Miniaturized millimeter wave filtering magnetoelectric dipole antenna with high out-of-band rejection

Abstract

The invention relates to a miniaturized millimeter wave filtering magnetoelectric dipole antenna with high out-of-band rejection, and relates to the technical field of communication antennae, and the miniaturized millimeter wave filtering magnetoelectric dipole antenna with the high out-of-band rejection effect comprises a strip line feed structure which is used for generating a lower stop band radiation zero point; the n-shaped feed structure is used for feeding the magnetoelectric dipole; according to the magnetoelectric dipole radiator, a U-shaped groove is etched in a dipole patch, so that the size of the antenna is reduced; the parasitic metal strips are used for enhancing the radiation suppression effect of the upper stop band; the folding split rings are folded to reduce the size of the split rings and enhance the radiation suppression effect of the lower stop band at the same time; the inverted L-shaped short circuit branch is used for enhancing the radiation suppression effect of the upper stop band, the absolute bandwidth of the antenna is 21.1 GHz to 31.0 GHz, the relative bandwidth is 37.0%, the lowest gain is 5.0 dBi, the highest gain can reach 7.8 dBi, the suppression level from the in-band highest gain to the radiation zero point of the upper stop band is larger than 40 dBi, and the suppression level from the in-band highest gain to the radiation zero point of the lower stop band is larger than 50.0 dBi.

Description

Technical Field

[0001] The present invention relates to the technical field of communication antennas, and in particular to a millimeter wave filtering electromagnetic dipole antenna. Background Art

[0002] 5G millimeter wave technology is an important basic technology in 5G applications. Millimeter wave refers to a special electromagnetic wave with a wavelength of 1mm to 10mm and a fluctuation frequency of 30GHz to 300GHz. Millimeter wave antenna is an antenna system specially designed to process and transmit electromagnetic waves in the millimeter wave frequency band. Millimeter wave antennas are widely used in 5G communications, unmanned driving, radar systems and other fields due to their high frequency, high bandwidth, narrow beam and multi-beam characteristics. As wireless communication equipment continues to pursue integration and compactness, the problem of external electromagnetic interference in the RF front end has become increasingly prominent. This interference greatly reduces the signal-to-noise ratio, resulting in an increasingly complex and severe electromagnetic environment. In millimeter wave communication systems, filtering antennas can improve the ability to suppress out-of-band noise and improve frequency selectivity, but since most millimeter wave antennas are multi-layer planar structures with limited design freedom, it is difficult to achieve good filtering performance and wide bandwidth at the same time.

[0003] The magnetoelectric dipole has the advantages of wide bandwidth, stable gain, symmetrical radiation pattern, and low cross-polarization. Therefore, it is of great significance to integrate filtering functions in electromagnetic dipole antennas. Most of today's electromagnetic dipole filter antennas focus on the relative bandwidth of the antenna and the in-band radiation performance. Few designers pay attention to the suppression effect of transmission and reception outside the working frequency band. Therefore, in order to meet the stringent requirements of various current and future wireless communication systems on the RF front end, it is necessary to design a new type of millimeter-wave magnetoelectric dipole antenna, which not only needs to have filtering characteristics, but also should be able to effectively suppress radiation outside the working frequency band. Such an antenna will be the key to future wireless communication systems. Summary of the invention

[0004] The object of the present invention is to provide a miniaturized millimeter-wave filtering magnetoelectric dipole antenna with high out-of-band suppression to solve the problems raised in the above background.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A miniaturized millimeter-wave filtering magnetoelectric dipole antenna with high out-of-band suppression, comprising a feeding structure, a magnetoelectric dipole radiation structure and an out-of-band radiation suppression structure

[0007] The feeding structure comprises a horizontal plane stripline structure (6) and a vertical plane Π-shaped feeding probe structure (4), wherein the horizontal stripline structure (6) is composed of a dielectric substrate (11), a dielectric substrate (12), an impedance matching network (61), a quarter-wavelength branch (62), a lower metal plate (21) and an upper metal plate (22). The vertical Π-shaped feeding probe is composed of a metal through hole (42), a metal through hole (43) and a horizontal metal patch (41);

[0008] Furthermore, the metal floor is located at the bottom of the first dielectric substrate (11) and at the top of the second dielectric substrate (12). The impedance matching network (61) and the quarter-wavelength branch (62) are located at the junction of the dielectric substrate (11) and the dielectric substrate (12).

[0009] Furthermore, the quarter-wavelength open-circuit branch structure (62) can introduce a first radiation zero point in the upper stop band.

[0010] Furthermore, the vertical Π-shaped feeding probe structure (4) penetrates the dielectric substrate (12), the dielectric substrate (13), and the dielectric substrate (14); the metal through hole (43) and the upper end of the metal through hole (42) are connected to the metal patch (31), and the lower end of the metal through hole (43) is connected to the strip line junction (6), and neither of the two through holes is in contact with the metal plate.

[0011] The magnetic electric dipole radiation structure comprises two rows of metal short-circuit through holes (32) and a pair of electric dipole patches (31);

[0012] Furthermore, the two rows of metal through holes (32) are connected to the first metal floor (21) at their lower ends and to the electric dipole patch (31) at their upper ends, penetrating through the four layers of dielectric substrate, wherein the metal through holes located above the impedance transformation network (61) are connected to the second metal floor (22) at their lower ends.

[0013] Furthermore, the electric dipole patch (31) is located on the top of the fourth dielectric layer (14); a U-shaped structural groove is etched on the electric dipole patch, the U-shaped groove prolongs the effective length of the current, can shorten the length of the electric dipole patch, and generates two slot radiations with opposite current directions in the upper stop band, and the two reverse radiations generate a second radiation zero point.

[0014] The out-of-band suppression structure comprises two split rings (8), a parasitic metal patch (5) and a pair of Γ-shaped short-circuit metal branches (4);

[0015] Furthermore, the split ring (8) is located on both sides of the electric dipole patch (31); the split ring increases the effective length of the current by folding, and the size of the split ring can be reduced. The current generated by the split ring in the lower stop band is opposite to the current of the electric dipole patch, and the two opposite currents cancel each other out in the radiation far field, thereby strengthening the out-of-band suppression effect of the lower stop band.

[0016] Furthermore, the parasitic metal patch (5) is located at the boundary between the dielectric substrate (13) and the dielectric substrate (14); the parasitic metal strip (5) can generate a magnetic current opposite to the magnetic dipole at the upper stop band, thereby generating two opposite far-field radiations that cancel each other out, thereby enhancing the out-of-band suppression effect of the upper stop band.

[0017] Furthermore, the Γ-shaped short-circuit metal branch (4) is located at the crack of the split ring (8) to further reduce the radiation efficiency of the upper stop band.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] a) The present invention is implemented in the millimeter wave 30.00GHz frequency band, which expands the application of the Ka-band for the magnetoelectric dipole antenna and is an ideal choice for Ka-band communication;

[0020] b) The feeding part of the proposed antenna adopts a multi-section impedance transformation structure and a quarter open-circuit branch structure; the multi-section impedance transformation structure can greatly expand the bandwidth; the quarter open-circuit structure can be equivalent to a short-circuit structure in a specific frequency band, thereby generating a radiation zero point;

[0021] c) The proposed antenna integrates a folded split ring, a U-shaped slot and a Γ-shaped short-circuit branch, and also uses a Π-shaped feeding structure; the folded split ring can not only suppress the radiation effect of the lower stop band and improve the in-band gain, but also increase the current flow through folding and reduce the size of the split ring; the U-shaped slot not only strengthens the out-of-band suppression at the upper stop band, but also reduces the patch size and achieves miniaturization; the Γ-shaped short-circuit branch can couple a large amount of energy in the upper stop band to form opposite radiation, thereby suppressing the upper stop band radiation; the Π-shaped feeding structure can be equivalent to an open-circuit branch in parallel with the electric dipole arm, thereby obtaining a radiation zero point;

[0022] d) The absolute bandwidth of the proposed antenna is 21.10 GHz-31.00 GHz, and the relative bandwidth reaches 37.00%. It has high out-of-band suppression performance while maintaining high gain performance in the working frequency band, while also maintaining a relatively compact size. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the overall structure diagram of the antenna

[0024] Figure 2 Antenna radiation patch structure diagram

[0025] Figure 3 Parasitic metal patch structure diagram

[0026] Figure 4 The vertical cross-section of the antenna

[0027] Figure 5 The structure diagram of the strip feeder

[0028] Figure 6 is the xoz plane pattern of the antenna at 30.00GHz

[0029] Figure 7 This is the reflection coefficient curve of the millimeter wave filtering magnetoelectric dipole antenna with high out-of-band suppression

[0030] Figure 8 This is the gain curve of the millimeter wave filtering magnetoelectric dipole antenna with high out-of-band suppression. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be understood that the description of the orientation, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc., is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In the description of the serial number, the first serial number represents a large structure, and the second serial number is a small structure, such as structures 72 and 71, 7 represents a Γ-shaped metal short-circuit branch structure, 72 represents the metal through-hole part of the Γ-shaped metal short-circuit branch, and structure 71 represents the metal patch structure of the Γ-shaped metal short-circuit branch.

[0033] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0034] See also Figure 1-Figure 5 The high out-of-band suppression millimeter wave filtering magnetoelectric dipole antenna based on etching U-shaped grooves includes a feeding structure, a radiation structure and an out-of-band suppression structure. The overall structure from top to bottom is a metal floor (21), a metal through hole (32) of the radiation structure, a dielectric substrate (11), a strip feed line (6), a Π-shaped feeding probe (4), a dielectric substrate (12), a metal floor (22), a Γ-shaped short-circuit metal branch (7), a dielectric substrate (13), a parasitic metal patch (5), a dielectric substrate (14), an electric dipole patch (31) of the radiation structure, a folded split ring (8), a metal patch portion of the Π-shaped feeding structure (41), and a metal patch portion of the Γ-shaped short-circuit metal branch.

[0035] In the example, the dielectric substrate is made of Rogers RT5880, with a dielectric constant of 2.2 and a tangent loss of 0.0009. The thickness of the dielectric substrate (11), (12), (13) is 0.25 mm, and the thickness of the dielectric substrate (14) is 1.58 mm.

[0036] In the example, the electric dipole patch (31) of the radiation structure and the two rows of metal through holes (32) form a magnetic electric dipole radiator, wherein the electric dipole is 1.4 mm long and 1.9 mm wide, symmetrical about two vertical X-axis and Y-axis, and is placed above the dielectric substrate (14). A U-shaped groove is introduced on the surface of the electric dipole patch to extend the current flow path, thereby realizing the miniaturization of the structure. The U-shaped groove is 1.5 mm wide and 0.75 mm long. Each row of metal through holes has three metal through holes, which are arranged at equal intervals to form a magnetic dipole with a radius of 0.4 mm. The two rows of metal through holes are symmetrical about two vertical X-axis and Y-axis, but the metal through hole located above the strip feeder (6) is shorter than the other metal through holes, and its lower end is connected to the metal floor (22).

[0037] In the example, the metal floor (21) (22) and the impedance transformation network (61) and the quarter-wavelength short-circuit branch (62) constitute a strip feed line in the feeding structure, and the impedance transformation network (61), the quarter-wavelength open-circuit branch (62) and the lower end of the second metal column (43) of the Π-shaped feeding structure (4) are connected at the same point; after the quarter-wavelength open-circuit branch (62) is transformed, the open line is short-circuited at the connection between the impedance transformation network (61) and the first metal column (43) at about 19.00 GHz in the lower stop band, so there will be a radiation zero point at 19.00 GHz; the total length of the quarter-wavelength open-circuit branch (62) is about 0.25 mm.

[0038] The P-shaped feeding structure (4) comprises a third metal patch (41), a first metal column (42) and a second metal column (43); the P-shaped feeding structure (4) is arranged between two rows of metal through holes (32) of the radiation structure, the third metal patch (41) is arranged on the surface of the dielectric substrate (14), the end of the second metal column (43) of the P-shaped feeding structure (4) is connected to the impedance transformation network (61) and the quarter-wavelength open-circuit branch (62) at the same point, the current at the middle position of the third metal patch (41) in the P-shaped feeding structure (4) is zero at about 35 GHz in the upper stop band, and the signal on the P-shaped feeding structure 5 cannot be effectively coupled to the magnetoelectric dipole radiator, thereby introducing a radiation zero point at 35 GHz.

[0039] In the example, the folded split ring (8) is located on both sides of the electric dipole (31), and the opening of the split ring (8) is flush with the electric dipole (31) patch near the Π-shaped feeding probe (41); the relationship between the split ring (8) and the electric dipole (31) is electrically coupled; in the lower stop band, the surface current on the split ring (8) is opposite to the surface current on the electric dipole (31), which can produce a radiation suppression effect in the lower stop band. The upper and lower sides of the split ring are folded, and the folding can extend the flow of the current of the split ring, and the miniaturization of the structure can be achieved. At the same time, the current at the folding point is divided into two sections of currents in opposite directions through spatial phase shift, which cancel each other out in the radiation field; the length of the split ring is 3.00 mm and the width is 1.30 mm. The folding structure starts from the middle of the upper and lower sides, and the folding structure is 0.50 mm long and 0.30 mm wide.

[0040] The Γ-shaped short-circuit branch (7) is located on both sides of the magnetoelectric dipole radiator and is divided into two parts: a metal through hole (72) and a metal patch (71). The lower end of the metal through hole part (72) is connected to the metal floor (22), and the upper end is connected to the metal patch (71), and the radius of the metal through hole is 0.29 mm; the metal patch (71) is located on the upper surface of the dielectric substrate (14), and its length is 0.95 mm and its width is 0.29 mm; the Γ-shaped short-circuit branch (7) can couple a large amount of energy in the upper stop band, and form opposite currents on the metal patch (71), so that the radiation cancels each other, thereby enhancing the radiation suppression effect of the upper stop band.

[0041] Two parasitic metal patches (5) are arranged on both sides of the Π-shaped feeding structure, respectively, and are located on the upper surface of the dielectric substrate (13); the metal strips extend from one side of the two rows of metal through holes (32) to the other side; the parasitic metal patch (5) and the magnetic dipole (32) form magnetic coupling; the magnetic currents generated by the parasitic metal patch (5) and the metal short-circuit through hole (32) below it in the upper stop band are opposite, and the radiation of the two in the far field cancels each other, and has a radiation suppression effect in the upper stop band; the length of the parasitic metal patch is 1.85 mm, and the width is 0.50 mm.

[0042] Figure 6 This is the E-plane radiation pattern of the high out-of-band suppression millimeter wave filtering magneto-electric dipole antenna based on etching U-shaped grooves at 30,00 GHz. It can be seen that the high out-of-band suppression millimeter wave filtering magneto-electric dipole antenna based on etching U-shaped grooves has a good gain pattern at the operating frequency.

[0043] Figure 7 The working bandwidth of the high out-of-band suppression millimeter-wave filtering magnetoelectric dipole antenna based on etched U-shaped grooves of the present invention is shown in the figure. As shown in the figure, the working absolute bandwidth of the magnetoelectric dipole antenna in this example is between 21.10 GHz and 31.00 GHz, and the relative bandwidth is 37.00%.

[0044] Figure 8 The in-band gain of the high out-of-band suppression millimeter-wave filtering magnetoelectric dipole antenna based on the etched U-shaped groove of the present invention is 5.00dBi at the lowest gain and 7.80dBi at the highest gain. The suppression level of the in-band highest gain to the upper stopband radiation zero point is greater than 40.00dBi, and the suppression level to the lower stopband radiation zero point is greater than 50.00dBi.

[0045] The above is a specific description of the implementation of the present invention. If one wants to obtain a high out-of-band suppression millimeter-wave filtering magneto-electric dipole antenna with an etched U-shaped groove in different frequency bands or different radiation zero points, one can adjust different parameters according to the specific situation, such as modifying the size of the electric dipole patch, modifying the length of the U-shaped groove, etc.

Claims

1. A miniaturized millimeter-wave filtering magnetoelectric dipole antenna with high out-of-band suppression, characterized in that: The invention comprises a radiation structure, a feeding structure and an out-of-band radiation suppression structure; the radiation structure is composed of an electric dipole radiation structure and a magnetic dipole radiation structure; the feeding structure is composed of a horizontal feeding line and a vertical plane Π-shaped metal through-hole feeding structure, which is used to expand the bandwidth and provide radio frequency energy to the radiation structure; the out-of-band suppression structure is composed of a folded open ring (8), a Γ-shaped short-circuit branch (7) and a suspended metal strip (5), which is used to suppress the out-of-band radiation effect.

2. A miniaturized millimeter-wave filtering magnetoelectric dipole antenna with high out-of-band suppression according to claim 1, characterized in that: The horizontal feed line comprises a main feed line (61), an open line (62) with a length of one quarter wavelength, a first metal ground (21), a second metal ground (22), a first dielectric plate (11) and a second dielectric plate (12); the main feed line (61) has a multi-section impedance transformation structure, which can expand the bandwidth; the open line can be equivalent to a short-circuit structure at a specific frequency point, thereby introducing a lower stopband radiation zero point; the main feed line (61) and the open line (62) are sandwiched between the metal ground (21) and the metal ground (22); the vertical plane II-shaped metal through hole feeding structure comprises a first rectangular metal sheet (41), a first metal through hole (42) and a second metal through hole (42); The invention relates to a first rectangular metal through hole (43); the first rectangular metal patch (41) is located in the middle of the upper surface of the first dielectric plate (14); the lower end of the first metal through hole (42) is connected to the main feed line (61), and the upper end is connected to the first rectangular metal patch (41); the upper end of the second metal through hole (43) is connected to the first rectangular metal patch (41), and the lower end is suspended; neither the first metal through hole (42) nor the first metal through hole (43) is grounded; the Π-shaped metal through hole structure can not only conduct electromagnetic energy to the radiation structure, but the second metal through hole (43) can also be equivalent to an open-circuit branch connected in parallel with the electric dipole, thereby introducing an upper stopband radiation zero point at a specific frequency point.

3. A miniaturized millimeter-wave filtering magnetoelectric dipole antenna with high out-of-band suppression according to claim 1, characterized in that: The radiation structure comprises a third metal through hole (32) and a grooved metal sheet (31); the grooved metal sheet (31) is symmetrically distributed on the upper surface of the fourth dielectric plate (14); the grooved metal sheet (31) radiates as an electric dipole radiation arm; etching a U-shaped groove can extend the current flow, reduce the size of the grooved metal sheet (31), and can also excite the U-shaped groove at a specific frequency point to form two opposite radiation modes, thereby canceling each other out to form a radiation zero point; the third metal through holes (32) are divided into two rows and are symmetrically distributed; the lower ends are connected to the first metal floor (21) and the upper ends are connected to the grooved metal sheet (31); the lower ends of the metal through holes located above the main feeder (61) are connected to the main feeder (61); the third metal through holes (32) radiate as magnetic dipoles, and form a magnetic electric dipole radiator with the grooved metal sheet (31).

4. A miniaturized millimeter-wave filtering magnetoelectric dipole antenna with high out-of-band suppression according to claim 1, characterized in that: The folded open ring (8) is located on both sides of the grooved metal sheet (31), and the folded open ring (8) can suppress the radiation suppression effect of the lower stop band. In addition, the size of the folded open ring (8) can be reduced by delaying the open ring current flow through the folded structure; the Γ-shaped short-circuit branches are symmetrically distributed on both sides of the vertical plane Π-shaped metal through-hole feeding structure, and are composed of a second rectangular metal sheet (71) and a fourth metal through-hole (72); the second rectangular metal sheet (71) is located on the upper surface of the fourth dielectric plate (14), and the lower end of the fourth metal through-hole (72) is connected to the second metal ground (22), and the upper end is connected to the second rectangular metal sheet (71); the Γ-shaped short-circuit branches can couple a large amount of energy in the upper stop band, and the symmetrical branches form an opposite radiation effect to suppress the radiation effect of the upper stop band; the suspended metal strip (5) is also rectangular and is located at the junction of the third dielectric plate (13) and the fourth dielectric plate (14), and can generate a magnetic current opposite to the magnetic dipole at a specific frequency point to enhance the radiation suppression effect of the upper stop band.

5. A miniaturized millimeter-wave filtering magnetoelectric dipole antenna with high out-of-band suppression according to claim 1, characterized in that: The first dielectric plate (11), the second dielectric plate (12), the third dielectric plate (13) and the fourth dielectric plate (14) are made of Rogers RT5880, with a dielectric constant of 2.2 and a tangent loss of 0.0009.

6. A miniaturized millimeter-wave filtering magnetoelectric dipole antenna with high out-of-band suppression according to claim 1, characterized in that: The antenna has an absolute bandwidth of 21.1GHz to 31.0GHz, a relative bandwidth of 37.0%, a minimum gain of 5.0dBi, and a maximum gain of 7.8dBi. The suppression level of the highest gain in the band to the upper stopband radiation zero point is greater than 40.0dBi, and the suppression level to the lower stopband radiation zero point is greater than 50.0dBi.

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