CN218415029U - Frequency selective surface structure - Google Patents

Abstract

The application provides a frequency selective surface structure includes first metal level, medium base plate and second metal level, the medium base plate includes first surface and second surface, first surface sets up with the second surface relatively, first metal level sets up on the first surface, the second metal level sets up on the second surface, be formed with cross aperture unit on the first metal level and set up connection aperture and broken line aperture at cross aperture unit circumference side, cross aperture unit communicates through the connection aperture with the broken line aperture, the broken line aperture is the periodic bending extension, the second metal level includes square paster unit. This structure has effectively increased electric size through tortuous design, has realized the miniaturization of structure, keeps good filtering characteristic when electromagnetic wave large angle incidence, and angle stability and polarization stability are good to square paster structure through loading second metal layer has improved frequency selective characteristic and outband rejection characteristic.

Description

Frequency selective surface structure

Technical Field

The application belongs to the technical field of electromagnetic waves and microwaves, and particularly relates to a frequency selective surface structure.

Background

The Frequency Selective Surface (FSS) is a one-dimensional or two-dimensional periodic array structure formed by periodically arranging a large number of identical metal patch units or aperture units on a metal screen, and exhibits band-stop or band-pass filtering characteristics for electromagnetic waves of different frequencies, and the filtering characteristics of the Frequency Selective Surface enable the Frequency Selective Surface to be widely applied to a plurality of fields such as electromagnetic stealth, radar communication, electromagnetic shielding, electromagnetic compatibility and the like.

The nature of the frequency selective surface is a spatial structure filter, and unlike a common filter, the frequency response of the filter is not only related to the structure parameters of the filter, but also has a great relationship with the incident angle, the polarization mode and the working frequency of the incident electromagnetic wave. The frequency selective surface is an infinite periodic array structure in theory, the filtering characteristic is realized mainly by the interaction between units, and enough periodic units must be arranged in a finite space to simulate the infinite periodic structure, so that the ideal filtering characteristic is realized. However, in practical applications, the frequency selective surface is often limited by the structural size, and the property of infinite period cannot be maintained when the number of period units is too small. The resonance wavelength of the frequency selective surface has integral multiple relation with the unit structure size, the unit size is reduced to arrange more units in the same area, and the unit size of the frequency selective surface breaks the limit of the working wavelength, so that the frequency selective surface can still obtain ideal filter characteristics in a limited space. Therefore, it is of great practical significance to design a miniaturized frequency selective surface.

The miniaturization technology of the frequency selective surface is an important direction for the development of the frequency selective surface, and generally, the unit size of the frequency selective surface is reduced by using a unit curling technology, an interdigital technology, a coupling technology of an inductive surface and a capacitive surface and the like, so that the limitation that the unit size is consistent with a resonance wavelength is broken through, and the characteristic of obtaining low-frequency filtering by a small-size structure is realized. The cell curling technique and the interdigitated technique increase the effective electrical length by closely filling cells, but a large number of grid or slit structures easily cause cell resonance modes to interact, thereby causing a serious influence on the filter characteristics.

SUMMERY OF THE UTILITY MODEL

The present invention aims at least solving one of the technical problems existing in the prior art or the related art.

For this reason, the application provides a frequency selective surface structure, including first metal level, medium base plate and second metal level, the medium base plate includes first surface and second surface, the first surface with the second surface sets up relatively, first metal level sets up on the first surface, the second metal level sets up on the second surface, be formed with cross aperture unit on the first metal level and set up and be in connect aperture and broken line aperture of cross aperture unit circumference side, cross aperture unit with the broken line aperture passes through connect aperture is linked together, the broken line aperture is the periodic bending and extends, the second metal level includes square paster unit.

Optionally, the cross-shaped aperture unit, the corresponding connecting aperture and the corresponding broken line aperture form a cross-shaped aperture unit structure, the cross-shaped aperture unit structure is a centrosymmetric structure, and the first metal layer includes a plurality of same cross-shaped aperture unit structures which are periodically arranged; the second metal layer comprises a plurality of square patch unit structures which are identical and are arranged periodically.

Optionally, the connection aperture includes a first section, a second section and a third section which are sequentially communicated, the first section and the second section are arranged at an angle, the second section and the third section are arranged at an angle, one end of the first section, which is far away from the second section, is communicated with one end of the cross-shaped aperture unit, and one end of the third section, which is far away from the second section, is communicated with one end of the broken line aperture.

Optionally, the first section and the second section are vertically arranged, so that an integral formed by the first section and the second section is in an L-shaped structure, the second section and the third section are vertically arranged, so that an integral formed by the second section and the third section is in an L-shaped structure, the first section is vertically communicated with the cross-shaped aperture unit, and the third section is vertically communicated with the broken line aperture.

Optionally, the polygonal line aperture is periodically bent and extended along a section from the second section toward the cross-shaped aperture unit connected to the first section, the polygonal line aperture includes a fourth section, a fifth section, a sixth section, a seventh section and an eighth section which are vertically communicated in sequence, the extending directions of the first section, the third section, the fifth section and the seventh section are the same, and the extending directions of the second section, the fourth section, the sixth section and the eighth section are the same.

Optionally, the third section, the fifth section and the seventh section have the same length, the fourth section, the sixth section and the eighth section have the same length, and the sections in the cross-shaped aperture unit, the first section, the second section, the third section, the fourth section, the fifth section, the sixth section, the seventh section and the eighth section have the same width.

Optionally, the first metal layer includes an outer frame, the outer frame is in a square ring structure, the side length of the outer frame is D, D = 6.3-6.5 mm, the width of a single side of the outer frame is g, and g = 0.1-0.3 mm;

the length of the first section is l, and l = 2.7-2.9 mm;

the width of the second section is s, and s = 0.3-0.5 mm;

the shortest spacing distance between the third section and the cross-shaped aperture unit and the shortest spacing distance between the seventh section and the cross-shaped aperture unit are w, and w = 0.2-0.4 mm.

Optionally, the dielectric substrate is of a square structure, the second metal layer is of a square structure, and a center point of the dielectric substrate and a center point of the second metal layer are located on the same normal line of the second metal layer.

Optionally, half of the distance between adjacent square patch units on the second metal layer is e, and e = 0.1-0.3 mm.

Optionally, a vertical distance between the first metal layer and the second metal layer is h, and h =0.2mm to 2mm.

Advantageous effects

The embodiment of the utility model provides a frequency selective surface structure, wherein frequency selective surface structure sets up first metal level and second metal level through setting up on the medium base plate, be formed with cross aperture unit and set up connection aperture and broken line aperture in cross aperture unit circumference side on making the first metal level, and make cross aperture unit and broken line aperture communicate through the connection aperture mutually, and the broken line aperture is the periodic bending extension, resonant length has effectively been increased in this design, resonant frequency has been reduced, frequency selective surface structure's miniaturization has been realized, still keep good filtering characteristic under the electromagnetic wave wide-angle incident condition. The square patch periodic unit is loaded on the second metal layer, so that the frequency selection characteristic is further improved, and the good out-of-band rejection characteristic is realized.

Drawings

Fig. 1 is a schematic perspective view of a frequency selective surface structure according to the present invention;

fig. 2 is a schematic structural diagram of a first metal layer according to the present invention;

fig. 3 is a schematic diagram of the dimensional parameters of the first metal layer according to the present invention;

fig. 4 is a schematic structural diagram of a second metal layer according to the present invention;

fig. 5 shows the transmission characteristics of the frequency selective surface structure according to the present invention when the electromagnetic wave is incident perpendicularly in the TE polarization mode;

fig. 6 shows the transmission characteristics of the frequency selective surface structure according to the present invention when the electromagnetic wave TM polarization mode is incident perpendicularly;

fig. 7 shows the transmission characteristics of the frequency selective surface structure of the present invention under the TE polarization of electromagnetic waves at different incident angles;

fig. 8 shows the transmission characteristics of the frequency selective surface structure according to the present invention under the TM polarization mode at different incident angles.

The reference numerals are represented as:

1. a first metal layer; 11. an outer frame; 121. a first stage; 122. a second stage; 123. a third stage; 124. a fourth stage; 125. a fifth stage; 126. a sixth stage; 127. a seventh stage; 128. an eighth stage; 13. a cross-shaped aperture unit; 2. a dielectric substrate; 3. a second metal layer.

Detailed Description

In the description of the present application, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on the orientations and positional relationships shown in the drawings, and are used only for convenience of description and for simplicity of description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral connections; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

The preferred embodiments of the present invention will be described hereinafter with reference to the accompanying drawings, and it should be understood that the preferred embodiments described herein are merely for purposes of illustration and explanation, and are not intended to limit the present invention.

Referring to fig. 1 to 4 in combination, according to an embodiment of the present application, a frequency selective surface structure includes a first metal layer 1, a dielectric substrate 2 and a second metal layer 3, the dielectric substrate 2 includes a first surface and a second surface, the first surface is disposed opposite to the second surface, the first metal layer 1 is disposed on the first surface, the second metal layer 3 is disposed on the second surface, a cross-shaped aperture unit 13, a connection aperture and a broken line aperture are formed on the first metal layer 1, the connection aperture and the broken line aperture are disposed on a circumferential side of the cross-shaped aperture unit 13, the cross-shaped aperture unit 13 is communicated with the broken line aperture through the connection aperture, the broken line aperture is periodically bent and extended, and the second metal layer 3 includes a square patch unit.

Through setting up first metal level 1 and second metal level 3 on dielectric substrate 2, make first metal level 1 be formed with cross aperture unit 13 and set up at the connection aperture and the broken line aperture of cross aperture unit 13 circumference side, and make cross aperture unit 13 and broken line aperture pass through the connection aperture and communicate, and the broken line aperture is the periodic bending extension, effectively increased resonant length, the miniaturization degree has been improved, still possess good filtering characteristic under the electromagnetic wave wide angle incident condition, possess good angle stability and polarization stability, stable band-pass type filtering characteristic has been realized, through loading square paster unit on second metal level 3, utilize the interlayer coupling effect with first metal level 1, the frequency selection characteristic has been improved, good outband suppression characteristic has been realized.

The dielectric substrate 2 may have a cubic structure, and the first surface and the second surface are two surfaces of the cubic structure that are opposite to each other in a normal direction of the first surface or in a normal direction of the second surface, and may also be understood as two surfaces of the cubic structure that are opposite to each other in the normal direction of the first surface.

Wherein the outer edge of the first metal layer 1 is arranged along the edge of the first surface.

Wherein, the cross aperture unit 13 is a cross structure.

Here, the circumferential side of the cross-shaped aperture unit 13, that is, the circumferential side of the center point of the cross-shaped aperture unit 13, may also be understood as the circumferential side of the center axis of the cross-shaped aperture unit 13.

Wherein, broken line aperture is the extension of periodic bending, also reflects the aperture and buckles with certain periodic law promptly, and whole orientation one direction extension.

Specifically, in this embodiment, the cross-shaped aperture unit 13 is divided into four sections by its center point, and the whole polygonal line aperture extends toward a section of the cross-shaped aperture unit 13 connected to the polygonal line aperture itself.

Wherein the frequency selective surface structure comprises a plurality of periodic units arranged periodically, i.e. the periodic units are arranged periodically to form the frequency selective surface structure, fig. 1 shows a schematic perspective view of one periodic unit, wherein each periodic unit comprises a cross aperture unit 13 and a connecting aperture and a polygonal aperture arranged at the circumferential side corresponding to the cross aperture unit 13.

The cross-shaped aperture unit 13 and the corresponding connecting aperture and the broken line aperture form a cross-shaped aperture unit structure, the cross-shaped aperture unit structure is a central symmetry structure, and the first metal layer 1 comprises a plurality of same cross-shaped aperture unit structures which are periodically arranged; the second metal layer 3 comprises a plurality of same square patch unit structures which are periodically arranged, so that the polarization stability of the frequency selection surface structure is improved, and stable filtering characteristics are kept for electromagnetic waves of different polarization modes.

Wherein, the symmetry axis of the cross-shaped aperture unit structure is a normal line of the first surface passing through the center point of the first metal layer 1.

As shown in fig. 1, each periodic unit includes a cross-shaped aperture unit 13, the number of the connection apertures and the broken line apertures in the periodic unit is even, one connection aperture and one broken line aperture correspond to form a group, and all the groups of connection apertures and broken line apertures are arranged in a central symmetry manner by using the center of the cross-shaped aperture unit 13 as a symmetry axis.

Specifically, in this embodiment, the number of the connection apertures and the broken line apertures in one period unit is four, and the connection apertures and the broken line apertures correspond to each other one by one to form four groups. Each group of the connecting aperture and the broken line aperture are respectively communicated with one section of the cross aperture unit 13 in the periodic unit. The four groups of connecting apertures and broken line apertures and the channel formed by the cross aperture unit 13 in the periodic unit are in a central symmetry structure taking the center of the cross aperture unit 13 as the center of the symmetry axis.

Specifically, as shown in fig. 2, one set of the connection aperture and the broken line aperture is disposed above and to the left of the center point of the cross-shaped aperture unit 13. One set of the connecting apertures and the broken line apertures is arranged at the upper right of the center point of the cross-shaped aperture unit 13. One set of the connecting apertures and the broken-line apertures is disposed at the lower left of the center point of the cross-shaped aperture unit 13. One set of the connecting aperture and the broken line aperture is arranged at the lower right of the center point of the cross-shaped aperture unit 13.

The connecting aperture comprises a first section 121, a second section 122 and a third section 123 which are sequentially communicated, the first section 121 and the second section 122 are arranged at an angle, the second section 122 and the third section 123 are arranged at an angle, one end of the first section 121, which is far away from the second section 122, is communicated with one end of the cross aperture unit 13, and one end of the third section 123, which is far away from the second section 122, is communicated with one end of the broken line aperture.

Wherein the first segment 121 and the second segment 122 are disposed at an angle other than 0 ° or 180 °.

The second section 122 and the third section 123 are disposed at an angle different from 0 ° or 180 °.

The first section 121 and the second section 122 are vertically arranged, so that the whole formed by the first section 121 and the second section 122 is in an L-shaped structure, the second section 122 and the third section 123 are vertically arranged, so that the whole formed by the second section 122 and the third section 123 is in an L-shaped structure, the first section 121 is vertically communicated with the cross-shaped aperture unit 13, and the third section 123 is vertically communicated with the broken line aperture. Through setting up connecting aperture and broken line aperture into tortuous structure, further increased electric size, reduced resonant frequency, realized frequency selection surface structure's miniaturization, improved filtering characteristic's angle stability.

Wherein, the end of the first section 121 far away from the cross-shaped aperture unit 13 is vertically communicated with the end of the second section 122 far away from the cross-shaped aperture unit 13 to form an L shape.

Wherein, connecting aperture and broken line aperture setting are in cross aperture unit 13 circumference side, and every group connecting aperture and broken line aperture all are located between two sections of cross aperture unit 13 in cross aperture unit 13 circumference, and second section 122 extends in a section of the cross aperture unit 13 that first section 121 is on a parallel with, and second section 122 extends towards the perpendicular one section of adjacent cross aperture unit 13 of orientation.

One end of the third segment 123 is vertically communicated with one end of the second segment 122 far away from the first segment 121, and the other end of the third segment 123 vertically extends towards a segment of the cross-shaped aperture 13 connected with the first segment 121.

Specifically, the first segment 121 and the third segment 123 extend in the same direction, that is, the first segment 121 and the third segment 123 both extend perpendicularly toward a segment of the cross-shaped aperture unit 13 connected to the first segment 121.

Specifically, the first section 121, the second section 122 and the third section 123 form a substantially U-shaped structure, wherein one of two parallel sides of the U-shaped structure is longer than the other.

The broken line aperture is periodically bent and extended along a section from the second section 122 to the cross-shaped aperture unit 13 connected with the first section 121, the broken line aperture comprises a fourth section 124, a fifth section 125, a sixth section 126, a seventh section 127 and an eighth section 128 which are sequentially and vertically communicated, the extending directions of the first section 121, the third section 123, the fifth section 125 and the seventh section 127 are the same, and the extending directions of the second section 122, the fourth section 124, the sixth section 126 and the eighth section 128 are the same, so that the electric size is further increased, the resonance wavelength is increased, and the resonance frequency is reduced.

The whole of the polygonal-line aperture is periodically bent and extended along a direction from the second segment 122 to a segment of the cross-shaped aperture unit 13 connected to the first segment 121.

Wherein, the fourth section 124, the fifth section 125, the sixth section 126, the seventh section 127 and the eighth section 128 are vertically communicated in sequence.

Specifically, the fifth section 125 and the seventh section 127 are arranged in parallel, the fifth section 125 is vertically communicated with the ends of the fourth section 124 and the sixth section 126 away from the third section 123, respectively, and the seventh section 127 is vertically communicated with the ends of the sixth section 126 and the eighth section 128 away from the fifth section 125, respectively, so that the whole formed by the fourth section 124, the fifth section 125, the sixth section 126, the seventh section 127 and the eighth section 128 is substantially in a shape of Chinese character 'ji'.

The third section 123, the fifth section 125, and the seventh section 127 are the same in length, the fourth section 124, the sixth section 126, and the eighth section 128 are the same in length, and the sections in the cross-shaped aperture unit 13, the first section 121, the second section 122, the third section 123, the fourth section 124, the fifth section 125, the sixth section 126, the seventh section 127, and the eighth section 128 are the same in width.

The lengths of the fourth, sixth and eighth segments 124, 126, 128 are all greater than the lengths of the third, fifth and seventh segments 123, 125, 127.

The widths of the sections, the first section 121, the second section 122, the third section 123, the fourth section 124, the fifth section 125, the sixth section 126, the seventh section 127 and the eighth section 128 in the cross-shaped aperture unit 13 are the same, that is, the widths of all apertures are the same.

Each section, the first section 121, the second section 122, the third section 123, the fourth section 124, the fifth section 125, the sixth section 126, the seventh section 127 and the eighth section 128 in the cross-shaped aperture unit 13 are all strip-shaped, the length direction is the extending direction, and the width direction is the direction parallel to the first surface and perpendicular to the length direction.

The first metal layer 1 comprises an outer frame 11, the outer frame 11 is of a square structure, the side length of the outer frame 11 is D, D = 6.3-6.5 mm, the width of a single side of the outer frame 11 is g, and g = 0.1-0.3 mm; the length of the first section 121 is l, l = 2.7-2.9 mm; the width of the second section 122 is s, s = 0.3-0.5 mm; the shortest distance between the third segment 123 and the cross-shaped aperture unit 13 and the shortest distance between the seventh segment 127 and the cross-shaped aperture unit 13 are w, w = 0.2-0.4 mm.

Specifically, in this example, D =6.4mm, g =0.2mm, w =0.3mm, s =0.4mm, and l =2.8mm.

Wherein, the width of a single side of the outer frame 11 is half of the distance between adjacent periodic units.

The first metal layer 1 includes an outer frame 11 and an inner extending bending portion, one end of the inner extending bending portion is connected to an inner edge of the outer frame 11, the other end of the inner extending bending portion extends to a range enclosed by the outer frame 11 in a bending manner, and the inner extending bending portion bends at a right angle in the extending process to divide the inner space enclosed by the outer frame 11, so as to form a cross-shaped aperture unit 13, a connection aperture and a broken-line aperture.

Wherein, the outer frame 11 encloses to form a square closed loop structure.

Wherein, the outer frame 11 and the inner extending and bending part are of an integrated structure.

Specifically, the first metal layer 1 may be disposed on the first surface using a photolithography technique or a printed circuit board manufacturing process. The second metal layer 3 may be provided on the second surface using a photolithographic technique or a printed circuit board manufacturing process.

The outer frame 11 and the inward extending bent portions within the outer frame form a group, and the first metal layer 1 includes a plurality of groups of outer frames 11 and the inward extending bent portions within the outer frame. Each set of outer frames 11 and the inwardly extending bent portions within the range thereof are disposed on the first surface, and the outer edge of the outer frame 11 is connected to the outer edge of the adjacent outer frame 11.

The dielectric substrate 2 is in a cube structure, the second metal layer 3 is in a square structure, and the central point of the dielectric substrate 2 and the central point of the second metal layer 3 are located on the same normal line of the second metal layer 3.

The dielectric substrate 2 in each period unit is in a cubic structure, the second metal layer 3 in each period unit is in a square structure, and the center point of the dielectric substrate 2 in each period unit and the center point of the second metal layer 3 in the period unit are on the same normal line of the second metal layer 3.

Half of the pitch of the adjacent square patch cells of the second metal layer 3 is e, and e =0.1 to 0.3mm.

Specifically, in this example, e =0.2mm.

The vertical distance between the first metal layer 1 and the second metal layer 3 is h, h =0.2mm to 2mm.

The vertical distance between the first metal layer 1 and the second metal layer 3, that is, the thickness of the dielectric substrate 2.

Specifically, in this example, h =0.5mm.

In order to verify the performance of the frequency selective surface structure in this embodiment, the filter characteristics of the frequency selective surface structure under different polarization modes and incident angles are simulated and analyzed.

Fig. 5 shows a transmission characteristic curve of the frequency selective surface structure of the present embodiment when an electromagnetic wave of the TE polarization mode is vertically incident, and it can be seen that the frequency selective surface structure of the present embodiment forms a resonance frequency band in the C-band, the center resonance frequency of the frequency selective surface structure is 4.02GHz, the-3 dB bandwidth is 0.72ghz3.63ghz to 4.35GHz, the in-band insertion loss is only 0.15dB, the frequency selective surface structure of the present embodiment has a very strong frequency selective characteristic near 4.02GHz, the out-of-band rejection in the frequency ranges of less than 2.80GHz and more than 4.96GHz is below-10 dB, and the out-of-band rejection has a very strong rejection effect on out-band signals.

Fig. 6 shows a transmission characteristic curve of the frequency selective surface structure of this embodiment when the electromagnetic wave of TM polarization is vertically incident, the frequency selective surface structure of this embodiment has a resonance frequency band near 4.02GHz, a-3 dB bandwidth is 0.70ghz3.60ghz to 4.30GHz, an in-band insertion loss is only 0.14dB, the frequency selective surface structure of this embodiment forms a highly selective band-pass filter characteristic near 4.02GHz, and out-of-band rejection in frequency ranges of less than 2.82GHz and greater than 4.89GHz is less than-10 dB.

Comparing the transmission wave characteristic curves of fig. 5 and fig. 6, the frequency selective surface structure of the present embodiment has a band-pass filtering performance of the C band in the TE polarization and TM polarization modes, and the structure has excellent polarization stability.

In addition, in order to investigate the angular stability of the frequency selective surface structure of the present embodiment, electromagnetic waves of the TE polarization mode and the TM polarization mode were incident at incidence angles of 0 °, 30 °, 45 °, and 60 °, respectively, to obtain the filter characteristics of the frequency selective surface structure of the present embodiment. Fig. 7 is a transmission characteristic of the frequency selective surface structure of the present embodiment when electromagnetic waves in the TE polarization mode are incident at different incident angles, and fig. 8 is a transmission characteristic of the frequency selective surface structure of the present embodiment when electromagnetic waves in the TM polarization mode are incident at different incident angles.

As can be seen from fig. 7, in the TE polarization mode, when the incident angle of the electromagnetic wave is increased from 0 ° to 60 °, the frequency selective surface structure of the present embodiment has stable resonance characteristics at 4.02GHz, has a small shift of the center resonance frequency, is only 0.04GHz, and has excellent transmission characteristics and interference rejection.

As can be seen from fig. 8, in the TM polarization mode, when electromagnetic waves are incident at different angles, the frequency selective surface structure of the present embodiment still has a stable filtering characteristic at 4.02GHz, the shift of the center resonance frequency is still small, and is only 0.03GHz, and the frequency selective surface structure has excellent transmission characteristics and interference resistance.

It can be seen from fig. 7 and 8 that, when electromagnetic waves under TE polarization and TM polarization are incident at different angles, the frequency selective surface structure of the present embodiment always has stable band-pass filtering characteristics in the C-band, the resonant frequency remains stable, and the frequency selective surface structure has excellent angle stability.

The first metal layer 1 and the second metal layer 3 are made of gold or copper or silver or aluminum, and good out-of-band rejection characteristics can be achieved by the interlayer coupling effect of the first metal layer 1 and the second metal layer 3.

The second metal layer 3 is formed by square metal patch units which are periodically arranged.

Specifically, in the present embodiment, the first metal layer 1 and the second metal layer 3 are made of copper.

The dielectric substrate 2 is made of a fiber or resin material or a composite material of a fiber and a resin.

Specifically, in this embodiment, the dielectric substrate 2 is made of F4B polytetrafluoroethylene, and has a relative dielectric constant ε _r =2.65, dielectric loss tangent tan δ =0.002, thickness h =0.5mm.

Specifically, in the present embodiment, the cell size of the first metal layer 1 and the second metal layer 3 is 6.4mm × 6.4mm, and 6.4mm is equivalent to 0.086 times of the resonance wavelength, which satisfies the trend of a compact structure.

Among them, the frequency selective surface structure can be used in satellite communication equipment, radar antenna equipment, and the like.

In particular, the frequency selective surface structure may be used in particular in radomes, subreflector antennas, for example in radomes for C-bands.

The embodiment of the utility model provides a frequency selective surface structure and radar communication system, wherein frequency selective surface structure has following beneficial effect:

1. the frequency selective surface structure in the embodiment has extremely strong filtering characteristics near 4.02GHz, has good out-of-band rejection performance, and can ensure that communication signals of corresponding frequency bands are not interfered by other frequency signals.

2. The frequency selective surface structure in the embodiment is a centrosymmetric structure, has excellent polarization stability, and maintains stable resonant frequency when electromagnetic waves with different polarizations are incident.

3. The frequency selection surface structure in the embodiment has excellent angle stability, and the resonance frequency is kept stable and the deviation is very small under the condition that electromagnetic waves are incident at an angle of 0-60 degrees.

4. The frequency selective surface structure in this embodiment improves the frequency selective characteristic by using the interlayer coupling effect of the first metal layer 1 and the second metal layer 3, and has a better out-of-band rejection characteristic.

5. In the frequency selective surface structure in the embodiment, the unit interval is only 6.4mm multiplied by 6.4mm, the 6.4mm is only equivalent to 0.086 time of the resonance wavelength, the structure is simple, and the manufacture is easy.

6. The frequency selective surface structure in the embodiment has the insertion loss of only 0.15dB, and can realize the characteristic of high wave-transmitting rate in a band.

7. The frequency selective surface structure in the embodiment can be applied to a radome of a C-band.

It is readily understood by a person skilled in the art that the advantageous ways described above can be freely combined, superimposed without conflict.

The present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features herein disclosed. The foregoing are only preferred embodiments of the present application, and it should be noted that, for those skilled in the art, many modifications and variations can be made without departing from the technical principle of the present application, and these modifications and variations should also be considered as the protection scope of the present application.

Claims (10)

1. The utility model provides a frequency selective surface structure, characterized in that, includes first metal level (1), dielectric substrate (2) and second metal level (3), dielectric substrate (2) include first surface and second surface, the first surface with the second surface sets up relatively, first metal level (1) set up on the first surface, second metal level (3) set up on the second surface, be formed with cross aperture unit (13) on first metal level (1) and set up in the connection aperture and the broken line aperture of cross aperture unit (13) circumference side, cross aperture unit (13) with broken line aperture is linked together through the connection aperture, the broken line aperture is the periodicity and buckles and extends, second metal level (3) include square paster unit.

2. The frequency selective surface structure according to claim 1, wherein the cross-shaped aperture unit (13) forms a cross-shaped aperture unit structure with the corresponding connecting aperture and the meander line aperture, the cross-shaped aperture unit structure being a central symmetric structure, the first metal layer (1) comprising a plurality of identical and periodically arranged cross-shaped aperture unit structures; the second metal layer (3) comprises a plurality of square patch unit structures which are identical and are arranged periodically.

3. The frequency selective surface structure according to claim 1, wherein the connecting aperture comprises a first section (121), a second section (122) and a third section (123) which are sequentially communicated, the first section (121) and the second section (122) are arranged at an angle, the second section (122) and the third section (123) are arranged at an angle, one end of the first section (121) far away from the second section (122) is communicated with one end of the cross-shaped aperture unit (13), and one end of the third section (123) far away from the second section (122) is communicated with one end of the polygonal-line aperture.

4. The frequency selective surface structure according to claim 3, wherein the first section (121) is arranged perpendicular to the second section (122) such that the whole of the first section (121) and the second section (122) is in an L-shaped configuration, the second section (122) is arranged perpendicular to the third section (123) such that the whole of the second section (122) and the third section (123) is in an L-shaped configuration, the first section (121) is vertically communicated with the cross-shaped aperture unit (13), and the third section (123) is vertically communicated with the polygonal line aperture.

5. The frequency selective surface structure according to claim 4, wherein the meander line aperture extends along a segment from the second segment (122) to the cross aperture unit (13) connected to the first segment (121) in a periodic bending manner, the meander line aperture comprises a fourth segment (124), a fifth segment (125), a sixth segment (126), a seventh segment (127) and an eighth segment (128) which are vertically connected in sequence, the first segment (121), the third segment (123), the fifth segment (125) and the seventh segment (127) extend in the same direction, and the second segment (122), the fourth segment (124), the sixth segment (126) and the eighth segment (128) extend in the same direction.

6. The frequency selective surface structure according to claim 5, characterized in that the third section (123), the fifth section (125), the seventh section (127) have the same length, the fourth section (124), the sixth section (126), and the eighth section (128) have the same length, and the width of each of the cross-shaped aperture units (13), the first section (121), the second section (122), the third section (123), the fourth section (124), the fifth section (125), the sixth section (126), the seventh section (127), and the eighth section (128) is the same.

7. The frequency selective surface structure according to claim 6, characterized in that the first metal layer (1) comprises an outer frame (11), the outer frame (11) has a square ring structure, the side length of the outer frame (11) is D, D = 6.3-6.5 mm, the width of a single side of the outer frame (11) is g, g = 0.1-0.3 mm;

the length of the first section (121) is l, l = 2.7-2.9 mm;

the width of the second section (122) is s, s = 0.3-0.5 mm;

the shortest distance between the third section (123) and the cross aperture unit (13) and the shortest distance between the seventh section (127) and the cross aperture unit (13) are w, and w = 0.2-0.4 mm.

8. The frequency selective surface structure according to claim 1, wherein the dielectric substrate (2) has a square structure and the second metal layer (3) has a square structure, and a center point of the dielectric substrate (2) and a center point of the second metal layer (3) are on the same normal line of the second metal layer (3).

9. The frequency selective surface structure according to claim 1, wherein half of the pitch between adjacent square patch elements on the second metal layer (3) is e, e = 0.1-0.3 mm.

10. The frequency selective surface structure according to claim 1, wherein the perpendicular distance between the first metal layer (1) and the second metal layer (3) is h, h =0.2 mm-2 mm.

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