Miniaturized corner-cut dual-frequency leaky-wave antenna based on cross-shaped groove

Abstract

The invention discloses a miniaturized chamfered dual-frequency leaky-wave antenna based on a cross-shaped groove. The miniaturized chamfered dual-frequency leaky-wave antenna comprises a dielectric substrate, a grounding coplanar waveguide structure, a leaky-wave structure, a miniaturized planar inverted-L-shaped structure, a metal sheet and a cylindrical metal connecting rod, the leaky-wave structure is formed by loading rectangular radiation grooves with equal intervals and different lengths in the middle of a microstrip line, and beam scanning of a millimeter wave frequency band can be achieved. Each radiation patch of the planar inverted L-shaped structure is chamfered at the diagonal position of the feed end, and a cross-shaped slot is formed in the center of the patch and is used for realizing miniaturization of the antenna; the cylindrical metal connecting rod is used for connecting the planar inverted-L-shaped structure and the bottom metal sheet, the-10dB impedance bandwidth in the microwave frequency band is 6.28%, the maximum gain is 7.31 dB, the-10dB impedance bandwidth in the millimeter wave frequency band is 31.42%, the maximum gain is 17.30 dB, the beam scanning range is-28 degrees to + 12 degrees, the dual-frequency microwave millimeter wave antenna has the advantages of microwave millimeter wave dual frequency, beam scanning function, miniaturization and the like, and the dual-frequency microwave millimeter wave antenna has a wide application prospect. The method is suitable for 5G systems.

Description

Technical Field

[0001] The invention relates to the field of antennas, and in particular to a miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot. Background Art

[0002] With the rapid development of communication technology, the fifth generation of mobile communications (5G) has become a global hotspot. The current 5G system can be divided into two categories based on the frequency band. One type operates at a frequency below 6GHz and is used for long-distance communication and wide-area coverage, but its spectrum resources are tight and the bandwidth is limited; the other type operates in the millimeter wave frequency band and has the characteristics of large spectrum bandwidth and high transmission rate. Antennas are an important part of wireless systems. In order to be applied to 5G scenarios, their design needs to be able to achieve efficient integration of microwave and millimeter wave antennas in a specific space.

[0003] In the early design of dual-band antennas, the antenna units of the two frequency bands were often placed separately and fed separately using two independent feeding ports, which resulted in a larger antenna size. In order to improve space utilization, the common aperture antenna technology was proposed, but currently most microwave millimeter wave common aperture antennas use multi-port feeding. In wireless communication systems, the same standard usually requires the same RF link for data transmission, which limits the design of multiple feeding ports in practical applications. In addition, in order to further reduce the size of the antenna, antenna miniaturization is also a hot topic in antenna research and design in the next generation of wireless communication systems. Therefore, the research on single-port miniaturized microwave millimeter wave dual-band antennas has become very important. Summary of the invention

[0004] In view of the above problems, the present invention is proposed to provide a miniaturized dual-frequency co-aperture antenna based on a leaky-wave structure that overcomes the above problems or at least partially solves the above problems.

[0005] An embodiment of the present invention provides a miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot, the antenna comprising a dielectric substrate (10), a grounded coplanar waveguide (20), a leaky-wave structure (30), a miniaturized planar inverted L-shaped structure (40), a metal sheet (50), and a cylindrical metal connecting rod (60).

[0006] Furthermore, the leaky wave structure (30) comprises a microstrip line (31) and a rectangular structure (32); the microstrip line (31) is located in the middle of a dielectric substrate (10); the rectangular structure (32) is located on both sides of the microstrip line (31); the rectangular structure (32) comprises a combination of a plurality of equally spaced rectangular grooves (33) of different lengths; the microstrip line (31) symmetrically cuts the rectangular structure (32) into two rectangular grooves (33); and the middle of the leaky wave structure (30) is connected to a miniaturized planar inverted L-shaped structure (40).

[0007] Furthermore, the miniaturized planar inverted L-shaped structure (40) is located on both sides of the leaky wave structure (30); and the miniaturized planar inverted L-shaped structure (40) realizes energy input through the leaky wave structure (30).

[0008] Furthermore, the grounded coplanar waveguide structure (20), the leaky wave structure (30) and the miniaturized planar inverted L-shaped structure (40) are located on the upper surface of the dielectric substrate (10); the metal sheet (50) is located on the lower surface of the dielectric substrate (10); the front end of the leaky wave structure (30) is connected to the grounded coplanar waveguide structure (20); and the transmission line width of the grounded coplanar waveguide structure (20) is gradually changed.

[0009] Furthermore, a plurality of the cylindrical metal connecting rods (60) penetrate the dielectric substrate (10) to connect the miniaturized planar inverted L-shaped structure (40) and the grounded coplanar waveguide structure (20) to the metal sheet (50).

[0010] Furthermore, the miniaturized planar inverted L-shaped structure (40) comprises a plurality of metal patch structures (41); each of the metal patch structures (41) is provided with a cross-shaped slot (42) at the center thereof, and a cut corner (43) is provided at the diagonal position of the energy input end; each of the metal patch structures (41) is connected to the metal sheet (50) via a plurality of cylindrical metal connecting rods (60); a portion of the cylindrical metal connecting rods (60) are close to the grounded coplanar waveguide (20), and the remaining cylindrical metal connecting rods (60) are close to the end of the leaky wave structure (30).

[0011] Furthermore, the dielectric substrate (10) is made of Rogers 4003C, which has a dielectric constant of 3.55 and a loss tangent of 0.0027.

[0012] The present invention has the following beneficial effects compared with the prior art:

[0013] 1. The present invention provides a miniaturized corner-cut dual-frequency leaky wave antenna based on a cross-shaped slot, and the radiation structure includes: a miniaturized planar inverted L-shaped structure and a leaky wave structure. The miniaturized planar inverted L-shaped structure is composed of 12 metal patch structures, which are placed in two groups on both sides of the leaky wave structure. The leaky wave structure is composed of 14 groups of symmetrical rectangular slots of inconsistent lengths, and are equidistantly distributed on both sides of the microstrip line along the x-axis, reducing the influence of the microwave array on the leaky wave antenna.

[0014] 2. The present invention provides a miniaturized cut-angle dual-frequency leaky wave antenna based on a cross-shaped groove. Each metal patch structure is provided with a plurality of cylindrical metal connecting rods away from the energy input end, and a cross-shaped slot groove is provided at the center of each patch. A cut angle is provided at the diagonal of the energy input end, which changes the current path on the patch surface and realizes miniaturization.

[0015] 3. The antenna of the present invention works in the microwave band of 3.41GHz-3.63GHz and the millimeter wave band of 29GHz-40GHz, respectively. The leaky wave structure antenna working in the millimeter wave band realizes the frequency sweep characteristic from -28° to 12°. The antennas of the two frequency bands use structural multiplexing to realize a microwave millimeter wave dual-frequency antenna with single-port feeding through a grounded coplanar waveguide.

[0016] The present invention is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A structural diagram of a miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot according to the present invention;

[0018] Figure 2 A top view of a miniaturized corner-cut dual-frequency leaky-wave antenna structure based on a cross-shaped slot according to the present invention;

[0019] Figure 3 A side structural diagram of a miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot according to the present invention;

[0020] Figure 4 is a structural diagram of a microwave band metal patch in an embodiment of the present invention;

[0021] Figure 5 is a leaky wave structure diagram in an embodiment of the present invention;

[0022] Figure 6 It is a simulated reflection coefficient diagram of an embodiment of the present invention in the microwave band;

[0023] Figure 7 is a simulation gain curve diagram of an embodiment of the present invention in the microwave band;

[0024] Figure 8 It is a simulated E-plane radiation pattern of an embodiment of the present invention in the microwave band;

[0025] Fig. 9 The simulated H-plane radiation pattern of the leaky wave structure according to the embodiment of the present invention;

[0026] Fig.10 is a simulated reflection coefficient diagram of an embodiment of the present invention in the millimeter wave band;

[0027] Fig.11 is a simulation gain curve diagram of an embodiment of the present invention in the millimeter wave band;

[0028] Fig.12 This is a simulated radiation pattern of an embodiment of the present invention in the millimeter wave band. DETAILED DESCRIPTION

[0029] 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.

[0030] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0031] See also Figure 1 , Figure 2 and Figure 3 The present invention proposes a miniaturized corner-cut dual-frequency leaky-wave antenna structure based on a cross-shaped slot, which comprises a dielectric substrate (10), a grounded coplanar waveguide structure (20), a leaky-wave structure (30), a miniaturized planar inverted L-shaped structure (40), a metal sheet (50), and a cylindrical metal connecting rod (60);

[0032] The metal sheet (50) is located on a surface of the dielectric substrate (10);

[0033] The grounded coplanar waveguide structure (20), the leaky wave structure (30) and the miniaturized planar inverted L-shaped structure (40) are located on the other surface of the dielectric substrate (10); the grounded coplanar waveguide structure (20) has a length L1 of 14 mm and a width W1 of 40 mm;

[0034] The cylindrical metal connecting rod (60) penetrates the dielectric substrate (10) and connects the upper layer of the dielectric substrate (including the grounded coplanar waveguide structure (20), the leaky wave structure (30) and the miniaturized planar inverted L-shaped structure (40) and the lower metal sheet (50) of the dielectric substrate;

[0035] See also Figure 5 The leaky wave structure (30) is composed of a microstrip line (31) and a rectangular structure (32); the microstrip line has a length L2 of 80 mm and a width W4 of 5 mm; the rectangular structure (32) includes 14 groups of rectangular grooves (33) that are equidistantly distributed but of inconsistent lengths, and the lengths of each group are Wr1=2.92 mm, Wr2=2.62 mm, Wr3=2.96 mm, Wr4=2.54 mm, Wr5=2.70 mm, Wr6=2.54 mm, Wr7=2.60 mm, Wr8=3.04 mm, Wr9=2.96 mm, Wr 10 =2.72mm, Wr 11 =3.12mm, Wr 12 =2.56mm, Wr 13 =2.80mm, Wr14 =2.76mm. The spacing p2 between each two groups is 1.65mm. Each group of rectangular slots (33) is divided into two groups with the x-axis as the symmetry axis and located on the upper and lower sides of the microstrip line (31). The first group of rectangular slots (33) has a smaller width to achieve antenna matching in the millimeter wave frequency band, and the remaining 13 groups have the same width, that is, the width of the upper and lower horizontal strips Wr0 is 0.1mm, and the width of the middle horizontal strip W5 is 0.7mm;

[0036] See also Figure 4 The miniaturized planar inverted L-shaped structure (40) includes a metal patch structure (41), a cylindrical metal connecting rod (60), a cross-shaped slot (42) and a cut corner (43); the metal patch structure (41) is divided into two groups and is symmetrically arranged with the leaky wave structure (30) as an axis, each group includes six metal patch structures (41), the unit spacing p3 is 10.5 mm, each unit is a patch with a length L4 of 9.8 mm and a width W3 of 12 mm, L4 is set to be one quarter of the working wavelength of the miniaturized planar inverted L-shaped structure (40), and the width W3 of the radiation patch can be adjusted to achieve control of the working frequency. Each patch is connected to the leaky wave structure (30) through a short stub with a length of 0.65 mm and a width of 1 mm to complete the energy input to the patch. In order to avoid the occurrence of zero points in the radiation pattern in the side-ray direction, the two central units (3 and 4) are not connected to the feeder, and the two units are coupled to radiate through the adjacent units (i.e., 2 and 5) connected to the feeder; the cylindrical metal connecting rods (60) are distributed at the edge of the metal patch structure (41), with a radius R0 of 0.3 mm and a spacing p1 of 1 mm, connecting the metal patch structure (41) with the metal sheet (50); the cylindrical metal connecting rods (60) of the first three metal patch structures (1-3) of each group are arranged at the guide end of the patch close to the grounded coplanar waveguide structure (20), and the cylindrical metal connecting rods (60) of the last three units (4-6) are arranged at the guide end of the patch close to the grounded coplanar waveguide structure (20). The rod (60) is arranged at the open end of the patch close to the leaky wave structure (30), and the number of cylindrical metal connecting rods of each patch is set to 7; the width W6 of the cross-shaped slot groove (42) is 0.3 mm, and the length L6 is 6 mm. The slotted structure is used to increase the flow path of the current on the surface of the microwave array, increase the impedance bandwidth, and achieve miniaturization of the structure; the cut corner (43) is arranged at the upper left corner of the metal patch structure (41) on the upper side of the leaky wave structure (30) and the lower left corner of the metal patch structure (41) on the lower side. The cut corner (43) is an isosceles right triangle with a side length L5 of 2 mm, which further achieves miniaturization of the structure;

[0037] The transmission line width of the grounded coplanar waveguide structure (20) changes gradually and is connected to the front end of the leaky wave structure (30); a cylindrical metal connecting rod (60) is arranged at the edge of the grounded coplanar waveguide structure (20);

[0038] In the example, the thickness h of the dielectric substrate (10) is selected to be 1.524 mm, and the material of the dielectric substrate (10) is selected to be Rogers 4003C with a dielectric constant of 3.55;

[0039] See also Figure 6 The simulated reflection coefficient of a miniaturized dual-band leaky-wave antenna operating in the microwave frequency band is given by Figure 6 It can be seen that the miniaturized dual-frequency leaky-wave antenna in this embodiment covers the frequency band of 3.41 GHz to 3.63 GHz in the microwave frequency band where the reflection coefficient is less than -10 dB, and achieves a bandwidth of 6.28%.

[0040] See also Figure 7 The gain curve of a miniaturized dual-band leaky-wave antenna operating in the microwave frequency band is given by Figure 7 It can be seen that the average gain of the miniaturized dual-frequency leaky-wave antenna in this embodiment is 6.20 dB in the passband, and the maximum gain is 7.31 dB, which occurs at 3.62 GHz.

[0041] See also Figure 8 and Fig. 9 The E-plane and H-plane radiation patterns of the miniaturized dual-frequency leaky-wave antenna at 3.5 GHz are given. It can be seen that the miniaturized dual-frequency leaky-wave antenna in this embodiment achieves side-radiation performance in the microwave frequency band.

[0042] See also Fig.10 The simulated reflection coefficient curve of a miniaturized dual-band leaky-wave antenna operating in the millimeter-wave frequency band is given. Fig.10 It can be seen that the miniaturized dual-frequency leaky-wave antenna in this embodiment covers 29 GHz-40 GHz in the millimeter-wave frequency band where the reflection coefficient is less than -10 dB, and achieves a bandwidth of 31.42%.

[0043] See also Fig.11 The gain curve of a miniaturized dual-band leaky-wave antenna operating in the millimeter-wave frequency band is given by Fig.11 It can be seen that the gain range of the miniaturized dual-band leaky-wave antenna in this embodiment in the millimeter wave band is 12.40dB-17.30dB, and the maximum gain of 17.30dB occurs at 40GHz.

[0044] See also Fig.12 From the given directional pattern simulation of the miniaturized dual-band leaky-wave antenna in the millimeter-wave frequency band, it can be seen that the miniaturized dual-band leaky-wave antenna in this embodiment realizes frequency scanning characteristics in the millimeter-wave frequency band, scanning from -28° to 12° in the 29 GHz-40 GHz frequency band, and the beam scanning angle range is 40°.

Claims

1. A miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot, characterized in that: The invention comprises a dielectric substrate (10), a grounded coplanar waveguide (20), a leaky wave structure (30), a miniaturized planar inverted L-shaped structure (40), a metal sheet (50), and a cylindrical metal connecting rod (60); the leaky wave structure (30) acts as a transmission line in the microwave frequency band to complete energy input to the miniaturized planar inverted L-shaped structure (40), and acts as an antenna radiator in the millimeter wave frequency band; the metal sheet (50) is located on the lower surface of the dielectric substrate (10); the grounded coplanar waveguide (20), the leaky wave structure (30), and the miniaturized planar inverted L-shaped structure (40) are located on the upper surface of the dielectric substrate (10); the leaky wave structure (30) comprises a microstrip line (31) and a rectangular structure (32); the cylindrical metal connecting rod (60) penetrates the dielectric substrate (10); and the cylindrical metal connecting rod (60) connects the metal sheet (50) and the grounded coplanar waveguide (20).

2. A miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot according to claim 1, characterized in that: The leaky wave structure (30) acts as a transmission line in the microwave frequency band to complete energy input to the miniaturized planar inverted L-shaped structure (40), and acts as an antenna radiator in the millimeter wave frequency band; the front end of the leaky wave structure (30) is connected to the grounded coplanar waveguide (20), so that the antenna has more stable performance at 30 GHz-40 GHz; miniaturized planar inverted L-shaped structures (40) are provided at both ends of the leaky wave structure (30); and the rectangular structure (32) is distributed in the middle of the microstrip line (31).

3. A miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot according to claim 2, characterized in that: The rectangular structure (32) is a combination of a plurality of rectangular grooves (33) of different lengths and at equal intervals, thereby reducing the loss of energy reflection; the rectangular grooves (33) are divided into two groups with the x-axis as the symmetry axis and are located on the upper and lower sides of the microstrip line (31).

4. The miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot according to claim 1, characterized in that: The miniaturized planar inverted L-shaped structure (40) works as an antenna radiator in the microwave frequency band and can improve the radiation gain of the leaky wave structure (30) in the millimeter wave frequency band. The miniaturized planar inverted L-shaped structure (40) realizes energy input by connecting the leaky wave structure (30). The miniaturized planar inverted L-shaped structure (40) includes a plurality of metal patch structures (41) and is arranged in two groups symmetrically with the leaky wave structure (30) as an axis. Each metal patch structure (41) includes a cross-shaped slot (42) and a cut corner (43). By changing the path of the current, the impedance bandwidth is increased and miniaturization is realized. Each metal patch structure (41) is arranged equidistantly along the y-axis.

5. A miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot according to claim 4, characterized in that: The cross-shaped slot (42) is located in the middle of the metal patch structure (41), and the current path is extended by slotting, thereby increasing the impedance bandwidth and achieving miniaturization.

6. The miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot according to claim 4, characterized in that: The cut corners (43) are distributed at the diagonal positions of the energy input end of the metal patch structure (41); the cut corners (43) are regular triangles; the input impedance of the antenna is adjusted by the cut corners (43), thereby improving the impedance matching performance of the antenna and further achieving miniaturization.

7. The miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot according to claim 1, characterized in that: The dielectric substrate (10) is made of Rogers 4003C, whose dielectric constant is 3.55 and loss tangent is 0.0027.

8. The miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot according to claim 1, characterized in that: The metal patch structure (41) is connected to the metal sheet (50) via a cylindrical metal connecting rod (60); a portion of the cylindrical metal connecting rod (60) is close to the grounded coplanar waveguide (20), and the remaining cylindrical metal connecting rods (60) are close to the end of the leaky wave structure (30), so as to form a short-circuit boundary condition of the metal patch structure (41), thereby reducing its influence on the leaky wave structure (30) at 30 GHz-40 GHz.

9. The miniaturized corner-cut dual-frequency leaky-wave antenna based on a cross-shaped slot according to claim 1, characterized in that: The antenna realizes microwave and millimeter wave dual-frequency functions by a leaky wave structure (30) and a miniaturized planar inverted L-shaped structure (40), forming a common aperture antenna; the frequency bands with return loss below -10 dB are 3.41-3.63 GHz and 29-40 GHz respectively, the gain at 3.62 GHz is 7.31 dB, and the gain at 40 GHz is 17.30 dB; the side radiation with a half-power beam angle of 75° is realized in the microwave frequency band, and the frequency scanning with a scanning angle range of -28°-12° is realized in the millimeter wave frequency band.

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