Filter and electronic device

Abstract

A filter and an electronic device. The filter comprises a substrate and a spoof surface plasmon polariton (SSPP) array. The SSPP array comprises m SSPP units, and the m SSPP units have the same size. Each of the m SSPP units comprises two first metal strips, which are symmetrically arranged and are not in contact, and a second metal strip, wherein the first metal strips are located on the upper surface of the substrate, and the second metal strip is located on the lower surface of the substrate. Each first metal strip comprises a rectangular structure and an anchor structure, wherein one end of the rectangular structure is coupled with an edge of the substrate, and the other end of the rectangular structure is coupled with the anchor structure; and the width of the anchor structure is greater than the width of the rectangular structure. The size of the first metal strips is related to tuning parameters of the filter. Thus, the tuning parameters of the filter can be determined directly by means of adjusting the size of the first metal strips, thereby improving the design flexibility of the filter.

Description

Filter and electronic device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on December 21, 2023, with application number 202311780869.8 and application name “A Filter and Electronic Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of electronic circuit technology, and specifically to a filter and an electronic device. Background Art

[0003] With the development of wireless communication and instrumentation electronics, filters, as key circuits, have become increasingly important.

[0004] Filters have frequency-selective properties, primarily used to extract useful signals from the spectrum and filter out other useless or interfering signals. Due to their dispersion properties, spoof surface plasmon polaritons (SSPPs) are natural low-pass filters. To achieve bandpass performance in SSPP-based filters, a transmission zero must be introduced. This low-frequency transmission zero allows SSPP-based filters to achieve bandpass performance. Furthermore, flexible tuning is a key requirement for SSPP-based bandpass filters.

[0005] However, SSPP-based filters can usually only achieve low-pass effects. Band-pass filters are not only difficult to implement, but also the tuning parameters of the filters cannot be controlled, making flexible design and tuning impossible.

[0006] Summary of the Invention

[0007] The embodiment of the present application provides a filter for realizing a bandpass filter based on SSPP and improving the design flexibility of the filter. The embodiment of the present application also provides a corresponding electronic device.

[0008] In a first aspect, the present application provides a filter comprising a substrate and a quasi-surface plasmon polaritons (SSPP) array. The SSPP array comprises m SSPP units, each having the same size, where m is an integer greater than 0. Each of the m SSPP units comprises two symmetrically arranged, non-contacting 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 comprises a rectangular structure and an anchor structure. One end of the rectangular structure is coupled to an edge of the substrate, and the other end of the rectangular structure is coupled to the anchor structure. The width of the anchor structure is greater than that of the rectangular structure. The size of the first metal strip is related to the tuning parameters of the filter.

[0009] In this application, the SSPP array can be understood as a circuit structure, where the first metal strip and the second metal strip in each SSPP unit are respectively fixed to the upper and lower surfaces of a substrate, and the material of the substrate is quartz, alumina, etc.

[0010] In this application, each SSPP unit has two first metal strips on the top and a second metal strip on the back. The two first metal strips are symmetrical about the signal propagation direction of the filter. One end of the first metal strip is coupled to the edge of the substrate and grounded, while both ends of the second metal strip are coupled to the edge of the substrate and grounded. The first and second metal strips form a double-sided coupling circuit, generating a capacitive effect. Since both sides of the coupling circuit are grounded, they achieve an equipotential effect, forming a resonant circuit, introducing a low-frequency zero point, and achieving a bandpass effect.

[0011] In this first aspect, the filter includes a substrate and a quasi-surface plasmon polariton (SSPP) array. The SSPP array includes m SSPP units, each of which has the same size. Each of the m SSPP units includes two symmetrically arranged and non-contacting first metal strips and a second metal strip, the first metal strip being located on the upper surface of the substrate, and the second metal strip being located on the lower surface of the substrate. The first metal strip includes a rectangular structure and an anchor structure, one end of the rectangular structure being coupled to an edge of the substrate, and the other end of the rectangular structure being coupled to the anchor structure, the width of the anchor structure being greater than the width of the rectangular structure, and the size of the first metal strip being related to the tuning parameters of the filter. Therefore, the tuning parameters of the filter can be determined directly by adjusting the size of the first metal strip, thereby improving the design flexibility of the filter.

[0012] In a possible implementation manner of the first aspect, the size of the first metal strip includes the length of the first metal strip and the length and width of the anchor structure.

[0013] In this possible implementation, the upper cutoff frequency of the filter can be changed by adjusting the length of the first metal strip and the length and width of the anchor structure, thereby improving the feasibility of the solution.

[0014] In a possible implementation manner of the first aspect, the width of the anchor structure is smaller than a first sum value, where the first sum value is the sum of the width of the rectangular structure and the spacing between the m SSPP units.

[0015] In this possible implementation, the width of the anchor structure is smaller than the sum of the width of the rectangular structure and the spacing between the m SSPP units. Otherwise, the anchor structures between the SSPP units will be coupled or blocked, thereby improving the feasibility of the solution.

[0016] 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.

[0017] In this possible implementation, the width of the rectangular structure is equal to the spacing between the m SSPP units, which reduces variables and design processes and improves the feasibility of the solution.

[0018] In a possible implementation manner of the first aspect, a width of the second metal strip is 0.6 to 1.4 times a width of the rectangular structure.

[0019] 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, bandpass filtering performance can be achieved, and the feasibility of the solution is improved.

[0020] In a possible implementation manner of the first aspect, a width of the second metal strip is the same as a width of the rectangular structure.

[0021] 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, thereby improving the performance of the filter.

[0022] In a possible implementation manner of the first aspect, a length of the second metal strip is the same as a length of the substrate.

[0023] In this possible implementation, the length of the second metal strip is the same as the length of the substrate, which facilitates the design and manufacture of the filter and improves the feasibility of the solution.

[0024] In a possible implementation of the first aspect, the filter further includes a transition structure, which 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 in sequence, where n is an integer greater than 0.

[0025] In this possible implementation, the transition structure realizes mode matching and impedance matching, achieves efficient transmission within the passband, and improves the electromagnetic wave power and performance of the filter.

[0026] In a possible implementation of the first aspect, a length of the first transition unit is greater than or equal to a length of the second transition unit, the first transition unit is a transition unit close to the SSPP array among the n transition units, and the second transition unit is a transition unit close to the waveguide port among the n transition units.

[0027] In this possible implementation, the transition units in the transition structure are arranged periodically and evenly in the signal propagation direction, and the lengths of the transition units in the transition structure increase or decrease in sequence to achieve mode matching and impedance matching, thereby improving the feasibility of the solution.

[0028] In a possible implementation manner of the first aspect, there are two transition structures, and the two transition structures are mirror-symmetrical along the SSPP array.

[0029] In this possible implementation, transition structures are provided on both the input side and the output side of the filter to further improve the effects of mode matching and impedance matching.

[0030] In a possible implementation manner of the first aspect, the filter further includes a waveguide port connected to the substrate.

[0031] In this possible implementation, when the filter is used as a single independent filter, the filter also includes a waveguide port to realize signal input and output, thereby improving the feasibility of the solution.

[0032] In a possible implementation manner of the first aspect, an operating frequency of the filter is greater than or equal to 50 gigahertz (GHz).

[0033] 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 W band. The specific operating frequency can also be extended to 75 GHz-110 GHz, which improves the feasibility of the solution.

[0034] A second aspect of the present application provides an electronic device, which includes the filter according to the first aspect or any possible implementation of the first aspect, and a radio frequency element coupled to the filter.

[0035] A third aspect of the present application provides a communication device, which includes a filter as described in the first aspect or any possible implementation of the first aspect, and a radio frequency element coupled to the filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is an application scenario architecture diagram of the filter;

[0037] FIG2 is a schematic diagram of an embodiment of a filter provided in an embodiment of the present application;

[0038] FIG3A is a schematic top view of a filter provided in an embodiment of the present application;

[0039] FIG3B is a front view schematic diagram of a filter provided in an embodiment of the present application;

[0040] FIG3C is a side view schematic diagram of a filter provided in an embodiment of the present application;

[0041] FIG4 is a schematic diagram of an embodiment of a SSPP unit provided in an embodiment of the present application;

[0042] FIG5 is a schematic diagram showing a comparison of simulation results of filters provided in an embodiment of the present application;

[0043] 6 and 7 are schematic diagrams of dispersion curves of the SSPP unit provided in the embodiments of the present application;

[0044] FIG8 is a schematic diagram of the electric field distribution of the filter provided in an embodiment of the present application;

[0045] FIG9 is a schematic diagram of simulation results of the filter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] The following describes the embodiments of the present application in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present application, rather than all the embodiments. Those skilled in the art will appreciate that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0047] The terms "first," "second," and the like in the specification and claims of this application and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions, e.g., a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatus.

[0048] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0049] In addition, numerous specific details are provided in the detailed description below to better illustrate the present application. Those skilled in the art will appreciate that the present application can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0050] The definitions of key terms involved in the embodiments of this application are explained below.

[0051] (1) Surface plasmonic polaritons (SPP):

[0052] When light or electromagnetic waves strike the interface between a metal and a dielectric, the free electrons in the metal conductor collectively oscillate, generating a surface electromagnetic mode (SPP). This surface electromagnetic mode is characterized by the electromagnetic field reaching a peak at the metal-dielectric interface and decaying exponentially with increasing distance in the direction perpendicular to the interface, with a faster decay rate within the metal. Therefore, SPPs possess a stronger surface binding ability for electromagnetic fields.

[0053] (2) Spoof surface plasmon polaritons (SSPP):

[0054] In lower frequency bands like the far infrared and terahertz, metals act as ideal conductors, making electromagnetic waves difficult to penetrate and eliminating true surface plasmons. Therefore, by etching or modifying periodic subwavelength artificial structures on metals or dielectrics, SSPPs can be generated in the microwave and terahertz bands. Because the structural dimensional parameters of SSPP units determine their dispersion characteristics and ability to confine electromagnetic fields, SSPP design and application offer considerable flexibility. Due to their dispersion properties, SSPP structures act as natural low-pass filters.

[0055] The following uses the above definitions of key terms to illustrate the application scenarios involved in the embodiments of the present application.

[0056] With the development of wireless communication and instrumentation electronics, filters, as key circuits, have become increasingly important.

[0057] Filters have frequency-selective functions. In radio frequency systems, filters are primarily used to extract useful signals from the spectrum and filter out useless or interfering signals. Making the filter's cutoff frequency easily tunable is crucial.

[0058] Filters are categorized by the frequency band of the signals they pass: low-pass, high-pass, band-pass, band-stop, and all-pass. A band-pass filter (BPF) allows frequency components within a certain range to pass, while attenuating frequency components in other ranges to extremely low levels. It allows signals within a certain frequency band to pass while suppressing signals, interference, and noise below and above that frequency band.

[0059] SPPs are special surface waves excited in the optical band and possess strong electric field confinement. Since metals behave as ideal conductors at low frequencies and true SPPs do not exist, SSPPs in the microwave and terahertz bands can be obtained by etching or modifying periodic subwavelength artificial structures on metals / dielectrics. Because the structural dimension parameters of an SSPP unit determine its dispersion characteristics and ability to confine electromagnetic fields, multiple dimension parameters allow for significant freedom in the design and application of SSPPs. Due to its dispersion characteristics, the SSPP structure is a natural low-pass filter. Therefore, to achieve bandpass performance, a low-frequency transmission zero must be introduced. Once this low-frequency transmission zero is introduced, SSPP-based filters can also achieve bandpass performance.

[0060] However, SSPP-based bandpass filters are not only difficult to implement (typically only achieving the effect of a low-pass filter), but also lack control over the filter's tuning parameters. Flexible tuning is also an important requirement for SSPP-based bandpass filters. Based on this, embodiments of the present application provide a filter for implementing an SSPP-based bandpass filter and improving filter design flexibility. Embodiments of the present application also provide corresponding electronic devices. These are described in detail below.

[0061] As shown in Figure 1, the filter provided by the embodiment of the present application can be used in wireless communication equipment or electronic equipment that includes a radio frequency system. The radio frequency system includes a multiplexer. The multiplexer can synthesize multiple signals of different frequencies or split a broadband signal into multiple signals of different frequencies. Usually, the multiplexer is composed of a certain number of filter combinations, and its design requires characteristics such as miniaturization and easy tuning. Using the filter provided by the embodiment of the present application, the effect of bandpass filtering is achieved based on SSPP, and the structure is simple, which can meet the requirements of miniaturization. The size can also be adjusted to change the tuning parameters of the filter to meet the requirements of easy tuning. Therefore, it can be well applied in the multiplexer.

[0062] The filter provided in the embodiment of the present application is described below in combination with the above key term definitions and application scenarios.

[0063] As shown in FIG2 , an embodiment of the present application provides a filter, which includes a substrate 100 and a quasi-surface plasmon polariton (SSPP) array.

[0064] The SSPP array includes m SSPP units, each of which has the same size, where m is an integer greater than 0. Each of the m SSPP units includes two symmetrically arranged, non-contacting first metal strips 210 and a second metal strip 220. 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 (indicated by dashed lines in the figures). The first metal strip 210 includes a rectangular structure 211 and an anchor 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 structure 212. The width of the anchor structure 212 is greater than that of the rectangular structure 211. The size of the first metal strip 210 is related to the tuning parameters of the filter.

[0065] 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 and includes n transition units. The lengths of the n transition units gradually change, where n is an integer greater than 0.

[0066] Optionally, the waveguide port 400 includes an input waveguide and an output waveguide. Similarly, there are two transition structures 300 , which are mirror-symmetrical along the SSPP array. The two transition structures 300 are an input transition structure and an output transition structure, respectively.

[0067] Specifically, in the top view shown in FIG3A , the filter comprises, from left to right, an input waveguide, an input transition structure, an SSPP array, an output transition structure, and an output waveguide. The input transition structure, SSPP array, and output transition structure are all located on a substrate 100 . Substrate 100 can be made of materials such as quartz and alumina. In this embodiment, quartz is used as an example.

[0068] In conjunction with Figure 3A, the description of length in the embodiment of the present application is understood as the distance from top to bottom of the structure, and the description of width is understood as the distance from left to right of the structure.

[0069] Combined with the front view shown in FIG3B and the side view shown in FIG3C , the input transition structure includes n transition units (n=4 is taken as an example in the embodiment of the present application), each of the n transition units includes two metal strips symmetrically arranged in the upper and lower parts, and the length l of the n transition units gradually changes, for example, increases 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, and the n transition units are periodically arranged at equal intervals in the signal propagation direction, with an interval of t. Each transition unit is two rectangular metal strips symmetrical about the signal propagation direction, one end of which is grounded through the wall of the substrate 100, the length of the inner wall of the substrate 100 is h, and the length of the transition unit increases in sequence, then: l1≤l2≤l3≤l4≤...≤l n <0.5h

[0070] For example, the input transition structure includes transition unit 1, transition unit 2, transition unit 3, and transition unit 4, whose lengths are l1, l2, l3, and l4, respectively. Taking transition unit 1 and transition unit 4 as an example, transition unit 1 is closer to waveguide port 400 than transition unit 4 and is the second transition unit, while 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 another example, transition unit 3 is closer to the SSPP array than transition unit 2 and is the first transition unit. Therefore, transition unit 2 is the second transition unit. Therefore, l3 is greater than or equal to l2.

[0071] The output transition structure is identical and symmetrical to the input transition structure, and is arranged periodically and evenly spaced in the direction of signal propagation. The length of the transition unit of each output transition structure decreases successively, which will not be described in detail in the embodiments of the present application.

[0072] The optional transition structure 300 is designed to excite the SSPP mode in the millimeter-wave E-plane waveguide bandpass filter, achieving both mode and impedance matching. Without the transition structure 300, the proposed bandpass filter's S11 (return loss) value approaches -3dB throughout the passband, meaning nearly half of the electromagnetic wave power is reflected. In contrast, a bandpass filter with input and output transition structures achieves efficient transmission within the passband.

[0073] As shown in Fig. 4, 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 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 adjacent anchor-shaped structures 212 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. Also, 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.

[0074] 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.

[0075] The second metal strip is located on the lower surface of the substrate. That is, on 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, 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.

[0076] 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.

[0077] 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.

[0078] Optionally, in practical applications, to reduce variables and design process, 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 the m SSPP units, that is, a=g.

[0079] The specific structural dimensions of the filter can be determined according to user needs. For example, the dimensions of the input waveguide and the output waveguide can be selected based on the waveguide operating frequency range of the international standard. After the size of the waveguide port is selected, the size of the substrate is proportional to or the same as the size of the waveguide port. Within the frequency band of 50 to 260 GHz, the relevant size range of the filter is as follows: l1 = 0.142 to 0.296 mm, l2 = 0.144 to 0.300 mm, l3 = 0.162 to 0.327 mm, l4 = 0.180 to 0.384 mm, c = 0.182 to 0.479 mm, a = 0.083 to 0.172 mm, g = 0.083 to 0.172 mm, w = 0.083 to 0.172 mm, t = 0.083 to 0.172 mm, f = 0.083 to 0.172 mm, d = 0.125 to 0.26 mm, e = 0.020 to 0.042 mm.

[0080] 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.

[0081] The operating frequency of the filter is greater than or equal to 50 GHz. For example, the frequency band of the operating frequency is W band, and the specific operating frequency can be further extended to 75 GHz-110 GHz.

[0082] In the embodiment of the present application, the values ​​of m and n can be determined based on user needs. The larger the m and n are, the greater the insertion loss of the filter, but the better the filtering effect.

[0083] It should be understood that the filter provided in the embodiments of the present application can be directly applied to an integrated circuit or used as a single independent filter. When the filter is used as part of an integrated circuit, the filter may not be provided with a waveguide port or a transition structure. When the filter is used as an independent filter, the filter needs to be provided with a waveguide port, but may not be provided with a transition structure. The number of transition structures and waveguide ports may also be only one, and the specific number is determined based on the user's needs.

[0084] In the embodiments of the present application, the substrate circuit is placed on the E-surface of the waveguide, upon which the input transition structure, SSPP array, and output transition structure are located. Bandpass is achieved through the SSPP array, which is double-sided coupled and grounded on both sides. An anchor structure is incorporated into the design of the top of the SSPP unit. By adjusting the width and length of the anchor structure, as well as the total length of the metal strip, the filter's upper and lower cutoff frequencies can be independently tuned, increasing design freedom and sensitivity. Furthermore, the filter's simple structure allows for miniaturization, reducing the complexity and difficulty of filter manufacturing.

[0085] The filter provided in the embodiment of the present application is further described in detail below with reference to two examples.

[0086] Example 1

[0087] 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 (ie, the first metal strip, the second metal strip, and the transition unit) is 2 μm.

[0088] The input transition circuit consists of four transition units (metal strips) of increasing length. The width w of each transition unit remains constant. The four transition units are periodically arranged in the direction of signal propagation, with a spacing of t between each unit. l1 = 0.296mm, l2 = 0.300mm, l3 = 0.327mm, and l4 = 0.384mm. The output transition structure is symmetrical to the input transition structure and has identical dimensions.

[0089] The SSPP array consists of four periodically arranged SSPP units. Each SSPP unit is composed of two symmetrical first metal strips and a second grounded metal strip on the back. One end of the first metal strip is grounded through the substrate wall. The designed SSPP unit dimensions are a = g = w = t = f = 0.172 mm and c = 0.479 mm.

[0090] The dimensions of the anchor structure are e = 0.042 mm and d = 0.2600 mm. Adjusting the width and length of the anchor structure enables independent tuning of the filter cutoff frequency, increasing the sensitivity of the design.

[0091] As shown in Figure 5, the filter provided by the embodiment of the present application has a 3dB bandwidth of 83-103 GHz and a return loss greater than 13 dB. Simulation curves for a waveguide low-pass filter without a back coupling circuit and with only the upper circuit grounded are also provided for comparison. It can be seen that the addition of a back coupling circuit and double-sided grounding achieves a bandpass effect.

[0092] As shown in Figure 6, the dispersion curves of the SSPP unit are different when the values ​​of e in the anchor structure are different, where e = 0.042 mm and d = 0.26 mm are the default parameter values. z It is found that after adjusting the width e of the anchor structure, the upper cutoff frequency decreases as e increases. Similarly, as shown in Figure 7, when the length d of the anchor structure increases, at the same frequency, the propagation constant β z As d increases, the upper cutoff frequency decreases, while the lower cutoff frequency remains unchanged. This shows that by adjusting the parameters d or e, the upper cutoff frequency can be independently controlled, increasing the sensitivity of the design.

[0093] As shown in Figure 8, this is the electric field distribution when the filter operates at a frequency of 93 GHz (the center frequency of the passband). It can be seen from the figure that electromagnetic waves can be effectively confined to propagate on the surface of the SSPP waveguide, realizing the strong confinement characteristics of the SSPP circuit on the electric field.

[0094] Example 2

[0095] This example 2 is based on example 1, but with the operating frequency of example 1 shifted to the 220 GHz band. Only the structural parameters are adjusted in the model.

[0096] The designed SSPP unit dimensions are: 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, and e = 0.020 mm.

[0097] As shown in Figure 9, in the S11 and S21 (return loss / gain) tests, the filter's 3dB bandwidth is 180-210GHz, successfully achieving a bandpass effect, and the return loss is greater than 12dB.

[0098] In another embodiment of the present application, an electronic device is provided. The electronic device includes the filter described in the above embodiment and a radio frequency element coupled to the filter.

[0099] The electronic device may specifically be an electronic instrument or a communication device. For example, the electronic device is a wireless receiver including an image rejection filter, a spurious rejection filter, a mixer, a frequency multiplier, or an amplifier. Another example is an electronic device including a multiplexer as shown in FIG1 , wherein the multiplexer includes the filter provided in an embodiment of the present application.

[0100] In another embodiment of the present application, a communication device is provided, which includes the filter described in the above embodiment and a radio frequency element coupled to the filter. The communication device can be a wireless receiver or other communication electronic device.

[0101] Those skilled in the art will appreciate that the structural units of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of this application.

[0102] In the several embodiments provided in this application, it should be understood that the disclosed structure can be implemented in other ways. For example, the embodiments described above are merely schematic. For example, the division of the structure can be divided in other ways in actual implementation, such as multiple units or components can be combined or integrated into another structure, or some features can be ignored. Some or all of the structures can be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, structures or units, which can be electrical, mechanical or other forms.

[0103] In addition, the various structures in the embodiments of the present application may be integrated into one structure, or each structure may exist physically separately, or two or more structures may be integrated into one structure.

[0104] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, 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 quasi-surface plasmon SSPP array; 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 symmetrically arranged and non-contacting first metal strips and a second metal strip, wherein 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 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 structure, the width of the anchor 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, characterized in that The dimensions of the first metal strip include the length of the first metal strip, the length and the width of the anchor structure.

3. The filter according to claim 1 or 2, characterized in that: The width of the anchor structure is smaller than a first sum value, which 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 to 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 to 4, characterized in that: The width of the second metal strip is 0.6 to 1.4 times the width of the rectangular structure.

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

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

9. The filter according to claim 8, characterized in that 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 a transition unit close to the SSPP array among the n transition units, and the second transition unit is a transition unit close to the waveguide port among the n transition units.

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-symmetrical along the SSPP array.

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

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

13. An electronic device, characterized in that: The invention comprises the filter according to any one of claims 1 to 12, and a radio frequency element coupled to the filter.

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