CN110957574B

CN110957574B - A stripline-fed broadband millimeter-wave antenna unit

Info

Publication number: CN110957574B
Application number: CN201911183190.4A
Authority: CN
Inventors: 罗俊; 陈志兴; 杨华
Original assignee: Guangdong Shenglu Telecommunication Tech Co Ltd
Current assignee: Guangdong Shenglu Telecommunication Tech Co Ltd
Priority date: 2019-11-27
Filing date: 2019-11-27
Publication date: 2025-08-08
Anticipated expiration: 2039-11-27
Also published as: CN110957574A

Abstract

The present invention discloses a stripline-fed broadband millimeter-wave antenna unit, comprising a dielectric substrate body and a plurality of metallized through-holes extending through the upper and lower surfaces of the dielectric substrate body. The dielectric substrate body is characterized in that the dielectric substrate body is composed of multiple layers of dielectric substrates stacked sequentially, with metal copper layers provided between two adjacent dielectric substrate layers and on the upper and lower surfaces of the dielectric substrate body. The metal copper layer provided on the lower surface of the dielectric substrate body is a fully covered, large-area copper layer, the metal copper layer provided between the bottom two dielectric substrate layers is a long stripline, and the remaining metal copper layers are large-area copper layers etched with rectangular slits. The metallized through-holes electrically connect the large-area copper layers. The present invention realizes a broadband, high-gain millimeter-wave antenna unit suitable for PCB processing, exhibiting advantages such as high gain, high efficiency, broadband, planarization, low cost, and ease of mass production.

Description

Broadband millimeter wave antenna unit with strip line feed

Technical Field

The invention relates to the technical field of antenna design, in particular to a broadband millimeter wave antenna unit fed by a strip line.

Background

Antennas are an important component of a communication system, and the performance of the antennas will directly affect the quality of the communication. The millimeter wave band is an important band of modern communication. Because millimeter waves have higher frequencies and larger path losses, high gain millimeter wave antennas are generally required for use in communication systems. The use of antenna elements for grouping to increase the gain of an overall antenna is a common approach, where the performance design of the elements in an array has a decisive influence on the overall array performance.

For millimeter wave antennas, the wavelength is in the order of millimeters, so that higher requirements are placed on the processing accuracy of the antenna. Although the metal cavity antenna can achieve better product stability, the cost is expensive due to the high precision machining required. The Printed Circuit Board (PCB) technology, the low-temperature co-fired ceramic (LTCC) technology and the like adopting the plane processing technology are used, so that the cost is low while the high finished product precision is realized, and the method is an important development direction of millimeter wave antennas.

The strip transmission line is a microwave transmission line with a common planar structure, and has the advantages of easy planar processing, no dispersion TEM field mode, low radiation leakage and the like. For the antenna element fed by the strip line, it is necessary to efficiently convert the transmission electromagnetic wave of the strip line into the spatially radiated electromagnetic wave. In addition, as communication systems continue to increase communication rate requirements, antennas with wideband characteristics are increasingly being used in antenna designs.

Based on the above background, a wideband millimeter wave antenna unit with strip line feed is needed in practical application, so as to meet the requirements of the modern millimeter wave communication on the aspects of wideband antenna, high efficiency, low processing cost and the like.

Disclosure of Invention

The invention aims to provide a broadband millimeter wave antenna unit fed by strip lines. The antenna has the advantages of wide bandwidth, high efficiency, low processing cost, planarization, easy mass production and the like.

In order to achieve the above purpose, the present invention adopts the following technical scheme.

A broadband millimeter wave antenna unit with strip line feed comprises a dielectric substrate body and a plurality of metalized through holes penetrating through the upper surface and the lower surface of the dielectric substrate body, and is characterized in that the dielectric substrate body is composed of a plurality of layers of dielectric substrates which are sequentially overlapped together, metal copper-clad layers are respectively arranged between two adjacent layers of dielectric substrates and on the upper surface and the lower surface of the dielectric substrate body, the metal copper-clad layers arranged on the lower surface of the dielectric substrate body are all covered large-area copper-clad layers, the metal copper-clad layers arranged between the two lowest layers of dielectric substrates are strip-shaped strip lines, the remaining metal copper-clad layers are all etched with rectangular gaps, and the metalized through holes electrically connect the large-area copper-clad layers.

More preferably, the length of each dielectric substrate is not more than 1 free space wavelength of the radiation wave of the antenna unit.

More preferably, the number of the metallized through holes is more than eight, the metallized through holes are symmetrically distributed along a horizontal line of the dielectric substrate body, each rectangular gap is between two rows of the metallized through holes, and the strip-shaped strip line is between two rows of the metallized through holes.

More preferably, the horizontal line is a horizontal center line.

More preferably, the strip-shaped strip line is arranged on a vertical central line of the dielectric substrate body, and each metallized through hole is symmetrically distributed along the vertical central line.

More preferably, the orthographic projections of each of the rectangular slits and the strip-shaped strip line on the lower surface coincide, and the rectangular slit opening size on the lower side is smaller than the rectangular slit opening size on the upper side.

More preferably, the spacing between the two adjacent rows and the two adjacent columns of the metallized through holes is smaller than 1/2 of the medium wavelength of the radiation wave of the antenna unit.

More preferably, two adjacent dielectric plates are laminated together by prepreg, and one end of the strip-shaped strip line is exposed at the side part of the dielectric substrate body.

More preferably, the working frequency band of the broadband millimeter wave antenna unit is 22-30GHz.

The beneficial effects achieved by adopting the technical proposal of the invention are as follows:

The dielectric substrate body adopts a multi-layer design, corresponding metal copper-clad layers are respectively arranged between the layers and the upper surface and the lower surface of the dielectric substrate body, the broadband millimeter wave antenna unit can be realized by combining the metallized via holes, the difficulty and the higher cost of blind hole processing are avoided, and the strip line feed is used, so that the whole structure is easy to use PCB processing, and the antenna can be widely applied to the design of array antennas. When in actual use, the high-gain millimeter wave antenna unit which is applicable to PCB processing in a broadband mode can be realized by designing the gap size of each metal copper-clad layer and the position of the metallized through hole, and the antenna unit has the advantages of high gain, high efficiency, broadband, planarization, low cost, easiness in mass production and the like.

Drawings

Fig. 1 is a schematic overall structure of an embodiment of an antenna of the present invention;

Fig. 2 is a schematic top view of the antenna of the present invention;

FIG. 3 is a graph of return loss frequency for an antenna of the present invention;

FIG. 4 is a graph of gain versus frequency for an antenna of the present invention;

FIG. 5 is a magnetic field plane radiation pattern of the center frequency of the antenna of the present invention;

fig. 6 is an electric field plane radiation pattern of the center frequency of the antenna of the present invention.

Reference numerals illustrate:

1, a first metal copper-clad layer, 11, a first rectangular gap, 21, a second rectangular gap, 2, a second metal copper-clad layer, 3, a third metal copper-clad layer, 4, a fourth metal copper-clad layer, 5, a metalized through hole, 61, a first dielectric substrate, 62, a second dielectric substrate and 63, a third dielectric substrate.

Detailed Description

In the description of the present invention, it should be noted that, for the azimuth words such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the azimuth and positional relationships are based on the azimuth or positional relationships shown in the drawings, it is merely for convenience of describing the present invention and simplifying the description, and it is not to be construed as limiting the specific scope of protection of the present invention that the device or element referred to must have a specific azimuth configuration and operation.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features. Thus, the definition of "a first", "a second" feature may explicitly or implicitly include one or more of such features, and in the description of the invention, "at least" means one or more, unless clearly specifically defined otherwise.

In the present invention, unless explicitly stated or limited otherwise, the terms "assembled," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, integrally connected, mechanically connected, directly connected, or connected via an intermediate medium, or two elements may be in communication. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless specified and limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "below," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply representing the first feature as having a higher level than the second feature. The first feature being "above," "below," and "beneath" the second feature includes the first feature being directly below or obliquely below the second feature, or simply indicating that the first feature is level below the second feature.

The following description of the specific embodiments of the present invention is further provided with reference to the accompanying drawings, so that the technical scheme and the beneficial effects of the present invention are more clear and definite. The embodiments described below are exemplary by referring to the drawings for the purpose of illustrating the invention and are not to be construed as limiting the invention.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, or may be learned by practice of the invention.

As shown in fig. 1 and 2, the broadband millimeter wave antenna unit for strip line feeding comprises a first dielectric substrate 61, a second dielectric substrate 62, a third dielectric substrate 63 and a metallized through hole 5 penetrating through each dielectric substrate, wherein the first dielectric substrate 61, the second dielectric substrate 62, the third dielectric substrate 63 and the lower surface of the third dielectric substrate 63 are sequentially laminated from top to bottom, a first metal copper layer 1, a second metal copper layer 2, a third metal copper layer 3 and a fourth metal copper layer 4 are respectively arranged on the upper surface of the first dielectric substrate 61, between the first dielectric substrate 61 and the second dielectric substrate 62 and between the second dielectric substrate 62 and the lower surface of the third dielectric substrate 63, the first metal copper layer 1, the second metal copper layer 2 and the fourth metal copper layer 4 are respectively in full-coverage large-area copper layers, the metallized through hole 5 is used for electrically connecting the large-area copper layers, the third metal copper layer 3 is in a strip shape, and rectangular gaps 11 and a second rectangular gap 21 are respectively etched on the first metal copper layer 1 and the second metal copper layer 2.

The third metal copper-clad layer 3, the second metal copper-clad layer 2 on the upper side and the lower side and the fourth metal copper-clad layer 4 form a strip transmission line. The second rectangular slit 21 is used to couple the resonance energy of the metallized via 5 in the second dielectric substrate 62 and the third dielectric substrate 63 to the first dielectric substrate 61. The first rectangular slit 11 is used for converting coupling energy into space radiation electromagnetic waves and adjusting matching. Thus, by adjusting the size of each rectangular slot, the position of the metallized through hole 5 and the thickness of each dielectric substrate, a broadband high-gain millimeter wave antenna unit suitable for PCB processing can be realized.

Referring to fig. 2, the number of the through holes of the metallized through holes 5 is generally more than 4, and is symmetrical with respect to the horizontal direction. The adjacent spacing of the metallized through holes 5 is generally less than 1/2 of the wavelength of the medium, so that it can be approximated as an electrical wall, limiting the diffusion of electromagnetic waves in the vertical direction. The metallized through-hole 5 thus achieves the two functions, firstly, the metallized through-hole 5 can be regarded as a metal resonant cavity in the part of the second dielectric substrate 62 and the third dielectric substrate 63, the strip-shaped transmission line consisting of the third metal copper-clad layer 3 and the like is excited to form resonance, resonance energy is coupled to the first dielectric substrate 61 through the second rectangular slot 21, and secondly, the metallized through-hole 5 can be regarded as a horn antenna structure in the part of the first dielectric substrate 61 together with the first rectangular slot 11, electromagnetic waves are coupled in from the second rectangular slot 21, and the electromagnetic waves are radiated to free space through the equivalent horn antenna structure.

The influence of each structure on the antenna performance is that the frequency and bandwidth of resonance can be adjusted by adjusting the position of the metallized through hole 5 and the size of the second rectangular slot 21, and the matching of the antenna can be adjusted by adjusting the position of the metallized through hole 5, the size of the third metal copper-clad layer 3 and the first rectangular slot 11. By selecting appropriate dimensional parameters as well as dielectric plate materials and thicknesses, wideband antenna element performance can be achieved.

According to one embodiment of the application, a wideband millimeter wave antenna unit is designed for stripline feed operating at 26 GHz. The dielectric substrates with a relative dielectric constant of 3.0, a loss tangent of 0.003, thicknesses of the dielectric substrates 61 and 62 of 0.529mm, thicknesses of the dielectric substrate 63 of 1.542mm and areas of the dielectric plates of 9mm×9mm are selected as the dielectrics 61 to 63. For lamination, a 0.1mm thick prepreg was placed between adjacent dielectric sheets. The width of the feed strip line 3 is chosen to be 0.6mm, and the electric field direction of the antenna element radiation field, i.e. along the strip line direction. The dimensions of the rectangular slit 21 were 3.2mm by 0.6mm, and the dimensions of the rectangular slit 11 were 6.5mm by 3.25mm. The metallized vias 5 had a diameter of 0.5mm, adjacent vias were 1mm apart, diagonal vias were 4.5mm apart along the stripline direction, and were 4mm apart along the direction perpendicular to the stripline direction.

The effects of the present invention can be further illustrated by the simulation results of this embodiment.

Referring to fig. 3, a frequency chart of return loss S11 obtained by simulation in this embodiment is shown. From the graph, the millimeter wave antenna provided by the embodiment realizes return loss performance below-10 dB at 23-29 GHz, has a relative bandwidth of 23%, and has good broadband matching characteristics.

Fig. 4 is a graph showing the gain versus frequency obtained by simulation in this example. From the graph, the millimeter wave antenna provided by the embodiment realizes the antenna gain of more than 6.5dB between 22 and 30GHz, and realizes higher gain and efficiency in a wide frequency band.

Fig. 5 is a main polarization radiation pattern of the magnetic field plane of each frequency point obtained by simulation in this embodiment. From the graph, it can be seen that, for the center frequency point and the edge frequency point, the magnetic field plane directional diagram of the millimeter wave antenna provided by the embodiment is very stable in the main lobe range.

Fig. 6 is a main polarization radiation pattern of the electric field plane of each frequency point obtained by simulation in this embodiment. From the graph, it can be seen that, for the center frequency point and the edge frequency point, the electric field plane direction diagram of the millimeter wave antenna provided by the embodiment slightly fluctuates, but is stable within a range of + -45 degrees, and no grating lobe is generated. Combining the results of fig. 5 and 6, the millimeter wave antenna unit design provided by the present embodiment has a stable radiation pattern with a wide band.

It will be understood by those skilled in the art from the foregoing description of the structure and principles that the present invention is not limited to the specific embodiments described above, but is intended to cover modifications and alternatives falling within the spirit and scope of the invention as defined by the appended claims and their equivalents. The portions of the detailed description that are not presented are all prior art or common general knowledge.

Claims

1. A stripline-fed broadband millimeter-wave antenna unit, comprising a dielectric substrate body and a plurality of metallized through-holes extending through the upper and lower surfaces of the dielectric substrate body; the broadband millimeter-wave antenna unit having an operating frequency band of 22-30 GHz; the dielectric substrate body comprising three layers of dielectric substrates stacked sequentially, with metal copper layers disposed between two adjacent layers of the dielectric substrates and on the upper and lower surfaces of the dielectric substrate body, respectively; the metal copper layer disposed on the lower surface of the dielectric substrate body being a fully covered, large-area copper layer; the metal copper layer disposed between the bottom two layers of the dielectric substrates being a long stripline; and the remaining metal copper layers being large-area copper layers etched with rectangular slits. The metallized through-holes electrically connect the large-area copper layers.

The three-layer dielectric substrate comprises, from top to bottom, a first dielectric substrate, a second dielectric substrate, and a third dielectric substrate. A first metal copper clad layer, a second metal copper clad layer, a third metal copper clad layer, and a fourth metal copper clad layer are respectively provided on the upper surface of the first dielectric substrate, between the first dielectric substrate and the second dielectric substrate, between the second dielectric substrate and the third dielectric substrate, and on the lower surface of the third dielectric substrate. A first rectangular slit and a second rectangular slit are respectively etched on the first metal copper clad layer and the second metal copper clad layer.

The third metal copper-clad layer and the second and fourth metal copper-clad layers on the upper and lower sides form a strip transmission line; the second rectangular slot is used to couple the resonant energy of the metallized through-holes in the second and third dielectric substrates to the first dielectric substrate; and the first rectangular slot is used to convert the coupled energy into spatially radiated electromagnetic waves to adjust the matching;

The length of each dielectric substrate does not exceed one free space wavelength of the radiation wave of the antenna unit;

The number of the metallized through holes is greater than eight and is symmetrically distributed in two rows along a horizontal line in the length direction of the dielectric substrate body, each of the rectangular gaps is located between the two rows of the metallized through holes, and the long strip line is located between the metallized through holes in the two columns; the spacing between the metallized through holes in two adjacent rows and two adjacent columns is less than 1/2 the dielectric wavelength of the electromagnetic wave of the antenna unit;

The adjacent spacing of the metallized through-holes is less than 1/2 dielectric wavelength, which is approximately an electric wall, limiting the diffusion of electromagnetic waves in the vertical direction; the metallized through-holes in the second and third dielectric substrates act as metal resonant cavities, and the strip transmission line composed of the third metal copper clad layer is fed and excited to form resonance, and the resonant energy is coupled to the first dielectric substrate through the second rectangular slot; the metallized through-holes in the first dielectric substrate and the first rectangular slot are considered to form a horn antenna structure together, and the electromagnetic waves are coupled in from the second rectangular slot and radiated into free space through this equivalent horn antenna structure.

2 . The stripline-fed broadband millimeter-wave antenna unit according to claim 1 , wherein the horizontal line is a horizontal center line.

3. A stripline-fed broadband millimeter-wave antenna unit according to claim 1, characterized in that the long stripline is arranged on the vertical center line of the dielectric substrate body, and the metallized through holes are symmetrically distributed along the vertical center line.

4. A stripline-fed broadband millimeter-wave antenna unit according to claim 1, characterized in that the orthographic projections of each of the rectangular slots and the long strip line on the lower surface overlap, and the opening size of the rectangular slot located on the lower side is smaller than the opening size of the rectangular slot located on the upper side.

5 . The stripline-fed broadband millimeter-wave antenna unit according to claim 1 , wherein two adjacent dielectric substrates are laminated together via a prepreg.

6 . The stripline-fed broadband millimeter-wave antenna unit according to claim 1 , wherein one end of the long stripline is exposed at a side of the dielectric substrate body.