Patent Grant
12088005
This application is a U.S. National Phase of International Patent Application No. PCT/JP2020/036679 filed on Sep. 28, 2020, which claims priority benefit of Japanese Patent Application No. JP 2019-183901 filed in the Japan Patent Office on Oct. 4, 2019. Each of the above-referenced applications is hereby incorporated herein by reference in its entirety.
The present disclosure relates to an antenna device and a wireless communication apparatus.
An antenna device using a patch antenna is disclosed in PTL 1. The antenna device disclosed in PTL 1 includes a first semiconductor substrate in which a patch antenna is patterned on the bottom of a cavity and a second semiconductor substrate in which a part or all of a surface of an opening side of the cavity including the bottom of the cavity is covered with a conductor serving as a ground and has a laminated structure of the first and second substrates.
[PTL 1]
It is desired to improve the performance of an antenna device.
The present disclosure has been made in view of such circumstances, and an object of the present disclosure is to provide an antenna device and a wireless communication apparatus capable of improving performance.
One aspect of the present disclosure is an antenna device including a first antenna element and a second antenna element disposed on the side of one surface of the first antenna element, wherein the first antenna element includes a first glass substrate and a first patch antenna provided on the first glass substrate, and the second antenna element includes a second glass substrate and a second patch antenna provided on the second glass substrate, wherein a shape of at least one of the first patch antenna and the second patch antenna in a plan view is a rectangle, and contours of one or more of four corners of the rectangle include a curved line or a plurality of obtuse angles in a plan view.
Accordingly, it is possible to curb electric field concentration on the corners and to curb the collapse of an excitation shape due to the electric field concentration in at least one of the first patch antenna and the second patch antenna. As a result, the performance (e.g., radiation characteristics) of the antenna device can be improved.
Another aspect of the present disclosure is an antenna device including a first antenna element and a second antenna element disposed on the side of one surface of the first antenna element, wherein the first antenna element includes a first glass substrate and a first patch antenna provided on the first glass substrate, and the second antenna element includes a second glass substrate and a second patch antenna disposed on the second glass substrate, wherein the first antenna element includes a first feeding point connected to the first patch antenna, a shape of the first patch antenna in a plan view is a rectangle, and when a straight line connecting centers of a pair of edges facing each other in a first direction is defined as a first straight line and a straight line connecting centers of a pair of edges facing each other in a second direction intersecting the first direction is defined as a second straight line in the rectangle, the first feeding point is located at a position separated from the first straight line and the second straight line.
Accordingly, the antenna device can improve the depth of resonance and the band and thus the performance can be improved (for example, the band is widened).
Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the descriptions of the drawings to be referred to hereinafter, same or similar portions are denoted by same or similar reference signs. However, it should be noted that the drawings are schematic and relationships between thicknesses and plan view dimensions, ratios of thicknesses of respective layers, and the like differ from those in reality. Therefore, specific thicknesses and dimensions should be determined by taking the following description into consideration. In addition, it is needless to say that drawings include portions where dimensional relationships and ratios differ between the drawings.
In addition, it is to be understood that definitions of directions such as up-down in the following descriptions are merely definitions provided for the sake of brevity and are not intended to limit the technical ideas of the present disclosure. For example, it is obvious that when an object is observed after being rotated by 90 degrees, up-down is converted into and interpreted as left-right, and when an object is observed after being rotated by 180 degrees, up-down is interpreted as being inverted.
Further, in the following description, a direction may be described using the words “X-axis direction,” “Y-axis direction,” and “Z-axis direction.” For example, the Z-axis direction is a thickness direction of an antenna device 1 which will be described later. The X-axis direction and the Y-axis direction are directions orthogonal to the Z-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other. Further, in the following description, “plan view” means a view in the Z-axis direction.
In addition, in the present disclosure, “the same” includes not only a case of completely “the same” but also a case of substantially “the same.” As a case of substantially “the same,” for example, a case in which, even if there is a difference between two things, the difference is within a range of manufacturing errors is conceivable.
The antenna device 1 includes a first antenna element 10 and a second antenna element 20 disposed on the side of one surface of the first antenna element 10 (for example, the side of the front surface 11a of a first glass substrate 11). The first antenna element 10 and the second antenna element 20 are bonded to each other through a bonding material 30. As the bonding material 30, for example, an adhesive or a solder ball can be used. Further, the antenna device 1 and the communication circuit board 5 are also bonded to each other through a bonding material that is not shown.
The first glass substrate 11 is provided with a first through hole 11H1 and a second through hole 11H2 that penetrate through the front surface 11a and the back surface 11b thereof. The first through hole 11H1 and the second through hole 11H2 are separated from each other. The first patch antenna 13 is disposed on one end side of the first through hole 11H1, and the terminal layer 17 is disposed on the other end side of the first through hole 11H1. Similarly, the first patch antenna 13 is disposed on one end side of the second through hole 11H2, and the terminal layer 17 is disposed on the other end side of the second through hole 11H2. One terminal layer 17 is provided for each of the first through hole 11H1 and the second through hole 11H2.
The first through hole 11H1 and the second through hole 11H2 have the same shape and the same dimensions. The shape of the first through hole 11H1 and the second through hole 11H2 in a plan view (hereinafter referred to as a planar shape) is, for example, circular.
When the diameter of the first through hole 11H1 and the second through hole 11H2 on the side of the front surface 11a is φa and the diameter thereof on the side of the back surface 11b is φb, the diameter φa is less than the diameter φb. As an example, φa is 0.1 mm and φb is 0.125 mm. By forming the first through hole 11H1 and the second through hole 11H2 from the side of the back surface 11b of the first glass substrate 11, φa<φb can be achieved.
The shapes of the first through hole 11H1 and the second through hole 11H2 are not limited to the aforementioned shape. For example, the first through hole 11H1 and the second through hole 11H2 may have a larger diameter φa on the side of the front surface 11a than the diameter φb on the side of the back surface 11b. By forming the first through hole 11H1 and the second through hole 11H2 from the side of the front surface 11a of the first glass substrate 11, φa>φb can be achieved.
As shown in
Each of the first patch antenna 13, the conductor layer 15, the terminal layer 17, and the connection layer 18 is formed of a conductor such as copper (Cu) or a Cu alloy containing Cu as a main ingredient. Alternatively, each of the first patch antenna 13, the conductor layer 15, the terminal layer 17, and the connection layer 18 may be a laminated film in which a plurality of types of conductors are laminated. For example, as shown in
Similarly, the conductor layer 15 is composed of a Cu layer 15A formed through electroplating, a Ni layer 15B formed through electroless plating, and an Au layer 15C formed through electroless plating. The Cu layer 15A, the Ni layer 15B, and the Au layer 15C are laminated in this order from the side of the first glass substrate 11.
The terminal layer 17 is composed of a Cu layer 17A formed through electroplating, a Ni layer 17B formed through electroless plating, and an Au layer 17C formed through electroless plating. The Cu layer 17A, the Ni layer 17B, and the Au layer 17C are laminated in this order from the side of the first glass substrate 11.
The connection layer 18 is composed of a Cu layer 18A formed through electroplating, a Ni layer 18B formed through electroless plating, and an Au layer 18C formed through electroless plating. The Cu layer 18A, the Ni layer 18B, and the Au layer 18C are laminated in this order from the side of the first glass substrate 11.
As an example of the thickness of each layer, each of the Cu layers 13A, 15A, 17A and 18A is 5.0 μm, each of the Ni layers 13B, 15B, 17B and 18B is 3.0 μm, and each of the Au layers 13C, 15C, 17C and 18C is 0.3 μm.
The junction between the connection layer 18 provided in the first through hole 11H1 and the first patch antenna 13 is a first feeding point FP1 of the first patch antenna 13. The junction between the connection layer 18 provided in the second through hole 11H2 and the first patch antenna 13 is a second feeding point FP2 of the first patch antenna 13. The second feeding point FP2 is located at a position separated from the first feeding point FP1. The first feeding point FP1 and the second feeding point FP2 are connected to impedances having the same magnitude (for example, 50Ω). As a result, the first feeding point FP1 and the second feeding point FP2 resonate with each other.
The first feeding point FP1 and the second feeding point FP2 may be connected to impedances having different magnitudes. Even in this case, the first feeding point FP1 and the second feeding point FP2 may resonate with each other.
As shown in
The first glass substrate 11 contains silicon (Si) and oxygen (O) as main ingredients. Further, the first glass substrate 11 may contain a metal element in addition to Si and O. The first glass substrate 11 has transmittance (for example, it can transmit visible light) and is colorless and transparent or colored and transparent. The transmittance is not limited to the property of transmitting visible light and may be a property of transmitting infrared rays or ultraviolet rays.
The length of the first glass substrate 11 in the vertical direction (for example, the Y-axis direction) is, for example, 5 mm or more and 25 mm or less. The length of the first glass substrate 11 in the horizontal direction (for example, the X-axis direction) is, for example, 5 mm or more and 25 mm or less. The thickness 11t of the first glass substrate 11 (refer to
As shown in
The length of the second glass substrate 21 in the vertical direction is, for example, 0.5 mm or more and 15 mm or less. The length of the second glass substrate 21 in the horizontal direction is, for example, 0.5 mm or more and 15 mm or less. The thickness of the second glass substrate 21 is, for example, 0.3 mm or more and 1.0 mm or less.
The lengths of the second patch antenna 23 in the vertical direction and the horizontal direction also depend on frequency and have a size of about ½ of the wavelength.
The first glass substrate 11 and the second glass substrate 21 may have the same shape and the same dimensions. That is, the length of the first glass substrate 11 in the vertical direction and the length and thickness thereof in the horizontal direction may be the same as the length of the second glass substrate 21 in the vertical direction and the length and thickness thereof in the horizontal direction. The first patch antenna 13 and the second patch antenna 23 may also have the same shape and the same dimensions.
The junction between the first through hole 11H1 and the first patch antenna 13 is the first feeding point FP1 of the first patch antenna 13. The junction between the second through hole 11H2 and the first patch antenna 13 is the second feeding point FP2 of the first patch antenna 13. The first patch antenna 13 is connected to a signal line through which a high frequency signal is supplied via at least one of the first feeding point FP1 and the second feeding point FP2. The second patch antenna 23 is not electrically connected to any component. The first patch antenna 13 and the second patch antenna 23 are in a resonance state. The signal line can be provided on the communication circuit board 5, but can also be provided on the first glass substrate 11.
When the first patch antenna 13 transmits or receives radio waves in a millimeter wave region, for example, the first patch antenna 13 and the second patch antenna 23 resonate with each other. The conductor layer 15 is a ground and serves as a reflective layer. As a result, the antenna device 1 has directivity in the normal direction (for example, the Z-axis direction) of the first patch antenna 13. The antenna device 1 can transmit radio waves in the millimeter wave region in the normal direction (for example, the Z-axis direction) of the first patch antenna 13 and receive radio waves in the Z-axis direction.
The substrate constituting the first patch antenna 13 and the substrate constituting the second patch antenna are made of glass. The dielectric constant of the glass is lower than that of semiconductors such as silicon. Further, the recess 25 is positioned between the first patch antenna 13 and the second patch antenna 23, and an air layer exists inside the recess 25. The dielectric constant of the air layer is lower than that of the glass. Due to the presence of the glass and the air layer instead of a semiconductor between the first patch antenna 13 and the second patch antenna 23, the antenna device 1 can transmit or receive radio waves in the millimeter wave region with a high gain in a wide band.
Next, a method of manufacturing the antenna device 1 will be described.
First, a method for manufacturing the first antenna element 10 will be described. As shown in
As shown in
Next, a method for manufacturing the second antenna element 20 will be described. As shown in
As a result, the second patch antenna 23 is formed from the copper 29, as shown in
Meanwhile, since the recess 25 is formed through isotropic etching, a boundary 25c between the bottom surface 25a and the inner side surface 25b of the recess 25 is formed in a rounded shape instead of an angular shape.
Next, a method for attaching the second antenna element 20 to the first antenna element 10 will be described. As shown in
In the above-described alignment process, the manufacturing device uses the first patch antenna 13 provided on the first glass substrate 11 and the second patch antenna 23 provided on the second glass substrate 21 as alignment marks. When the first glass substrate 11 and the second glass substrate 21 are aligned as designed, the first patch antenna 13 and the second patch antenna 23 are formed to overlap each other in a plan view.
For example, it is assumed that the first patch antenna 13 and the second patch antenna 23 have the same planar shape and the same size. In this case, in the alignment process, the manufacturing device relatively moves the second glass substrate 21 with respect to the first glass substrate 11 such that the first patch antenna 13 and the second patch antenna 23 overlap in a plan view and the contour of the first patch antenna 13 and the contour of the second patch antenna 23 match, as shown in
As another example, it is assumed that the first patch antenna 13 and the second patch antenna 23 have the same planar shape and one of the first patch antenna 13 and the second patch antenna 23 is smaller than the other. In this case, the manufacturing device relatively moves the second glass substrate 21 with respect to the first glass substrate 11 such that the center position of the first patch antenna 13 and the center position of the second patch antenna 23 overlap in a plan view and each side of the outer circumference of the first patch antenna 13 is parallel to each side of the outer circumference of the second patch antenna 23. As a result, the manufacturing device can align the first glass substrate 11 and the second glass substrate 21 with high accuracy.
A device for aligning the glass substrates includes at least one of a first imaging device disposed on the side of the front surface 21a of the second glass substrate 21 and a second imaging device disposed on the side of the back surface 11b of the first glass substrate 11. The second glass substrate 21 has transmittance. Accordingly, the first imaging device disposed on the side of the front surface 21a of the second glass substrate 21 can capture an image of the second patch antenna 23 and also capture an image of the first patch antenna 13 through the second glass substrate 21.
In addition, not only the second glass substrate 21 but also the first glass substrate 11 has transmittance. Accordingly, the second imaging device disposed on the side of the back surface 11b of the first glass substrate 11 can capture an image of the first patch antenna 13 through the first glass substrate 11 and capture an image of the second patch antenna 23 through the first glass substrate 11 and the second glass substrate 21. From this captured data, the device for aligning the glass substrates can detect the positions of the first patch antenna 13 and the second patch antenna 23.
Next, a configuration example of the wireless communication circuit provided on the communication circuit board 5 will be described.
As shown in
Meanwhile, although
As described above, the wireless communication apparatus 100 according to embodiment 1 of the present disclosure includes the antenna device 1 and the wireless communication circuit 50 connected to the antenna device 1. The antenna device 1 includes the first antenna element 10 and the second antenna element 20 disposed on the side of one surface of the first antenna element 10. The first antenna element 10 includes the first glass substrate 11 and the first patch antenna 13 provided on the first glass substrate 11. The second antenna element 20 includes the second glass substrate 21 and the second patch antenna 23 provided on the second glass substrate 21. At least a part of the first patch antenna 13 faces the second patch antenna 23 through a cavity (for example, the recess 25).
Accordingly, a patch antenna having a cavity stack structure in which the first patch antenna 13 and the second patch antenna 23 are laminated via a cavity is constructed. The antenna device 1 can transmit or receive radio waves in the millimeter wave region by using the patch antenna having the cavity stack structure. Since the dielectric constant between the first patch antenna 13 and the second patch antenna 23 is kept low by the air layer in the glass substrate and the recess 25, generation of surface waves can be curbed. The antenna device 1 can transmit or receive radio waves in the millimeter wave region with a high gain in a wide band.
Further, since the first glass substrate 11 and the second glass substrate 21 have a lower dielectric constant than semiconductors, the antenna device 1 can curb a dielectric loss in the first patch antenna 13 and the second patch antenna 23 to be low and maintain high antenna efficiency.
The glass substrate can be made into a panel (large area), and more first antenna elements 10 or second antenna elements 20 can be obtained from one substrate as compared to a semiconductor substrate. As a result, the manufacturing cost of the antenna device 1 can be reduced.
The first glass substrate 11 and the second glass substrate 21 have smaller dimensional changes with respect to heat and stable dimensional accuracy as compared to an organic substrate formed of an organic material. The first glass substrate 11 and the second glass substrate 21 can be wet-etched using a solution containing hydrogen fluoride and have high processing accuracy.
In general, the higher the frequency band of transmitted or received radio waves, the smaller the size of an antenna. When the size of the antenna changes, the frequency band of the transmitted or received radio waves changes. Accordingly, in particular, an antenna that transmits or receives radio waves in the millimeter wave is required to have high dimensional accuracy. As described above, since the antenna device 1 has stable dimensional accuracy and high processing accuracy, it is possible to curb changes in the band and improve antenna characteristics.
The recess 25 is provided in the second glass substrate 21. The circumference of the recess 25 has a frame structure. This frame structure increases the rigidity of the second glass substrate 21 and contributes to stabilization of the dimensional accuracy of the second glass substrate 21.
Further, the first glass substrate 11 and the second glass substrate 21 have transmittance. Accordingly, it is possible to capture an image of the first patch antenna 13 from the side of the front surface 21a of the second glass substrate 21 through the second glass substrate 21 or capture an image of the second patch antenna from the side of the back surface 11b of the first glass substrate 11 through the first glass substrate 11. It is easy to align the first glass substrate and the second glass substrate.
In the above-described embodiment 1, the recess 25 in provided in the second glass substrate 21. However, embodiments of the present disclosure are not limited thereto. The cavity positioned between the first patch antenna 13 and the second patch antenna 23 may be provided in the first glass substrate 11 instead of the second glass substrate 21.
The first antenna element 10A has a recess 111 (an example of a first recess as a cavity) provided on the side of the front surface 11a of the first glass substrate 11. The planar shape of the recess 111 is rectangular. The first patch antenna 13 is provided on the bottom surface 12a of the recess 111. In the second antenna element 20A, the recess 25 (refer to
In the antenna device 1A, a cavity (for example, the recess 111) is also present between the first patch antenna 13 and the second patch antenna 23. The dielectric constant between the first patch antenna 13 and the second patch antenna 23 is kept low by the air layer in the recess 111. Accordingly, the antenna device 1A can transmit or receive radio waves in the millimeter wave region with a high gain in a wide band.
In the above-described embodiment 1, the first patch antenna 13 and the second patch antenna 23 are used as alignment marks. However, embodiments of the present disclosure are not limited thereto. Any pattern may be used as an alignment mark.
The first antenna element 10B has a first alignment mark 121 provided on the side of the front surface 11a or the back surface 11b of the first glass substrate 11.
The second antenna element 20B has a second alignment mark 221 provided on the side of the front surface 21a or the back surface 21b of the second glass substrate 21.
When the first glass substrate 11 and the second glass substrate 21 are aligned as designed, the first alignment mark 121 and the second alignment mark 221 are formed to overlap each other in a plan view. Even in such a configuration, the manufacturing device can align the first glass substrate 11 and the second glass substrate 21 with high accuracy using the first alignment mark 121 and the second alignment mark 221.
The manufacturing device may align the first glass substrate 11 and the second glass substrate 21 using both the first patch antenna 13 and the second patch antenna 23, and the first alignment mark 121 and the second alignment mark 221. Accordingly, the number of marks used for alignment increases, and thus the accuracy of alignment is improved.
Alternatively, a plurality of first alignment marks 121 and a plurality of second alignment marks 221 may be provided. The manufacturing device may align the first glass substrate 11 and the second glass substrate 21 such that the plurality of first alignment marks 121 and the plurality of second alignment marks 221 respectively overlap each other in a plan view. In this case, the number of marks used for alignment also increases, and thus the accuracy of alignment is improved.
In embodiments of the present disclosure, the antenna device 1 may include an end fire antenna in addition to the first patch antenna 13 and the second patch antenna 23.
The first antenna element 10C includes an end fire antenna 131 provided on the side of the back surface 11b of the first glass substrate 11. The planar shape of the end fire antenna 131 is a rectangle that extends long in one direction (for example, in the Y-axis direction). The end fire antenna 131 is formed at the same time as the conductor layer 15 and the terminal layer 17 through the same process. As a result, the end fire antenna 131 is formed of the same material (as an example, Cu or Cu alloy) and have the same film thickness as the conductor layer 15 and the terminal layer 17.
The end fire antenna 131 is connected to a signal line through which a high frequency signal is supplied. The end fire antenna 131 is not electrically connected to either the conductor layer 15 or the terminal layer 17. The end fire antenna 131 has a directivity in the horizontal direction parallel to the first patch antenna 13 and orthogonal to the above-mentioned one direction (for example, the X-axis direction). As a result, the antenna device 1C can transmit radio waves in the millimeter wave region in the X-axis direction or receive radio waves in the millimeter wave region in the X-axis direction via the end fire antenna 131. The antenna device 1C has a directivity not only in the normal direction of the first patch antenna 13 but also in the horizontal direction of the first patch antenna 13 and thus can cover a wider area.
Meanwhile,
In the above-described embodiment 1, the bottom surface of the recess of the second glass substrate 21 is flat. However, embodiments of the present disclosure are not limited thereto. The bottom surface 25a of the recess 25 of the second glass substrate 21 may be uneven.
In the second antenna element 20D, a plurality of protrusions 241 are provided on the bottom surface 25a of the recess 25. The plurality of protrusions 241 have the same shape and the same size, for example. The plurality of protrusions 241 are arranged at equal intervals in the X-axis direction and at equal intervals in the Y-axis direction. The arrangement interval of the plurality of protrusions 241 in the X-axis direction and the arrangement interval in the Y-axis direction may be the same or different from each other. At least some of the plurality of protrusions 241 are positioned between the first patch antenna 13 and the second patch antenna 23.
The plurality of protrusions 241 may be provided integrally with the second glass substrate 21. When the plurality of protrusions 241 are provided integrally with the second glass substrate 21, the plurality of protrusions 241 are formed by etching the bottom surface 25a of the recess 25 through photolithography and wet etching techniques. Since the bottom surface 25a of the recess 25 is glass, a solution containing hydrogen fluoride is used for wet etching.
Since the plurality of protrusions 241 are present at equal intervals in the X-axis direction and the Y-axis direction, the dielectric constant between the first patch antenna 13 and the second patch antenna 23 periodically changes in the X-axis direction and the Y-axis direction. As a result, the band and resonance point of the antenna device 1D shifts from a band and resonance point when the bottom surface 25a of the recess 25 is not uneven.
The plurality of protrusions 241 shift the band and resonance point of the antenna device 1D. Shift amounts of the band and resonance point of the antenna device 1D are values depending on the shape, size, arrangement, and the like of the plurality of protrusions 241. It is possible to adjust the band and resonance point of the antenna device 1D by arbitrarily designing the shape, size, arrangement, and the like of the plurality of protrusions 241. In embodiment 5, the plurality of protrusions 241 may have different shapes or different sizes. Even in such a configuration, the band and resonance point can be adjusted.
In the above-described embodiment 1, one recess 25 is provided in the second glass substrate 21. However, in the present disclosure, the number of recesses 25 provided in the second glass substrate 21 is not limited to one and may be plural.
The plurality of slits 251 are formed by etching the bottom surface 25a of the recess 25 through photolithography and wet etching techniques. For each of the plurality of slits 251, it is desirable that an aspect ratio be 3 or more and 8 or less. The aspect ratio is a ratio of a length D of the slit in the depth direction (for example, the Z-axis direction) to a length W of the slit in the width direction (for example, the X-axis direction) and is represented by D/W.
In the antenna device 1E, a cavity (for example, a plurality of slits 251) is also present between the first patch antenna 13 and the second patch antenna 23. The first patch antenna 13 faces the second patch antenna 23 via the plurality of slits 251. The dielectric constant between the first patch antenna 13 and the second patch antenna 23 is kept low by the air layer in the slits 251. Accordingly, the antenna device 1E can transmit or receive radio waves in the millimeter wave region with a high gain in a wide band.
In the above-described embodiment 1, the antenna device 1 includes one first patch antenna 13 and one second patch antenna 23. However, embodiments of the present disclosure are not limited thereto. The antenna device 1 may include a plurality of first patch antennas 13 and a plurality of second patch antennas 23.
The first antenna element 10F has a plurality of first patch antennas 13 provided on the side of the front surface of the first glass substrate 11. The second antenna element 20F has a plurality of second patch antennas 23 provided on the side of the front surface of the second glass substrate 21. The plurality of first patch antennas 13 respectively face the plurality of second patch antennas 23. Further, one recess 25 is provided in the second antenna element 20F. The plurality of first patch antennas 13 and the plurality of second patch antennas 23 are provided at positions where they overlap with the recess 25 in a plan view.
In the antenna device 1F, a cavity (for example, the recess 25) is also present between the plurality of first patch antennas 13 and the plurality of second patch antennas 23. The dielectric constant between the plurality of first patch antennas 13 and the plurality of second patch antennas 23 is kept low by the air layer in the recess 25. Accordingly, the antenna device 1F can transmit or receive radio waves in the millimeter wave region with a high gain in a wide band.
In the antenna device 1F, it is possible to transmit or receive radio waves with a narrower directivity by arranging a plurality of patch antennas having a cavity stack structure composed of the first patch antennas 13 and the second patch antennas 23. At the same time, radio waves can be superimposed and thus the antenna gain can be increased.
In embodiments of the present disclosure, the antenna device 1 may include a linear antenna (for example, a dipole antenna or a monopole antenna) in addition to the first patch antenna 13 and the second patch antenna 23.
As shown in
In embodiment 7, the first glass substrate 11 has a third through hole 11H3 penetrating through the front surface 11a and the back surface 11b of the first glass substrate 11 and a terminal layer 171 provided on the back surface 11b. As shown in
In the first glass substrate 11, the first conductive wire layer 161 is disposed on the one side of the third through hole 11H3 and the terminal layer 171 is disposed on the other side of the third through hole 11H3. The first patch antenna 13 and the terminal layer 171 are electrically connected to each other via the third through hole 11H3. The third through hole 11H3 may be filled with a conductor. An example of the conductor is Cu or a Cu alloy.
The first conductive wire layer 161, the terminal layer 171, and the second conductive wire layer 162 are connected to the phase shifter 55 (refer to
The first conductive wire layer 161 and the third conductive wire layer 163 are formed at the same time as the first patch antenna 13 through the same process, for example. As a result, the first conductive wire layer 161 and the third conductive wire layer 163 are formed of the same material (for example, Cu or a Cu alloy) and have the same film thickness as the first patch antenna 13.
Similarly, the second conductive wire layer 162, the fourth conductive wire layer 164, and the terminal layer 171 are formed at the same time as the conductor layer 15 and the terminal layer 17 through the same process, for example. As a result, the second conductive wire layer 162, the fourth conductive wire layer 164, and the terminal layer 171 are formed of the same material (as an example, Cu or Cu alloy) and have the same film thickness as the conductor layer 15 and the terminal layer 17.
The dipole antenna 160 has a directivity in the horizontal direction (for example, the X-axis direction or the Y-axis direction) parallel to the first patch antenna 13. As a result, the antenna device 1G can transmit radio waves in the millimeter wave region in the horizontal direction and receive radio waves in the millimeter wave region in the horizontal direction through the dipole antenna 160. The antenna device 1G has a directivity not only in the normal direction of the first patch antenna 13 but also in the horizontal direction of the first patch antenna 13 and thus can cover a wider area.
The first antenna element 10H has a plurality of first patch antennas 13H provided on the side of the front surface 11a of the first glass substrate 11. The first patch antennas 13H face the second patch antenna 23 of the second antenna element 20. The only difference between the first patch antennas 13H shown in
One end of the first edge L1 and one end of the fourth edge L4 are connected at C1. The other end of the first edge L1 and one end of the second edge L2 are connected at a corner C2. The other end of the second edge L2 and one end of the third edge L3 are connected at a corner C3. The other end of the third edge L3 and the other end of the fourth edge L4 are connected at a corner C4.
In the first patch antenna 13H, one or more contours of the corners C1 to C4 have a shape including a curve in a plan view. A contour may also be called an outer edge. For example, as shown in
Alternatively, one or more contours of the corners C1 to C4 may have a shape including a plurality of obtuse angles (angles greater than 90° and less than) 180° in a plan view.
Similarly, each of the contours of the corners C2 to C4 also has a shape including two obtuse angles CA1 and CA2 in a plan view. As a result, electric field concentration on the corners C1 to C4 can be curbed and thus an excitation shape of the first patch antenna 13H can be curbed from collapsing.
Similarly, each of the contours of the corners C2 to C4 also has a shape including three obtuse angles CA1, CA3, and CA2 in a plan view. It is desirable that the number of obtuse angles be larger in each of the corners C1 to C4. The larger the number of obtuse angles, the wider the obtuse angles and the closer the obtuse angles are disposed. As a result, each of the corners C1 to C4 approaches a shape including a curve as shown in
In embodiments of the present disclosure, not only the first patch antenna but also the second patch antenna may include at least one corner thereof having a shape including a curved line or a plurality of obtuse angles in a plan view.
Similarly to the first patch antenna 13H, the second patch antenna 23H includes at least one corner thereof having a shape including a curved line or a shape including a plurality of obtuse angles in a plan view. For example, the second patch antenna 23H has the same shape and the same dimensions as those of the first patch antenna 13H. Accordingly, electric field concentration on the corners can be curbed in the second patch antenna 23H as well as the first patch antenna 13H. Therefore, it is possible to curb collapse of the excitation shape in each of the first patch antenna 13H and the second patch antenna 23H.
Further, in embodiments of the present disclosure, only the corners of the second patch antenna, not the first patch antenna, may have a shape including a curved line or a shape including a plurality of obtuse angles in a plan view.
In the example shown in
Further, the shape of the first patch antenna 13H in a plan view is a rectangle. In this rectangle, a straight line connecting the centers of a set of edges (for example, the fourth edge CL4 and the second edge L2) facing each other in a first direction (for example, the Y-axis direction) is defined as a first straight line VL. A straight line connecting the centers of a set of edges (for example, the first edge CL1 and the third edge L3) facing each other in a second direction (for example, the X-axis direction) intersecting the first direction is defined as a second straight line HL. As shown in
The position where the first straight line VL intersects the second straight line HL is the center position CP of the first patch antenna 13H. The first feeding point FP1 is located at a position deviated from the center position CP in two axial directions (X-axis direction and Y-axis direction). For example, the first feeding point FP1 is separated from the first straight line VL and the second straight line HL by 0.05 mm or more, respectively. This improves an excitation state when the first patch antenna 13H transmits or receives a single-polarized signal. In an antenna device that transmits or receives a single-polarized signal, the depth of resonance and the band can be improved and the band can be widened.
With this structure, the first patch antenna 13H transmits or receives a signal polarized in one of the vertical direction and the horizontal direction according to excitation of the circumference of the fourth edge L4 and the circumference of the second edge L2. Further, the first patch antenna 13H transmits or receives a signal polarized in the other of the vertical direction and the horizontal direction according to excitation of the circumference of the third edge L3 and the circumference of the first edge L1. That is, the first patch antenna 13H transmits or receives a bipolarized signal.
In the example shown in
Further, as shown in
Even in such a case, the antenna device 1J includes at least one of the first patch antenna 13H and the second patch antenna 23H having corners in a shape including a curved line (or a shape including a plurality of obtuse angles), and thus the excitation shape can be curbed from collapsing. Further, in the antenna device 1J, at least one of the first feeding point FP1 and the second feeding point FP2 is present at a position where it is deviated with respect to the center position CP in two axial directions (the X-axis direction and the Y-axis direction), and thus the depth of resonance and the band can be improved and the band can be widened.
Further, as shown in
The metal plate 180 is provided on the side of the front surface 11a of the first glass substrate 11 like the first patch antenna 13. The metal plate 180 has the same layer structure as that of the first patch antenna 13. For example, the metal plate 180 is composed of a Cu layer formed through electroplating, a Ni layer formed through electroless plating, and an Au layer formed through electroless plating. The Cu layer, the Ni layer and the Au layer are laminated in this order from the side of the first glass substrate 11. The metal plate 180 is formed at the same time as the first patch antenna 13 through the same process.
A plurality of fourth through holes 11H4 penetrating through the front surface 11a and the back surface 11b of the first glass substrate 11 are provided in the first glass substrate 11 of the antenna device 1J. The metal plate 180 is disposed on the side of one end of the fourth through holes 11H4, and the conductor layer 15 is disposed on the side of the other end of the fourth through holes 11H4. The fourth through holes 11H4 may be filled with a conductor. An example of the conductor is Cu or a Cu alloy.
The metal plate 180 is electrically connected to the conductor layer 15 via the fourth through holes 11H4. When the conductor layer 15 is a ground and serves as a reflective layer, the metal plate 180 is connected to the conductor layer 15 via the fourth through holes 11H4. The conductor layer 15 is fixed to an arbitrary potential (for example, a ground potential (0 V)). As a result, the antenna device 1J can improve a radiation shape of transmitted radio waves.
Further, as shown in
(Evaluation results)
In each of
This evaluation was performed using an antenna device having the two configurations described in the embodiments 9 and 10. Specifically, the antenna device used for the evaluation includes the first patch antenna 13H and the second patch antenna 23H. Both the first patch antenna 13H and the second patch antenna 23H have a rectangular shape in a plan view, and the four corners of the rectangle are curved and rounded (configuration 1). Further, the antenna device used for the evaluation has the first feeding point FP1 and the second feeding point FP2. The first feeding point FP1 and the second feeding point FP2 are respectively displaced in two axial directions (configuration 2).
As shown in
In general, when radio waves in a wide band are transmitted or received, patch antennas having a plurality of sizes are prepared corresponding to a plurality of bands. For a higher frequency, a smaller patch antenna is designed. However, if patch antennas having a plurality of sizes are prepared, the number of parts increases, which hinders miniaturization of the device and increases the manufacturing cost. In order to prevent this, it is conceivable to handle wide band radio waves with a common patch antenna having one size, but in this case, electric fields tend to concentrate on the corners of the patch antenna, particularly, at the time of transmitting or receiving high frequencies. When electric fields concentrate on the corners of the patch antenna, the excitation shape may collapse to cause deterioration of radiation characteristics of radio waves and the gain.
However, it is confirmed that the antenna device having the configurations 1 and 2 curbs electric field concentration on the corners even at the time of transmitting or receiving high-frequency radio waves (for example, 43.5 GGz) and thus curb the excitation shape from collapsing as compared to a device without the configurations 1 and 2. It is confirmed that a decrease in radiation characteristics and a decrease in the gain are curbed even at the time of transmitting or receiving high-frequency radio waves (for example, 43.5 GGz). From these results, it is confirmed that the antenna device having the configurations 1 and 2 can widen the band as compared to a device without the configurations 1 and 2.
As mentioned above, the present disclosure has been described by embodiments and modified examples, but the statement and drawings that form part of this disclosure should not be understood to limit the present disclosure. It is to be understood that various alternative embodiments, examples, and operable techniques will become apparent from this disclosure to those skilled in the art.
For example, in the embodiments of the present disclosure, a mobile device, an automobile, and building parts may be provided with any one or more of the above-mentioned antenna devices 1, 1A to 1J. When a mobile device includes any one or more of the antenna devices 1, 1A to 1J, the second glass substrate 21 may be used as a part of a display panel of the mobile device. As a result, it is possible to provide a mobile device capable of transmitting and receiving radio waves in the millimeter wave region in a wide band.
When an automobile is equipped with any one or more of the antenna devices 1, 1A to 1J, the second glass substrate 21 may be used as a part of the windshield or the rear glass of the automobile. As a result, it is possible to provide an automobile having a transmission function capable of transmitting and receiving radio waves in the millimeter wave region in a wide band.
When building parts include any one or more of the antenna devices 1, 1A to 1J, the second glass substrate 21 may be used a part of the building parts. Examples of building parts include glass windows. As a result, it is possible to provide building parts capable of transmitting and receiving radio waves in the millimeter wave region in a wide band.
In this manner, the present technology obviously includes various embodiments and the like that are not described herein. At least one of various omissions, substitutions and modifications of components may be performed without departing from the gist of the embodiments and the modified examples described above. Further, the effects described in the present specification are merely exemplary and not limited, and other effects may be obtained.
Meanwhile, the present disclosure can also take the following configurations.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-183901 | Oct 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/036679 | 9/28/2020 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2021/065819 | 4/8/2021 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 10135155 | Sudo | Nov 2018 | B2 |
| 10957982 | Kang | Mar 2021 | B2 |
| 20150084814 | Rojanski | Mar 2015 | A1 |
| 20150194730 | Sudo et al. | Jul 2015 | A1 |
| 20170229769 | Yokoyama et al. | Aug 2017 | A1 |
| 20170346177 | Nagata | Nov 2017 | A1 |
| 20180337458 | Rodríguez | Nov 2018 | A1 |
| 20190207304 | Kim | Jul 2019 | A1 |
| 20190386400 | Wu | Dec 2019 | A1 |
| 20200021008 | Yong | Jan 2020 | A1 |
| Number | Date | Country |
|---|---|---|
| 104662737 | May 2015 | CN |
| 107078406 | Aug 2017 | CN |
| 2899807 | Jul 2015 | EP |
| 05-167335 | Jul 1993 | JP |
| 2000-223927 | Aug 2000 | JP |
| 2006-229871 | Aug 2006 | JP |
| 2006-304006 | Nov 2006 | JP |
| 2007-097115 | Apr 2007 | JP |
| 2020-127079 | Aug 2020 | JP |
| 10-2015-0041054 | Apr 2015 | KR |
| 201622509 | Jun 2016 | TW |
| 2000045466 | Aug 2000 | WO |
| 2014045966 | Mar 2014 | WO |
| 2016067969 | May 2016 | WO |
| Entry |
|---|
| International Search Report and Written Opinion of PCT Application No. PCT/JP2020/036679, issued on Nov. 24, 2020, 15 pages of ISRWO. |
| Number | Date | Country | |
|---|---|---|---|
| 20220320743 A1 | Oct 2022 | US |
