CN219779178U - Slow wave substrate integrated waveguide filter - Google Patents

Abstract

The embodiment of the utility model provides a slow wave substrate integrated waveguide filter, which is used for solving the defects of larger structural size and complex manufacturing process of the conventional slow wave substrate integrated waveguide filter with a multilayer structure. The filter comprises a single-layer medium matrix, a first metal layer and a second metal layer, wherein peripheral metallized through hole arrays are arranged at equal intervals on the periphery of the medium matrix, a coupling metallized through hole array and an internal metallized blind hole array are arranged in the middle of the medium matrix, the metallized through holes are electrically connected with the first metal layer and the second metal layer, and the metallized blind holes are electrically connected with the second metal layer; the peripheral metallized through hole array, the coupling metallized through hole array and the internal metallized blind hole array form a slow wave filter structure consisting of a resonant cavity and a coupling window, so that a slow wave effect is realized, and the single-layer and miniaturization of the slow wave substrate integrated waveguide filter are further realized.

Description

Slow wave substrate integrated waveguide filter

Technical Field

The utility model relates to the technical field of microwave radio frequency, in particular to a slow wave substrate integrated waveguide filter.

Background

As the related research of the fifth generation mobile communication system (Fifth Generation Mobile Communications System, 5G) is fully spread, the performance of microwave devices and subsystems, such as miniaturization and systemizable integration, is critical to the performance of the entire wireless communication system. The slow wave substrate integrated waveguide is miniaturized by reducing the transverse and longitudinal dimensions of the device, can be effectively combined with other miniaturization technologies, and is a miniaturized scheme with great development prospect.

In 2015, matthieu Bertrand first applied a slow wave substrate integrated waveguide to the design of a bandpass filter. In 2020, y.l.zhou proposed and studied a slow wave substrate integrated waveguide loaded by antipodal double-metallized blind hole array and an improved topology structure thereof, which realizes a more compact longitudinal dimension and further reduces the phase velocity. 2021, y.zhang proposed a slow wave substrate integrated waveguide that increased the effective permeability and effective permittivity by loading metallized blind vias and patches shorter than the metallized blind vias, resulting in a reduction in longitudinal and lateral dimensions.

However, the inventor finds that, in the process of implementing the technical solution in the embodiment of the present utility model, the existing slow-wave substrate integrated waveguide filter has at least the following technical problems:

the existing slow wave substrate integrated waveguide filter is of a multi-layer substrate structure, so that an additional metal layer is needed to realize the electrical connection between the substrate layers, and a bonding pad is needed to be added at the top of the metalized blind hole to realize the electrical connection.

Disclosure of Invention

Accordingly, an object of the embodiments of the present utility model is to provide a slow-wave substrate integrated waveguide filter, which has the defects of larger structural size and complex manufacturing process in the existing slow-wave substrate integrated waveguide filter with a multilayer structure. According to the embodiment of the utility model, through the arrangement of the single-layer dielectric matrix, the peripheral metallized through hole array, the coupling metallized through hole array and the internal metallized blind hole array, the metallized blind holes are only electrically connected with the second metal layer, the internal metallized blind hole array limits an electric field inside, a magnetic field flows around the metallized through holes and the metallized blind holes and continues in the whole dielectric matrix, so that a waveguide resonant cavity with a slow wave effect is formed in the single-layer dielectric matrix, and the single-layer and miniaturization of the slow wave substrate integrated waveguide filter are realized.

In order to achieve the above object, the technical scheme adopted in the embodiment of the present utility model is as follows:

the embodiment of the utility model provides a slow wave substrate integrated waveguide filter, which comprises the following components:

a dielectric substrate; the medium matrix is of a single-layer cuboid structure;

a first metal layer; the first metal layer covers the upper surface of the dielectric substrate;

a second metal layer; the second metal layer covers the lower surface of the dielectric substrate;

a peripheral metallized via array; the periphery metallized through hole array is a rectangular metallized through hole array formed by arranging metallized through holes on the medium matrix in an equidistant mode, and the metallized through holes are electrically connected with the first metal layer and the second metal layer; the peripheral metallized through hole array is provided with an input interface window and an output interface window;

an input feed line; the input feeder is electrically connected with the input interface window and is used for inputting an original frequency signal;

an output feeder; the output feeder is electrically connected with the output interface window and is used for outputting the filtered frequency signal;

an array of internally metallized blind holes; the inner metallized blind hole array is a rectangular metallized blind hole array formed by arranging metallized blind holes row by row and column on the medium matrix in the peripheral metallized blind hole array, and the metallized blind holes are electrically connected with the second metal layer;

n coupling metallized through-hole queues; n coupling metallized through hole queues are embedded in the inner metallized blind hole array, the inner space of the peripheral metallized through hole array is divided into m waveguide resonant cavities, and metallized through holes of the coupling metallized through hole queues are electrically connected with the first metal layer and the second metal layer;

when an original frequency signal is input through the input feeder line, an electric field is limited between the metallized blind holes of the inner metallized blind hole array and the second metal layer, and a magnetic field flows around the metallized through holes and the metallized blind holes, so that a slow wave effect is generated;

the coupling metallized through hole queue between the two waveguide resonant cavities through which the frequency signals flow front and back is provided with a coupling window; m waveguide resonant cavities and m-1 coupling windows inserted in the waveguide resonant cavities are alternately arranged to form a filtering structure with a slow wave effect;

wherein n is a positive integer greater than or equal to 0, and m is a positive integer greater than or equal to 1.

Optionally, the filter further includes:

an input metallized blind hole queue for guiding frequency signal input; the input metallized blind hole array is arranged on the medium matrix below the input feeder line, and the metallized blind holes of the input metallized blind hole array are electrically connected with the second metal layer;

the output metallized blind hole queue is used for guiding the output of the frequency signal; the output metallized blind hole array is arranged on the medium matrix below the output feeder line, and the metallized blind holes of the output metallized blind hole array are electrically connected with the second metal layer.

Optionally, the depth of the metallized blind holes in the array of internal metallized blind holes is 60% -80% of the thickness of the dielectric substrate.

Optionally, the depth of the metallized blind holes in the array of internal metallized blind holes is in particular 75% of the thickness of the dielectric substrate.

Optionally, the hole structures of the metallized through holes and the metallized blind holes are made by etching process; the metal layers in the metallized through holes and the metallized blind holes are manufactured through an electroplating process and/or a sputtering process.

Optionally, the material of the dielectric substrate is a quartz glass material.

Based on the technical scheme, the slow wave substrate integrated waveguide filter in the embodiment of the utility model constructs a rectangular wave conductive wall by arranging metallized through holes on a single-layer dielectric substrate in an equidistant mode; by arranging metallized blind holes row by row and column by column on the dielectric substrate in the peripheral metallized through hole array, an electric field region in which a frequency signal can run is constructed; the inner space of the peripheral metallized through hole array is divided into m waveguide resonant cavities by embedding n coupling metallized through hole queues in the inner metallized blind hole array, so as to construct a unit for filtering frequency signals; and a coupling window is arranged in the coupling metallized through hole array between the two waveguide resonant cavities through which the frequency signals flow in front of and behind, so that a frequency signal channel between the two waveguide resonant cavities is constructed. Thus, on the one hand, the electric field is limited between the top of the metallized blind via and the first metal layer, and the magnetic field flows around the metallized through via and the metallized blind via and continuously exists in the whole dielectric matrix, so that the slow wave effect is realized; the slow wave effect enables the frequency signal to propagate in the structure at a low speed, so that the interaction time between the frequency signal and the structure is prolonged, and the filtering processing of the frequency signal is facilitated. On the other hand, m-1 coupling windows are used for connecting m waveguide resonant cavities to form a filtering structure with a slow wave effect. The filtering structure enables the frequency signal to be reflected and coupled for multiple times in the structure, the frequency selectivity is stronger, and the filtering effect is better. In the embodiment of the utility model, the dielectric constant of the dielectric matrix of the slow-wave substrate integrated waveguide filter with the filtering structure of the slow-wave effect can be selected to be larger, the cut-off frequency of the slow-wave substrate integrated waveguide resonant cavity is lower, and the size of the substrate integrated waveguide resonant cavity can be made smaller.

Compared with the conventional slow-wave substrate integrated waveguide filter with a multilayer substrate structure, the slow-wave substrate integrated waveguide filter in the embodiment of the utility model adopts a single-layer medium matrix, has simpler manufacturing process, higher production efficiency and higher yield, and is beneficial to mass production of products and cost reduction; the structure is more compact, the size is smaller, the integrated circuit is easier to combine with other integrated schemes, the integration level is higher, and the integrated cost is lower; the shielding performance is higher, the leakage emission is lower, the radiation resistance is higher, and the shielding material is more suitable for being used under the conditions of high power and high sensitivity. In short, compared with the prior art, the slow wave substrate integrated waveguide filter in the embodiment of the utility model has a much smaller structural size, can be effectively combined with other miniaturization schemes, and has correspondingly much better integrability. Meanwhile, the low-power integrated waveguide filter has the characteristics of high power capacity, low loss, low radiation, high Q value and the like which are the same as those of the conventional slow-wave integrated waveguide filter with the multilayer substrate structure.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the present utility model, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic block diagram of a view of a second metal layer of a slow wave substrate integrated waveguide filter in an embodiment of the present utility model;

FIG. 2 shows a schematic block diagram of a view of a first metal layer of a slow wave substrate integrated waveguide filter in an embodiment of the present utility model;

FIG. 3 shows a schematic cross-sectional view of a slow wave substrate integrated waveguide filter in an embodiment of the utility model;

fig. 4 shows a diagram of S-parameter simulation results of a slow-wave substrate integrated waveguide filter in an embodiment of the present utility model.

Wherein, the correspondence between the reference numerals and the component names in the figures is as follows:

the dielectric substrate 1, the first metal layer 2, the second metal layer 3, the peripheral metallized through hole array 4, the input interface window 401, the output interface window 402, the internal metallized blind hole array 5, the coupling metallized through hole array 6, the coupling window 601, the waveguide resonant cavity 7, the input metallized blind hole array 8 and the output metallized blind hole array 9.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the drawings of the embodiments of the present utility model in conjunction with practical applications, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In the embodiment of the utility model, the slow wave substrate integrated waveguide filter can be widely applied to various communication systems.

The antenna tuning unit can be used in a radio frequency transceiver to select and filter signals with different frequencies, and can also be used in an antenna tuning unit to change the working frequency band and the directional characteristic of the antenna by selecting or filtering different frequencies.

In the radar system, the selection and filtering of radar signals with different pulse widths and repetition frequencies can be realized, the method is used for receiving and processing the signals, and the method can also be applied to frequency synthesis, and the required working frequency is obtained by selecting and filtering different frequencies.

In the satellite communication system, the method can be applied to an uplink and a downlink to realize the selection and the filtering of different frequency signals, such as selecting a certain carrier frequency in an operating frequency band or filtering interference frequencies.

In the direction finding and navigation system, the method can be used for selecting and filtering different carrier frequencies, codes and phases so as to realize the receiving and processing of specific signals.

In the wireless local network, the method can be used for selecting and filtering different carrier frequencies and frequency channels, realizing the selection of specific working frequency bands and frequencies and improving the utilization rate of frequency resources.

In the optical fiber communication system, the method can be used for selecting and filtering different optical carrier frequencies to realize the selection and processing of optical signals.

Based on the integrated circuit manufacturing process, the slow wave substrate integrated waveguide filter can be integrated on the same chip together with other microwave passive devices or active devices to construct a microwave integrated circuit, is suitable for a system with higher frequency and wider bandwidth, and realizes higher-level functions and smaller volume.

In order to facilitate a clear and complete understanding of the technical solutions of the embodiments of the present utility model, terms related to the present utility model in the following description of the present utility model will be given.

The term "Electric wall" is any curved surface that satisfies the boundary condition of an ideal conductor (epslon=infinite). Et and Hn are both 0 inside the conductor; the power line is perpendicular to the conductor surface; the magnetic lines of force are parallel to the conductor surface. The electrical wall is a radio frequency shielding structure that limits and shields the propagation of electromagnetic waves by providing metallized through holes or slits in the dielectric layer. The electric wall may confine electromagnetic energy to its interior while also preventing leakage of the electromagnetic field to the exterior.

The slow wave substrate integrated waveguide filter with the existing multilayer structure has the defects of larger structure size and complex manufacturing process.

The inventor finds that the structure has compact size when researching the existing multilayer slow wave substrate integrated resonant cavity filter structure, but has larger loss in practical application to limit the application range, and needs excessive metal layers and bonding pads to realize electric connection, thereby increasing the complexity and the manufacturing difficulty of the structure.

The inventor finds that if a slow wave substrate integrated waveguide filter with a single-layer medium matrix can be designed in the process of realizing the technical scheme in the embodiment of the utility model, the technical problem brought by the multi-layer substrate structure in the prior art can be solved. However, a single-layer dielectric matrix suffers from the difficulty of achieving the same slow wave effect and the same functions and performances on a single-layer dielectric matrix as a multi-layer substrate structure.

The inventor has found through intensive researches that if metallized through holes are arranged on the peripheral matrix of the single-layer cuboid dielectric matrix in an equidistant mode to obtain a rectangular peripheral metallized through hole array so as to form rectangular wave conductive walls, metallized blind holes are arranged on the dielectric matrix in the peripheral metallized through hole array row by row and column by column to obtain an internal metallized blind hole array so as to form an electric field region in which a frequency signal can operate, n coupling metallized through hole queues are embedded in the internal metallized blind hole array, and therefore, a structure of a rectangular waveguide filter in which waveguide resonant cavities are sequentially inserted into waveguide coupling windows is formed on the dielectric matrix and the second metal layer, and then the same slow wave effect and the same functions and performances as those of the multilayer substrate structure can be realized on the single-layer cuboid dielectric matrix.

Based on the above knowledge, the inventors provide a slow wave substrate integrated waveguide filter.

The technical scheme of the present utility model will be described below with reference to the accompanying drawings and examples.

Referring now to fig. 1 and 2, and referring to fig. 3, an embodiment of the present utility model provides a slow wave substrate integrated waveguide filter, including:

a dielectric substrate 1; the medium substrate 1 is of a single-layer cuboid structure;

a first metal layer 2; the first metal layer 2 covers the upper surface of the dielectric substrate 1;

a second metal layer 3; the second metal layer 3 covers the lower surface of the dielectric substrate 1;

a peripheral metallized via array 4; the peripheral metallized through hole array 4 is a rectangular metallized through hole array formed by arranging metallized through holes on the dielectric substrate 1 in an equidistant mode, and the metallized through holes are electrically connected with the first metal layer 2 and the second metal layer 3; the peripheral metallized via array 4 has an input interface window 401 and an output interface window 402;

an input feed line; the input feeder is electrically connected to the input interface window 401 and is used for inputting an original frequency signal;

an output feeder; the output feeder is electrically connected to the output interface window 402, and is configured to output a filtered frequency signal;

an array of internally metallized blind holes 5; the inner metallized blind hole array 5 is a rectangular metallized blind hole array formed by arranging metallized blind holes row by row and column on the dielectric substrate 1 in the peripheral metallized blind hole array 4, and the metallized blind holes are electrically connected with the second metal layer 3;

n coupling metallized via queues 6; n coupling metallized through hole queues 6 are embedded in the inner metallized blind hole array 5, so as to divide the inner space of the peripheral metallized through hole array 4 into m waveguide resonant cavities 7, and the metallized through holes of the m waveguide resonant cavities are electrically connected with the first metal layer 2 and the second metal layer 3;

when the original frequency signal is input through the input feeder line, an electric field is limited between the metallized blind holes of the inner metallized blind hole array 5 and the second metal layer 3, and a magnetic field flows around the metallized through holes and the metallized blind holes, so that a slow wave effect is generated;

the coupling metallized through hole queue 6 between the two waveguide resonant cavities 7 through which the frequency signals flow front and back is provided with a coupling window 601; the m waveguide resonant cavities 7 and m-1 coupling windows 601 inserted therein are alternately arranged to form a filtering structure with a slow wave effect;

wherein n is a positive integer greater than or equal to 0, and m is a positive integer greater than or equal to 1.

In the embodiment of the utility model, the dielectric substrate 1 is of a single-layer cuboid structure, and the cuboid structure is of a general integrated structure of the filter, so that the structure is conveniently and effectively combined with other integrated schemes. The dielectric substrate 1 is made of a material having a relatively high dielectric constant and mechanical strength, such as alumina, polytetrafluoroethylene, ceramic, and quartz glass.

In the embodiment of the utility model, the first metal layer 2 covers the upper surface of the dielectric substrate 1; the second metal layer 3 covers the lower surface of the dielectric substrate 1. The first metal layer 2 and the second metal layer 3 are respectively covered on the two surfaces of the dielectric substrate 1 by electroplating, metal deposition or other modes. The first metal layer 2 and the second metal layer 3 are made of metal materials with high conductivity; the second metal layer 3 and the first metal layer 2 jointly define and guide the high-frequency electromagnetic field to flow and propagate in the medium matrix 1, so as to realize the filtering effect.

In the embodiment of the utility model, the peripheral metallized through hole array 4 is arranged on the medium substrate 1 in an equidistant manner, and the metallized through holes are electrically connected with the first metal layer 2 and the second metal layer 3 to form a rectangular waveguide structure, so as to play a role of electromagnetic shielding and limit the frequency signal to propagate in the rectangular waveguide structure. I.e. the peripheral metallized via array 4 may perform a shielding effect and define the boundaries of the waveguide cavity 7.

The peripheral metallized via array 4 has an input interface window 401 and an output interface window 402. The input interface window 401 is electrically connected to the input feeder line and receives an input of an original frequency signal, the output interface window 402 is electrically connected to the output feeder line, and the filtered frequency signal is output through the output feeder line. The input interface window 401 directs frequency signals input by the input feed line to the peripheral metallized via array 4; the output interface window 402 directs frequency signals output by the peripheral metallized via array 4 to the output feed line.

In the embodiment of the utility model, the input feeder line and the output feeder line are input feeder lines and output feeder lines commonly used for the filter, and can be microstrip lines.

In the embodiment of the present utility model, the inner metallized blind hole array 5 is a metallized blind hole which is disposed on the dielectric substrate 1 in the peripheral metallized blind hole array 4 row by row and column by column, and the metallized blind hole is electrically connected with the second metal layer 3, so as to define the electric field and the magnetic field therein, and is an area where the frequency signal can operate. The electric field is confined between the top of the metallized blind via and said first metal layer 2 and the magnetic field flows around the metallized through via and the metallized blind via, thus realizing a slow wave effect.

In the embodiment of the present utility model, n coupling metallized through hole queues 6 are embedded in the inner metallized blind hole array 5, and the metallized through holes thereof are electrically connected with the first metal layer 2 and the second metal layer 3. n of the coupling metallized via queues 6 divide the internal space of the peripheral metallized via array 4 into m of the waveguide resonant cavities 7. The waveguide resonant cavity 7 repeatedly propagates, couples and filters the frequency signal therein, and plays a role in cutting, guiding and coupling the frequency signal. A coupling window 601 is arranged in the coupling metallized through hole array 6 between two adjacent waveguide resonant cavities 7, and the coupling window 601 plays a role of electromagnetic field coupling so that frequency signals between the two adjacent waveguide resonant cavities 7 are transmitted through coupling. The width of the coupling window 601 determines the coupling strength of the frequency signal between two adjacent waveguide resonators 7, which affects the propagation effect and the coupling effect of the frequency signal in the device, and thus affects the frequency selectivity. And the m waveguide resonant cavities 7 are coupled and transmitted through m-1 coupling windows 601 to form a filtering structure with a slow wave effect. The input raw frequency signal is filtered and processed in the structure.

In the embodiment of the utility model, n is a positive integer greater than or equal to 0, and m is a positive integer greater than or equal to 1. n refers to the number of coupling metallized via queues 6 disposed in the array of internal metallized blind vias 5. When n=0, the inner metallized blind hole array 5 is not provided with any coupling metallized through hole array 6, and the inner space of the outer metallized through hole array 4 forms a waveguide resonant cavity 7, and the waveguide resonant cavity 7 can also realize slow wave effect. When n is equal to 1, the internal space of the peripheral metallized through-hole array 4 is divided into 2 waveguide resonant cavities 7; when n is greater than 1, when n of the coupling metallized via queues 6 are arranged in parallel in the inner metallized blind via array 5, then the inner space of the peripheral metallized via array 4 is divided into m waveguide resonant cavities 7 by n of the coupling metallized via queues 6, and the value of m is equal to n+1. When i of the n coupling metallized via queues 6 are arranged in parallel in the inner metallized blind via array 5, n-i intersects with the i coupling metallized via queues 6 arranged in parallel, the inner space of the peripheral metallized via array 4 is divided into (i+1) × (n-i+1) waveguide resonators 7, m= (i+1) × (n-i+1). For example, n=2, i=1, 4 waveguide resonators 7 are obtained, m=4; n= 3,i =2, then 6 waveguide resonators 7 are obtained, m=6; n=4, i=2, 9 waveguide resonators 7 are obtained, m=9.

In the embodiment of the utility model, two adjacent waveguide resonant cavities 7 are coupled through coupling windows 601 arranged in corresponding coupling metallized through hole queues 6, and m waveguide resonant cavities 7 and m-1 coupling windows 601 are alternately arranged to form a filtering structure with a slow wave effect.

Therefore, the values of n and m determine the waveguide structure form inside the filter, directly influence the propagation path and the coupling effect of the frequency signal in the structure, and determine the frequency response characteristic and the filtering effect of the slow wave substrate integrated waveguide filter. When the values of n and m are increased, the propagation path and the number of coupling times of the frequency signal in the structure are increased, the frequency selectivity is improved, but the filter size is also increased. Therefore, the values of n and m are comprehensively considered according to specific design requirements, and the device size is made as small as possible while the frequency selectivity is met.

In the embodiment of the present utility model, the arrangement of the inner metallized blind hole array 5 is such that the electric field is confined between the metallized blind holes and the first metal layer, and the magnetic field flows around the metallized through holes and the metallized blind holes, thereby realizing the slow wave effect, and the array size and the pitch should also be set to be one tenth of the corresponding wavelength to obtain the optimal slow wave effect.

In the embodiment of the present utility model, the first metal layer 2 and the second metal layer 3 are respectively covered on two surfaces of the dielectric substrate 1 by electroplating or metal deposition; the metallized through holes, the coupling metallized through holes 6 and the internal metallized blind holes 5 may be achieved using conventional drilling and metallization techniques. The second metal layer 3 is electrically connected with the inner metallized blind hole array 5, the first metal layer 2 is electrically connected with the input feeder line and the output feeder line, and the peripheral metallized through hole array 4 penetrates through the dielectric substrate and is electrically connected with the first metal layer 2 and the second metal layer 3, so that a closed three-dimensional waveguide structure is formed.

The working process of the slow wave substrate integrated waveguide filter in the embodiment of the utility model is as follows:

input of a frequency signal: frequency signals propagate between the first metal layer 2 and the second metal layer 3 through the input feed lines and the input interface window 401 into the rectangular wave-conducting walls built up by the peripheral metallized via array 4. The dielectric substrate 1 guides the frequency signal to propagate along the waveguide direction. During transmission, frequency signals propagate within the waveguide structure defined by the first metal layer 2 and the second metal layer 3, the electric field is confined between the metallized blind holes of the inner array of metallized blind holes 5 and the second metal layer 3, and the magnetic field flows around the metallized through holes and the metallized blind holes, thereby achieving a slow wave effect throughout the dielectric matrix 1. The slow wave effect makes the input frequency signal propagate in the structure at a slower phase speed, the energy is stored, and the interaction time with the structure is longer, so that the filtering processing of the frequency signal is facilitated, and the high-broadband and high-Q value signal transmission is realized.

Transmission and coupling within the medium matrix 1: the frequency signal is repeatedly propagated, coupled and filtered in m waveguide resonators 7. In the transmission process, the frequency signals can be coupled between the adjacent resonant cavities 7 through the coupling window 601, and the high-frequency signals between the adjacent resonant cavities 7 reach a certain coupling degree to contribute to the broadband characteristic of the filter. The peripheral metallized through hole array 4 shields the frequency signal, limits the range of the waveguide resonant cavity 7 and the waveguide structure, and improves the frequency domain selectivity of the filter. The number m of waveguide resonators 7 and the width of the coupling window 601 determine the propagation path and the number of couplings of the frequency signal in the structure, affecting the frequency selectivity and the effect of the filtering.

Output of the filtered frequency signal: through multiple coupling and filtering, the desired frequency signal is output from the output interface window and the output feed line. The frequency signal at this time is mainly concentrated in the designed pass band, and the signals (interference signals and noise) in the stop band are suppressed and eliminated. And finally, the filtered frequency signals are output to a next stage circuit through the output feeder line.

Therefore, in the slow wave substrate integrated waveguide filter provided by the embodiment of the utility model, the rectangular wave conductive wall is constructed by arranging the metallized through holes on the single-layer dielectric substrate 1 in an equidistant mode; by arranging metallized blind holes row by row and column by column on the dielectric substrate 1 in the peripheral metallized through hole array 4, an electric field region in which a frequency signal can run is constructed; through embedding n coupling metallized through hole queues 6 in the inner metallized blind hole array 5, dividing the inner space of the peripheral metallized through hole array 4 into m waveguide resonant cavities 7, and constructing a unit for filtering and processing frequency signals; a coupling window 601 is arranged through the coupling metallized through hole array 6 between the two waveguide resonant cavities 7 through which the frequency signals flow before and after, so that a frequency signal channel between the two waveguide resonant cavities 7 is constructed. Thus, on the one hand, the electric field is confined between the top of the metallized blind via and the first metal layer 2, and the magnetic field flows around the metallized through via and the metallized blind via and persists throughout the dielectric matrix 1, achieving a slow wave effect; the slow wave effect enables the frequency signal to propagate in the structure at a low speed, so that the interaction time between the frequency signal and the structure is prolonged, and the filtering processing of the frequency signal is facilitated. On the other hand, m-1 coupling windows 601 connect m waveguide resonators 7 to form a filtering structure with slow wave effect. The filtering structure enables the frequency signal to be reflected and coupled for multiple times in the structure, the frequency selectivity is stronger, and the filtering effect is better. In the slow-wave substrate integrated waveguide filter with the filtering structure of the slow-wave effect, the dielectric constant of the dielectric substrate 1 can be selected to be larger, the cut-off frequency of the slow-wave substrate integrated waveguide resonant cavity 7 is lower, and the size of the substrate integrated waveguide resonant cavity 7 can be made smaller.

Compared with the conventional slow-wave substrate integrated waveguide filter with a multilayer substrate structure, the slow-wave substrate integrated waveguide filter provided by the embodiment of the utility model adopts the single-layer medium substrate 1, so that the manufacturing process is simpler, the production efficiency is higher, the yield is higher, and the mass production of products and the cost reduction are facilitated; the structure is more compact, the size is smaller, the integrated circuit is easier to combine with other integrated schemes, the integration level is higher, and the integrated cost is lower; the shielding performance is higher, the leakage emission is lower, the radiation resistance is higher, and the shielding material is more suitable for being used under the conditions of high power and high sensitivity. In short, compared with the prior art, the slow wave substrate integrated waveguide filter in the embodiment of the utility model has a much smaller structural size, can be effectively combined with other miniaturization schemes, and has correspondingly much better integrability. Meanwhile, the low-power integrated waveguide filter has the characteristics of high power capacity, low loss, low radiation, high Q value and the like which are the same as those of the conventional slow-wave integrated waveguide filter with the multilayer substrate structure.

In order to improve the input quality of the original frequency signal and improve the output quality of the filtered frequency signal, in an embodiment of the present utility model, optionally, the filter further includes:

an input metallized blind hole queue 8 for guiding frequency signal input; the input metallized blind hole array 8 is arranged on the medium substrate 1 below the input feeder line, and the metallized blind holes of the input metallized blind hole array are electrically connected with the second metal layer 3;

an output metallized blind hole queue 9 for guiding the frequency signal output; the output metallized blind hole array 9 is arranged on the dielectric substrate 1 below the output feeder line, and the metallized blind holes of the output metallized blind hole array are electrically connected with the second metal layer 3.

In this embodiment, the input metallized blind hole array 8 on the dielectric substrate 1 disposed below the input feed line, acts as a guide to facilitate smooth input of the frequency signal from the input feed line into the filter interior; the output metallized blind hole queue 9 arranged on the medium substrate 1 below the output feeder line plays a role of guiding and is beneficial to smoothly outputting the frequency signal from the filter inside to the output feeder line.

In order to meet various performance requirements, in the embodiment of the present utility model, optionally, the depth of the metallized blind holes in the inner metallized blind hole array 5 is 60% -80% of the thickness of the dielectric substrate 1. The deeper the depth of the metallized blind holes of the inner metallized blind hole array 5 is, the better the energy storage of signals, the longer the propagation path of the high-frequency signals between the inner metallized blind hole array 5 and the second metal layer 3 is, the bandwidth of the filter is enlarged, and the miniaturization of the slow wave substrate integrated waveguide filter in the embodiment of the utility model is also better facilitated. However, the deep depth of the metallized blind holes of the inner metallized blind hole array 5 causes an increase in signal loss and a decrease in structural strength of the filter. Multiple experiments prove that the depth of the metallized blind holes in the internal metallized blind hole array 5 is 60% -80% of the thickness of the medium matrix 1, and the method is an implementation mode which can achieve the miniaturization effect, low signal loss and structural strength meeting the requirements. The depth of the metallized blind holes in the inner metallized blind hole array 5 is in particular 75% of the thickness of the dielectric substrate 1, which is a preferred embodiment for this embodiment.

In order to improve the pore-forming quality of the metallized through holes and the metallized blind holes, in the embodiment of the utility model, optionally, pore structures of the metallized through holes and the metallized blind holes are manufactured through an etching process; the metal layers in the metallized through holes and the metallized blind holes are manufactured through an electroplating process and/or a sputtering process. The hole structures of the metallized through holes and the metallized blind holes are formed through an etching process, so that the hole structures with high precision and good perpendicularity can be obtained, and the collimation and propagation of high-frequency signals are facilitated. And a metal layer is formed in the hole through an electroplating process and/or a sputtering process, so that a thicker metal layer can be obtained, and the corrosion resistance and the high power bearing capacity of the slow wave substrate integrated waveguide filter in the embodiment of the utility model are improved, which are beneficial to the high performance and the high reliability of the product.

In order to improve the applicability of the slow-wave substrate integrated waveguide filter in the embodiment of the present utility model, optionally, the material of the dielectric substrate 1 is a quartz glass material. The quartz glass material has good dielectric property, low loss and high mechanical strength. The larger dielectric constant of the quartz glass material is beneficial to realizing smaller filter structure size and wider working frequency band. The dielectric substrate 1 is made of quartz glass material, so that the filter can obtain larger bandwidth, higher power capacity and higher Q value, and is more stable and reliable in use under the high-power high-frequency condition. The quartz glass material is more stable to the change of environmental parameters, and is beneficial to improving the environmental adaptability of the product.

Example 1

Embodiment 1 provides a slow wave substrate integrated waveguide filter. The center frequency of the slow wave substrate integrated waveguide filter is 32GHz, the passband bandwidth is 4.2GHz, the passband frequency is (29.9 GHz-34.1 GHz), the maximum insertion loss in the passband is-0.4 dB, the return loss is less than-20 dB, and the out-of-band rejection is less than-30 dB.

The area of the slow wave substrate integrated waveguide filter is 0.42 lambdag multiplied by 0.42 lambdag.

The dielectric substrate is made of quartz glass, the dielectric constant of the quartz glass is 3.78, the loss factor is 3 multiplied by 10 < -4 >, and the thickness of the substrate is 0.4mm.

The first metal layer and the second metal layer are both made of gold, and the thickness of the first metal layer and the second metal layer is 0.003mm.

The input feeder line and the output feeder line are microstrip lines with 50 ohms, the width of the microstrip lines is 0.6mm, and the length of the microstrip lines is 1.6mm.

The peripheral metallized through hole array is of a rectangular structure with the width of 3.4mm and the length of 5.76 mm. The diameter of the metallized through holes is 0.08mm, and the hole center distance between adjacent metallized through holes is 0.16mm.

The diameter of each metallized blind hole of the internal metallized blind hole array is 0.08mm, the hole center distance between every two adjacent metallized blind holes is 0.32mm, and the hole heights of the metallized blind holes are all 0.3mm.

The pitch of the metallized through holes of the peripheral metallized through hole array and the nearest metallized blind holes is 0.42mm.

The metallized via parameters of the coupling metallized via queue are the same as the metallized via parameters of the peripheral metallized via array. And the width of a coupling window arranged in the coupling metallized through hole queue is 1.02mm.

The diameters of the metallized blind holes of the input metallized blind hole array and the metallized blind hole of the output metallized blind hole array are 0.08mm, the hole center distance between adjacent metallized blind holes is 0.4mm, and the hole heights of the metallized blind holes are 0.3mm.

The material for the metallized through holes and metallized blind holes in example 1 was copper.

Fig. 4 shows a diagram of S-parameter simulation results of a slow-wave substrate integrated waveguide filter in an embodiment of the present utility model.

Referring now to fig. 4, in fig. 4, S11 represents the reflection coefficient of port 1 when port 2 is matched, and S21 represents the forward transmission coefficient of port 1 to port 2 when port 2 is matched.

As can be seen from the simulation results shown in FIG. 4, the slow wave substrate integrated waveguide filter in the embodiment 1 of the present utility model has the advantages of low high frequency loss, compact size, and effective combination with other miniaturization schemes.

Claims (6)

1. The slow wave substrate integrated waveguide filter is characterized by comprising:

a dielectric substrate (1); the medium substrate (1) is of a single-layer cuboid structure;

a first metal layer (2); the first metal layer (2) covers the upper surface of the medium substrate (1);

a second metal layer (3); the second metal layer (3) covers the lower surface of the medium matrix (1);

a peripheral array of metallized vias (4); the periphery metallized through hole array (4) is a rectangular metallized through hole array formed by arranging metallized through holes on the medium substrate (1) in an equidistant mode, and the metallized through holes are electrically connected with the first metal layer (2) and the second metal layer (3); the peripheral metallized via array (4) has an input interface window (401) and an output interface window (402);

an input feed line; the input feeder is electrically connected with the input interface window (401) and is used for inputting an original frequency signal;

an output feeder; the output feeder is electrically connected with the output interface window (402) and is used for outputting the frequency signal after filtering;

an array of internally metallized blind holes (5); the inner metallized blind hole array (5) is a rectangular metallized blind hole array formed by arranging metallized blind holes row by row and column on the medium substrate (1) in the peripheral metallized through hole array (4), and the metallized blind holes are electrically connected with the second metal layer (3);

n coupling metallized via queues (6); n coupling metallized through hole queues (6) are embedded in the inner metallized blind hole array (5) to divide the inner space of the peripheral metallized through hole array (4) into m waveguide resonant cavities (7), and the metallized through holes of the n coupling metallized through hole queues are electrically connected with the first metal layer (2) and the second metal layer (3);

when the original frequency signal is input through the input feeder line, an electric field is limited between the metallized blind holes of the inner metallized blind hole array (5) and the second metal layer (3), and a magnetic field flows around the metallized through holes and the metallized blind holes, so that a slow wave effect is generated;

the coupling metallization through hole queue (6) between the two waveguide resonant cavities (7) through which the frequency signals flow front and back is provided with a coupling window (601); m waveguide resonant cavities (7) and m-1 coupling windows (601) inserted in the waveguide resonant cavities are alternately arranged to form a filtering structure with a slow wave effect;

wherein n is a positive integer greater than or equal to 0, and m is a positive integer greater than or equal to 1.

2. The slow wave substrate integrated waveguide filter of claim 1 or claim 1, wherein the filter further comprises:

an input metallized blind hole queue (8) for guiding the frequency signal input; the input metallized blind hole array (8) is arranged on the medium substrate (1) below the input feeder line, and the metallized blind holes of the input metallized blind hole array are electrically connected with the second metal layer (3);

an output metallized blind hole queue (9) for guiding the output of the frequency signal; the output metallized blind hole array (9) is arranged on the medium substrate (1) below the output feeder line, and the metallized blind holes of the output metallized blind hole array are electrically connected with the second metal layer (3).

3. The slow wave substrate integrated waveguide filter according to claim 1, characterized in that the depth of the metallized blind holes in the inner array of metallized blind holes (5) is 60% -80% of the thickness of the dielectric substrate (1).

4. A slow wave substrate integrated waveguide filter according to claim 3, characterized in that the depth of the metallized blind holes in the inner array of metallized blind holes (5) is in particular 75% of the thickness of the dielectric substrate (1).

5. The slow wave substrate integrated waveguide filter of claim 1, wherein the hole structures of the metallized through holes and the metallized blind holes are made by an etching process; the metal layers in the metallized through holes and the metallized blind holes are manufactured through an electroplating process and/or a sputtering process.

6. The slow wave substrate integrated waveguide filter according to claim 1, characterized in that the material of the dielectric substrate (1) is a quartz glass material.