CN210468104U

CN210468104U - Electromagnetic band gap structure and radio frequency antenna structure

Info

Publication number: CN210468104U
Application number: CN201922023986.5U
Authority: CN
Inventors: 庄凯杰; 李珊; 王典
Original assignee: Calterah Semiconductor Technology Shanghai Co Ltd
Current assignee: Calterah Semiconductor Technology Shanghai Co Ltd
Priority date: 2019-11-21
Filing date: 2019-11-21
Publication date: 2020-05-05
Anticipated expiration: 2029-11-21

Abstract

The utility model discloses an electromagnetism band gap structure and radio frequency antenna structure. The electromagnetic bandgap structure comprises at least one first pattern and at least one second pattern; the first pattern comprises two first straight line segments and one arc line segment, and two ends of each arc line segment are respectively connected with the first end of one first straight line segment; the second pattern comprises a second straight line segment, one end of the second straight line segment is grounded, and the other end of the second straight line segment is a free end; the second straight line segment and the adjacent first straight line segment are parallel to each other to form a capacitor structure. The embodiment of the utility model provides a but when the miniaturization of structure is realized to the electromagnetism band gap structure filtering radio frequency coupling signal.

Description

Electromagnetic band gap structure and radio frequency antenna structure

Technical Field

The embodiment of the utility model provides an electromagnetic radiation technical field especially relates to an electromagnetism band gap structure and radio frequency antenna structure.

Background

With the continuous development and updating of communication networks, radio frequency spectrum becomes increasingly crowded, and meanwhile, the bandwidth and the speed of data traffic are required to be high in both daily communication of people and some key scientific and technological fields such as the internet of things. Therefore, the millimeter wave band has been receiving attention in recent years. In such a high frequency band, the wavelength is only several millimeters, which greatly reduces the design size of many radio frequency devices, such as an antenna at the front end of the radio frequency. However, at such a size, there is strong coupling between the antennas and between the feed lines of the antennas, which seriously affects the quality of the received signal.

In recent years, an EBG (electromagnetic band gap) structure is widely used in microwave devices and antenna designs, and can effectively reduce coupling between antennas and between feed lines of the antennas, and improve isolation.

However, the EBGs in the prior art require a plurality of cells to be arranged, which results in a large size of the EBG structure, and requires a complete reference ground to be arranged below the EBG structure. Under the background that radio frequency systems are increasingly miniaturized, requirements on machining precision are higher and higher, the space of the systems is smaller and smaller, and effective isolation effects of EBG structures under existing machining conditions and precision are often difficult to achieve.

SUMMERY OF THE UTILITY MODEL

The utility model provides an electromagnetism band gap structure and radio frequency antenna structure, the utility model provides an electromagnetism band gap structure realizes the effect of the appointed frequency radio frequency coupling signal of filtering, reduces the effect of the interference between the passageway

An embodiment of the present invention provides an electromagnetic bandgap structure, which includes at least one first pattern and at least one second pattern;

the first pattern comprises two first straight line segments and an arc line segment, and two ends of each arc line segment are respectively connected with the first end of one first straight line segment;

the second pattern comprises a second straight line segment, one end of the second straight line segment is grounded, and the other end of the second straight line segment is a free end;

and the second straight line segment and the adjacent first straight line segment are parallel to each other to form a capacitor structure.

Optionally, each of the first straight line segments extends from the first end to the concave side of the arc segment, and in the same first pattern, the two first straight line segments do not intersect;

the first patterns are adjacently arranged, the first straight lines of the two adjacent first patterns are oppositely arranged, and the first patterns are diverged from the concave side of each first pattern to the convex side of each first pattern;

the second pattern is positioned in a slit between two adjacent first patterns, and the extending direction of the slit is the same as that of the first straight line segment.

Optionally, the electromagnetic bandgap structure further comprises at least one third pattern;

the third pattern comprises a third straight line segment;

the third straight line segment is positioned in a slit between two adjacent first patterns and connects second ends of the two first straight line segments forming the slit.

Optionally, the electromagnetic bandgap structure comprises four of the first patterns and four of the second patterns;

splicing the first patterns to form an oval;

the four second straight line segments are sequentially distributed at the ends of the major axis and the minor axis of the ellipse, and extend to the two ends of the center point of the ellipse along the length direction of the major axis or the minor axis.

Optionally, the major axis of the ellipse is L1, 480 μm & lt L1 & lt 520 μm, and the minor axis of the ellipse is L2, 380 μm & lt L2 & lt 420 μm.

Optionally, the electromagnetic bandgap structure comprises a first metal layer;

the electromagnetic band gap structure is a structure obtained by etching the first metal layer.

Optionally, the first pattern and the second pattern are patterns formed by metal wires or slits.

Based on the same inventive concept, the embodiment of the present invention further provides an electromagnetic bandgap structure, where the electromagnetic bandgap structure has a bandgap isolation region and a peripheral metal region surrounding the bandgap isolation region, and the electromagnetic bandgap structure includes:

a peripheral metal sheet disposed in the peripheral metal region;

the interdigital structure comprises a first interdigital unit and a second interdigital unit; the first interdigital unit is nested in the second interdigital unit; the interdigital structure is connected with the peripheral metal sheet through the first interdigital unit; and

the inductance structure is connected with the second interdigital unit;

wherein the interdigital structure is used for providing a capacitor of the electromagnetic band gap structure, and the inductance structure is used for providing an inductance connected with the capacitor in series; and

the electromagnetic band gap structure is used for isolating electromagnetic signals with preset frequency according to the capacitor and the inductor.

Optionally, the shape of the band gap isolation region is square, circular or oval.

Optionally, the first interdigital unit comprises a strip-shaped protrusion, and the second interdigital unit comprises a U-shaped recess;

one end of the strip-shaped protrusion is connected with the peripheral metal sheet, and the other end of the strip-shaped protrusion is inserted into the U-shaped recess.

Optionally, the second interdigital unit further comprises two parallel strip-shaped structures;

one end of the strip-shaped bulge is connected with the peripheral metal sheet, and the other end of the strip-shaped bulge is inserted into an area between the two parallel strip-shaped structures;

wherein the second inter-finger unit structures between adjacent inter-finger structures are different.

Based on the same inventive concept, the embodiment of the present invention further provides an electromagnetic bandgap structure, where the electromagnetic bandgap structure has an oval bandgap isolation region and a peripheral metal region surrounding the oval bandgap isolation region, and the electromagnetic bandgap structure includes:

a peripheral metal sheet disposed in the peripheral metal region;

the four interdigital structures comprise two first interdigital structures and two second interdigital structures; the two first interdigital structures are symmetrically distributed on the long axis of the oval band-gap isolation region, and the two second interdigital structures are symmetrically distributed on the short axis of the oval band-gap isolation region; and

the adjacent interdigital structures are electrically connected through the arc-shaped inductance units;

the interdigital structure and the arc-shaped inductance unit are alternately and electrically connected and are used for isolating radio frequency signals with preset frequency, which are emitted by at least two radio frequency components symmetrically distributed on two sides of the electromagnetic band gap structure; and the radio frequency signal with the preset frequency is a millimeter wave signal.

Optionally, the first interdigital structure comprises a first strip-shaped protrusion and a U-shaped recess; one end of the first strip-shaped bulge is connected with the peripheral metal sheet, and the other end of the first strip-shaped bulge is inserted into the U-shaped recess; and

the second interdigital structure comprises a second strip-shaped bulge and two parallel strip-shaped structures; one end of the second strip-shaped bulge is connected with the peripheral metal sheet, and the other end of the second strip-shaped bulge is inserted into the area between the two parallel strip-shaped structures;

and the two ends of the U-shaped recess are respectively connected with one strip-shaped structure in the second interdigital structure through an arc inductance unit to form a curve section.

Optionally, the curved line segment is respectively the same as the intervals between the peripheral metal sheet, the first strip-shaped protrusion and the second strip-shaped protrusion.

Based on the same inventive concept, the embodiment of the present invention further provides a radio frequency antenna structure, which includes:

at least two antennas; and

the electromagnetic bandgap structure described above;

wherein at least one electromagnetic bandgap structure is arranged between two adjacent antennas.

Optionally, the electromagnetic bandgap structure and the at least two antennas are disposed in the same metal layer.

Optionally, the radio frequency antenna structure includes a bottom metal layer, a second dielectric layer, a middle metal layer, a first dielectric layer, and a top metal layer, which are sequentially stacked;

wherein the electromagnetic bandgap structure and the at least two antennas are disposed in the top metal layer.

Optionally, each of the antennas includes a channel, and the channel of each of the antennas is connected to the intermediate metal layer through a metal via hole;

wherein the electromagnetic bandgap structure is disposed in a region between channels of adjacent ones of the antennas.

Optionally, the bottom metal layer comprises a reference ground cell;

wherein, the perpendicular projection of the electromagnetic band gap structure on the plane of the reference ground unit at least partially overlaps with the reference ground unit.

The utility model provides an electromagnetic band gap structure comprises at least one first pattern and at least one second pattern; the first pattern comprises two first straight line segments and one arc line segment, and two ends of each arc line segment are respectively connected with the first end of one first straight line segment; the second pattern comprises a second straight line segment, one end of the second straight line segment is grounded, and the other end of the second straight line segment is a free end; the second straight line segment and the adjacent first straight line segment are parallel to each other to form a capacitor structure. The utility model discloses a second straightway and adjacent first straightway are parallel to each other and constitute the interdigital structure, and on the one hand this interdigital structure's length is controllable, and then can be nimble adjust the resonant frequency of electromagnetism band gap structure, reach the effect of the specified frequency radio frequency coupling signal of filtering, reduce the interference between the passageway and then improve the quality of received signal; on the other hand, the interdigital structure provides a capacitor, so compared with the traditional electromagnetic bandgap structure, the interdigital structure of the embodiment does not need a floor on the back surface to provide the capacitor, does not need to periodically arrange a plurality of units to provide a coupling capacitor, has no special requirement on a metal reference plane below the interdigital structure, can realize the performance of single unit operation, and is suitable for a system with compact space.

In summary, the electromagnetic bandgap structure provided in the present application can adjust the size of the structure (e.g., the length of the interdigital structure, etc.), so that the resonant frequency of the electromagnetic bandgap structure can be flexibly adjusted by adjusting the size of the electromagnetic bandgap structure, and thus the electromagnetic bandgap structure can be applied to isolating radio frequency signals with different frequencies. Meanwhile, the shape of the electromagnetic band gap structure can be in a circular shape, an oval shape and other geometric shapes so as to be matched with the shapes of other devices, so that the space utilization rate of the devices can be greatly improved, the devices are more compactly arranged, and the miniaturization of the device structure is realized. In addition, because the interdigital structure in the electromagnetic band gap structure can provide a filter capacitor, a plurality of units are not required to be arranged to provide a coupling capacitor like the traditional EBG structure, the arrangement of devices can be further compact, and a back plate is not required to provide a capacitor, namely when the electromagnetic band gap structure in the embodiment of the application is applied to a radio frequency antenna structure, the back surface of the radio frequency antenna structure can realize electromagnetic isolation between antennas without arranging a metal ground.

Drawings

Fig. 1 is a schematic structural diagram of an electromagnetic bandgap structure provided by an embodiment of the present invention;

fig. 2 is a schematic structural diagram of another electromagnetic bandgap structure provided by an embodiment of the present invention;

fig. 3 is a schematic structural diagram of another electromagnetic bandgap structure provided by an embodiment of the present invention;

fig. 4 is a schematic structural diagram of another electromagnetic bandgap structure provided by an embodiment of the present invention;

fig. 5 is a schematic structural diagram of another electromagnetic bandgap structure provided by an embodiment of the present invention;

fig. 6 is a schematic structural diagram of another electromagnetic bandgap structure provided by an embodiment of the present invention;

fig. 7 is a schematic structural diagram of another electromagnetic bandgap structure provided by an embodiment of the present invention;

fig. 8 is a schematic structural diagram of another electromagnetic bandgap structure provided by an embodiment of the present invention;

fig. 9 is a schematic structural diagram of another electromagnetic bandgap structure provided by an embodiment of the present invention;

fig. 10 is a schematic structural diagram of another electromagnetic bandgap structure provided by an embodiment of the present invention;

fig. 11 is a schematic structural diagram of another electromagnetic bandgap structure provided by an embodiment of the present invention;

fig. 12 is a schematic plane structure diagram of an electromagnetic bandgap structure applied to a radio frequency antenna according to an embodiment of the present invention;

fig. 13 is a cross-sectional view of a radio frequency antenna structure according to an embodiment of the present invention;

fig. 14 is a schematic structural diagram of an intermediate metal layer according to an embodiment of the present invention;

FIG. 15 is a schematic view of the top metal layer and intermediate laminate;

FIG. 16 is a schematic illustration of the isolation without the electromagnetic bandgap structure;

fig. 17 is a schematic diagram of isolation with an electromagnetic bandgap structure according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Fig. 1 is a schematic structural diagram of an electromagnetic bandgap structure provided by an embodiment of the present invention, as shown in fig. 1, the electromagnetic bandgap structure includes at least one first pattern 11 and at least one second pattern 12; the first pattern 11 includes two first straight line segments 111 and one arc segment 112, and two ends of each arc segment 112 are respectively connected with a first end of one first straight line segment 111; the second pattern 12 comprises a second straight line segment, one end of the second straight line segment is grounded, and the other end of the second straight line segment is a free end; the second straight line segment and the adjacent first straight line segment 111 are parallel to each other to form a capacitor structure.

The outline formed by splicing the first pattern 11 and the second pattern 12 may be, for example, an oval shape, a square shape, and the like, and this embodiment is not particularly limited, and fig. 1 illustrates only the outline formed by splicing the first pattern 11 and the second pattern 12 as an oval shape.

Specifically, the second straight line segment and the adjacent first straight line segment 111 are parallel to each other to form an interdigital structure AA, and the resonant frequency of the electromagnetic band gap structure can be controlled by controlling the length of the interdigital structure AA (the length of the first straight line segment 111 and the length of the second straight line segment), so that the radio frequency coupling signal with the specified frequency is filtered. Meanwhile, the interdigital structure AA formed by the parallel arrangement of the second straight line segment and the adjacent first straight line segment 111 can provide capacitance, compared with the traditional electromagnetic band gap structure, the electromagnetic band gap structure does not need to periodically arrange a plurality of units to provide coupling capacitance, and the miniaturization of the structure is realized.

It should be noted that fig. 1 is only illustrated as an example in which the electromagnetic bandgap structure includes one first pattern 11 and one second pattern 12. In other alternative embodiments, the number of the electromagnetic bandgap structure including the first pattern 11 and the second pattern 12 may not be limited in particular, but it can be generally considered that the first pattern 11 and the second pattern 12 may have a one-to-one correspondence relationship. For example, the electromagnetic bandgap structure may include one first pattern 11 and one second pattern 12, and may also include two first patterns 11 and two second patterns 12, and referring to fig. 2 in particular, fig. 2 is another electromagnetic bandgap structure provided by the embodiment of the present invention, and the electromagnetic bandgap structure includes two first patterns 11 and two second patterns 12.

It should be noted that, the adjustment of the resonant frequency of the electromagnetic bandgap structure provided in the embodiment of the present application can be achieved by adjusting the lengths of the first straight line segment 111 and the second straight line segment, and further, the principle of achieving the effect of filtering the electromagnetic wave with the specified frequency can be referred to the conventional related principle, which is not described in detail herein.

Fig. 3 is a further electromagnetic bandgap structure provided by the embodiment of the present invention, based on the above solution, optionally, referring to fig. 3, each first straight line segment 111 extends from the first end to the concave side of the arc segment 112, and in the same first pattern 11, two first straight line segments 111 do not intersect; the plurality of first patterns 11 are adjacently arranged, the first straight line segments 111 of two adjacent first patterns 11 are oppositely arranged, and the plurality of first patterns 11 are diverged from the direction of the concave side of each first pattern 11 pointing to the convex side of the first pattern 11; the second patterns 12 are located in the slits between two adjacent first patterns 11, and the extending direction of the slits is the same as the extending direction of the first straight line segments 111.

The first straight line segments 111 arranged oppositely in the two adjacent first patterns 11 and the second straight line segments positioned in the slits between the two adjacent first patterns 11 form an interdigital structure AA, and the resonant frequency of the electromagnetic band gap structure can be controlled by controlling the lengths of the interdigital structure AA (the lengths of the first straight line segments 111 and the second straight line segments), so that radio-frequency coupling signals with specified frequency are filtered. Meanwhile, the interdigital structure AA formed by the first straight line segments 111 oppositely arranged in the two adjacent first patterns 11 and the second straight line segments positioned in the slits between the two adjacent first patterns 11 can provide capacitance, compared with the conventional electromagnetic bandgap structure, the structure does not need a metal layer (i.e., a reference stratum) on the back surface to provide capacitance, and does not need to periodically arrange a plurality of units to provide coupling capacitance, thereby realizing the miniaturization of the structure.

For example, with continued reference to fig. 3, the plurality of first patterns 11 may be spliced to form an oval shape, the oval electromagnetic bandgap structure has four inward protruding interdigital structures AA, and increasing the protruding length or decreasing the distance between the interdigital structures AA can effectively increase the capacitance of the electromagnetic bandgap structure; increasing the length of the arc segment 112 can effectively increase the inductance of the bandgap structure; under the condition of certain capacitance and inductance, a filter circuit for specific frequency can be formed. On the other hand, the resonance frequency of the electromagnetic band gap structure can be reduced by increasing the size of the ellipse (the inward protruding length of the interdigital structure AA is unchanged), so that a radio frequency coupling signal with lower frequency is filtered; conversely, reducing the size of the ellipse (the length of the inward protrusion of the interdigital structure AA is unchanged) can increase the resonant frequency of the electromagnetic band gap structure, thereby filtering out a higher-frequency radio frequency coupling signal. That is, the size of the ellipse formed by the joining of the plurality of first patterns 11 and the length of the interdigital structure AA are inversely proportional to the resonant frequency, respectively.

Fig. 3 shows the electromagnetic bandgap structure including 4 interdigital structures AA by way of example only, but the present invention is not limited thereto, and it should be noted that fig. 3 shows the plurality of first patterns 11 by way of example only to be combined to form an oval shape, and in other embodiments, the plurality of first patterns 11 may be combined to form a circle shape, etc. as shown in fig. 4.

According to the technical scheme, the interdigital structure is formed by the first straight line segments oppositely arranged in the two adjacent first patterns and the second straight line segment positioned in the slit between the two adjacent first patterns, so that on one hand, the length of the interdigital structure is controllable, the resonance frequency of the electromagnetic band gap structure can be flexibly adjusted, the effect of filtering radio frequency coupling signals with specified frequency is achieved, and the interference between channels is reduced; on the other hand, the interdigital structure provides a capacitor, so compared with the traditional electromagnetic band gap structure, the interdigital structure of the embodiment does not need a floor on the back to provide the capacitor, does not need to periodically arrange a plurality of units to provide a coupling capacitor, does not have special requirements on a metal reference plane below the interdigital structure, can realize the working performance of a single unit, and is suitable for a system with compact space; meanwhile, the plurality of first patterns are diverged from the direction of the concave side of each first pattern to the convex side of each first pattern, so that the space utilization rate is greatly improved, and the miniaturization of the structure is further realized.

Fig. 5 is a schematic structural diagram of another electromagnetic bandgap structure provided by the embodiment of the present invention, and on the basis of the above scheme, optionally, as shown in fig. 5, the electromagnetic bandgap structure further includes at least one third pattern 13; the third pattern 13 includes a third straight line segment; the third straight line segment is located in the slit between two adjacent first patterns 11, and connects the second ends of the two first straight line segments 111 forming the slit.

In this embodiment, the first straight line segment 111, the second straight line segment 12, and the third straight line segment, which are oppositely disposed in two adjacent first patterns 11, form an interdigital structure AA.

Fig. 5 shows only exemplarily an interdigital structure AA comprising only one first pattern 11, one second pattern 12 and one third pattern 13. In other embodiments, the electromagnetic bandgap structure may include both an interdigital structure formed by the first straight line segment 111, the second straight line segment and the third straight line segment which are oppositely arranged in the two adjacent first patterns 11 and an interdigital structure formed by the first straight line segment 111 and the second straight line segment 12 which are oppositely arranged (as shown in fig. 6). For example, fig. 7 is a schematic structural diagram of another electromagnetic bandgap structure provided in the embodiment of the present invention, as shown in fig. 7, the electromagnetic bandgap structure includes four interdigital structures AA, where the interdigital structure AA is formed by a first straight line segment 111, a second straight line segment, and a third straight line segment that are oppositely disposed in two adjacent first patterns 11.

The electromagnetic bandgap structure of the present technical solution has the same beneficial effects as the electromagnetic bandgap structure in the above embodiments, and is not described herein again.

Preferably, with continued reference to fig. 6 and 7, the electromagnetic bandgap structure comprises four first patterns 11 and four second patterns 12; the first patterns 11 are spliced to form an oval shape; the four second straight line segments 12 are respectively positioned at two ends of the major axis and two ends of the minor axis of the ellipse. This is because, although the larger the number of interdigital structures AA, the lower the resonance frequency can be, and the more miniaturized the structure can be, considering that the length of the interdigital structure AA is an important optimization parameter, when the number of interdigital structures AA is 4, the longer the interdigital structure AA is compared with the case of a plurality of interdigital structures AA, and further, the resonance frequency is lowered, and the structure is realized.

The electromagnetic band gap structure of the technical scheme comprises 4 interdigital structures, so that the space utilization rate of the electromagnetic band gap structure is further improved, and the miniaturization of the electromagnetic band gap structure is realized.

Based on the above scheme, optionally, with continued reference to fig. 7, the major axis of the ellipse is L1, 480 μm ≦ L1 ≦ 520 μm (e.g., L1 may take on values of 480 μm, 490 μm, 500 μm, 510 μm, 520 μm, etc.), and the minor axis of the ellipse is L2, 380 μm ≦ L2 ≦ 420 μm (e.g., L2 may take on values of 380 μm, 390 μm, 400 μm, 410 μm, 420 μm, etc.).

Although the size of the electromagnetic band gap structure provided by the technical scheme is small, the electromagnetic band gap structure can filter out radio frequency coupling signals with specified frequency by adjusting the length of the interdigital structure, and can be suitable for radio frequency devices which are gradually miniaturized.

Based on the above scheme, optionally, with reference to fig. 7, the electromagnetic bandgap structure includes a first metal layer, that is, the electromagnetic bandgap structure may be an electromagnetic signal isolation structure obtained by etching the first metal layer, and each pattern in the electromagnetic bandgap structure may be a pattern formed by an etched gap or a fine metal wire (that is, a metal wire). Meanwhile, the widths of the gap and the metal thin line can be set to different widths according to different positions and electrical parameters, and the width can be larger than or equal to the critical dimension (namely CD) of the etching process.

The following describes the etching of the first metal layer to obtain the electromagnetic bandgap structure with reference to a typical example, but the present application is not limited thereto.

With continued reference to fig. 3, the first metal layer 10 includes a plurality of metal lines; the metal lines constitute a first pattern 11 and a second pattern 12 of an electromagnetic bandgap structure. The present embodiment may constitute the first pattern 11 and the second pattern 12 of the electromagnetic bandgap structure by metal lines,

alternatively, fig. 8 is a further electromagnetic bandgap structure provided by the embodiment of the present invention, as shown in fig. 8, the first metal layer includes a plurality of metal patterns; the kerf between adjacent metal patterns constitutes a first pattern 11 and a second pattern 12 of an electromagnetic bandgap structure.

It is worth mentioning that, as shown in fig. 3 and 8, the shape of the electromagnetic bandgap structure of fig. 8 is a complementary shape of the electromagnetic bandgap structure of fig. 3. The electromagnetic bandgap structure in fig. 3 and the electromagnetic bandgap structure in fig. 8 have the same resonant frequency, so that the rf coupled signal with the same frequency can be filtered, specifically, fig. 3 is an effect of filtering by disposing a metal strip in a corresponding region; fig. 8 achieves this effect by etching of the metal strips in the corresponding areas. It should be noted that the present embodiment is only exemplified by four interdigital structures, but the present embodiment is not limited thereto.

Based on the same inventive concept, the embodiment of the utility model provides an electromagnetism band gap structure again. Fig. 9 is a schematic structural diagram of another electromagnetic bandgap structure provided by the embodiment of the present invention, referring to fig. 9, the electromagnetic bandgap structure has a bandgap isolation region ZZ and a peripheral metal region YY disposed around the bandgap isolation region ZZ, and the electromagnetic bandgap structure includes: a peripheral metal sheet 20 disposed in the peripheral metal region YY; an interdigital structure 21 comprising a first interdigital unit 211 and a second interdigital unit 212; the first interdigital unit 211 is nested in the second interdigital unit 212; the interdigital structure 21 is connected with the peripheral metal sheet 20 through a first interdigital unit 211; and an inductance structure 22 connected to the second interdigital unit; wherein, the interdigital structure 21 is used for providing a capacitor of the electromagnetic band gap structure, and the inductance structure 22 is used for providing an inductance connected in series with the capacitor; and the electromagnetic band gap structure is used for isolating the electromagnetic signals with preset frequency according to the capacitance and the inductance.

It should be noted that, in order to distinguish differences from the above embodiments, different reference numerals are used for the same structures in this embodiment, and the following embodiments are the same and will not be described again.

The shape of the bandgap isolation region ZZ may include, for example, a square, a circle, or an ellipse, which is specifically defined in this embodiment. When the shape of the isolation zone ZZ is square, the shape of the inductance structure 22 is folded, and when the shape of the isolation zone ZZ is round or oval, the shape of the inductance structure 22 is arc. When the number of the interdigital structures 21 is plural, for example, 4, both ends of the inductor structure 22 are respectively connected to two second interdigital units 212 disposed adjacently. Fig. 9 is only illustrated by way of example with one interdigital structure 21.

Specifically, the resonant frequency of the electromagnetic bandgap structure can be controlled by controlling the length of the interdigital structure 21 (e.g., the length of the first interdigital unit 211 and the second interdigital unit 212), so as to filter out the radio frequency coupling signal of a specific frequency. Meanwhile, the interdigital structure 21 can provide capacitance, and compared with the conventional electromagnetic bandgap structure, the interdigital structure does not need a metal layer (i.e., a reference ground layer) on the back surface to provide capacitance, and does not need to periodically arrange a plurality of units to provide coupling capacitance, thereby realizing the miniaturization of the structure.

According to the technical scheme, the first interdigital unit and the second interdigital unit form an interdigital structure, so that on one hand, the length of the interdigital structure is controllable, the resonance frequency of the electromagnetic band gap structure can be flexibly adjusted, the effect of filtering radio frequency coupling signals with specified frequency is achieved, and the interference between channels is reduced; on the other hand, the interdigital structure provides a capacitor, so compared with the electromagnetic bandgap structure in the prior art, the interdigital structure of the present embodiment does not need a floor on the back side to provide the capacitor, and does not need to periodically arrange a plurality of units to provide a coupling capacitor, and the interdigital structure has no special requirement for a metal reference plane located below the interdigital structure, and the electromagnetic bandgap structure can realize the performance of single unit operation, and is suitable for a system with compact space.

Based on the above scheme, optionally, with continued reference to fig. 9, the first interdigital unit 211 comprises a strip-shaped protrusion, and the second interdigital unit 212 comprises a U-shaped recess; wherein one end of the strip-shaped protrusion is connected with the peripheral metal sheet 20 and the other end is inserted into the U-shaped recess.

Fig. 10 is a schematic structural diagram of another electromagnetic bandgap structure provided by an embodiment of the present invention. On the basis of the above scheme, optionally, referring to fig. 10, the second interdigital unit 212 further includes two parallel strip-shaped structures; one end of the strip-shaped protrusion is connected with the peripheral metal sheet 20, and the other end is inserted into the area between the two parallel strip-shaped structures; wherein the second interdigital units 212 between adjacent interdigital structures 21 have different structures.

Based on the same inventive concept, the embodiment of the utility model also provides an electromagnetic band gap structure. Fig. 11 is a schematic structural diagram of another electromagnetic bandgap structure provided by the embodiment of the present invention, referring to fig. 11, the electromagnetic bandgap structure has an oval bandgap isolation region XX and a peripheral metal region PP disposed around the oval bandgap isolation region XX, and the electromagnetic bandgap structure includes: a peripheral metal sheet 30 disposed in the peripheral metal region PP; four interdigital structures 31, including two first interdigital structures 311 and two second interdigital structures 312; the two first interdigital structures 311 are symmetrically distributed on the long axis of the oval band-gap isolation region, and the two second interdigital structures 312 are symmetrically distributed on the short axis of the oval band-gap isolation region; the adjacent interdigital structures 31 are electrically connected through the arc inductance units 32; the interdigital structure 31 is electrically connected with the arc-shaped inductance unit 32 alternately, and is used for isolating radio-frequency signals with preset frequency, which are emitted by at least two radio-frequency components symmetrically distributed on two sides of the electromagnetic band gap structure; the radio frequency signal with the preset frequency is a millimeter wave signal.

Optionally, the first interdigital structure 311 comprises a first strip-shaped protrusion and a U-shaped recess; one end of the first bar-shaped protrusion is connected with the peripheral metal sheet 30, and the other end is inserted into the U-shaped recess; and the second interdigital structure 312 comprises a second strip-shaped protrusion and two parallel strip-shaped structures; one end of the second strip-shaped protrusion is connected with the peripheral metal sheet 30, and the other end of the second strip-shaped protrusion is inserted into an area between the two parallel strip-shaped structures; wherein, two ends of the U-shaped recess are connected to one bar structure of the second interdigital structure 312 through an arc-shaped inductance unit 32, respectively, to form a curve segment.

Optionally, the curved line segment is the same as the distance between the peripheral metal sheet 30 and the first and second bar-shaped protrusions, respectively.

The length of the strip-shaped bulges is increased or the distance between the interdigital structures 31 is reduced, so that the capacitance of the electromagnetic band gap structure can be effectively increased; increasing the length of the arc-shaped inductance unit 32 can effectively increase the inductance of the band gap structure; under the condition of certain capacitance and inductance, a filter circuit for specific frequency can be formed. On the other hand, the resonance frequency of the electromagnetic band gap structure can be reduced by increasing the size of the ellipse (the length of the strip-shaped bulge of the interdigital structure 32 is unchanged), so that a radio frequency coupling signal with lower frequency is filtered; on the contrary, the size of the ellipse is reduced (the length of the strip-shaped bulge of the interdigital structure 32 is unchanged), so that the resonance frequency of the electromagnetic band gap structure can be improved, and a radio frequency coupling signal with a higher frequency can be filtered.

It should be noted that the adjustment of the resonant frequency of the electromagnetic bandgap structure provided in the embodiment of the present application can be achieved by adjusting the lengths of the U-shaped recess and the first strip-shaped protrusion and the second strip-shaped protrusion, and further, the principle of achieving the effect of filtering out the electromagnetic wave with the specified frequency can be referred to the conventional related principle, and is not described in detail herein.

According to the technical schemes, on one hand, the lengths of the first interdigital unit and the second interdigital unit are controllable, so that the resonant frequency of the electromagnetic band gap structure can be flexibly adjusted, the effect of filtering radio frequency coupling signals with specified frequency is achieved, and the interference between channels is reduced; on the other hand, the interdigital structure provides a capacitor, so compared with the traditional electromagnetic bandgap structure, the interdigital structure of the embodiment does not need a floor on the back surface to provide the capacitor, does not need to periodically arrange a plurality of units to provide a coupling capacitor, has no special requirement on a metal reference plane below the interdigital structure, can realize the performance of single unit operation, and is suitable for a system with compact space.

As shown in fig. 12, in an alternative embodiment, the electromagnetic gap structures 100 in the above embodiments may be applied to isolate the transmission lines of the adjacent antennas 110, that is, at least one electromagnetic gap structure 100 may be disposed in the region between the transmission lines of the adjacent channels DD for electromagnetic isolation, and when the electromagnetic gap structure 100 is an elliptical structure, the major axis of the electromagnetic gap structure is perpendicular to the extending direction of the transmission line of each channel DD, that is, the minor axis of the elliptical electromagnetic gap structure 100 is parallel to the extending direction of the transmission line of each channel DD, so as to isolate the interference between the transmission lines of the adjacent channels DD. Meanwhile, in order to improve the isolation of the transmission lines of the adjacent channels DD, a plurality of elliptical electromagnetic gap structures 100 may be sequentially disposed along the extending direction of the transmission lines, and in order to further improve the isolation between two adjacent antennas, one or more electromagnetic gap structures 100 may also be disposed between the antenna radiation structures (not shown in the figure) connected to the channels DD.

The electromagnetic band gap structure 100 in this embodiment can isolate the radio frequency signals with preset frequency emitted by the antennas 110 on both sides; the radio frequency signal of the preset frequency may be, for example, a millimeter wave signal.

Alternatively, with continued reference to fig. 12, the electromagnetic bandgap structure 100 and the transmission line of the antenna 110 may be disposed in the same metal layer, that is, the electromagnetic bandgap structure 100 and the transmission line of the antenna 110 may be device structures formed in the same metal layer by using the same or the same etching process.

Fig. 13 is a cross-sectional view of a radio frequency antenna structure according to an embodiment of the present invention, fig. 14 is a schematic top view of an intermediate metal layer according to an embodiment of the present invention, and fig. 15 is a schematic top view of the top metal layer shown in fig. 12 and the intermediate metal layer shown in fig. 14. As shown in fig. 12, 13, 14 and 15, the rf antenna structure may include a bottom metal layer 5000, a second dielectric layer 4000, an intermediate metal layer 3000, a first dielectric layer 2000, a top metal layer 1000, and the like, which are sequentially stacked; the electromagnetic bandgap structure 100 and the radiation structure of the antenna 110 are disposed in the same metal layer, or the electromagnetic bandgap structure may be disposed in a metal layer where the transmission line of the antenna 110 is located, for example, the transmission line, the radiation structure and the electromagnetic bandgap structure may be disposed in the top metal layer 1000, and the transmission line and the radiation structure may be electrically connected through the middle metal layer 300 by using the metal via CC.

Specifically, each antenna 110 may include a channel DD, and the channel DD of each antenna 110 may be connected to the middle metal layer 3000 through the metal via CC; wherein the electromagnetic bandgap structure 100 is arranged in the region between the channels DD of adjacent antennas 110, i.e. the electromagnetic bandgap structure 100 may be arranged in the top metal layer 1000 and/or the intermediate dielectric layer 3000.

Alternatively, the electromagnetic bandgap structure 100 and a part of the antenna 110 may be formed by etching the top metal layer 1000 (as shown in fig. 15). Because the electromagnetic bandgap structure 100 is located between adjacent channels DD in the top metal layer 1000, the coupling strength between the adjacent channels DD can be reduced.

It should be noted that the rf antenna structure of the embodiment of the present application has various shapes, that is, the rf antenna structure may also be an antenna with other structures, as long as the electromagnetic band gap structure described above is provided between adjacent antennas 110, for example, between transmission lines and/or between radiation structures, to improve the electromagnetic isolation between adjacent antennas.

Specifically, referring to fig. 16 and 17, fig. 16 is a schematic diagram of an isolation without an electromagnetic bandgap structure, and fig. 17 is a schematic diagram of an isolation with an electromagnetic bandgap structure (i.e., the structure shown in fig. 15) provided by an embodiment of the present invention. As can be seen from fig. 16 and 17, the frequency band of interest is about 25-30dB, the electromagnetic bandgap structure provided by the embodiment of the present invention realizes effective isolation in the frequency band of interest, can generally realize 5-8dB isolation improvement in the frequency band, and can realize improvement of more than 20dB in individual frequency points.

On the basis of the above scheme, optionally, the bottom metal layer 5000 further includes a reference ground cell; wherein, the electromagnetic bandgap structure 100 at least partially overlaps the reference ground unit as long as the perpendicular projection on the plane of the reference ground unit is located.

Wherein, need not set up complete reference ground to the radio frequency antenna structure in this embodiment, only need set up the part even need not to set up the reference ground layer based on the demand promptly, also the radio frequency antenna structure in this application need not ground connection, just can realize more excellent electromagnetic isolation between the antenna to promote the flexibility that the radio frequency antenna structure distributes greatly.

Optionally, each antenna further includes a feeder line and a plurality of radiation units or radiation pieces (not shown in the figure) connected through the feeder line, and is configured to transmit or receive radio frequency signals, that is, one end of the feeder line is connected to the plurality of radiation units, and the other end of the feeder line is connected to a corresponding channel; the electromagnetic band gap structures can be only arranged between the channels of the adjacent antennas, and a plurality of electromagnetic band gap structures can also be sequentially arranged along the extending direction of the antennas, so that a strip-shaped isolation strip is formed between the adjacent antennas, and the electromagnetic isolation between the adjacent antennas is further improved.

It should be noted that fig. 12, fig. 13, fig. 14 and fig. 15 are only exemplary diagrams showing a structure of a radio frequency antenna structure, and the radio frequency antenna structure provided by the above embodiment for filtering out radio frequency coupling signals of corresponding frequencies all falls into the scope of the present invention.

According to the technical scheme, the electromagnetic band gap structure is applied to the radio frequency antenna structure, so that the effect of radio frequency coupling signals with specified frequency are effectively filtered, and the quality of received signals is improved.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims

1. An electromagnetic bandgap structure, comprising at least one first pattern and at least one second pattern;

2. The electromagnetic bandgap structure of claim 1, wherein each of the first straight line segments extends from the first end to the concave side of the arc segment, and the two first straight line segments do not intersect in the same first pattern;

3. The electromagnetic bandgap structure of claim 2, further comprising at least one third pattern;

the third pattern comprises a third straight line segment;

4. The electromagnetic bandgap structure according to claim 1, wherein the electromagnetic bandgap structure comprises four of the first patterns and four of the second patterns;

splicing the first patterns to form an oval;

the four second straight line segments are sequentially distributed at the ends of the major axis and the minor axis of the ellipse and extend to the central point of the ellipse along the length direction of the major axis or the minor axis.

5. The electromagnetic bandgap structure of claim 4, wherein the major axis of the ellipse is L1, 480 μm L1 μm 520 μm, and the minor axis of the ellipse is L2, 380 μm L2 μm 420 μm.

6. The electromagnetic bandgap structure according to claim 1, wherein the electromagnetic bandgap structure comprises a first metal layer;

7. The electromagnetic bandgap structure of claim 1, wherein the first and second patterns are patterns of metal lines or slits.

8. An electromagnetic bandgap structure having a bandgap isolation region and a peripheral metal region disposed around the bandgap isolation region, the electromagnetic bandgap structure comprising:

a peripheral metal sheet disposed in the peripheral metal region;

the inductance structure is connected with the second interdigital unit;

9. The electromagnetic bandgap structure of claim 8, wherein the bandgap isolation region has a square, circular or elliptical shape.

10. The electromagnetic bandgap structure according to claim 8 or 9, wherein the first interdigital unit comprises a strip-shaped protrusion, and the second interdigital unit comprises a U-shaped recess;

11. The electromagnetic bandgap structure according to claim 10, wherein the second interdigital unit further comprises two parallel strip-shaped structures;

12. An electromagnetic bandgap structure having an oval bandgap isolation region and a peripheral metal region disposed around the oval bandgap isolation region, the electromagnetic bandgap structure comprising:

a peripheral metal sheet disposed in the peripheral metal region;

13. The electromagnetic bandgap structure of claim 12, wherein the first interdigital structure comprises a first linear protrusion and a U-shaped recess; one end of the first strip-shaped bulge is connected with the peripheral metal sheet, and the other end of the first strip-shaped bulge is inserted into the U-shaped recess; and

14. The electromagnetic bandgap structure according to claim 13, wherein the curved line segments are at the same pitch as the peripheral metal sheet, the first bar-shaped projections and the second bar-shaped projections, respectively.

15. A radio frequency antenna structure, comprising:

at least two antennas; and

an electromagnetic bandgap structure as claimed in any one of claims 1 to 14;

16. The radio frequency antenna structure of claim 15, wherein the electromagnetic bandgap structure and the at least two antennas are disposed in a same metal layer.

17. The radio frequency antenna structure of claim 16, comprising a bottom metal layer, a second dielectric layer, an intermediate metal layer, a first dielectric layer, and a top metal layer stacked in this order;

18. The rf antenna structure of claim 17, wherein any one of the antennas includes a channel, and the channel of each of the antennas is connected to the middle metal layer through a metal via hole;

19. The radio frequency antenna structure of claim 17, wherein the bottom metal layer includes a ground reference cell;