Filter and electronic equipment

Abstract

The invention discloses a filter and electronic equipment. The filter comprises a substrate and a quasi-surface plasmon polariton (SSPP) array. The SSPP array comprises m SSPP units, and the m SSPP units are the same in size. Each SSPP unit in the m SSPP units comprises a first metal strip and a second metal strip which are symmetrically arranged and do not make contact with each other, the first metal strip is located on the upper surface of the substrate, and the second metal strip is located on the lower surface of the substrate. The first metal strip comprises a rectangular structure and an anchor-shaped structure, one end of the rectangular structure is coupled with the edge of the substrate, the other end of the rectangular structure is coupled with the anchor-shaped structure, the width of the anchor-shaped structure is larger than that of the rectangular structure, and the size of the first metal strip is related to tuning parameters of the filter. Therefore, the tuning parameter of the filter can be determined by directly adjusting the size of the first metal strip, and the design flexibility of the filter is improved.

Description

Technical Field

[0001] Embodiments of the present application relate to the technical field of electronic circuits, and particularly to a filter and an electronic device. Background Art

[0002] With the development of wireless communication and instrumentation electronic devices, filters, as their key circuits, have become increasingly important.

[0003] Filters have a frequency selection function and are mainly used to extract useful signals in the spectrum and filter out other useless or interfering signals. According to the dispersion characteristics, spoof surface plasmon polaritons (SSPPs) are natural low-pass filters. To enable a filter based on SSPP to achieve band-pass performance, transmission zeros need to be introduced. After introducing low-frequency transmission zeros, the filter based on SSPP can also achieve band-pass performance. In addition, for a band-pass filter based on SSPP, achieving flexible tuning is also an important required function.

[0004] However, filters based on SSPP usually can only achieve low-pass effects. Band-pass filters are not only difficult to implement but also unable to control the tuning parameters of the filter and cannot achieve flexible design and tuning. Summary of the Invention

[0005] Embodiments of the present application provide a filter for implementing a band-pass filter based on SSPP and improving the design flexibility of the filter. Embodiments of the present application also provide a corresponding electronic device.

[0006] In a first aspect of the present application, a filter is provided. The filter includes a substrate and a spoof surface plasmon polariton (SSPP) array. The SSPP array includes m SSPP units, and the sizes of the m SSPP units are the same, where m is an integer greater than 0. Each of the m SSPP units includes two symmetrically arranged and non-touching first metal strips and a second metal strip. The first metal strip is located on the upper surface of the substrate, and the second metal strip is located on the lower surface of the substrate. The first metal strip includes a rectangular structure and an anchor-shaped structure. One end of the rectangular structure is coupled to the edge of the substrate, and the other end of the rectangular structure is coupled to the anchor-shaped structure. The width of the anchor-shaped structure is greater than the width of the rectangular structure, and the size of the first metal strip is related to the tuning parameters of the filter.

[0007] In the present application, the SSPP array can be understood as a circuit structure. The first metal strip and the second metal strip in each SSPP unit are respectively fixed on the upper surface and the lower surface of the substrate, and the material of the substrate is quartz, alumina, etc.

[0008] In this application, the top of each SSPP unit consists of two first metal strips, and the back is a second metal strip. The two first metal strips are symmetric with respect to the signal propagation direction of the filter. One end of the first metal strip is coupled to the ground at the edge of the substrate, and both ends of the second metal strip are coupled to the ground at the edge of the substrate. The first metal strip and the second metal strip form a double-sided coupled circuit, generating a capacitive effect, and both sides of the coupled circuit are grounded to achieve an equipotential effect, forming a resonant circuit, introducing a low-frequency zero point, and realizing a band-pass effect.

[0009] In the first aspect, the filter includes a substrate and a surface plasmon polariton (SSPP) array. The SSPP array includes m SSPP units, and the m SSPP units have the same size. Each SSPP unit in the m SSPP units includes two symmetrically arranged and non-touching first metal strips and a second metal strip. The first metal strip is located on the upper surface of the substrate, and the second metal strip is located on the lower surface of the substrate. The first metal strip includes a rectangular structure and an anchor-shaped structure. One end of the rectangular structure is coupled to the edge of the substrate, and the other end of the rectangular structure is coupled to the anchor-shaped structure. The width of the anchor-shaped structure is greater than the width of the rectangular structure. The size of the first metal strip is related to the tuning parameters of the filter. Therefore, the tuning parameters of the filter can be directly determined by adjusting the size of the first metal strip, improving the design flexibility of the filter.

[0010] In a possible implementation manner of the first aspect, the size of the first metal strip includes the length of the first metal strip, the length and width of the anchor-shaped structure.

[0011] In this possible implementation manner, by adjusting the length of the first metal strip, the length and width of the anchor-shaped structure, the upper cut-off frequency of the filter can be changed, improving the feasibility of the solution.

[0012] In a possible implementation manner of the first aspect, the width of the anchor-shaped structure is less than a first sum value, and the first sum value is the sum of the width of the rectangular structure and the spacing between the m SSPP units.

[0013] In this possible implementation manner, the width of the anchor-shaped structure is less than the sum of the width of the rectangular structure and the spacing between the m SSPP units. Otherwise, the anchor-shaped structures between the SSPP units will be coupled or blocked, improving the feasibility of the solution.

[0014] In a possible implementation manner of the first aspect, the width of the rectangular structure is equal to the spacing between the m SSPP units.

[0015] In this possible implementation manner, the width of the rectangular structure is equal to the spacing between the m SSPP units, reducing the variables and design processes, and improving the feasibility of the solution.

[0016] In a possible implementation of the first aspect, the width of the second metal strip is 0.6 to 1.4 times the width of the rectangular structure.

[0017] In this possible implementation, when the width of the second metal strip is 0.6 to 1.4 times the width of the rectangular structure, the return loss of the filter is greater than 10 dB, and the band-pass filtering performance can be achieved, improving the feasibility of the solution.

[0018] In a possible implementation of the first aspect, the width of the second metal strip is the same as the width of the rectangular structure.

[0019] In this possible implementation, when the width of the second metal strip is the same as the width of the rectangular structure, the best in-band return loss can be obtained, improving the performance of the filter.

[0020] In a possible implementation of the first aspect, the length of the second metal strip is the same as the length of the substrate.

[0021] In this possible implementation, the length of the second metal strip is the same as the length of the substrate, facilitating the design and manufacture of the filter and improving the feasibility of the solution.

[0022] In a possible implementation of the first aspect, the filter further includes a transition structure located on the upper surface of the substrate; the transition structure includes n transition units, and the lengths of the n transition units gradually change, where n is an integer greater than 0.

[0023] In this possible implementation, the transition structure realizes mode matching and impedance matching, achieving efficient transmission in the passband and improving the electromagnetic wave power and performance of the filter.

[0024] In a possible implementation of the first aspect, the length of the first transition unit is greater than or equal to the length of the second transition unit. The first transition unit is the transition unit close to the SSPP array among the n transition units, and the second transition unit is the transition unit close to the waveguide port among the n transition units.

[0025] In this possible implementation, the transition units in the transition structure are arranged periodically at equal intervals in the signal propagation direction, and the lengths of the transition units of the transition structure increase or decrease in sequence, realizing mode matching and impedance matching and improving the feasibility of the solution.

[0026] In a possible implementation of the first aspect, the number of transition structures is two, and the two transition structures are mirror-symmetrical along the SSPP array.

[0027] In this possible implementation, transition structures are correspondingly arranged on both the input side and the output side of the filter, further improving the effect of mode matching and impedance matching.

[0028] In a possible implementation of the first aspect, the filter further includes a waveguide port, and the waveguide port is connected to the substrate.

[0029] In this possible implementation, when the filter is used as a single independent filter, the filter further includes a waveguide port to realize signal input and output, improving the feasibility of the solution.

[0030] In a possible implementation of the first aspect, the operating frequency of the filter is greater than or equal to 50 gigahertz (GHz).

[0031] In this possible implementation, the operating frequency of the filter is greater than or equal to 50 GHz. For example, the frequency band range of the operating frequency is the W band, and the specific operating frequency can also be extended to 75 GHz - 110 GHz, improving the feasibility of the solution.

[0032] The second aspect of the present application provides an electronic device, which includes a filter as described in the above first aspect or any possible implementation of the first aspect, and a radio frequency component coupled to the filter.

[0033] The third aspect of the present application provides a communication device, which includes a filter as described in the above first aspect or any possible implementation of the first aspect, and a radio frequency component coupled to the filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is an architecture diagram of the application scenario of the filter;

[0035] Figure 2 It is a schematic diagram of an embodiment of the filter provided by the embodiment of the present application;

[0036] Figure 3A It is a top view schematic diagram of the filter provided by the embodiment of the present application;

[0037] Figure 3B It is a front view schematic diagram of the filter provided by the embodiment of the present application;

[0038] Figure 3C It is a side view schematic diagram of the filter provided by the embodiment of the present application;

[0039] Figure 4 It is a schematic diagram of an embodiment of the SSPP unit provided by the embodiment of the present application;

[0040] Figure 5 It is a schematic diagram of the comparison of the simulation results of the filter provided by the embodiment of the present application;

[0041] Figure 6 andFigure 7 Schematic diagram of the dispersion curve of the SSPP unit provided by the embodiment of the present application;

[0042] Figure 8 Schematic diagram of the electric field distribution of the filter provided by the embodiment of the present application;

[0043] Figure 9 Schematic diagram of the simulation result of the filter provided by the embodiment of the present application. Detailed implementation manners

[0044] The embodiments of the present application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Those of ordinary skill in the art will know that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0045] The terms "first", "second", etc. in the specification, claims and drawings of the present application are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments described here can be implemented in an order different from that shown or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these process, method, product or device.

[0046] The special term "exemplary" here means "serving as an example, embodiment or illustration". Any embodiment described as "exemplary" here does not have to be construed as superior to or better than other embodiments.

[0047] In addition, for better illustration of the present application, numerous specific details are given in the following detailed implementation manners. Those skilled in the art should understand that the present application can also be implemented without some specific details. In some instances, methods, means, elements and circuits well-known to those skilled in the art are not described in detail so as to highlight the gist of the present application.

[0048] The key term definitions related to the embodiments of the present application will be explained below.

[0049] (1) Surface plasmonic polaritons (SPP):

[0050] When light or electromagnetic waves are incident on the interface between a metal and a dielectric, the free electrons in the metal conductor undergo collective oscillations, thereby generating a surface electromagnetic mode. At this time, the metal conductor is a SPP. The characteristics of this surface electromagnetic mode are as follows: The electromagnetic field reaches its peak at the interface between the metal and the dielectric, and in the direction perpendicular to the interface, it decays exponentially with the increase of distance, and the decay rate is faster in the metal. Therefore, this mode of SPP has a stronger surface confinement ability for the electromagnetic field.

[0051] (2) Spoof surface plasmon polaritons (SSPP):

[0052] In frequency bands with relatively low frequencies such as far-infrared and terahertz, the metal is equivalent to an ideal conductor, and electromagnetic waves are difficult to penetrate, and there are no true surface plasmon polaritons. Therefore, by etching or modifying periodic sub-wavelength artificial structures on the metal or dielectric, SSPP in the microwave and terahertz bands can be obtained. Since the structural size parameters of the SSPP unit determine its dispersion characteristics and the ability to confine the electromagnetic field, the design and application of SSPP have a great degree of freedom. According to the dispersion characteristics, the SSPP structure is a natural low-pass filter.

[0053] The following is an example of the application scenario involved in the embodiments of this application in combination with the above key term definitions.

[0054] With the development of wireless communication and instrumentation electronic devices, the filter, as a key circuit thereof, has also increased in importance.

[0055] The filter has a frequency selection function. For a radio frequency system, the filter is mainly used to extract useful signals in the spectrum and filter out other useless or interfering signals. For the cut-off frequency of the filter, it is very important to make the filter easier to tune.

[0056] Filters are classified into five types: low-pass, high-pass, band-pass, band-stop, and all-pass filters according to the frequency band of the signals they pass. A band-pass filter (BPF) is a filter that can pass frequency components within a certain frequency range, but attenuates frequency components in other ranges to a very low level. It allows signals in a certain frequency band to pass and suppresses signals, interference, and noise below or above this frequency band.

[0057] SPP is a special surface wave excited in the optical band with strong electric field confinement. Since metals behave as perfect conductors in the low-frequency band and there is no true SPP, periodic sub-wavelength artificial structures can be etched / modified on metal / dielectrics to obtain SSPP in the microwave and terahertz bands. Since the structural size parameters of the SSPP unit determine its dispersion characteristics and the ability to confine electromagnetic fields, the multi-size parameters give great freedom to the design and application of SSPP; according to the dispersion characteristics, the SSPP structure is a natural low-pass filter. Therefore, in order to achieve band-pass performance, it is necessary to introduce low-frequency transmission zeros. After introducing low-frequency transmission zeros, the SSPP-based filter can also achieve band-pass performance.

[0058] However, the SSPP-based band-pass filter is not only difficult to implement (usually only the effect of a low-pass filter can be achieved), but also unable to control the tuning parameters of the filter. For the SSPP-based band-pass filter, flexible tuning is also an important required function. Based on this, the embodiments of the present application provide a filter for implementing an SSPP-based band-pass filter and improving the design flexibility of the filter. The embodiments of the present application also provide corresponding electronic devices. The following will be described in detail respectively.

[0059] As Figure 1 shown, the filter provided by the embodiments of the present application can be used in a wireless communication device or an electronic device including a radio frequency system. The radio frequency system includes a multiplexer. The multiplexer can synthesize multiple signals with different frequencies or split a broadband signal into multiple signals with different frequencies. Usually, the multiplexer is composed of a certain number of filter combinations, and its design requirements include miniaturization, easy tuning, etc. Using the filter provided by the embodiments of the present application, the effect of band-pass filtering is achieved based on SSPP, and the structure is simple, which can meet the requirements of miniaturization. The tuning parameters of the filter can also be adjusted by changing the size to meet the requirements of easy tuning. Therefore, it can be well applied in the multiplexer.

[0060] The filter provided by the embodiments of the present application will be described below in combination with the above key term definitions and application scenarios.

[0061] As Figure 2 shown, the embodiments of the present application provide a filter. An embodiment of the filter includes a substrate 100 and a surface plasmon polariton (SSPP) array.

[0062] Among them, the SSPP array includes m SSPP units. The m SSPP units have the same size, and m is an integer greater than 0. Each of the m SSPP units includes two first metal strips 210 and a second metal strip 220 that are symmetrically arranged and do not touch. The first metal strip 210 is located on the upper surface of the substrate 100, and the second metal strip 220 is located on the lower surface of the substrate 100 (represented by a dotted line in the drawing). The first metal strip 210 includes a rectangular structure 211 and an anchor-shaped structure 212. One end of the rectangular structure 211 is coupled to the edge of the substrate 100, and the other end of the rectangular structure 211 is coupled to the anchor-shaped structure 212. The width of the anchor-shaped structure 212 is greater than the width of the rectangular structure 211. The size of the first metal strip 210 is related to the tuning parameters of the filter.

[0063] Optionally, the filter further includes a transition structure 300 and a waveguide port 400. The waveguide port 400 is connected to the substrate 100. The transition structure 300 is located between the SSPP array and the waveguide port 400. The transition structure 300 is located on the upper surface of the substrate 100. The transition structure 300 includes n transition units, and the lengths of the n transition units gradually change. n is an integer greater than 0.

[0064] Optionally, the waveguide port 400 includes an input waveguide and an output waveguide. Similarly, the number of transition structures 300 is two. The two transition structures 300 are mirror-symmetric along the SSPP array. The two transition structures 300 are an input transition structure and an output transition structure respectively.

[0065] Specifically, in the top view as Figure 3A shown, the filter sequentially includes an input waveguide, an input transition structure, an SSPP array, an output transition structure, and an output waveguide from left to right. The input transition structure, the SSPP array, and the output transition structure are all located on the substrate 100. The substrate 100 can be made of materials such as quartz and alumina. In this embodiment of the application, the substrate 100 is taken as an example of quartz for illustration.

[0066] Combined with Figure 3A , in this embodiment of the application, the description of the length is understood as the distance from top to bottom of the structure, and the description of the width is understood as the distance from left to right of the structure.

[0067] Combined with the front view as Figure 3B shown and the Figure 3CThe side view shown, the input transition structure includes n transition units (taking n = 4 as an example in the embodiments of the present application). Each of the n transition units includes two metal strips that are symmetric up and down. The lengths l of the n transition units gradually change in sequence, for example, increase in sequence, that is, the length of the first transition unit is greater than or equal to the length of the second transition unit. The first transition unit is the transition unit close to the SSPP array among the n transition units, and the second transition unit is the transition unit close to the waveguide port 400 among the n transition units. The width w of each transition unit remains unchanged. The n transition units are arranged at equal intervals periodically in the signal propagation direction, and the interval is t. Each transition unit is two rectangular metal strips that are symmetric about the signal propagation direction. One end of them is grounded through the wall surface of the substrate 100. The length of the inner wall of the substrate 100 is h, and the lengths of the transition units increase in sequence, then there is:

[0068] l1≤l2≤l3≤l4≤…≤l n <0.5h

[0069] Exemplarily, in the input transition structure, it includes transition unit 1, transition unit 2, transition unit 3, and transition unit 4, and their lengths are l1, l2, l3, and l4 respectively. Taking transition unit 1 and transition unit 4 as an example, transition unit 1 is the transition unit closer to the waveguide port 400 compared to transition unit 4, and it is the second transition unit. Then transition unit 4 is the first transition unit. Therefore, l4 is greater than or equal to l1. Taking transition unit 2 and transition unit 3 as an example again, transition unit 3 is the transition unit closer to the SSPP array compared to transition unit 2, and it is the first transition unit. Then transition unit 2 is the second transition unit. Therefore, l3 is greater than or equal to l2.

[0070] The output transition structure is the same as and symmetric to the input transition structure, and is arranged at equal intervals periodically in the signal propagation direction. The lengths of the transition units of each output transition structure decrease in sequence, which will not be elaborated in the embodiments of the present application.

[0071] Optionally, the transition structure 300 is to excite the SSPP mode in the millimeter-wave E-plane waveguide bandpass filter to achieve mode matching and impedance matching. If the transition structure 300 is not used, the S11 (return loss) value of the proposed bandpass filter is close to -3 dB in the entire passband, which means that nearly half of the electromagnetic wave power is reflected. In contrast, the bandpass filter with the input transition structure and the output transition structure can achieve efficient transmission in the passband.

[0072] Such as Figure 4As shown, the SSPP array is composed of m identical SSPP units arranged periodically. At the top of each SSPP unit are two first metal strips 210 that are symmetric about the signal propagation direction (from the input waveguide to the output waveguide). The first metal strips 210 are located on the upper surface of the substrate 100. The first metal strip 210 includes a rectangular structure 211 and an anchor-shaped structure 212. One end of the rectangular structure 211 is coupled to the ground at the edge of the substrate 100. In this SSPP unit, the total length of the first metal strip 210 is b, the width of the rectangular structure 211 is a, the length is c, the width of the anchor-shaped structure 212 is d, the length is e, and the interval between the metal strips of the anchor-shaped structures 212 adjacent in the signal propagation direction is g, that is, the interval between each SSPP unit is g. In addition, d > a, b = c + e, and e < c. In addition, a < d < a + g, that is, the width of the anchor-shaped structure 212 is less than the first sum value, and the first sum value is the sum of the width of the rectangular structure 211 and the spacing between m SSPP units.

[0073] Among them, the dimensions of the first metal strip are related to the tuning parameters of the filter. The dimensions of the first metal strip include the length of the first metal strip, the length and width of the anchor-shaped structure. That is, by changing the width d and length e of the anchor-shaped structure, and adjusting the length b of the first metal strip, the independent tuning ability of the upper cut-off frequency and lower cut-off frequency of the filter can be achieved, increasing the sensitivity of the design.

[0074] The second metal strip is located on the lower surface of the substrate, that is, the back of the SSPP unit is a rectangular metal strip that overlaps the widths of the two symmetric first metal strips at the top up and down, that is, the second metal strip. Both ends of the second metal strip are coupled to the ground at the edge of the substrate. The width of the second metal strip is f, and the length of the second metal strip is the same as the length of the substrate, that is, the length of the second metal strip is h.

[0075] Optionally, the width of the second metal strip is 0.6 times to 1.4 times the width of the rectangular structure. That is, when 0.6a ≤ f ≤ 1.4a, the return loss is greater than 10 dB, and the band-pass filtering performance can be achieved. When the width of the second metal strip is the same as the width of the rectangular structure, that is, f = a, the best in-band return loss can be obtained. The first metal strip and the second metal strip form a double-sided coupling circuit, generating a capacitance effect, and both sides of the coupling circuit are grounded to achieve an equipotential effect, forming a resonant circuit, introducing a low-frequency zero point, and achieving a band-pass effect.

[0076] It should be understood that the second metal strips of each SSPP unit can also be all coupled into one metal strip, that is, increasing the width of each rectangular structure to make f = a + g, but this will also affect the in-band return loss of the filter.

[0077] Optionally, in practical applications, to reduce variables and design processes, the sizes of w, t, a, g, and f can be the same. For example, the width of the rectangular structure is equal to the spacing between m SSPP units, i.e., a = g.

[0078] The specific structural dimensions of this filter can be determined according to user requirements. Exemplarily, the sizes of the input waveguide and the output waveguide can be selected based on the waveguide operating frequency range of international standards. After determining the sizes of the waveguide ports, the size of the substrate is proportional to or the same as the size of the waveguide ports. In the frequency band range of 50 - 260 GHz, the size ranges related to this filter are as follows: l1 = 0.142 - 0.296 mm, l2 = 0.144 - 0.300 mm, l3 = 0.162 - 0.327 mm, l4 = 0.180 - 0.384 mm, c = 0.182 - 0.479 mm, a = 0.083 - 0.172 mm, g = 0.083 - 0.172 mm, w = 0.083 - 0.172 mm, t = 0.083 - 0.172 mm, f = 0.083 - 0.172 mm, d = 0.125 - 0.26 mm, e = 0.020 - 0.042 mm.

[0079] Among them, the low frequency of the filter corresponds to the upper limit of the above size range, and the high frequency of the filter corresponds to the lower limit of the above size range.

[0080] The operating frequency of this filter is greater than or equal to 50 GHz. For example, the frequency band range of the operating frequency is the W band, and the specific operating frequency can also be extended to 75 GHz - 110 GHz.

[0081] In the embodiments of this application, the values of m and n can be determined based on user requirements. The larger m and n are, the greater the insertion loss of this filter, but the better the filtering effect.

[0082] It should be understood that the filter provided in the embodiments of this application can be directly applied to an integrated circuit or used as a single independent filter. When this filter is used as part of an integrated circuit, this filter can be provided without waveguide ports or without a transition structure. When this filter is used as an independent filter, this filter needs to be provided with waveguide ports, but can also be provided without a transition structure. The number of the transition structure and the waveguide ports can also be only one, and its specific number is determined based on user requirements.

[0083] In the embodiments of the present application, the substrate circuit is placed on the E-plane of the waveguide, and there are an input transition structure, an SSPP array, and an output transition structure thereon. The band-pass effect is achieved through the SSPP array with double-sided coupling and bilateral circuit grounding. An anchor structure is introduced in the design of the top of the SSPP unit. By adjusting the width and length of the anchor structure and the total length of the metal strip, the independent tuning ability of the upper and lower cut-off frequencies of the filter can be realized, increasing the design freedom and sensitivity. In addition, the structure of the filter is simple, and the miniaturization of the filter can also be realized, reducing the manufacturing complexity and difficulty of the filter.

[0084] The following further describes the filter provided by the embodiments of the present application in conjunction with two examples.

[0085] Example 1

[0086] In this example, the waveguide port is a standard rectangular waveguide WR-10, the substrate is quartz, the substrate thickness is 50 μm, and the thickness of the metal layer (i.e., the first metal strip, the second metal strip, and the transition unit) is 2 μm.

[0087] The input transition circuit consists of 4 transition units (metal strips) with gradually increasing lengths. The width w of each transition unit remains unchanged. The 4 transition units are arranged periodically in the signal propagation direction, and the interval between every two transition units is t. l1 = 0.296 mm, l2 = 0.300 mm, l3 = 0.327 mm, l4 = 0.384 mm. The output transition structure is symmetric to the input transition structure and has exactly the same dimensions.

[0088] The SSPP array consists of 4 periodically arranged SSPP units. Each SSPP unit is composed of two symmetric first metal strips and the second metal strip on the back for grounding. One end of the first metal strip is grounded through the substrate wall. The designed dimensions of the SSPP unit are a = g = w = t = f = 0.172 mm, c = 0.479 mm.

[0089] The dimensions of the anchor structure are e = 0.042 mm, d = 0.2600 mm. By adjusting the width and length of the anchor structure, the independent tuning ability of the cut-off frequency of the filter can be realized, increasing the design sensitivity.

[0090] As Figure 5 shown, it can be seen that the 3 dB bandwidth of the filter provided by the embodiments of the present application is 83 - 103 GHz, and the return loss is greater than 13 dB. For comparison, the simulation curve of a waveguide low-pass filter with no back-coupling circuit and only the upper circuit grounded is also given. It can be seen that the band-pass effect is achieved by adding the back-coupling circuit and double-sided grounding.

[0091] As Figure 6As shown, when different values of e are used in the anchor structure, the dispersion curves of the SSPP unit are also different, where e = 0.042 mm and d = 0.26 mm are the default parameter values. Figure 6 In it, β z represents the propagation constant along the propagation direction. It can be found that after adjusting the width e of the anchor structure, the upper cut-off frequency decreases as e increases. Similarly, as Figure 7 shown, when the length d of the anchor structure increases, at the same frequency, the propagation constant β z increases and the upper cut-off frequency decreases, while the lower cut-off frequency remains unchanged. This indicates that independent control of the upper cut-off frequency can be achieved by adjusting the parameter d or e, increasing the sensitivity of the design.

[0092] As Figure 8 shown, for the electric field distribution when the operating frequency of this filter is 93 GHz (center frequency of the passband), it can be seen from the figure that the electromagnetic wave can be effectively confined to propagate on the surface of the SSPP waveguide, realizing the strong confinement characteristic of the SSPP circuit to the electric field.

[0093] Example 2

[0094] This Example 2 is a model that moves the operating frequency of Example 1 to the 220 GHz band on the basis of Example 1. Only the structural parameters are adjusted in the model.

[0095] Among the designed SSPP unit dimensions, l1 = 0.142 mm, l2 = 0.144 mm, l3 = 0.162 mm, l4 = 0.180 mm. c = 0.182 mm,, a = g = w = t = f = 0.083 mm, d = 0.125 mm, e = 0.020 mm.

[0096] As Figure 9 shown, in the S11 and S21 (return loss / gain) tests, the 3 dB bandwidth of this filter is 180 - 210 GHz, successfully achieving the band-pass effect, and the return loss is greater than 12 dB.

[0097] In another embodiment of the present application, an electronic device is further provided. This electronic device includes the filter described in the above embodiment, and a radio frequency component coupled to the filter.

[0098] This electronic device can specifically be an electronic instrument device or a communication device. For example, this electronic device is a wireless receiver including an image frequency rejection filter, a spurious rejection filter, a mixer, a frequency multiplier or an amplifier. For another example, this electronic device is an electronic device including a multiplexer as Figure 1 shown, and this multiplexer includes the filter provided in the embodiment of the present application.

[0099] In another embodiment of the present application, a communication device is further provided. The communication device includes the filter described in the above embodiment and a radio frequency component coupled to the filter. The communication device may specifically be a wireless receiver or other communication electronic device.

[0100] Those of ordinary skill in the art can realize that the structural units of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the embodiments of the present application.

[0101] In several embodiments provided by the present application, it should be understood that the disclosed structure can be implemented in other ways. For example, the above-described embodiments are merely illustrative. For example, the division of the structure may have other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another structure, or some features can be ignored. One can select some or all of the structures according to actual needs to achieve the purpose of the solution of this embodiment. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of structures or units can be in electrical, mechanical or other forms.

[0102] In addition, the various structures in the embodiments of the present application can be integrated into one structure, or each structure can exist physically alone, or two or more structures can be integrated into one structure.

[0103] The above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A filter, characterized in that, It includes a substrate and a spoof surface plasmon polariton (SSPP) array; The SSPP array includes m SSPP units, and the m SSPP units have the same size, where m is an integer greater than 0; Each of the m SSPP units includes two symmetrically arranged and non-touching first metal strips and a second metal strip. The first metal strip is located on the upper surface of the substrate, and the second metal strip is located on the lower surface of the substrate; The first metal strip includes a rectangular structure and an anchor-shaped structure. One end of the rectangular structure is coupled to the edge of the substrate, and the other end of the rectangular structure is coupled to the anchor-shaped structure. The width of the anchor-shaped structure is greater than the width of the rectangular structure, and the size of the first metal strip is related to the tuning parameters of the filter.

2. The filter according to claim 1, wherein The size of the first metal strip includes the length of the first metal strip, the length and width of the anchor-shaped structure.

3. The filter according to claim 1 or 2, characterized in that, The width of the anchor-shaped structure is less than a first sum value, and the first sum value is the sum of the width of the rectangular structure and the spacing between the m SSPP units.

4. The filter according to any one of claims 1-3, characterized in that, The width of the rectangular structure is equal to the spacing between the m SSPP units.

5. The filter according to any one of claims 1-4, characterized in that The width of the second metal strip is 0.6 times to 1.4 times the width of the rectangular structure.

6. The filter according to any one of claims 1-4, characterized in that The width of the second metal strip is the same as the width of the rectangular structure.

7. The filter according to any one of claims 1-6, characterized in that, The length of the second metal strip is the same as the length of the substrate.

8. The filter according to any one of claims 1-7, characterized in that The filter further includes a transition structure, and the transition structure is located on the upper surface of the substrate; The transition structure includes n transition units, and the lengths of the n transition units gradually change, where n is an integer greater than 0.

9. The filter according to claim 8, wherein The length of the first transition unit is greater than or equal to the length of the second transition unit. The first transition unit is the transition unit among the n transition units that is closer to the SSPP array, and the second transition unit is the transition unit among the n transition units that is closer to the waveguide port.

10. The filter according to claim 8 or 9, characterized in that, The number of the transition structures is two, and the two transition structures are mirror-symmetric along the SSPP array.

11. The filter according to any one of claims 1-10, characterized in that, The filter further includes a waveguide port, and the waveguide port is connected to the substrate.

12. The filter according to any one of claims 1-11, characterized in that, The operating frequency of the filter is greater than or equal to 50 gigahertz (GHz).

13. An electronic device, characterized in that, It includes a filter as described in any one of claims 1-12, and a radio frequency component coupled to the filter.

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