Ultra-wideband miniaturized band-pass filter based on slot line and defected ground resonator

Abstract

The invention discloses an ultra-wideband miniaturized band-pass filter based on slot lines and defected ground resonators, which belongs to the technical field of communication and comprises three metal layers, two dielectric layers and metal holes. The three metal layers comprise a top metal layer, a middle metal layer and a bottom metal layer from top to bottom, and the bottom metal layer is a ground plane; the metal holes penetrate through the three metal layers and the two dielectric layers; the two dielectric layers comprise a first dielectric layer and a second dielectric layer, the first dielectric layer is located between the top metal layer and the middle metal layer, and the second dielectric layer is located between the middle metal layer and the bottom metal layer; the top metal layer comprises a CPW feeder line and a slot line resonator, and LPUs are embedded in the CPW feeder line; the middle metal layer comprises a DGS resonator; and the slot line resonator and the DGS resonator are electromagnetically coupled to form a passband together. According to the invention, ultra wide band and miniaturization are realized through coupling of the slot line and the defected ground resonator.

Description

Technical Field

[0001] This invention belongs to the field of communication technology and relates to an ultrawideband miniaturized bandpass filter based on slot wire and defective ground resonator. Background Technology

[0002] With the maturity of 5G and the gradual development of 6G, people are pursuing higher speeds and greater bandwidth in the field of communication. Bandpass filters can help us select the frequency bands we need to use and filter out signals and noise from other frequency bands.

[0003] Filters with interdigitated coupling structures can increase coupling bandwidth by increasing the number of fingers to enhance electromagnetic coupling between adjacent lines. However, as the number of fingers increases, the insertion loss also increases, limiting the bandwidth that can be improved.

[0004] Multi-section cascaded coupled line structures are also commonly used to implement ultra-wideband bandpass filters. In addition to limitations similar to interdigitated coupled structures, they also suffer from difficulties in miniaturization due to structural redundancy and layout constraints. Summary of the Invention

[0005] The purpose of this invention is to provide an ultrawideband miniaturized bandpass filter based on slot wire and defect ground resonators, thereby solving the above-mentioned problems.

[0006] The technical solution adopted in this invention is as follows: An ultrawideband miniaturized bandpass filter based on slot wire and defect ground resonators includes three metal layers, two dielectric layers, and a metal aperture; the three metal layers, from top to bottom, include a top metal layer, a middle metal layer, and a bottom metal layer, with the bottom metal layer being a ground plane; the metal aperture penetrates the three metal layers and the two dielectric layers. The two dielectric layers include a first dielectric layer and a second dielectric layer. The first dielectric layer is located between the top metal layer and the middle metal layer, and the second dielectric layer is located between the middle metal layer and the bottom metal layer. The top metal layer includes a CPW feed line and a slot line resonator, wherein LPUs are embedded in the CPW feed line; The intermediate metal layer includes a DGS resonator; The slot wire resonator and the DGS resonator are electromagnetically coupled to form a passband together.

[0007] Furthermore, an adhesive layer is provided between the second dielectric layer and the intermediate metal layer.

[0008] Furthermore, the adhesive layer is an R04450F adhesive layer with a relative permittivity of 3.52 and a thickness of 0.101 mm.

[0009] Furthermore, both the first dielectric layer and the second dielectric layer are RT5880 high-frequency boards, with the thickness h1 of the first dielectric layer being 0.127 mm and the thickness h2 of the second dielectric layer being 0.381 mm.

[0010] Furthermore, the top metal layer includes a CPW feed line and two slot line resonators; the middle metal layer includes a DGS resonator.

[0011] Furthermore, the DGS resonator is a DGS dual-mode resonator.

[0012] Furthermore, the passband frequency range of the filter is 6.87GHz-18.4GHz, the insertion loss IL<1dB, and the return loss RL>11.8dB.

[0013] Furthermore, the center frequency of the filter passband is 12.635 GHz, and the relative bandwidth is 91.25%.

[0014] Furthermore, the core area of ​​the filter is 14.16 mm². 2 .

[0015] Furthermore, the LPUs are embedded in the CPW feeder, introducing a low-pass frequency response. The bandwidth of the LPUs is controlled by the length of the interdigitated stubs. The width of the stub in the middle of the interdigitated stubs that directly connects the LPUs to the CPW feeder is twice that of the other interdigitated stubs.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention provides an ultra-wideband miniaturized bandpass filter based on slot wire and defective ground resonator, which achieves ultra-wideband and miniaturization through slot wire and defective ground resonator coupling; 2. This invention embeds improved LPUs in the CPW feed line, which improves stopband suppression while enhancing the coupling between the feed line and the resonator; 3. In order to further improve the stopband suppression, the present invention embeds the low-pass filter unit (LPU) into the CPW feed line, introducing a low-pass frequency response. Its bandwidth can be adjusted by the length of the interdigitated stub; the longer the length, the smaller the bandwidth. In order to strengthen the coupling between the feed line and the resonator, the width of the stub that directly connects the two in the middle is twice that of the other interdigitated stubs, thus improving the return loss. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a cross-sectional view of the ultra-wideband miniaturized bandpass filter of the present invention; Figure 2 This is a schematic diagram of the structure of a 12GHz-18GHz bandpass filter, a technology currently in use. Figure 3 This is a schematic diagram of the structure of a 3.1GHz-10.6GHz bandpass filter, which is a prior art technology. Figure 4 This is a top view of the ultrawideband miniaturized bandpass filter of Embodiment 1 of this application; Figure 5 This is a 3D diagram of the ultrawideband miniaturized bandpass filter of Embodiment 1 of this application; Figure 6 It is the top metal layer of the ultrawideband miniaturized bandpass filter in Embodiment 1 of this application; Figure 7 It is the intermediate metal layer of the ultrawideband miniaturized bandpass filter in Embodiment 1 of this application; Figure 8 This is the frequency response diagram of the DGS layer under the weakly coupled feeder in Embodiment 1 of this application; Figure 9 This is a schematic diagram of the low-pass filter unit with embedded CPW feeder in Embodiment 1 of this application; Figure 10 This is a schematic diagram of the simulation results of the ultrawideband miniaturized bandpass filter in Embodiment 1 of this application; Figure 11 This is a schematic diagram of the simulation results of the ultrawideband miniaturized bandpass filter in Embodiment 2 of this application; Figure 12 This is a comparison diagram of the frequency response of embodiment 2 of this application with reduced w1; Figure 13 This is a comparison diagram of the frequency response of embodiment 2 of this application with increased l1; Figure 14 This is a comparison graph of the frequency response of reducing w2 / w3 in Embodiment 2 of this application.

[0018] The markings in the diagram are: 1-Top metal layer, 2-Intermediate metal layer, 3-Bottom metal layer, 4-First dielectric layer, 5-Second dielectric layer, 6-Adhesive layer. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0022] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0023] Definitions of abbreviations and key terms DGS (Damaged Ground Structure), SIDGS (Dielectric Integrated Damaged Ground Structure), CPW (Coplanar Waveguide), LPUs (Low-Pass Filter Units), Microstrip, Slotline, Insertion Loss, Return Loss, MMR (Multimode Resonator).

[0024] Example 1:

[0025] like Figure 1 , Figure 4 , Figure 5 , Figure 6 , Figure 7As shown, a preferred embodiment of the present invention provides an ultrawideband miniaturized bandpass filter based on slot wire and defect ground resonators, comprising three metal layers, two dielectric layers, and a metal via; the three metal layers, from top to bottom, include a top metal layer 1, a middle metal layer 2, and a bottom metal layer 3, wherein the bottom metal layer is a ground plane; the metal via penetrates the three metal layers and the two dielectric layers; The two dielectric layers include a first dielectric layer 4 and a second dielectric layer 5. The first dielectric layer is located between the top metal layer and the middle metal layer, and the second dielectric layer is located between the middle metal layer and the bottom metal layer. The top metal layer 1 includes a CPW feed line and a slot resonator. The CPW feed line embeds LPUs. The LPUs embedded in the CPW feed line introduce a low-pass frequency response, and its bandwidth is controlled by the length of the interdigitated stubs. The width of the stub in the middle of the interdigitated stubs that directly connects the LPUs to the CPW feed line is twice that of the other interdigitated stubs. The intermediate metal layer 2 includes a DGS resonator; The slot wire resonator and the DGS resonator are electromagnetically coupled to form a passband together.

[0026] An adhesive layer 6 is provided between the second dielectric layer and the intermediate metal layer. The adhesive layer 6 is an R04450F adhesive layer with a relative permittivity of 3.52 and a thickness of 0.101 mm.

[0027] Both the first dielectric layer 4 and the second dielectric layer 5 are RT5880 high-frequency boards. The thickness h1 of the first dielectric layer 4 is 0.127 mm, and the thickness h2 of the second dielectric layer 5 is 0.381 mm.

[0028] The top metal layer 1 includes a CPW feed line and two slot line resonators; the middle metal layer 2 includes a DGS resonator, which is a DGS dual-mode resonator.

[0029] Description of prior art: Prior art is as follows Figure 2 The 12GHz–18GHz bandpass filter shown is illustrated in (a) as a 3D diagram, (b) as a CPW layer, (c) as a DGS layer, and (d) as a microstrip line layer. Existing technology has achieved a 12GHz–18GHz broadband bandpass filter by using a hybrid dual-mode SIDGS and a microstrip line resonator, achieving ultra-wideband and miniaturization. However, this technology requires three metal layers and four dielectric layers, making the structure relatively complex.

[0030] Existing technology two Figure 3The diagram shows a 3.1 GHz-10.6 GHz bandpass filter. This scheme realizes a novel microstrip ultra-wideband (UWB) bandpass filter through MMR. By adjusting the first three relevant frequencies of the MMR, it is placed quasi-uniformly within the ultra-wideband range to achieve ultra-wideband. However, the frequency range of this technology is only 3.1 GHz-10.6 GHz, and the area is relatively large.

[0031] Therefore, the main objectives of this application are: 1. to achieve ultra-wideband without deteriorating basic performance indicators such as insertion loss, return loss, and out-of-band suppression; 2. to achieve miniaturization through transmission line structures such as slotted lines and defective grounds.

[0032] The principles of this application are explained as follows: Figure 1 As shown, this application has two dielectric layers and three metal layers. The bottom metal layer is a complete ground layer, which, together with the metal aperture that extends from the bottom metal layer to the top metal layer, can reduce radiation loss, thereby reducing the impact on other devices in the entire communication system. The top metal layer has two resonators formed by slot lines and a CPW feed line with LPUs. The LPUs filter out noise outside the passband and improve stopband suppression. The middle metal layer has one resonator formed by the DGS layer, which, together with the two resonators of the top slot line, forms four resonant points, realizing the characteristics of ultra-wideband miniaturization. This invention employs a CPW (Content-Driven Wavelength) embedded LPU (Low-Power Processing Unit) structure in its feeder, combining the slot lines of the top metal layer and the DGS (Distributed Gaussian Gas Grid) of the middle metal layer to achieve an ultra-wideband miniaturized bandpass filter. The core of the microwave filter is the resonator, and the size of the resonator is proportional to the wavelength, which decreases as the phase velocity decreases. It is known that increasing the equivalent dielectric constant can reduce the size of the resonator. DGS alters the electromagnetic field distribution by etching defects in the ground plane, causing more electric field energy to concentrate in the dielectric substrate and defect region. This increases the equivalent dielectric constant of the transmission line, thereby reducing the propagation speed of electromagnetic waves and generating a slow-wave effect. Miniaturization of the filter is achieved without sacrificing filter performance.

[0033] Figure 6 The top metal layer of the filter in this embodiment contains two resonators, contributing two resonant points within the passband; Figure 7 The intermediate metal layer of the filter in this embodiment contains a dual-mode resonator, which also contributes two resonant points within the passband, such as... Figure 8 As shown, several resonators are coupled to each other, forming a passband together.

[0034] To further improve stopband rejection, this application embeds low-pass filter units (LPUs) into the CPW feeder, such as... Figure 9As shown, a low-pass frequency response is introduced, the bandwidth of which can be adjusted by the length of the interdigitated stub. The longer the length, the smaller the bandwidth (in this embodiment, I=1mm). In order to strengthen the coupling between the feed line and the resonator, the width of the stub that directly connects the two in the middle is twice that of the other interdigitated stubs (in this embodiment, w=0.2mm), which improves the return loss.

[0035] Figure 10 This is a schematic diagram of simulation results for an embodiment of this application. This application embeds improved LPUs in the CPW feed line, improving stopband suppression while enhancing the coupling between the feed line and the resonator. This embodiment achieves ultra-wideband and miniaturization through three resonators: a slotted line and a defective ground. The passband frequency range of the filter described in this embodiment is 6.87GHz-18.4GHz, and the core area is 14.16mm². 2 Insertion loss IL < 1dB, return loss RL > 11.8dB, center frequency 12.635GHz, relative bandwidth 91.25%, stopband can be extended to 40GHz.

[0036] Example 2:

[0037] Based on Embodiment 1, this application, by adjusting the size of the DGS, can separate harmonics over a wider frequency range. The basic resonant frequency characteristics can be adjusted by the total physical length of each DGS structure, such as... Figure 11 As shown; The specific adjustment methods include the following: (1) Decreasing w1 will shift the resonance points 2 and 4 to the left, such as Figure 12 As shown.

[0038] (2) Increasing l1 will shift resonance points 2 and 3 to the right, and resonance point 4 to the left, such as Figure 13 As shown; (3) Decreasing w2 / w3 will shift resonance points 1, 2, and 4 to the left, and resonance point 3 to the right, such as Figure 14 As shown; The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ultrawideband miniaturized bandpass filter based on slot wire and defect ground resonators, characterized in that: It includes three metal layers, two dielectric layers, and a metal hole; the three metal layers, from top to bottom, include a top metal layer (1), a middle metal layer (2), and a bottom metal layer (3), the bottom metal layer being a ground plane; the metal hole penetrates the three metal layers and the two dielectric layers; The two dielectric layers include a first dielectric layer (4) and a second dielectric layer (5). The first dielectric layer is located between the top metal layer and the middle metal layer, and the second dielectric layer is located between the middle metal layer and the bottom metal layer. The top metal layer (1) includes a CPW feed line and a slot resonator, wherein LPUs are embedded in the CPW feed line; The intermediate metal layer (2) includes a DGS resonator; The slot wire resonator and the DGS resonator are electromagnetically coupled to form a passband together.

2. The ultrawideband miniaturized bandpass filter based on slot wire and defect ground resonators according to claim 1, characterized in that: An adhesive layer (6) is also provided between the second dielectric layer and the intermediate metal layer.

3. The ultrawideband miniaturized bandpass filter based on slot wire and defect ground resonators according to claim 2, characterized in that: The adhesive layer (6) is an R04450F adhesive layer with a relative permittivity of 3.52 and a thickness of 0.101 mm.

4. The ultrawideband miniaturized bandpass filter based on slot wire and defect ground resonators according to claim 1, characterized in that: The first dielectric layer (4) and the second dielectric layer (5) are both RT5880 high-frequency boards. The thickness h1 of the first dielectric layer (4) is 0.127 mm, and the thickness h2 of the second dielectric layer (5) is 0.381 mm.

5. The ultrawideband miniaturized bandpass filter based on slot wire and defect ground resonators according to claim 4, characterized in that: The top metal layer (1) includes a CPW feed line and two slot line resonators; the middle metal layer (2) includes a DGS resonator.

6. A miniaturized ultrawideband bandpass filter based on a slot wire and defective ground resonator according to claim 1 or 5, characterized in that: The DGS resonator is a DGS dual-mode resonator.

7. The ultrawideband miniaturized bandpass filter based on slot wire and defect ground resonators according to claim 1, characterized in that: The filter has a passband frequency range of 6.87GHz-18.4GHz, an insertion loss IL<1dB, and a return loss RL>11.8dB.

8. The ultrawideband miniaturized bandpass filter based on slot wire and defect ground resonators according to claim 5, characterized in that: The center frequency of the filter passband is 12.635 GHz, and the relative bandwidth is 91.25%.

9. The ultrawideband miniaturized bandpass filter based on slot wire and defective ground resonators according to claim 5, characterized in that: The core area of ​​the filter is 14.16 mm². 2 .

10. The ultrawideband miniaturized bandpass filter based on slot wire and defect ground resonators according to claim 1, characterized in that: The LPUs are embedded in the CPW feeder, introducing a low-pass frequency response. Their bandwidth is controlled by the length of the interdigitated stubs. The width of the middle interdigitated stub that directly connects the LPUs to the CPW feeder is twice that of the other interdigitated stubs.

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