameter simulation diagram.

[0023] Figure 8 Electric field distribution diagrams at different frequencies of a 6G reconfigurable multi - passband modulation and filtering device of SSPP designed by the present invention when C v1 = 0.08 pF and C v2 = 0.56 pF.

[0024] Figure 9 Principle framework diagram of the modulation signal of a 6G reconfigurable multi - passband modulation and filtering device of SSPP designed by the present invention.

[0025] Figure 10 Electric field distribution diagrams at 14.1 GHz in two coding states of a 6G reconfigurable multi - passband modulation and filtering device of SSPP designed by the present invention.

[0026] Figure 11 2FSK modulation of a 6G reconfigurable multi - passband modulation and filtering device of SSPP designed by the present invention under different digital signals.

[0027] Figure 12 Schematic diagram of the physical object processed of a 6G reconfigurable multi - passband modulation and filtering device of SSPP designed by the present invention.

[0028] Figure 13 S parameters of a 6G reconfigurable multi - passband modulation and filtering device of SSPP designed by the present invention when C v = 0.12 pF 21 parameters.

[0029] Figure 14 S parameters of a 6G reconfigurable multi - passband modulation and filtering device of SSPP designed by the present invention when C v1 = 0.08 pF and C v2 = 0.56 pF. 21 parameters. Detailed implementation manners

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0031] Those skilled in the art should understand that in the disclosure of the present invention, the orientation or positional relationship indicated by terms such as "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting the present invention.

[0032] Embodiment 1

[0033] As Figure 4 shown, this technical solution provides a 6G reconfigurable multi-band modulation and filtering device for SSPP, including:

[0034] A dielectric substrate;

[0035] A top-layer design structure disposed on the top surface of the dielectric substrate, including a first CPW structure, a first conversion structure, an active SSPP waveguide unit structure, a second conversion structure, and a second CPW structure arranged along the propagation direction of electromagnetic waves. The first conversion structure and the second conversion structure are sawtooth transition band structures with multiple sawteeth arranged at intervals, and the depths of the multiple sawteeth in the sawtooth transition band structure gradually increase in the direction of the active SSPP waveguide unit structure. The active SSPP waveguide unit structure includes a plurality of serially connected active SSPP units. Each active SSPP unit includes an H-shaped waveguide and two resonant units disposed in the upper and lower directions of the H-shaped waveguide. Each resonant unit is obtained by connecting two split rings through a variable capacitance diode;

[0036] A feeding structure disposed on the back surface of the dielectric substrate, where the feeding structure is connected to each variable capacitance diode through a via hole.

[0037] It should be noted that the active SSPP unit in this 6G reconfigurable multi-band modulation and filtering device for SSPP is different from the traditional SSPP unit structure. A variable capacitance diode and a corresponding external bias circuit are introduced into the active SSPP unit to achieve the effect of having an encoding modulation function.

[0038] The specific structure of each active SSPP unit is as Figure 1 shown. The active SSPP unit is composed of an H-shaped waveguide, a first resonant unit located above the H-shaped waveguide, and a second resonant unit located below the H-shaped waveguide, where the first resonant unit and the second resonant unit are vertically symmetric with respect to the center of the H-shaped waveguide. Specifically, the H-shaped waveguide includes a first vertical bar and a second vertical bar of the same length arranged in parallel, and the middle positions of the first vertical bar and the second vertical bar are connected by a first horizontal bar, where the first resonant unit and the second resonant unit are symmetrically arranged with respect to the first horizontal bar.

[0039] The first resonant unit and the second resonant unit have the same structure. In each resonant unit, the two split rings are arranged in an interleaved manner in a finger-like pattern, and the two split rings are connected by a varactor diode. Specifically, each resonant unit includes a first split ring and a second split ring. The first split ring and the second split ring both include split ring vertical bars and a plurality of split ring horizontal bars that are perpendicularly arranged with respect to the split ring vertical bars. The split ring horizontal bars at the top of the first split ring and the second split ring are arranged on the same horizontal line and are connected by a varactor diode. The split ring horizontal bars at other positions of the first split ring and the second split ring are arranged in an interleaved and parallel manner, and the split ring horizontal bars at other positions of the first split ring are spaced apart from the split ring vertical bars of the second split ring, and the split ring horizontal bars at other positions of the second split ring are spaced apart from the split ring vertical bars of the first split ring. It is worth mentioning that the varactor diodes in the first resonant unit and the second resonant unit are located at the position farthest from the first horizontal bar of the H-shaped waveguide.

[0040] In some specific embodiments, the split ring horizontal bars at other positions of the first split ring and the second split ring are equally spaced from each other, that is, the multiple split ring horizontal bars arranged in an interleaved and parallel manner are equidistant from each other.

[0041] In some specific embodiments, the top of the first resonant unit is flush with the tops of the first vertical bar and the second vertical bar of the H-shaped waveguide, and there is a gap between the bottom of the first resonant unit and the first horizontal bar of the H-shaped waveguide; the top of the second resonant unit is flush with the tops of the first vertical bar and the second vertical bar of the H-shaped waveguide, and there is a gap between the bottom of the second resonant unit and the first horizontal bar of the H-shaped waveguide.

[0042] It should be emphasized that in the active SSPP unit designed in this solution, a unique resonant unit is formed by loading varactor diodes between two split rings. This resonant unit enables the two split rings to be tightly connected through the varactor diode to achieve the resonance effect. This active SSPP unit breaks through the constraints of the physical parameters of passive plasma devices, makes a good foundation for the active SSPP waveguide unit structure and modulation system, and has better practical performance.

[0043] Regarding the equivalent circuit of this active SSPP unit as Figure 2 shown, in the circuit model, L 1 and L 2 represent the inductance generated by the surface current of the metal, C 1 represents the coupling capacitance between the first resonant unit and the second resonant unit, C 2 represents the self-capacitance formed by the first resonant unit and the second resonant unit. Among them, C 2 is the variable capacitance in the varactor diode controlled by an external bias circuit. According to the calculation formula of the center frequency f as , to better design the real-time modulation function of the filter.

[0044] Since the electrical response between the two split rings changes the resonance regulation of the entire resonant unit, the dispersion curve of the active SSPP unit in this solution is dynamically adjusted with the change of the varactor diode.

[0045] Specifically, as Figure 3 shown, under the symmetric coplanar waveguide structure (Coplanar Waveguide, CPW), only mode 1 and mode 3 are excited. Three capacitance values are applied to the varactor diode respectively. As the phase kp / π increases, the dispersion curves of mode 1 and mode 3 gradually tend to a constant value, forming a cut-off frequency. In mode 1, the decrease in capacitance will cause the cut-off frequency to increase; and the gap between mode 1 and mode 3 (corresponding to Figure 3 the gray part) forms the stopband of the filter, and the cut-off frequency range can be flexibly regulated between 10.8 - 18.02 GHz.

[0046] In some embodiments, the first CPW structure and the second CPW structure of the 6G reconfigurable multi-band modulation filtering device of SSPP are arranged relative to the active SSPP waveguide unit structure.

[0047] As Figure 4 shown, the first CPW structure includes a metal conductor strip connected to the first conversion structure and ground conductor strips located on both sides of the metal conductor strip, where the ground conductor strips are arranged close to the metal conductor strip and the ground conductor strips on both sides of the metal conductor strip are symmetrically arranged relative to the metal conductor strip.

[0048] Similarly, the second CPW structure includes a metal conductor strip connected to the second conversion structure and ground conductor strips located on both sides of the metal conductor strip, where the ground conductor strips are arranged close to the metal conductor strip and the ground conductor strips on both sides of the metal conductor strip are symmetrically arranged relative to the metal conductor strip.

[0049] In a specific embodiment, the first CPW structure is 50Ω, and the symmetric design of the first CPW structure itself can excite the fundamental mode (mode 1) and the high-order mode (mode 3), which plays a key role in the stopband of the filter.

[0050] Similarly, the first conversion structure and the second conversion structure of the 6G reconfigurable multi-band modulation filtering device of SSPP are arranged relative to the active SSPP waveguide unit structure, so that the wave numbers of the conventional microstrip line supporting the quasi-transverse electromagnetic mode and the SSPP structure are not in the same phase. The matching method adopted by the first conversion structure and the second conversion structure is a branch conversion structure with gradually increasing gradient length, which can effectively convert between the SSPP waveguide unit structure and the CPW microstrip line for exciting the SSPP mode.

[0051] In addition, the active SSPP waveguide unit structure of this solution is obtained by connecting active SSPP units in series. It should be noted that when the number of active SSPP units is smaller, the in-band ripple is smaller, but the out-of-band rejection ability also becomes correspondingly lower. Increasing the number of active SSPP units can enhance the out-of-band rejection ability.

[0052] In some embodiments, in order to balance the in-band ripple and the out-of-band rejection ability, the number of active SSPP units is set to 4 to 7, preferably 6, which is beneficial for the filter to have better plasma transmission and stronger out-of-band rejection ability.

[0053] In some embodiments, a feeding structure of a bias circuit is arranged on the back of the filter, and a direct current (DC) voltage is applied to the varactor diode through a via hole. An inductor of 118 uH can isolate the DC signal.

[0054] Figure 12 This is a physical diagram of the 6G reconfigurable multi-band modulation filter device of SSPP in this solution. The first CPW structure and the second CPW structure of the 6G reconfigurable multi-band modulation filter device of SSPP are respectively welded to the 50 Ω RF connector SMA interfaces for signal input and output.

[0055] In addition, in some specific embodiments, Figure 1 and Figure 4 The parameters in are a = 2.2, b = 0.4, c = 0.1, d = 2, e = 1.8, r = 0.15, n = 4.7, L1 = 7, L2 = 28.025, L3 = 28.2, L4 = 13.72, S = 0.28, with the unit of mm.

[0056] Embodiment 2 Dual-band realization

[0057] When the 6G reconfigurable multi-band modulation filter device of SSPP needs to realize a dual-band, a unified bias voltage is applied to the varactor diode in the 6G reconfigurable multi-band modulation filter device of SSPP. When the capacitance of the varactor diode is smaller, the stopband position of the 6G reconfigurable multi-band modulation filter device of SSPP moves towards the high-frequency direction and the stopband bandwidth broadens, which is consistent with the gray forbidden band gap in the dispersion curve.

[0058] Specifically, when the capacitance values of the varactor diodes on the 6G reconfigurable multi-band modulation filter device of SSPP are different, the corresponding resonant frequencies of the 6G reconfigurable multi-band modulation filter device of SSPP will also change, and the stopband position will change. At this time, all working stopbands respond within the passband frequency range, also showing the effect of dual-band filtering.

[0059] In some embodiments, the capacitance of the varactor diode is adjusted between 0.3 - 0.34 pF under the control of an external bias voltage. The center frequency of the stopband varies between 18.5 - 11.3 GHz. As the capacitance of the diode decreases, the center frequency of the stopband shifts towards the high-frequency direction.

[0060] In some specific embodiments, as Figure 5 shown, when the varactor diode has capacitance values Cv of 0.32 pF, 0.12 pF, and 0.06 pF respectively, the stopband frequencies of the 6G reconfigurable multi-band modulation filter device of SSPP are 10.8 - 12.64 GHz, 13.23 - 14.96 GHz, and 15.3 - 17.06 GHz. And, through the S 21 parameter diagram, it can be seen that when the 6G reconfigurable multi-band modulation filter device of SSPP operates in the low-frequency band, the transmission coefficient of the passband gradually becomes smooth. When operating in the stopband range, the suppression ability reaches -25 dB, the transmission loss of the high-frequency passband is less than 1.5 dB, the out-of-band suppression attenuation is steeper, and the suppression intensity is -35 dB, finally forming a dynamically adjustable function of dual-band filtering.

[0061] In addition, Figure 6 is the simulated electric field distribution diagram at 11.8 GHz, 13.9 GHz, and 16.8 GHz when the capacitance Cv of the varactor diode is 0.12 pF. It can be seen that these three frequency points are located at the low-frequency passband frequency, stopband frequency, and high-frequency passband frequency respectively, reflecting the transmission performance of the 6G reconfigurable multi-band modulation filter device of SSPP within this range. At the low-frequency passband and high-frequency passband, the electric field can be transmitted smoothly through the entire plane. At the stopband frequency, the electric field is blocked and cannot pass effectively. It can be seen from the electric field diagram that the electric field energy is concentrated and confined around the plasmonic waveguide, more intuitively and dynamically demonstrating the working transmission effect of the filter.

[0062] Figure 13 is when the filter realizes the dual-band filtering performance, selecting C v = 0.12 pF of S 21 measurement results. At this time, the applied bias voltage is 12V. It can be seen from the black dashed line that the measured filter has two passband frequencies of 1.68 GHz - 13.18 GHz and 14.9 GHz - 19.98 GHz, and the transmission coefficient of the passband can reach -1.68 dB. The stopband frequency is 13.18 GHz - 14.9 GHz, and the suppression ability can reach -22 dB, which is consistent with the parameters of the electromagnetic simulation, with a certain controllable error.

[0063] Embodiment 3 Three-passband implementation

[0064] When the 6G reconfigurable multi-band modulation and filtering device of SSPP needs to achieve three bands, two different bias voltages are simultaneously applied to the varactor diodes in the 6G reconfigurable multi-band modulation and filtering device of SSPP to change the capacitance of different varactor diodes. The 6G reconfigurable multi-band modulation and filtering device of SSPP forms two stop bands and realizes the three-band filtering function.

[0065] In some embodiments, when the 6G reconfigurable multi-band modulation and filtering device of SSPP contains 6 active SSPP units, a first bias voltage is applied to the three active SSPP units on the left to make the varactor diodes in the three active SSPP units on the left have a first capacitance value, and a second bias voltage is applied to the three active SSPP units on the right to make the varactor diodes in the three active SSPP units on the right have a second capacitance value, where the first capacitance value and the second capacitance value are different. This configuration can generate two different resonant frequencies.

[0066] As Figure 7 shown, the research team of this application selected three groups of capacitance values to demonstrate the real-time multi-band reconfiguration ability of the 6G reconfigurable multi-band modulation and filtering device of SSPP. When the selected capacitance values are C v1 = 0.06 pF / C v2 = 0.27 pF, C v1 =0.08 pF / C v2 = 0.56 pF, and C v1 = 0.12 pF / C v2 = 1.24 pF, the corresponding stop band frequency ranges are 15.3–17.06 GHz and 10.96–12.04 GHz, 14.54–16.08 GHz and 9.08–10.33 GHz, and 13.23–14.96 GHz and 8.76–9.65 GHz, where C v1 is the first capacitance value, C v2 is the second capacitance value. The influence of the resonance pairs generated by loading the two groups of capacitance values on the transmission loss is small. The band-pass transmission coefficient is -2.67 dB, and the stop band rejection ability remains strong, reaching -25 dB. This shows that using multiple capacitance values can significantly improve the performance of the filter and support subsequent coding and modulation functions.

[0067] Select the capacitance C v1 = 0.08pF, Cv2 = 0.56 pF. Electric field monitors are set at three frequency points of 10.2 GHz, 12.5 GHz, and 15.4 GHz. Here, the three frequency points are the band-stop frequency, the passband frequency, and the band-stop frequency respectively. From Figure 8 the electric field distribution, it can be seen that when the frequency is 10.2 GHz and 15.4 GHz, the electric field energy cannot be completely transmitted through and starts to be blocked in the plasma waveguide unit; when the frequency is 12.5 GHz, the electric field energy can be perfectly transmitted in the filter, and the energy gathers around the plasma waveguide and mainly propagates in the dielectric and metal layers.

[0068] Figure 14 shows that when the filter realizes the three-way filtering performance, two groups of capacitors are selected C v1 = 0.08 pF, C v2 = 0.56 pF of S 21 measurement results. The corresponding DC voltages in the bias circuit are 3.7 V and 14 V respectively. It can be seen from the black dotted line that at this time, the filter has three passband frequencies. The measured passband transmission coefficient is -2.82 dB. The suppression ability of the two stopbands is 3.68 dB worse than the simulation results, but it can still reach -20 dB, which is also quite remarkable. The performance parameters of the overall filter are excellent, and the error between the measurement and the simulation is also within the allowable range because the welding ports, processing wear, and the thickness error of the substrate have a certain impact on the results.

[0069] Example 4 Realization of 2FSK modulation function

[0070] According to the carrier signal frequency to be switched, different bias voltages are applied to the varactor diodes in the 6G reconfigurable multi-band modulation and filtering device of SSPP by using digital signals to change the capacitance of different varactor diodes.

[0071] Specifically, according to the first carrier signal frequency and the second carrier signal frequency to be switched, the first bias voltage group and the second bias voltage group are determined. Among them, the first carrier signal frequency corresponds to the first bias voltage group, and the second carrier signal frequency corresponds to the second bias voltage group; the switching of the first bias voltage group and the second bias voltage group is controlled by digital signals, and the corresponding first bias voltage group or second bias voltage group is encoded and applied to the varactor diodes in the 6G reconfigurable multi-band modulation and filtering device of SSPP.

[0072] As described above, when different capacitance values are grouped and loaded into the active SSPP units of the 6G reconfigurable multi-band modulation filtering device of the SSPP, the 6G reconfigurable multi-band modulation filtering device of the SSPP will resonate to generate different stop bands. Therefore, by programming in groups with bias voltages, the diversification of band signal selection can be effectively achieved. By encoding and adjusting the baseband signal of the 6G reconfigurable multi-band modulation filtering device of the SSPP, the frequency switching of the carrier signal can be realized at different frequencies, thus realizing the frequency modulation of 2FSK, as Figure 9 shown.

[0073] Taking the carrier signals of 14.1 GHz and 16.8 GHz as examples, the implementation scheme of 2FSK modulation of the signal by encoding is as follows: Define C v1 = 0.12 pF, C v2 = 1.24 pF as the "0" state, C v1 = 0.06 pF, C v2 = 0.27 pF as the "1" state. The two states are regulated by digital signals. When the baseband signal is in the "0" state, the carrier signal with a frequency of 14.1 GHz cannot be transmitted through the digital signal and is in a blocked state, while the carrier signal with a frequency of 16.8 GHz can be transmitted through the digital signal and is in a conducting state. When the baseband signal is in the "1" state, the carrier signal with a frequency of 14.1 GHz can perfectly pass through the digital signal and is in a conducting state, while the carrier signal with a frequency of 16.8 GHz cannot pass through the digital signal and is in a blocked state. The electric field distribution of 14.1 GHz in the two coding states is as Figure 10 shown.

[0074] The function of the 2FSK modulation system is realized under the modulation of the digital signal as Figure 11 shown. In fact, since the position of the stop band is determined by the bias voltage of the varactor diode, therefore, according to the actual situation of the frequencies of the two carrier signals, selecting appropriate bias voltage values for coding definition can also achieve 2FSK modulation, rather than being limited to 14.1 GHz and 16.8 GHz, thus improving the flexibility and practical value.

[0075] Figure 14 When the filter realizes the three-way filtering performance, two groups of capacitors C v1 = 0.08 pF, C v2 = 0.56 pF of S 21The measurement results show that the DC voltages in the bias circuit are 3.7V and 14V respectively. As can be seen from the black dashed line, the filter has three passband frequencies at this time. The measured passband transmission coefficient is -2.82dB. The suppression ability of the two stopbands is 3.68dB worse than the simulation results, but it can still reach -20dB, which is quite impressive. The performance parameters of the overall filter are excellent, and the error between the measurement and the simulation is also within the allowable range, because the welding ports, machining wear, and thickness error of the substrate have a certain impact on the results.

[0076] Those skilled in the art should understand that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, 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, it should be considered as the scope described in this specification.

[0077] The above embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A 6G reconfigurable multi-band modulation and filtering device for SSPP, characterized in that, Comprising: A dielectric substrate; A top-layer design structure disposed on the top surface of the dielectric substrate, including a first CPW structure, a first conversion structure, an active SSPP waveguide unit structure, a second conversion structure, and a second CPW structure arranged along the propagation direction of electromagnetic waves. The first conversion structure and the second conversion structure are sawtooth transition band structures with multiple sawteeth arranged at intervals, and the depths of the multiple sawteeth in the sawtooth transition band structure gradually increase in the direction towards the active SSPP waveguide unit structure. The active SSPP waveguide unit structure includes multiple serially connected active SSPP units. Each active SSPP unit includes an H-shaped waveguide and two resonant units disposed above and below the H-shaped waveguide in the vertical direction. The first resonant unit and the second resonant unit have the same structure. Each resonant unit includes a first split ring and a second split ring. The first split ring and the second split ring both include split ring vertical bars and multiple split ring horizontal bars perpendicularly disposed with respect to the split ring vertical bars. The split ring horizontal bars at the top of the first split ring and the second split ring are arranged on the same horizontal line and are connected by a varactor diode. The split ring horizontal bars at other positions of the first split ring and the second split ring are arranged in a staggered and parallel manner, and the split ring horizontal bars at other positions of the first split ring are spaced apart from the split ring vertical bars of the second split ring, and the split ring horizontal bars at other positions of the second split ring are spaced apart from the split ring vertical bars of the first split ring; A feeding structure disposed on the back surface of the dielectric substrate, wherein the feeding structure is connected to each varactor diode through a via hole.

2. The 6G reconfigurable multi-band modulation and filtering device of SSPP according to claim 1, wherein The active SSPP unit is composed of an H-shaped waveguide, a first resonant unit located above the H-shaped waveguide, and a second resonant unit located below the H-shaped waveguide. The H-shaped waveguide includes a first vertical bar and a second vertical bar of the same length arranged in parallel, and the middle positions of the first vertical bar and the second vertical bar are connected by a first horizontal bar. The first resonant unit and the second resonant unit are symmetrically arranged with respect to the first horizontal bar.

3. The 6G reconfigurable multi-band modulation and filtering device of the SSPP according to claim 2, characterized in that, The top end of the first resonant unit is flush with the top ends of the first vertical bar and the second vertical bar of the H-shaped waveguide, and the bottom end of the first resonant unit is spaced apart from the first horizontal bar of the H-shaped waveguide; the top end of the second resonant unit is flush with the top ends of the first vertical bar and the second vertical bar of the H-shaped waveguide, and the bottom end of the second resonant unit is spaced apart from the first horizontal bar of the H-shaped waveguide.

4. The 6G reconfigurable multi-band modulation and filtering device of SSPP according to claim 1, characterized in that, The capacitance of the varactor diode is adjusted between 0.3 - 0.34 pF under the control of an external bias voltage, and the center frequency of the stopband varies between 18.5 - 11.3 GHz. As the capacitance of the diode decreases, the center frequency of the stopband moves towards the high-frequency direction.

5. The 6G reconfigurable multi-band modulation and filtering device of the SSPP according to claim 1, characterized in that, When the 6G reconfigurable multi-band modulation and filtering device of SSPP needs to achieve a dual-band, a unified bias voltage is applied to the varactor diodes in the 6G reconfigurable multi-band modulation and filtering device of SSPP.

6. The 6G reconfigurable multi-band modulation and filtering device of SSPP according to claim 1, characterized in that, When the 6G reconfigurable multi-band modulation and filtering device of SSPP needs to achieve a triple-band, two different bias voltages are simultaneously applied to the varactor diodes in the 6G reconfigurable multi-band modulation and filtering device of SSPP.

7. The 6G reconfigurable multi-band modulation and filtering device of the SSPP according to claim 1, characterized in that, When the 6G reconfigurable multi-band modulation and filtering device of SSPP contains 6 active SSPP units, a first bias voltage is applied to the three left active SSPP units so that the varactor diodes in the three left active SSPP units are at a first capacitance value, and a second bias voltage is applied to the three right active SSPP units so that the varactor diodes in the three right active SSPP units are at a second capacitance value, where the first capacitance value and the second capacitance value are different.

8. The 6G reconfigurable multi-band modulation and filtering device of SSPP according to claim 1, characterized in that, According to the frequency of the carrier signal to be switched, digital signals are used to apply different bias voltages to the varactor diodes in the 6G reconfigurable multi-band modulation and filtering device of SSPP to change the capacitance of different varactor diodes.

9. The 6G reconfigurable multi-band modulation and filtering device of SSPP according to claim 8, characterized in that, A first bias voltage group and a second bias voltage group are determined according to the frequency of the first carrier signal and the second carrier signal to be switched, where the first carrier signal frequency corresponds to the first bias voltage group and the second carrier signal frequency corresponds to the second bias voltage group. The switching of the first bias voltage group and the second bias voltage group is controlled by digital signals, and the corresponding first bias voltage group or second bias voltage group is encoded and applied to the varactor diodes in the 6G reconfigurable multi-band modulation and filtering device of SSPP.

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