A stripline-fed broadband millimeter-wave antenna unit

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

Technical Field

[0001] The present invention relates to the technical field of antenna design, and in particular to a stripline-fed broadband millimeter-wave antenna unit. Background Art

[0002] Antennas are a crucial component of communication systems, and their performance directly impacts communication quality. The millimeter wave band is a crucial frequency band for modern communications. Due to the higher frequency of millimeter waves, their path loss is greater, necessitating the use of high-gain millimeter wave antennas in communication systems. Arraying antenna elements to increase overall antenna gain is a common approach, and the performance of the individual elements in an array has a decisive impact on overall array performance.

[0003] Millimeter-wave antennas, with wavelengths on the order of millimeters, place higher demands on manufacturing precision. While metal cavity antennas offer excellent product stability, they require high-precision machining, making them expensive. However, printed circuit board (PCB) and low-temperature co-fired ceramic (LTCC) technologies, which utilize planar processing techniques, offer high product precision at a lower cost, making them a key development direction for millimeter-wave antennas.

[0004] Stripline transmission lines are commonly used planar microwave transmission lines, offering advantages such as easy planar processing, a dispersion-free TEM field pattern, and low radiation leakage. For stripline-fed antenna units, efficient conversion of the stripline's transmitted electromagnetic waves into spatially radiated electromagnetic waves is essential. Furthermore, as communication systems continue to increase their speed requirements, antennas with broadband characteristics are increasingly being used in antenna design.

[0005] Based on the above background, a stripline-fed broadband millimeter-wave antenna unit is needed in practical applications to meet the requirements of modern millimeter-wave communications for antenna broadband, high efficiency, and low processing cost. Summary of the Invention

[0006] The present invention aims to provide a stripline-fed broadband millimeter-wave antenna unit, which has the advantages of broadband, high efficiency, low processing cost, planarity, and ease of mass production.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions.

[0008] A stripline-fed broadband millimeter-wave antenna unit comprises 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 comprises a plurality 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.

[0009] More preferably, the length of each dielectric substrate does not exceed one free space wavelength of the radiation wave of the antenna unit.

[0010] More preferably, the number of the metallized through holes is more than eight and they are symmetrically distributed along a horizontal line of the dielectric substrate body, each of the rectangular gaps is between two rows of the metallized through holes, and the long strip lines are between two columns of metallized through holes.

[0011] More preferably, the horizontal line is a horizontal center line.

[0012] More preferably, the long strip line 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.

[0013] More preferably, the orthographic projections of the rectangular slits and the long strip lines on the lower surface overlap, and the opening size of the rectangular slits on the lower side is smaller than the opening size of the rectangular slits on the upper side.

[0014] More preferably, the spacing between the metallized through holes in two adjacent rows and two adjacent columns is less than 1 / 2 of the medium wavelength of the antenna unit radiation wave.

[0015] More preferably, two adjacent dielectric plates are laminated together via a prepreg sheet, and one end of the long strip line is exposed at a side of the dielectric base plate body.

[0016] More preferably, the operating frequency band of the broadband millimeter wave antenna unit is 22-30 GHz.

[0017] The beneficial effects that can be achieved by the present invention using the above technical solutions are:

[0018] The dielectric substrate utilizes a multilayer design, with corresponding copper clad layers positioned between each layer and on the upper and lower surfaces. This allows the realization of a broadband millimeter-wave antenna element solely through the use of metallized vias, avoiding the difficulty and high cost of blind via fabrication. Furthermore, the use of stripline feeds makes the overall structure easy to fabricate on PCBs, making it widely applicable to array antenna designs. In practice, by tailoring the gap size between the copper clad layers and the location of the metallized vias, a broadband, high-gain millimeter-wave antenna element suitable for PCB fabrication can be realized. This antenna element exhibits advantages such as high gain, high efficiency, broadband, planarity, low cost, and ease of mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the overall structure of an embodiment of the antenna of the present invention;

[0020] Figure 2 is a schematic top view of the structure of the antenna of the present invention;

[0021] Figure 3 is a frequency curve diagram of the return loss of the antenna of the present invention;

[0022] Figure 4 is a graph showing how the gain of the antenna of the present invention varies with frequency;

[0023] Figure 5 is the magnetic field surface radiation pattern of the center frequency of the antenna of the present invention;

[0024] Figure 6 is the electric field radiation pattern of the center frequency of the antenna of the present invention.

[0025] Description of reference numerals:

[0026] 1: first metal copper clad layer, 11: first rectangular slit, 21: second rectangular slit, 2: second metal copper clad layer, 3: third metal copper clad layer, 4: fourth metal copper clad layer, 5: metallized through hole, 61: first dielectric substrate, 62: second dielectric substrate, 63: third dielectric substrate. DETAILED DESCRIPTION

[0027] In the description of the present invention, it should be noted that, for directional words, such as the terms "center", "horizontal", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and so on, indicating directions and positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific scope of protection of the present invention.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Therefore, the terms "first" and "second" may explicitly or implicitly include one or more of these features. Throughout the description of the present invention, "at least" means one or more than one, unless otherwise specifically defined.

[0029] In the present invention, unless otherwise specified or limited, the terms "assemble," "connect," and "connect" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integral connection; mechanical connection; direct connection, connection through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0030] In the present invention, unless otherwise specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature therebetween. Furthermore, a first feature being "above," "below," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "above," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0031] The following description of the embodiments of the present invention is further described in conjunction with the accompanying drawings to make the technical solutions and beneficial effects of the present invention clearer and more specific. The following description of the embodiments with reference to the accompanying drawings is illustrative and intended to explain the present invention, but is not to be construed as limiting the present invention.

[0032] Additional aspects and advantages of the invention will become apparent from the description which follows, or may be learned by practice of the invention.

[0033] like Figure 1 、 Figure 2As shown, a stripline-fed broadband millimeter-wave antenna unit includes: a first dielectric substrate 61, a second dielectric substrate 62, and a third dielectric substrate 63 laminated together from top to bottom, and a metallized through-hole 5 extending through each of the dielectric substrates; a first metal copper clad layer 1, a second metal copper clad layer 2, a third metal copper clad layer 3, and a fourth metal copper clad layer 4 are respectively provided on the upper surface of the first dielectric substrate 61, between the first dielectric substrate 61 and the second dielectric substrate 62, between the second dielectric substrate 62 and the third dielectric substrate 63, and on the lower surface of the third dielectric substrate 63; the first metal copper clad layer 1, the second metal copper clad layer 2, and the fourth metal copper clad layer 4 are fully covered large-area copper clad layers; the metallized through-hole 5 electrically connects the large-area copper clad layers; the third metal copper clad layer 3 is a long stripline; a first rectangular slit 11 and a second rectangular slit 21 are respectively etched on the first metal copper clad layer 1 and the second metal copper clad layer 2.

[0034] The third copper-clad metal layer 3 and the upper and lower second and fourth copper-clad metal layers 2 and 4 form a stripline transmission line. The second rectangular slot 21 couples the resonant energy of the plated through-hole 5 within the second and third dielectric substrates 62 and 63 to the first dielectric substrate 61. The first rectangular slot 11 converts the coupled energy into spatially radiated electromagnetic waves, adjusting the matching. By adjusting the size of each rectangular slot, the position of the plated through-hole 5, and the thickness of each dielectric substrate, a broadband, high-gain millimeter-wave antenna unit suitable for PCB processing can be achieved.

[0035] See also Figure 2 As shown, the number of metallized through-holes 5 is generally greater than four and symmetrical about the horizontal direction. The spacing between adjacent metallized through-holes 5 is generally less than 1 / 2 dielectric wavelength, thus being approximated as an electric wall, limiting the vertical diffusion of electromagnetic waves. Therefore, the metallized through-holes 5 can achieve two functions: First, the metallized through-holes 5 in the second dielectric substrate 62 and the third dielectric substrate 63 can be regarded as a metal resonant cavity. The strip transmission line composed of the third metal copper clad layer 3 and other components is fed and excited to form resonance, and the resonant energy is coupled to the first dielectric substrate 61 through the second rectangular slot 21. Second, the metallized through-holes 5 in the first dielectric substrate 61 and the first rectangular slot 11 can be regarded as forming a horn antenna structure. Electromagnetic waves are coupled in from the second rectangular slot 21 and radiated into free space through this equivalent horn antenna structure.

[0036] The various structures affect antenna performance in the following ways: Adjusting the position of the plated via 5 and the size of the second rectangular slot 21 adjusts the resonant frequency and bandwidth; adjusting the position of the plated via 5, the size of the third copper clad layer 3, and the size of the first rectangular slot 11 adjusts the antenna matching. By selecting appropriate dimensional parameters, as well as the dielectric material and thickness, broadband antenna unit performance can be achieved.

[0037] According to one embodiment of the present application, a broadband millimeter-wave antenna unit with stripline feed is designed to operate at 26 GHz. Dielectrics 61 through 63 are all constructed using a dielectric substrate with a relative permittivity of 3.0 and a loss tangent of 0.003. The thickness of dielectrics 61 and 62 is 0.529 mm, and the thickness of dielectric 63 is 1.542 mm. The dielectric plates each measure 9 mm x 9 mm. This allows for a 0.1 mm thick prepreg sheet between adjacent dielectric plates for lamination. The width of the feed stripline 3 is 0.6 mm, and the electric field direction of the antenna unit's radiation field is along the stripline. The dimensions of the rectangular slot 21 are 3.2 mm x 0.6 mm, and the dimensions of the rectangular slot 11 are 6.5 mm x 3.25 mm. The diameter of the metallized through-hole 5 is 0.5 mm, with a distance of 1 mm between adjacent through-holes. The distance between diagonal through-holes along the stripline is 4.5 mm, and the distance perpendicular to the stripline is 4 mm.

[0038] The effect of the present invention can be further illustrated by the simulation results of this embodiment.

[0039] See also Figure 3 As shown in FIG, which is a frequency curve of the return loss S11 obtained by simulation of this embodiment. As can be seen from this figure, the millimeter wave antenna provided by this embodiment achieves a return loss performance of less than -10dB between 23 and 29GHz, with a relative bandwidth of 23%, and has good broadband matching characteristics.

[0040] Figure 4 The graph shows the gain versus frequency obtained from the simulation of this embodiment. As can be seen from the graph, the millimeter-wave antenna provided by this embodiment achieves an antenna gain of more than 6.5 dB between 22 and 30 GHz, achieving high gain and efficiency across a wide frequency band.

[0041] Figure 5 The main polarization radiation pattern of the magnetic field plane at each frequency point obtained by simulation of this embodiment is shown in FIG. As can be seen from the figure, for both the center frequency point and the edge frequency point, the magnetic field plane pattern of the millimeter wave antenna provided by this embodiment is very stable within the main lobe range.

[0042] Figure 6The following are the main polarization radiation patterns of the electric field at each frequency point obtained by simulation of this embodiment. As can be seen from the figure, for the center frequency point and the edge frequency point, the electric field pattern of the millimeter wave antenna provided by this embodiment fluctuates slightly, but is relatively stable within the range of ±45 degrees, without the generation of grating lobes. Figure 5 and Figure 6 As a result, the millimeter wave antenna unit design provided in this embodiment has a broadband and stable radiation pattern.

[0043] Through the description of the above structure and principle, those skilled in the art should understand that the present invention is not limited to the above specific embodiments. Improvements and substitutions based on the present invention using the known technology in the art fall within the scope of protection of the present invention, which is defined by the claims and their equivalents. Any parts not described in the specific embodiments are prior art or common knowledge.

Claims

1. A stripline-fed broadband millimeter-wave antenna unit, comprising a dielectric substrate body and a plurality of metallized through holes penetrating the upper and lower surfaces of the dielectric substrate body; characterized in that: The broadband millimeter-wave antenna unit operates in a frequency band of 22-30 GHz. The dielectric substrate body is composed of three layers of dielectric substrates stacked sequentially. Metal copper layers are provided between two adjacent layers of the dielectric substrates 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 layers of the dielectric substrates is a long strip-shaped line. The remaining metal copper layers are large-area copper layers etched with rectangular gaps. The metalized 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 between the metallized through-holes is less than half the 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. 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 gap. The portion of the metallized through hole in the first dielectric substrate and the first rectangular slot are considered to constitute a horn antenna structure. Electromagnetic waves are coupled in from the second rectangular slot and radiated to free space through the equivalent horn antenna structure.

2. The stripline-fed broadband millimeter-wave antenna unit according to claim 1, characterized in that: The horizontal line is a horizontal center line.

3. The stripline-fed broadband millimeter-wave antenna unit according to claim 1, characterized in that: The long strip line 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. The stripline-fed broadband millimeter-wave antenna unit according to claim 1, characterized in that: The orthographic projections of the rectangular slits and the long strip lines on the lower surface overlap, and the opening size of the rectangular slits located on the lower side is smaller than the opening size of the rectangular slits located on the upper side.

5. The stripline-fed broadband millimeter-wave antenna unit according to claim 1, characterized in that: Two adjacent dielectric substrates are laminated together via a prepreg sheet.

6. The stripline-fed broadband millimeter-wave antenna unit according to claim 1, characterized in that: One end of the long strip line is exposed at a side of the dielectric substrate body.

Images