End-fire viarold filter antenna based on equivalent artificial surface plasmon with independently controllable cutoff frequency

Abstract

This invention provides an end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on an equivalent artificial surface plasmon polariton (ESP). It comprises a dielectric substrate, with a top layer and a bottom layer formed on the upper and lower surfaces of the substrate, respectively. The bottom layer has a ground metal layer. An ESP bandpass filter based on a hybrid substrate integrated waveguide structure is embedded in the middle of the substrate. The top layer has a first microstrip line, a second microstrip line, and a first Vivaldi antenna. One end of the first microstrip line serves as the antenna feed port and is connected to the ground metal layer via a microwave high-frequency connector. The other end of the first microstrip line is connected to the first Vivaldi antenna sequentially via the second microstrip line and the ESP bandpass filter based on the hybrid substrate integrated waveguide structure. This invention enables independent control of the passband cutoff frequency and out-of-band cutoff frequency, exhibiting independently controllable bandwidth, stable stopband, and deep out-of-band suppression capabilities.

Description

Technical Field

[0001] This invention relates to an end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons, belonging to the field of antenna technology. Background Technology

[0002] Surface plasmon polaritons (SPPs) are nonradiative electromagnetic modes formed by the coupling of free electrons and incident photons on a metal surface, localized between the metal and dielectric interface. When an electromagnetic wave is incident, surface electromagnetic wave oscillations are generated at the interface, with the amplitude being strongest at the interface and exhibiting exponential decay within the metal and dielectric after leaving the interface. The high degree of confinement of electromagnetic fields by SPPs can overcome their diffraction limit, achieving subwavelength confinement. In order to realize a phenomenon similar to that of SPPs in the optical band in the microwave or terahertz band, Pendry et al. proposed the concept of artificial surface plasmon polaritons (SSPPs) in 2004. This solved for the first time the problem of SPPs not being generated in the microwave and terahertz bands. By etching periodic structural voids on the metal surface, electromagnetic modes similar to those of SPPs in the optical band can propagate on the surface. These modes exhibit subwavelength, localized, near-field enhanced, and novel dispersion characteristics.

[0003] In 2016, Engheta et al. proposed a method to realize various plasma phenomena by utilizing the modal dispersion of electromagnetic waves in a bounded waveguide filled with a positive permittivity medium. They introduced the concept of Effective Surface Plasmon Polaritons (ESPPs). According to equivalent medium theory, the equivalent permittivity of the medium filling the waveguide can be tuned by changing the operating frequency, the relative permittivity of the filling medium, and the waveguide dimensions. When the equivalent permittivity of different media filling the waveguide has opposite signs, electromagnetic modes similar to optical SPPs can be observed at the interface of the media. Unlike artificial surface plasmon polaritons (SSPPs), ESPPs are not generated by periodic metallic structures, thus eliminating the influence of metal losses on signal transmission and reducing the complexity of structural design. Similarly, ESPPs exhibit strong field confinement and field enhancement near asymptotic frequencies.

[0004] N. Cselyuszka et al. introduced a dual-band passband filter antenna that relies on two discrete ESPP modes in a three-layer substrate integrated waveguide configuration and uses different dielectric materials. However, due to interference between the upper and lower ESPP interfaces, the transmission performance within the passband is limited, and the passband cutoff frequency and out-of-band cutoff frequency cannot be controlled independently; the problem of independent bandwidth control remains unresolved. Therefore, ESPPs, SSPPs, and SPPs cannot control the passband cutoff frequency and out-of-band cutoff frequency relatively independently.

[0005] The above-mentioned problems should be considered and solved in the design and production of end-fire Vivaldi filter antennas with independently controllable cutoff frequencies based on equivalent artificial surface plasmons. Summary of the Invention

[0006] The purpose of this invention is to provide an end-fire Vivaldi filter antenna with independently controllable cutoff frequencies based on equivalent artificial surface plasmons, which solves the problems in the prior art where the passband cutoff frequency and out-of-band cutoff frequency cannot be independently controlled, and the stability of the stopband needs to be improved.

[0007] The technical solution of this invention is:

[0008] An end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons (ESPs) comprises a dielectric substrate. A top layer and a bottom layer are formed on the upper and lower surfaces of the dielectric substrate, respectively. A ground metal layer is provided on the bottom layer. An ESPs bandpass filter based on a hybrid substrate integrated waveguide structure is embedded in the middle of the dielectric substrate. The top layer of the dielectric substrate has a first microstrip line, a second microstrip line, and a first Vivaldi antenna. One end of the first microstrip line serves as the antenna feed port and is connected to the ground metal layer via a microwave high-frequency connector. The other end of a microstrip line is connected to a first Vivaldi antenna via a second microstrip line and an equivalent artificial surface plasmon bandpass filter based on a hybrid substrate integrated waveguide structure. The equivalent artificial surface plasmon bandpass filter based on a hybrid substrate integrated waveguide structure includes a substrate integrated waveguide, a metal stud layer, an air cavity layer, and a copper sheet layer stacked sequentially. The substrate integrated waveguide, the metal stud layer, the air cavity layer, and the copper sheet layer are fixed by several positioning screw holes. A second Vivaldi antenna is provided on the bottom layer of the dielectric substrate, and the grounding metal layer is connected to the second Vivaldi antenna through the substrate integrated waveguide.

[0009] Furthermore, the substrate integrated waveguide adopts a substrate integrated waveguide based on equivalent surface plasmons. The substrate integrated waveguide includes a first dielectric substrate, which is provided with two rows of first metal vias, a first U-shaped copper sheet and several spaced first metal strips, and the first metal strips are disposed between the two rows of first metal vias.

[0010] Furthermore, the metal pile layer adopts a periodic transmission structure, and the metal pile layer is provided with two rows of second metal through holes, with a number of metal piles arranged at intervals between the two rows of second metal through holes.

[0011] Furthermore, the metal pile layer includes a second medium substrate and a second U-shaped copper sheet disposed on the second medium substrate. The second U-shaped copper sheet is provided with second metal strips spaced apart. The second medium substrate is provided with periodically arranged slots. The sidewalls of the slots are covered with copper sheets. The slots are corresponding to the first metal strip and the second metal strip. The copper sheets together with the first metal strip and the second metal strip form a metal pile.

[0012] Furthermore, the air cavity layer includes a third dielectric substrate, which has two rows of third metal vias and a third U-shaped copper sheet. The third dielectric substrate also has a rectangular cavity groove, the sidewalls of which are covered with copper.

[0013] Furthermore, the copper sheet layer has two rows of fourth metal vias.

[0014] Furthermore, the first microstrip line is a long strip microstrip line, and the second microstrip line is a gradient microstrip line, with the width of the second microstrip line increasing from the end near the first microstrip line to the end far from the first microstrip line.

[0015] Furthermore, the substrate integrated waveguide forms the first dielectric layer, and the lower cutoff frequency of the passband is controlled by controlling the width of the two rows of first metal vias in the substrate integrated waveguide; the metal stud layer forms the second dielectric layer, and the upper cutoff frequency of the passband is independently controlled by controlling the width of the two rows of second metal vias in the metal stud layer; the air cavity layer forms the third dielectric layer, and the upper cutoff frequency outside the band is controlled by controlling the width of the two rows of third metal vias in the air cavity layer.

[0016] Furthermore, as the width of the two rows of first metal vias increases, the lower cutoff frequency of the passband decreases; as the width of the two rows of second metal vias increases, the upper cutoff frequency of the passband increases; and as the width of the two rows of third metal vias continuously increases, the upper cutoff frequency outside the band decreases.

[0017] The beneficial effects of this invention are:

[0018] I. This end-fire Vivaldi filter antenna, based on equivalent artificial surface plasmons with independently controllable cutoff frequency, can achieve independent control of the passband cutoff frequency and out-of-band cutoff frequency, and has independently controllable bandwidth, stable stopband and deep out-of-band suppression capabilities.

[0019] II. This type of end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons integrates an equivalent artificial surface plasmon bandpass filter based on a hybrid substrate integrated waveguide structure with a Vivaldi antenna to form a filter antenna. It has good skirt selectivity and flat antenna gain in the passband and high suppression performance in a stable wide impedance band.

[0020] Third, this invention, by employing an equivalent artificial surface plasmon bandpass filter based on a hybrid substrate integrated waveguide structure, can flexibly control the cutoff frequency. Compared with ESPP filters where each layer has multiple cutoff frequencies, this invention can guarantee independent passband and out-of-band control. At the same time, it can achieve edge selectivity without extending the filter length. It can generate better vector matching based on good balun feeding and impedance matching, thereby reducing in-band reflections, and the size is more compact.

[0021] Fourth, this end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons combines the stable in-band radiation function of traditional antennas with the dual capabilities of out-of-band suppression and clutter elimination of filters, while reducing the complexity and size of the RF front-end architecture. This facilitates the miniaturization and high integration of communication systems and has broad application prospects in mobile communications, satellite communications, and other fields. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons, according to an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the top structure of an end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons, as described in the embodiment.

[0024] Figure 3 This is a schematic diagram of the bottom structure of an end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons, as described in the embodiment.

[0025] Figure 4 This is a schematic diagram of the structure of the integrated waveguide on the dielectric substrate and the substrate in the embodiment;

[0026] Figure 5 This is a schematic diagram of the structure of the metal pile layer guide in the embodiment;

[0027] Figure 6 This is a schematic diagram of the air cavity layer in the embodiment;

[0028] Figure 7 This is a schematic diagram of the copper sheet layer in the embodiment;

[0029] Figure 8 These are physical schematic diagrams of the equivalent artificial surface plasmon bandpass filter based on a hybrid substrate integrated waveguide structure in the embodiment. (a) is a front view of the equivalent artificial surface plasmon bandpass filter based on a hybrid substrate integrated waveguide structure in the embodiment, and (b) is a rear view of the equivalent artificial surface plasmon bandpass filter based on a hybrid substrate integrated waveguide structure in the embodiment.

[0030] Figure 9 The embodiment is based on an end-fire Vivaldi filter antenna with independently controllable cutoff frequency of equivalent artificial surface plasmon resonance, where the width W of the two rows of third metal vias in the air cavity layer is... Ⅲ For the out-of-band upper cutoff frequency parameter S 21 Simulation diagram illustrating the impact;

[0031] Figure 10 The embodiment is based on an end-fire Vivaldi filter antenna with independently controllable cutoff frequency of equivalent artificial surface plasmons, where the width W of the two rows of second metal vias in the metal pile layer is... Ⅱ For the cutoff frequency parameter S in the passband 21 Simulation diagram illustrating the impact;

[0032] Figure 11 The embodiment is based on an end-fire Vivaldi filter antenna with independently controllable cutoff frequency of equivalent artificial surface plasmon resonance, where the width W of the two rows of first metal vias on the main substrate integrated waveguide is [missing information]. Ⅰ For the cutoff frequency parameter S in the passband 21 Simulation diagram illustrating the impact;

[0033] Figure 12 This is a schematic diagram of the simulation and measured S-parameters of an end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on an equivalent artificial surface plasmon polariton.

[0034] Figure 13 This is a schematic diagram of the simulation and measured radiation pattern of an end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons at 8.5G.

[0035] Figure 14 This is a schematic diagram of the simulated and measured radiation pattern of a 9.0G end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons in the embodiment.

[0036] Figure 15 This is a schematic diagram of the simulation and measured radiation pattern of a 10.0G end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons in the embodiment.

[0037] Wherein: 1-dielectric substrate, 2-top layer of dielectric substrate, 3-bottom layer of dielectric substrate, 4-ground metal layer, 5-first microstrip line, 6-second microstrip line, 7-equivalent artificial surface plasmon bandpass filter based on hybrid substrate integrated waveguide structure, 8-first Vivaldi antenna, 9-second Vivaldi antenna;

[0038] 71-Substrate integrated waveguide, 72-Metal pile layer, 73-Air cavity layer, 74-Copper sheet layer, 75-Positioning screw hole, 76-Fourth metal via;

[0039] 711-First dielectric substrate, 712-First metal via, 713-First U-shaped copper sheet, 714-First metal strip;

[0040] 721-Second metal via, 722-Second dielectric substrate, 723-Second U-shaped copper sheet, 724-Second metal strip, 725-Gap, 726-Copper sheet;

[0041] 731 - Third dielectric substrate, 732 - Third metal via, 733 - Third U-shaped copper sheet, 734 - Rectangular cavity groove. Detailed Implementation

[0042] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0043] Example

[0044] An end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons, such as... Figure 1 , Figure 2 and Figure 3 The system includes a dielectric substrate 1, with a top dielectric substrate 2 and a bottom dielectric substrate 3 formed on its upper and lower surfaces, respectively. The bottom dielectric substrate 3 has a ground metal layer 4. An equivalent artificial surface plasmon bandpass filter 7 based on a hybrid substrate integrated waveguide structure is embedded in the middle of the dielectric substrate 1. The top dielectric substrate 2 has a first microstrip line 5, a second microstrip line 6, and a first Vivaldi antenna 8. One end of the first microstrip line 5 serves as the antenna feed port and is connected to the ground metal layer 4 via a microwave high-frequency connector. The other end of the first microstrip line 5 is connected sequentially via the second microstrip line 6 and the hybrid substrate integrated waveguide structure. The equivalent artificial surface plasmon bandpass filter 7 based on the substrate integrated waveguide structure is connected to the first Vivaldi antenna 8. The equivalent artificial surface plasmon bandpass filter 7 based on the hybrid substrate integrated waveguide structure includes a substrate integrated waveguide 71, a metal stud layer 72, an air cavity layer 73 and a copper sheet layer 74 stacked in sequence, and the substrate integrated waveguide 71, the metal stud layer 72, the air cavity layer 73 and the copper sheet layer 74 are fixed by a number of positioning screw holes 75. The bottom layer 3 of the dielectric substrate is provided with a second Vivaldi antenna 9, and the ground metal layer 4 is connected to the second Vivaldi antenna 9 through the substrate integrated waveguide 71.

[0045] This end-fire Vivaldi filter antenna, based on equivalent artificial surface plasmons with independently controllable cutoff frequency, can achieve independent control of the passband cutoff frequency and out-of-band cutoff frequency through the equivalent artificial surface plasmon bandpass filter 7 based on a hybrid substrate integrated waveguide structure. It has independently controllable bandwidth, stable stopband and deep out-of-band suppression capabilities.

[0046] like Figure 4 The substrate integrated waveguide 71 is based on equivalent surface plasmons. The substrate integrated waveguide 71 includes a first dielectric substrate 711. The first dielectric substrate 711 is provided with two rows of first metal vias 712, a first U-shaped copper 713 and a number of spaced first metal strips 714, and the first metal strips 714 are disposed between the two rows of first metal vias 712.

[0047] like Figure 5 The metal pile layer 72 adopts a periodic transmission structure. The metal pile layer 72 has two rows of second metal through holes 721, and a number of metal piles are arranged at intervals between the two rows of second metal through holes 721. The metal pile layer 72 includes a second dielectric substrate 722 and a second U-shaped copper sheet 723 disposed on the second dielectric substrate 722. Second metal strips 724 are arranged at intervals in the second U-shaped copper sheet 723. The second dielectric substrate 722 has periodically arranged slots 725. The sidewalls of the slots 725 are covered with copper sheets 726. The slots 725 are correspondingly arranged with the first metal strip 714 and the second metal strip 724, and the copper sheets 726 together with the first metal strip 714 and the second metal strip 724 form metal piles.

[0048] like Figure 6 The air cavity layer 73 includes a third dielectric substrate 731, which has two rows of third metal vias 732 and a third U-shaped copper strip 733. The third dielectric substrate 731 also has a rectangular cavity slot 734, the sidewalls of which are covered with copper. The air cavity layer 73 forms a third dielectric layer to control the out-of-band upper cutoff frequency. Figure 7 The copper sheet layer 74 has two rows of fourth metal vias.

[0049] like Figure 2 The first microstrip line 5 is a long strip microstrip line, and the second microstrip line 6 is a tapered microstrip line. The width of the second microstrip line 6 increases from the end near the first microstrip line 5 to the end far from the first microstrip line 5, which can form a good balun feed, improve the impedance matching degree, and reduce S 11 This reduces reflection.

[0050] The substrate integrated waveguide 71 forms the first dielectric layer. The lower cutoff frequency of the passband is controlled by controlling the width of the two rows of first metal vias 712 in the substrate integrated waveguide 71. As the width W of the two rows of first metal vias 712 increases... ⅠAs the frequency increases, the lower cutoff frequency of the passband decreases. The metal pile layer 72 forms a second medium, and the width W of the two rows of second metal vias in the metal pile layer 72 is controlled. Ⅱ The upper cutoff frequency of the passband can be independently controlled; as the width of the two rows of second metal vias increases, the upper cutoff frequency of the passband increases. The air cavity layer 73 forms a third dielectric layer, and the width W of the two rows of third metal vias 732 in the air cavity layer 73 is controlled. Ⅲ This controls the out-of-band upper cutoff frequency; as the width of the two rows of third metal vias 732 increases, the out-of-band upper cutoff frequency decreases.

[0051] This type of end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons (ESPs) comprises an ESP bandpass filter 7 based on a hybrid substrate integrated waveguide structure. The ESP bandpass filter 7 includes a substrate integrated waveguide 71, a metal stud layer 72, an air cavity layer 73, and a copper sheet layer 74. The dielectric of the bottom layer of the substrate integrated waveguide 71 is Rogers RO4350B with a dielectric constant ε. r =3.48. The bottom layer has a thickness of 0.772mm. A row of first metal strips 71476 is formed on the top of the substrate integrated waveguide, serving as the bottom surface of the metal pile. Above the first metal strips 71476 is the metal pile layer 72, with a row of slots 725 cut out at a period of 1mm. The sidewalls of the slots 725 are covered with copper sheets 726, which form the side surface of the metal pile. The thickness of the slots 725 is 0.772mm. Second metal strips 724 are spaced apart within the second U-shaped copper sheets 723, forming the top surface of the metal pile with a thickness of 0.101mm. The air cavity layer 73 has a dielectric layer with a size of 6.9×10mm that penetrates the layer. 2 A rectangular cavity slot 734 is formed, with its sidewalls also covered with copper. A substrate integrated waveguide 71, a metal stud layer 72, an air cavity layer 73, and a copper sheet layer 74 are stacked and fixed using positioning screw holes 75, resulting in an equivalent artificial surface plasmon bandpass filter 7 based on a hybrid substrate integrated waveguide structure. A first Vivaldi antenna 8 and a second Vivaldi antenna 9 are connected to the rightmost side to achieve signal propagation and radiation. The entire process from the signal entering through the microwave high-frequency connector to the final antenna section achieves signal filtering and transmission.

[0052] This end-fire Vivaldi filter antenna, based on equivalent artificial surface plasmons with independently controllable cutoff frequency, has substrate integrated waveguide 71, metal pile layer 72, and air cavity layer 73 with dielectric constants ε0, ... rI ,ε rII ,ε rIII Adjusting the dielectric constant ε of the metal pile layer rIIThis will affect the change in the dispersion curve of the ESSPP mode; the smaller the dielectric constant, the wider the bandwidth for the same wavenumber. The electrical wall widths formed by the metal vias in the substrate integrated waveguide 71, the metal stud layer 72, and the air cavity layer 73 are different. The electrical wall width of the substrate integrated waveguide 71 is greater than that of the metal stud layer 72, and the electrical wall width of the metal stud layer 72 is greater than that of the air cavity layer 73. The difference in electrical wall width is mainly to adjust the corresponding cutoff frequency.

[0053] This type of end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons (APPs) has a slot depth h in the metal pile layer 72 that affects the dispersion curve of the periodic structure and thus the cutoff frequency of the equivalent artificial surface plasmon bandpass filter 7 based on the hybrid substrate integrated waveguide structure. By selecting a good slot depth h, simulation results show that when h = 0.772 mm, it can provide good vector matching between the TE10 mode and the equivalent artificial surface plasmons in the passband, which is beneficial for reducing reflection.

[0054] This end-fire Vivaldi filter antenna, based on an equivalent artificial surface plasmon polariton with independently controllable cutoff frequency, addresses the issue that the stopband of an ESPPs bandpass filter originates from the bandgap of the ESPP mode. Therefore, an extended ESPP structure leads to more pronounced out-of-band suppression. This invention improves out-of-band suppression by using metal studs. The out-of-band suppression of the equivalent artificial surface plasmon polariton bandpass filter 7 based on a hybrid substrate integrated waveguide structure is better than that of a twice-length ESPPs bandpass filter, achieving a more compact size.

[0055] This end-fire Vivaldi filter antenna, with independently controllable cutoff frequency based on equivalent artificial surface plasmons, utilizes the transmission characteristics of equivalent artificial surface plasmon modes to design an equivalent artificial surface plasmon bandpass filter 7 based on a hybrid substrate integrated waveguide structure. The equivalent artificial surface plasmon bandpass filter 7 based on the hybrid substrate integrated waveguide structure is integrated with the first Vivaldi antenna 8 and the first Vivaldi antenna 9 to form a filter antenna. It has good skirt selectivity and flat antenna gain in the passband and high suppression performance in a stable wide impedance band.

[0056] Figure 8 This is a physical schematic diagram of the equivalent artificial surface plasmon bandpass filter based on a hybrid substrate integrated waveguide structure in the embodiment. Figure 8 (a) is a front view of the equivalent artificial surface plasmon bandpass filter based on the hybrid substrate integrated waveguide structure of the embodiment. Figure 8 (b) is a schematic diagram of the back of the equivalent artificial surface plasmon bandpass filter based on the hybrid substrate integrated waveguide structure in the embodiment.

[0057] This invention employs an equivalent artificial surface plasmon bandpass filter 7 based on a hybrid substrate integrated waveguide structure, enabling independent control of the passband and out-of-band cutoff frequencies. Compared to ESPP filters where multiple cutoff frequencies are determined for each layer, this invention ensures independent passband and out-of-band control. Furthermore, it improves edge selectivity without extending the filter length. Based on good balun feeding and impedance matching, it achieves better vector matching, reducing in-band reflections. It is also more compact, smaller in size, has a wider bandwidth, and stable stopband. In communication transmission, this invention is of great significance for the miniaturization and integration of communication systems.

[0058] This end-fire Vivaldi filter antenna, based on equivalent artificial surface plasmons with independently controllable cutoff frequency, combines the stable in-band radiation capability of traditional antennas with the out-of-band suppression and clutter elimination capabilities of filters. It also reduces the complexity and size of the RF front-end architecture, facilitating the miniaturization and high integration of communication systems. The more pronounced the synergistic effect between the filtering antenna's services and the filter, the greater the performance improvement of the communication system, making it a promising candidate for applications in mobile communications, satellite communications, and other fields.

[0059] The simulation and experimental results are as follows:

[0060] Figure 9 The embodiment is based on an end-fire Vivaldi filter antenna with independently controllable cutoff frequency of equivalent artificial surface plasmon resonance, where the air cavity layer width affects the out-of-band upper cutoff frequency parameter S. 21 Simulation diagram illustrating the impact. Figure 10 This embodiment is based on an end-fire Vivaldi filter antenna with independently controllable cutoff frequency of equivalent artificial surface plasmon resonance, where the width of the metal stake is related to the cutoff frequency parameter S in the passband. 21 Simulation diagram illustrating the impact. Figure 11 This embodiment is based on an end-fire Vivaldi filter antenna with independently controllable cutoff frequency of equivalent artificial surface plasmon resonance (ESR). The width of the main substrate integrated waveguide corresponds to the cutoff frequency parameter S in the passband. 21 Simulation diagram illustrating the impact. Figure 9 , Figure 10 and Figure 11 The results verified that the widths of the three dielectric layers—substrate integrated waveguide 71, metal stud layer 72, and air cavity layer 73—allow for independent manipulation of each cutoff frequency: the lower cutoff frequency of the passband, the upper cutoff frequency of the passband, and the upper cutoff frequency outside the band. The embodiment demonstrates that each cutoff frequency can be individually adjusted by changing the width dimensions of the substrate integrated waveguide 71, metal stud layer 72, and air cavity layer 73.

[0061] Figure 12 The |S| of the filtered antenna is shown in both simulated and physically measured values. 11| and the realized gain. Analog bandwidth (S 11 The <10dB band rejection (<10dB) range is 7.96-11.46GHz, which is approximately 0.15G lower than the measured results. The 3dB gain bandwidth is 8.02-11.3GHz, and the average gain is 9.6dBi, which is in good agreement with the measured results. The results also indicate that this end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons exhibits good out-of-band suppression capability. Therefore, the design method of equivalent artificial surface plasmons-substrate integrated waveguides is suitable for rapid filter design and relatively accurate structural parameter estimation.

[0062] Figure 13 , Figure 14 , Figure 15 These are schematic diagrams of the simulated and measured radiation patterns at 8.5 GHz, 9.0 GHz, and 10 GHz for an end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons. Figures 13-15 As can be seen, the measured antenna radiation mode remains stable in the end-fire direction, showing good consistency with the simulation prediction. Comprehensive performance evaluation, comparing the work of this invention with other bandpass filters, shows good results in operating bandwidth, gain, gain selectivity, and gain flatness. Edge selectivity is also demonstrated. Notably, the integrated filter antenna achieves a considerable bandwidth of 36.2%, excellent gain flatness of 0.9 dBi, and significant high-frequency selectivity. These results prove that the design method of this invention has significant advantages in the design and application of filter antennas.

[0063] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons, comprising a dielectric substrate, wherein a top dielectric substrate and a bottom dielectric substrate are respectively formed on the upper and lower surfaces of the dielectric substrate, and a grounding metal layer is provided on the bottom dielectric substrate, characterized in that: An equivalent artificial surface plasmon bandpass filter based on a hybrid substrate integrated waveguide structure is embedded in the middle of the dielectric substrate. The top layer of the dielectric substrate contains a first microstrip line, a second microstrip line, and a first Vivaldi antenna. One end of the first microstrip line serves as the antenna's feed port and is connected to a grounded metal layer via a microwave high-frequency connector. The other end of the first microstrip line is connected to the first Vivaldi antenna sequentially via the second microstrip line and the equivalent artificial surface plasmon bandpass filter based on the hybrid substrate integrated waveguide structure. The equivalent artificial surface plasmon bandpass filter based on the hybrid substrate integrated waveguide structure includes a substrate integrated waveguide, a metal stud layer, an air cavity layer, and a... stacked sequentially. The copper sheet layer, substrate integrated waveguide, metal stud layer, air cavity layer, and copper sheet layer are fixed by several positioning screw holes; a second Vivaldi antenna is provided on the bottom layer of the dielectric substrate, and the grounding metal layer is connected to the second Vivaldi antenna through the substrate integrated waveguide; the substrate integrated waveguide forms the first dielectric layer, and the lower cutoff frequency of the passband is controlled by controlling the width of the two rows of first metal vias in the substrate integrated waveguide; the metal stud layer forms the second dielectric layer, and the upper cutoff frequency of the passband is independently controlled by controlling the width of the two rows of second metal vias in the metal stud layer; the air cavity layer forms the third dielectric layer, and the upper cutoff frequency outside the band is controlled by controlling the width of the two rows of third metal vias in the air cavity layer; As the width of the two rows of first metal vias increases, the lower cutoff frequency of the passband decreases; as the width of the two rows of second metal vias increases, the upper cutoff frequency of the passband increases; as the width of the two rows of third metal vias continues to increase, the upper cutoff frequency outside the band decreases.

2. The end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons as described in claim 1, characterized in that: The substrate integrated waveguide adopts a substrate integrated waveguide based on equivalent surface plasmons. The substrate integrated waveguide includes a first dielectric substrate, which has two rows of first metal vias, a first U-shaped copper sheet and several spaced first metal strips, with the first metal strips disposed between the two rows of first metal vias.

3. The end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons as described in claim 2, characterized in that: The metal pile layer adopts a periodic transmission structure. The metal pile layer is provided with two rows of second metal through holes, and a number of metal piles are arranged at intervals between the two rows of second metal through holes.

4. The end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons as described in claim 3, characterized in that: The metal pile layer includes a second medium substrate and a second U-shaped copper sheet disposed on the second medium substrate. The second U-shaped copper sheet is provided with second metal strips spaced apart. The second medium substrate has periodically arranged slots. The sidewalls of the slots are covered with copper sheets. The slots are arranged in correspondence with the first metal strip and the second metal strip. The copper sheets together with the first metal strip and the second metal strip form a metal pile.

5. The end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons as described in claim 1, characterized in that: The air cavity layer includes a third dielectric substrate, which has two rows of third metal vias and a third U-shaped copper sheet. The third dielectric substrate has a rectangular cavity groove, and the sidewalls of the rectangular cavity groove are covered with copper.

6. The end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons as described in claim 1, characterized in that: The copper sheet layer has two rows of fourth metal vias.

7. The end-fire Vivaldi filter antenna with independently controllable cutoff frequency based on equivalent artificial surface plasmons as described in any one of claims 1-6, characterized in that: The first microstrip line is a long strip microstrip line, and the second microstrip line is a gradient microstrip line, with the width of the second microstrip line increasing from the end near the first microstrip line to the end far from the first microstrip line.

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