Antenna device, antenna module, and communication device

A ground plane, at least one composite antenna, and a power feeding line configured to supply power to the at least one composite antenna are provided in or on a substrate. The composite antenna includes a power feeding element configuring a patch antenna together with the ground plane, and at least one linear antenna configured to flow an electric current having a component in a vertical direction with respect to the ground plane. The power feeding line includes a main line connected to the power feeding element, and a branch line branched from the main line and connected to the linear antenna.

BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

The present invention relates to an antenna device, an antenna module, and a communication device.

Description of the Related Art

As an antenna for radio frequency wireless communication, a microstrip antenna (patch antenna) is used. The following Non Patent Document 1 describes basic characteristics of a patch antenna. The patch antenna includes a patch (power feeding element) made of metal disposed on a dielectric substrate in or on which a ground plane is provided. An antenna gain of the patch antenna is maximized in a normal direction of the ground plane. That is, a main beam of the patch antenna is directed in the normal direction of the ground plane.Non Patent Document 1: D. M. Pozar, “Microstrip antennas”, Proceedings of IEEE, Vol. 80, No. 1, pp. 79-91, January 1992

BRIEF SUMMARY OF THE DISCLOSURE

In some cases, it may be desirable to increase the antenna gain in a direction inclined from the normal direction of the ground plane. In other words, there is a case where the beam is desired to be tilted. However, it is difficult for the patch antenna of the related art to tilt the beam.

An object of the present invention is to provide an antenna device capable of tilting a beam from a normal direction of a ground plane. Another object of the present invention is to provide an antenna module having the antenna device. Still another object of the present invention is to provide a communication device including the antenna module.

According to one aspect of the present invention, there is provided an antenna device includinga substrate,a ground plane provided in or on the substrate,at least one composite antenna provided in or on the substrate, anda power feeding line configured to supply power to the composite antenna, whereinthe composite antenna includesa power feeding element configuring a patch antenna together with the ground plane, andat least one linear antenna configured to flow an electric current having a component in a perpendicular direction with respect to the ground plane, andthe power feeding line includesa main line connected to the power feeding element, anda branch line branched from the main line and connected to the linear antenna.

According to another aspect of the present invention, there is provided an antenna module includinga substrate,a ground plane provided in or on the substrate,a composite antenna provided in or on the substrate,a power feeding line configured to supply power to the composite antenna, anda radio frequency integrated circuit element configured to supply a radio frequency signal to the composite antenna through the power feeding line, whereinthe composite antenna includesa power feeding element configuring a patch antenna together with the ground plane, andat least one linear antenna configuring an electric current source having a component in a vertical direction with respect to the ground plane, andthe power feeding line includesa main line connected to the power feeding element, anda branch line branched from the main line and connected to the linear antenna.

According to still another aspect of the present invention, there is provided a communication device includingthe antenna module described above, anda baseband integrated circuit element configured to supply an intermediate frequency signal to the radio frequency integrated circuit element of the antenna module.

According to still another aspect of the present invention, there is provided a communication device includingan antenna device, anda housing configured to accommodate the antenna device, whereinthe antenna device includesa substrate,a ground plane provided in or on the substrate,at least one composite antenna provided in or on the substrate, anda power feeding line configured to supply power to the composite antenna, whereinthe composite antenna includesa power feeding element configuring a patch antenna together with the ground plane, andat least one vertical portion configured to flow an electric current having a component in a vertical direction with respect to the ground plane,the power feeding line includesa main line connected to the power feeding element, anda branch line branched from the main line and connected to the vertical portion, andthe housing includesa conductor portion connected to the vertical portion, the conductor portion configuring a linear antenna together with the vertical portion.

A radiation electric field from the patch antenna and a radiation electric field from the linear antenna strengthen each other in a partial region of space, and weaken each other in another partial region. An antenna gain increases in the region where the radiation electric field from the patch antenna and the radiation electric field from the linear antenna strengthen each other, whereas the antenna gain decreases in the region where the radiation electric fields weaken each other, and thus, a direction in which a beam of the antenna device is directed can be tilted.

DETAILED DESCRIPTION OF THE DISCLOSURE

First Embodiment

An antenna device according to a first embodiment will be described with reference to the drawings fromFIG.1AtoFIG.1C.FIG.1Ais a perspective view schematically illustrating the antenna device according to the first embodiment. The antenna device according to the first embodiment includes a composite antenna10provided with a power feeding element11formed of a conductor having a plate shape or a film shape, and two linear antennas15. A planar shape of the power feeding element11is a square shape or a rectangular shape. An xyz orthogonal coordinate system is defined in which directions parallel to two edges orthogonal to each other of the power feeding element11are respectively defined as an x-axis direction and a y-axis direction.

The two linear antennas15are arranged at positions sandwiching the power feeding element11in the y-axis direction. A power feeding line20includes a main line21and a branch line22. The main line21is connected to a power feeding point12of the power feeding element11. Here, “connected” means that conduction is ensured in a direct-current manner or coupling is generated in at least one mode of electric field coupling, magnetic field coupling, and electromagnetic field coupling. The power feeding point12is arranged at a position shifted in a negative direction of the x-axis from a geometric center of the power feeding element11in a plan view, and the main line21extends from the power feeding point12in a positive direction of the x-axis. High-frequency power is supplied to the power feeding element11through the main line21.

Two branch lines22are branched from a branch point23of the main line21. The branch point23is positioned inside the power feeding element11in a plan view. The two branch lines22are individually connected to the two linear antennas15, and high-frequency power is supplied to each of the two linear antennas15through the corresponding two branch lines22.

FIG.1Bis a schematic cross-sectional view perpendicular to the x-axis of the antenna device according to the first embodiment. The power feeding element11is disposed on a surface (hereinafter referred to as an upper surface) facing a positive direction of a z-axis of a substrate30made of a dielectric, and a ground plane32is disposed on a surface (hereinafter referred to as a lower surface) facing a negative direction of the z-axis. Further, a ground plane31is also disposed in an inner layer of the substrate30. The power feeding element11and the ground plane31configure a patch antenna. An E-plane and an H-plane of radio waves radiated from the patch antenna are parallel to an xz plane and a yz plane, respectively. The main line21(FIG.1A) and the two branch lines22are disposed between the ground plane31and the ground plane32.

The linear antenna15extends from the ground plane31to the upper surface side of the substrate30. For example, the linear antenna15is a monopole antenna, and the ground plane31functions as a ground of the monopole antenna. Each of the two branch lines22is connected to a power feeding point16of the linear antenna15. The power feeding point16is disposed at the same position as that of the ground plane31of the inner layer in a thickness direction of the substrate30. In other words, the power feeding point16is positioned in a clearance hole provided in the ground plane31. A line length from the branch point23to the power feeding point16of one linear antenna15is equal to a line length from the branch point23to the power feeding point16of the other linear antenna15.

At a position different from the cross-section illustrated inFIG.1Bin the x-axis direction, the main line21(FIG.1A) passes through the inside of the clearance hole provided in the ground plane31, and is connected to the power feeding point12of the power feeding element11.

FIG.1Cis a diagram illustrating radiation electric fields by the power feeding element11(FIG.1A) and the linear antennas15(FIG.1A). It can be considered that magnetic currents Ms having the same phase and serving as a wave source are generated between the vicinity of a pair of edges parallel to the y-axis direction of the power feeding element11and the ground plane31. The magnetic current Ms generates a radiation electric field EM. In space on a positive side of the z-axis from the power feeding element11, directions of x-components of the radiation electric fields EM generated from a pair of magnetic currents Ms are the same as each other. For example,FIG.1Cillustrates a state in which the x-components of the radiation electric fields EM are directed in the negative direction of the x-axis.

The two linear antennas15configure electric current sources that allow electric currents Is having the same phase to flow in a direction (a direction parallel to the z-axis) perpendicular to the ground plane31(FIG.1B). This electric current Is serves as a wave source to generate the radiation electric field EI. In the space on the positive side of the z-axis from the ground plane31, the x-component of the radiation electric field EI on the positive side of the x-axis from the electric current Is serving as the wave source, and the x-component of the radiation electric field EI on the negative side of the x-axis from the electric current Is are opposite to each other. For example,FIG.1Cillustrates a state in which the x-components of the radiation electric fields EI generated in the spaces on the positive side and the negative side of the x-axis from the linear antenna15are directed in the positive and negative directions, respectively.

Next, an excellent effect of the first embodiment will be described. In the first embodiment, as described with reference toFIG.1C, in the space on the positive side of the z-axis from the ground plane31, the x-components of the radiation electric fields EI are opposite to each other in the space on the positive side of the x-axis and the space on the negative side of the x-axis with a virtual line connecting the two linear antennas15being as a boundary therebetween. On the other hand, the x-components of the radiation electric fields EM are directed in the same direction. Thus, with a virtual plane (hereinafter referred to as a “boundary surface”) which includes a virtual straight line connecting the two linear antennas15and which is parallel to the yz plane being as a boundary, the radiation electric fields EM and EI strengthen each other in one space, and weaken each other in the other space. A direction of a beam of a radiation electric field radiated from the composite antenna10is inclined in a direction in which the radiation electric fields EM and EI strengthen each other with respect to the normal direction of the ground plane31. As described above, in the antenna device according to the first embodiment, it is possible to tilt a beam.

In which space the radiation electric fields EM and EI strengthen each other with the boundary surface being as the boundary depends on a phase relationship between the electric current Is and the magnetic current Ms which serve as the wave sources. The phase relationship between the electric current Is and the magnetic current Ms depends on a difference between the line length of the main line21from the branch point23(FIG.1A) to the power feeding point12(FIG.1A) of the power feeding element11and the line length of the branch line22from the branch point23to the power feeding point16(FIG.1B) of the linear antenna15. Thus, by adjusting the two line lengths, it is possible to adjust a tilt direction and a tilt angle of a beam.

In order to obtain a sufficient effect of strengthening or weakening the radiation electric field EI from the electric current Is and the radiation electric field EM from the magnetic current Ms, it is preferable to bring the magnetic current Ms and the electric current Is that serve as the wave sources sufficiently close to each other. For this reason, in an E-plane direction (x-axis direction), the electric current Is serving as the wave source is preferably disposed between the two magnetic currents Ms serving as the wave sources. In other words, it is preferable to dispose the linear antenna15(FIG.1A) in a range in which the power feeding element11(FIG.1A) is arranged in the E-plane direction. In an H-plane direction (y-axis direction), a distance from the geometric center of the power feeding element11to the linear antenna15is preferably equal to or smaller than ½ of a wave length in a vacuum at a lower limit of an operating frequency band of the antenna device.

Next, a modified example of the first embodiment will be described. In the first embodiment, the two linear antennas15are provided, but only one linear antenna15may be provided in some cases. Even in the case where only one linear antenna15is provided, an effect of superimposing the radiation electric field EI due to the electric current Is and the radiation electric field EM due to the magnetic current Ms can be obtained. In order to ensure symmetry in the H-plane direction (y-axis direction), it is preferable to arrange the two linear antennas on both sides of the power feeding element11in the y-axis direction.

It is preferable that the line length of the branch line22from the branch point23(FIG.1A, andFIG.1B) to the power feeding point16(FIG.1B) of the linear antenna15be set to ¼ of a resonant wave length of the linear antenna15. When this configuration is adopted, an input impedance when the linear antenna15is viewed from the branch point23becomes high. Therefore, when the branch line22(FIG.1A) is connected to the main line21(FIG.1A), the influence on the input impedance characteristics of the patch antenna including the power feeding element11is reduced.

Second Embodiment

Next, an antenna device according to a second embodiment will be described with reference to the drawings fromFIG.2AtoFIG.3B. Hereinafter, the description of a configuration common to the antenna device (FIG.1A,FIG.1B, andFIG.1C) according to the first embodiment will be omitted.

FIG.2Ais a perspective view of a main portion of the antenna device according to the second embodiment. InFIG.2A, the illustration of a ground plane is omitted.FIG.2BandFIG.2Care a cross-sectional view perpendicular to the y-axis and a cross-sectional view perpendicular to the x-axis of the antenna device according to the second embodiment, respectively.

In the second embodiment, the power feeding element11is loaded with a parasitic element13. The parasitic element13is disposed at a position farther than the power feeding element11when viewed from the ground plane31(FIG.2B). In addition, in the second embodiment, the power feeding element11and the parasitic element13have a planar shape in which a square shape is cut off from each of the vertices of a square shape or a rectangular shape. Note that the power feeding element11and the parasitic element13may have a square shape or a rectangular shape.

The main line21includes a transmission line disposed between the ground planes31and32(FIG.2B), and a via conductor14that connects the transmission line to the power feeding point12of the power feeding element11. The via conductor14passes through the inside of a clearance hole provided in the ground plane31. Note that, in the inside of the clearance hole provided in the ground plane31, a conductor pattern disposed in the same layer as the ground plane31is provided.

Each of the linear antennas15includes a vertical portion15A (FIG.2C) extending in the thickness direction (z-axis direction) of the substrate30, and a horizontal portion15B (FIG.2C) extending in the y-axis direction from an upper end of the vertical portion15A. The power feeding point16is positioned at a lower end of the vertical portion15A. The branch line22includes a transmission line that is disposed between the ground planes31and32, and via conductors17that connect the transmission line to the power feeding points16. The vertical portion15A and the via conductor17are disposed in the clearance hole provided in the ground plane31in a plan view. In the clearance hole, a conductor pattern disposed in the same layer as the ground plane31is provided.

The horizontal portion15B is disposed between the power feeding element11and the parasitic element13in the thickness direction of the substrate30. The vertical portion15A is constituted by a via conductor for interlayer connection and a conductor pattern disposed in the same layer as the power feeding element11.

Next, an excellent effect of the second embodiment will be described. In the second embodiment as well, a beam can be tilted in a similar manner to that in the first embodiment. Further, in the second embodiment, the power feeding element11is loaded with the parasitic element13, and thus, it is possible to widen a bandwidth of the antenna device. Further, since the linear antenna15includes the vertical portion15A and the horizontal portion15B, it is possible to adjust the resonant frequency of the linear antenna15by adjusting a length of the horizontal portion15B. Further, since the horizontal portions15B are disposed in a layer different from both the power feeding element11and the parasitic element13, it is possible to set the length of the horizontal portion15B without being influenced by the arrangement of the power feeding element11and the parasitic element13.

A direction of a high-frequency electric current flowing through the horizontal portion15B of the linear antenna15is parallel to the y-axis. On the other hand, a direction of a high-frequency electric current flowing through the power feeding element11and the parasitic element13is parallel to the x-axis. Since the direction of the electric current flowing through the power feeding element11and the parasitic element13and the direction of the electric current flowing through the horizontal portion15B of the linear antenna15are orthogonal to each other, the influence on the patch antenna by arranging the horizontal portions15B is small. For this reason, when the patch antenna is designed under a condition that the linear antenna15is not disposed, and then the linear antenna15is designed, it is not necessary to modify the design of the patch antenna. Therefore, it is possible to design the patch antenna and the linear antenna almost independently. As a result, it is possible to obtain an excellent effect that the degree of freedom in design is improved.

Next, a simulation performed in order to confirm that a beam is tilted in the antenna device according to the second embodiment will be described with reference toFIG.3AandFIG.3B.

FIG.3Ais a graph illustrating a simulation result related to angle dependency of antenna gains of the antenna device according to the second embodiment and an antenna device according to a comparative example. The horizontal axis represents a tilt angle in the x-axis direction from the normal direction (the positive direction of the z-axis) of the ground plane31by using the unit “°”, and the vertical axis thereof represents an antenna gain by using the unit “dB”.

FIG.3Bis a schematic perspective view of an antenna device according to the comparative example. The antenna device according to the comparative example has the same configuration as a configuration in which the linear antennas15and the branch lines22are removed from the antenna device (FIG.2A,FIG.2B, andFIG.2C) according to the second embodiment. The antenna device according to the comparative example includes the power feeding element11and the parasitic element13. Note that in the second embodiment, the power feeding point12of the power feeding element11is positioned on the negative side of the x-axis from the geometric center of the power feeding element11, but in the comparative example, the power feeding point12is positioned on the positive side of the x-axis from the geometric center of the power feeding element11.

As illustrated inFIG.3A, in the antenna device according to the comparative example, a beam is not substantially tilted, but in the antenna device according to the second embodiment, the antenna gain has a maximum value in a direction in which an angle is approximately −30°. This means that a beam is tilted at approximately 30° on the negative side of the x-axis. Further, in the antenna device according to the second embodiment, the antenna gain is larger than or equal to 0 dB even in a direction in which the angle is −90°. By the simulation, it has been confirmed that a beam can be tilted by adding the linear antennas15to the patch antenna, as in the antenna device according to the second embodiment.

Next, a modified example of the second embodiment will be described. In the second embodiment, the horizontal portion15B of the linear antenna15extends from the vertical portion15A toward the geometric center of the power feeding element11. On the contrary, the horizontal portion15B may extend in a direction away from the geometric center of the power feeding element11.

Third Embodiment

Next, an antenna device according to a third embodiment will be described with reference toFIG.4. Hereinafter, the description of a configuration common to that of the antenna device (FIG.2A,FIG.2B, andFIG.2C) according to the second embodiment will be omitted.

FIG.4is a schematic perspective view of a main portion of an antenna device according to a third embodiment. In the second embodiment, the power feeding point12(FIG.2A) of the power feeding element11is positioned on the negative side of the x-axis from the geometric center of the power feeding element11. On the contrary, in the third embodiment, the power feeding point12is positioned on the positive side of the x-axis from the geometric center of the power feeding element11. In a plan view, the position of the power feeding point12and a position of the branch point23coincide with each other. The branch point23and the power feeding point12are connected to each other by the via conductor14. The main line21extends from the branch point23toward the positive direction of the x-axis, and one branch line22extends toward the negative direction. The one branch line22branches to two branch lines22at the branch point24, and each of the two branches is connected to the power feeding point16of the linear antenna15.

Next, an excellent effect of the third embodiment will be described. Also, in the third embodiment, an excellent effect similar to that in the second embodiment can be obtained. Additionally, in the third embodiment, a line length from the branch point23to the power feeding point12of the power feeding element11is substantially equal to a height of the via conductor14extending in the thickness direction of the substrate30(FIG.2B), and thus, is shorter than the line length from the branch point23to the power feeding point12in the second embodiment. The line length of the branch line22from the branch point23to the power feeding point16of the linear antenna15is longer than the line length of the branch line22(FIG.2A) in the second embodiment. For this reason, in the third embodiment, a difference between the line length from the branch point23to the power feeding point12of the power feeding element11and the line length from the branch point23to the power feeding point16of the linear antenna15is larger than a difference between the line lengths in the second embodiment. In a case where the difference between the line lengths is desired to be increased, the configuration of the third embodiment is more suitable than that of the second embodiment.

Fourth Embodiment

Next, an antenna device according to a fourth embodiment will be described with reference toFIG.5. Hereinafter, the description of a configuration common to that of the antenna device (FIG.2A,FIG.2B, andFIG.2C) according to the second embodiment will be omitted.

FIG.5is a schematic view illustrating planar positional relationships and shapes of the power feeding line20, the power feeding element11, and the linear antenna15of the antenna device according to the fourth embodiment. In the second embodiment (FIG.2A), the branch line22from the branch point23to the power feeding point16of the linear antenna15is a straight line, but in the fourth embodiment, the branch line22includes a meandering portion. For this reason, the line length of the branch line22from the branch point23to the power feeding point16of the linear antenna15is longer than the shortest distance from the branch point23to the power feeding point16of the linear antenna15. The main line21from the branch point23to the power feeding point12of the power feeding element11is a straight line.

Next, an excellent effect of the fourth embodiment will be described. Also, in the fourth embodiment, an excellent effect similar to that of the second embodiment can be obtained. In addition, in the fourth embodiment, the line length of the branch line22from the branch point23to the linear antenna15is longer than that in the second embodiment. As described in the first embodiment, in order to increase an impedance when the linear antenna15is viewed from the branch point23, it is preferable to set the line length of the branch line22from the branch point23to the power feeding point16to ¼ of the resonant wave length of the linear antenna15. In a case where a configuration is adopted in which the branch point23and the power feeding point16are connected to each other by a straight line, when a sufficient line length is not obtained, a part of the branch line22may be caused to meander as in the fourth embodiment. This makes it possible to sufficiently lengthen the line length of the branch line22from the branch point23to the power feeding point16. As a result, it is possible to obtain an excellent effect that the degree of freedom in design of a power feeding phase difference between the power feeding element11and the linear antenna15is increased.

Fifth Embodiment

Next, an antenna device according to a fifth embodiment will be described with reference to the drawings fromFIG.6AtoFIG.6C. Hereinafter, the description of a configuration common to that of the antenna device (FIG.2A,FIG.2B, andFIG.2C) according to the second embodiment will be omitted.

FIG.6Ais a cross-sectional view of the antenna device according to the fifth embodiment. In the second embodiment, the horizontal portion15B (FIG.2C) of the linear antenna15is disposed between the power feeding element11and the parasitic element13in the thickness direction of the substrate30. In contrast, in the fifth embodiment, the horizontal portion15B of the linear antenna15is disposed in the same layer as the parasitic element13. For this reason, the height of the linear antenna15when the ground plane31is used as a height reference is equal to the height from the ground plane31to the parasitic element13.

Next, an excellent effect of the fifth embodiment will be described. The linear antenna15according to the fifth embodiment has a large dimension in the height direction (z-axis direction), compared with the linear antenna15according to the second embodiment (FIG.2C). Components flowing in the height direction of the high-frequency electric current flowing through the linear antenna15contribute to the radiation electric field, and components flowing in the horizontal direction hardly contribute to the radiation electric field. In the fifth embodiment, the components that contribute to the radiation electric field among the high-frequency electric current flowing through the linear antenna15are larger than those in the second embodiment. For this reason, it is possible to increase an antenna gain of the linear antenna15.

In the fifth embodiment, since the horizontal portion15B of the linear antenna15is disposed in the same layer as the parasitic element13, the horizontal portion15B and the parasitic element13cannot be disposed to overlap each other in a plan view. For this reason, the length of the horizontal portion15B is limited by the positional relationship with the parasitic element13. When it is necessary to lengthen the horizontal portion15B to a position overlapping with the parasitic element13in relation to a target resonant wave length, the configuration of the second embodiment may be employed.

FIG.6Bis a cross-sectional view of an antenna device according to a modified example of the fifth embodiment. In the present modified example, the horizontal portion15B of the linear antenna15is disposed at a higher position than that of the parasitic element13. In the present modified example, the linear antenna15becomes higher than that in the fifth embodiment (FIG.6A). As a result, the antenna gain of the linear antenna15can be further increased. Further, in the present modified example, since the horizontal portion15B is disposed in a layer different from the parasitic element13, as in the case of the second embodiment, the horizontal portion15B and the parasitic element13can be arranged so as to overlap each other in a plan view. For this reason, it is possible to cope with the target resonant wave length of the linear antenna15more flexibly.

FIG.6Cis a cross-sectional view of an antenna device according to another modified example of the fifth embodiment. In the present modified example, instead of the horizontal portion (FIG.6A) of the linear antenna15of the fifth embodiment, a conductor pillar15C extending in a vertical direction with respect to the ground plane31is used. A conductor pillar15C is fixed to a land provided on the upper surface of the substrate30by using solder, for example. In the present modified example, the components in a height direction of a high-frequency electric current flowing through the linear antenna15become larger. As a result, it is possible to further increase the antenna gain of the linear antenna15.

Sixth Embodiment

Next, an antenna device according to a sixth embodiment will be described with reference toFIG.7AandFIG.7B. Hereinafter, the description of a configuration common to that of the antenna device according to the second embodiment (FIG.2A,FIG.2B, andFIG.2C) will be omitted.

FIG.7Ais a schematic perspective view of a main portion of an antenna device according to a sixth embodiment.FIG.7Bis a cross-sectional view perpendicular to the x-axis of the antenna device according to the sixth embodiment. In the sixth embodiment, the horizontal portion15B of one of the linear antennas15and the horizontal portion15B of the other of the linear antennas15are connected to each other at the tips thereof. That is, the two linear antennas15are connected to each other at the tips thereof. As described above, in the sixth embodiment, a loop antenna is constituted by the two linear antennas15. Since a magnitude of a high-frequency electric current is always 0 at the tip of the horizontal portion15B of each of the two linear antennas15, even in a configuration in which both of the tips are connected to each other, a high-frequency electric current similar to that in the case where both of the tips are not connected to each other flows through each of the linear antennas15.

In the sixth embodiment, an excellent effect similar to that in the second embodiment can be obtained. Further, in the sixth embodiment, the horizontal portion15B can be made longer than that in the second embodiment. Depending on the target resonant wave length, it may be preferable to adopt the configuration of the sixth embodiment.

Seventh Embodiment

Next, an antenna device according to a seventh embodiment will be described with reference toFIG.8. Hereinafter, the description of a configuration common to that of the antenna device according to the second embodiment (FIG.2A,FIG.2B, andFIG.2C) will be omitted.

FIG.8is a schematic perspective view of a main portion of the antenna device according to the seventh embodiment. The antenna device according to the second embodiment includes one composite antenna10(FIG.2A), but the antenna device according to the seventh embodiment includes two composite antennas10. A configuration of each of the composite antennas10is the same as the configuration of the composite antenna10according to the second embodiment. Directions of the two composite antennas are different from each other. That is, directions of vectors when the geometric centers of the power feeding elements11of the two composite antennas10are defined as start points, and the power feeding points12of the power feeding elements11are defined as end points differ between the two composite antennas10. For example, in one of the composite antennas10, the vector directed from the geometric center of the power feeding element11toward the power feeding point12is directed in the negative direction of the x-axis, and in the other composite antenna10, the vector is directed in the positive direction of the x-axis. Thus, a tilt direction of a beam of one of the composite antennas10is different from a tilt direction of a beam of the other of the composite antennas10.

A power feeding line20is provided for each of the two composite antennas10, and power is supplied to the composite antenna10through the power feeding line20. A radio frequency integrated circuit element (RFIC)45configured to transmit and receive a radio frequency signal is connected to two power feeding lines20with a switch element40interposed therebetween. The switch element40selects one composite antenna10from the two composite antennas10, and supplies power to the selected composite antenna10. Further, the switch element40can simultaneously supply power to both of the composite antennas10. It should be noted that a switch element may be provided corresponding to each of the two composite antennas10, and power may be supplied to the corresponding composite antennas10through the two switch elements.

Next, an excellent effect of the seventh embodiment will be described. In the seventh embodiment, a tilt direction of a beam can be switched by switching the composite antenna10to be selected by the switch element40. For example, in the antenna device illustrated inFIG.3A, one composite antenna10can cover a range of a tilt angle in the x-axis direction from 0° to −90°. In the seventh embodiment, by switching the composite antennas10, the tilt angle in the x-axis direction can cover a range equal to or larger than −90° and equal to or smaller than +90°. Further, by simultaneously selecting the two composite antennas10, it is possible to increase an antenna gain in the normal direction (the positive direction of the z-axis).

Next, a modified example of the seventh embodiment will be described. In the seventh embodiment, the two composite antennas are provided, but three or more composite antennas10may be provided. By making directions of vectors to be directed from the geometric centers of the power feeding elements11of the three or more composite antennas10toward the power feeding points12different from one another in the xy plane, it is possible to change an azimuth direction in which a beam is tilted in the xy plane.

Eighth Embodiment

Next, an antenna module according to an eighth embodiment will be described with reference toFIG.9.FIG.9is a cross-sectional view of the antenna module according to the eighth embodiment. The ground planes31and32are disposed in the inner layer of the substrate30. Further, the composite antenna having the same configuration as the composite antenna10(FIG.2A,FIG.2B, andFIG.2C) of the antenna device according to the second embodiment is provided in or on the substrate30. The radio frequency integrated circuit element45is mounted on the lower surface of the substrate30.

The radio frequency integrated circuit element45supplies a radio frequency signal including information to be transmitted to the composite antenna10. Further, when a radio frequency signal received by the composite antenna10is inputted to the radio frequency integrated circuit element45, the radio frequency integrated circuit element45down-converts the input radio frequency signal to an intermediate frequency signal.

Next, an excellent effect of the eighth embodiment will be described. In the eighth embodiment, the composite antenna10having the same configuration as that of the composite antenna of the antenna device according to the second embodiment is used, and therefore, it is possible to tilt a beam.

Next, a modified example of the eighth embodiment will be described. In the eighth embodiment, the composite antenna10having the same configuration as that of the composite antenna of the antenna device according to the second embodiment has been used, but in another case, the composite antenna10having the same configuration as that of the composite antenna10according to any one of the first embodiment to the seventh embodiment may be used.

Ninth Embodiment

Next, a communication device according to a ninth embodiment will be described with reference toFIG.10andFIG.11. In the ninth embodiment, a phased array antenna is configured of the composite antennas10of the antenna device according to any one of the first embodiment to the sixth embodiment.

FIG.10is a block diagram of the communication device according to the ninth embodiment. The communication device is installed in, for example, a mobile terminal such as a mobile phone, a smartphone, or a tablet terminal, a personal computer having a communication function, and the like. The communication device according to the ninth embodiment includes an antenna module50, and a baseband integrated circuit element (BBIC)46that performs baseband signal processing.

The antenna module50includes an antenna array formed of a plurality of composite antennas10, and the radio frequency integrated circuit element45. An intermediate frequency signal including information to be transmitted is inputted from the baseband integrated circuit element46to the radio frequency integrated circuit element45. The radio frequency integrated circuit element45up-converts the intermediate frequency signal inputted from the baseband integrated circuit element46into a radio frequency signal, and supplies the radio frequency signal to the plurality of composite antennas10.

Further, the radio frequency integrated circuit element45down-converts radio frequency signals received by the plurality of composite antennas10. The down-converted intermediate frequency signal is inputted from the radio frequency integrated circuit element45to the baseband integrated circuit element46. The baseband integrated circuit element46processes the down-converted intermediate frequency signal.

Next, description will be given of a transmission operation of the radio frequency integrated circuit element45. An intermediate frequency signal is inputted from the baseband integrated circuit element46to an up/down conversion mixer59with an intermediate frequency amplifier60interposed therebetween. The radio frequency signal up-converted by the up/down conversion mixer59is inputted to a power divider57with a transmission/reception selection switch58interposed therebetween. Each of the radio frequency signals divided by the power divider57is supplied to the corresponding composite antenna10among the plurality of composite antennas10via a phase shifter56, an attenuator55, a transmission/reception selection switch54, a power amplifier52, a transmission/reception selection switch51, and the power feeding line20. The phase shifter56, the attenuator55, the transmission/reception selection switch54, the power amplifier52, the transmission/reception selection switch51, and the power feeding line20which perform the processing of each of the radio frequency signals divided by the power divider57are provided for each of the composite antennas10.

Next, a reception operation of the radio frequency integrated circuit element45will be described. A radio frequency signal received by each of the plurality of composite antennas10is inputted to the power divider57via the power feeding line20, the transmission/reception selection switch51, a low-noise amplifier53, the transmission/reception selection switch54, the attenuator55, and the phase shifter56. The radio frequency signal synthesized by the power divider57is inputted to the up/down conversion mixer59via the transmission/reception selection switch58. The intermediate frequency signal down-converted by the up/down conversion mixer59is inputted to the baseband integrated circuit element46via the intermediate frequency amplifier60.

The radio frequency integrated circuit element45is provided as, for example, a one-chip integrated circuit component including the above-described functions. Alternatively, the phase shifter56, the attenuator55, the transmission/reception selection switch54, the power amplifier52, the low-noise amplifier53, and the transmission/reception selection switch51corresponding to the composite antenna10may be provided as a one-chip integrated circuit for each of the composite antennas10.

Next, an excellent effect of the ninth embodiment will be described with reference toFIG.11.FIG.11is a schematic view for explaining an excellent effect of the ninth embodiment. The plurality of composite antennas10is classified into a plurality of composite antennas10belonging to a first group71and a plurality of composite antennas10belonging to a second group72. The plurality of composite antennas10belonging to the same group has the same directional characteristics, and the composite antennas10belonging to different groups have different directional characteristics.

The plurality of composite antennas10belonging to the first group71is aligned in the x-axis direction, and the plurality of composite antennas10belonging to the second group72is also aligned in the x-axis direction. An xyz orthogonal coordinate system in which a front direction of the composite antenna10is the z-axis direction is defined. A main beam73of each of the plurality of composite antennas10belonging to the first group71is inclined in the negative direction of the x-axis from the front direction. A main beam74of each of the plurality of composite antennas10belonging to the second group72is inclined in the positive direction of the x-axis from the front direction.

When the plurality of composite antennas10belonging to the first group71is operated as a phased array antenna to perform beam steering, a main beam75indicating the maximum gain is inclined in the negative direction of the x-axis with respect to the front direction. Therefore, a coverage area of the phased array antenna formed of the plurality of composite antennas10belonging to the first group71is biased in the negative direction of the x-axis with the front direction being as a reference. Note that when the plurality of composite antennas10belonging to the first group71is operated, the composite antennas10belonging to the second group72are not operated.

On the contrary, when the plurality of composite antennas10belonging to the second group72is operated as a phased array antenna to perform beam steering, a main beam76indicating the maximum gain is inclined in the positive direction of the x-axis with respect to the front direction. Therefore, a coverage area of the phased array antenna formed of the plurality of composite antennas10belonging to the second group72is biased in the positive direction of the x-axis with the front direction being as a reference. Note that when the plurality of composite antennas10belonging to the second group72is operated, the composite antennas10belonging to the first group71are not operated.

Compared to a case of configuring the phased array antenna in which the plurality of antennas is used and whose main beam is directed in the front direction, the coverage area can be further widened by switching the groups of the composite antennas10to be operated in the ninth embodiment.

Next, a modified example of the ninth embodiment will be described. In the ninth embodiment, the phased array antenna is configured of the plurality of composite antennas10of the first group71whose main beam73is inclined in the negative direction of the x-axis, and the plurality of composite antennas10of the second group72whose main beam74is inclined in the positive direction of the x-axis. Further, a third group of a plurality of antennas whose main beam is directed in the front direction may be arranged. For example, in the ninth embodiment, when a sufficient antenna gain cannot be obtained when beam steering is performed in the front direction, it is possible to obtain a sufficient antenna gain in the front direction by providing the plurality of antennas belonging to the third group.

Tenth Embodiment

Next, a communication device according to a tenth embodiment will be described with reference toFIG.12AandFIG.12B. Hereinafter, the description of a configuration common to the antenna device (FIG.6A,FIG.6B, andFIG.6C) according to the sixth embodiment will be omitted.

FIG.12AandFIG.12Bare cross-sectional views respectively illustrating the antenna device of the communication device according to the tenth embodiment before and after the antenna device is fixed to the housing. In the sixth embodiment and the modified example thereof, the horizontal portion15B or the conductor pillar (conductor portion)15C connected to the tip of the vertical portion15A of the linear antenna15is provided in or on the substrate30of the antenna device. On the other hand, in the tenth embodiment, conductor pillars (conductor portions)15D are attached to an inner surface of the housing80with an adhesive or the like. As the conductor pillars15D, pogo pins are used. The pogo pin is expandable and contractable in a length direction by a spring or the like, and in a state in which the pogo pin is more contracted than its natural length, a force in an extending direction is generated.

In a state where the antenna device is housed in and fixed to the housing80, a tip of the conductor pillar15D on the housing80side contacts with a land provided at the tip of the vertical portion15A on the antenna device side. The vertical portion15A and the conductor pillar15D are electrically connected to each other with a land interposed therebetween. Accordingly, the linear antenna15is constituted by the vertical portion15A and the conductor pillar15D.

Next, an excellent effect of the tenth embodiment will be described. In the tenth embodiment, the conductor pillar15D attached to the housing80operates as the linear antenna15together with the vertical portion15A of the antenna device. Thus, the linear antenna15is longer than the vertical portion provided in the antenna device. As a result, it is possible to obtain an excellent effect that a gain of the linear antenna is improved.

Further, in the tenth embodiment, since the pogo pin is used as the conductor pillar15D, it is possible to flexibly cope with a variation in interval between the antenna device and the housing80.

Eleventh Embodiment

Next, a communication device according to an eleventh embodiment will be described with reference toFIG.13AandFIG.13B. Hereinafter, the description of a configuration common to the antenna device (FIG.12AandFIG.12B) according to the tenth embodiment will be omitted.

FIG.13AandFIG.13Bare cross-sectional views respectively illustrating an antenna device of the communication device according to the eleventh embodiment before and after the antenna device is fixed to the housing. In the eleventh embodiment, as in the case of the tenth embodiment, the conductor pillars15D are attached to the housing80. In the eleventh embodiment, conductor pillars (conductor portions)15E are further embedded in the housing80. The embedded conductor pillar15E is disposed along an extension line extending in an axial direction of the conductor pillar15D protruding from the inner surface of the housing80, and is electrically connected to the conductor pillar15D. The linear antenna15is constituted by the vertical portion15A, the conductor pillar and the conductor pillar15E of the antenna device.

Next, an excellent effect of the eleventh embodiment will be described. A substantial length of the linear antenna15according to the eleventh embodiment is substantially equal to the sum of the lengths of the vertical portion15A, the conductor pillar15D formed of the pogo pin, and the conductor pillar15E embedded in the housing80. Since the linear antenna in this embodiment is longer than that in the tenth embodiment, it is possible to obtain an excellent effect that the gain of the linear antenna15is further improved.

Next, a communication device according to a modified example of the eleventh embodiment will be described with reference toFIG.14AandFIG.14B.

FIG.14AandFIG.14Bare cross-sectional views respectively illustrating an antenna device of the communication device according to the modified example of the eleventh embodiment before and after the antenna device is fixed to the housing. In the present modified example, instead of the conductor pillars (FIG.15AandFIG.15B) embedded in the housing80of the communication device according to the eleventh embodiment, conductor members (conductor portions)15F disposed along the inner surface of the housing80are disposed. One end of the conductor member15F is connected to the conductor pillar15D. The conductor member15F extends from a connection point with the conductor pillar15D toward the parasitic element13in a plan view.

In the present modified example, the linear antenna15is constituted by the vertical portion15A, the conductor pillar and the conductor member15F. Also, in the present modified example, as in the case of the eleventh embodiment, the linear antenna15is longer than that in the case of the tenth embodiment, and thus, it is possible to obtain an excellent effect that the gain of the linear antenna15is further improved.

Twelfth Embodiment

Next, a communication device according to a twelfth embodiment will be described with reference toFIG.15AandFIG.15B. Hereinafter, the description of a configuration common to the antenna device (FIG.13AandFIG.13B) according to the eleventh embodiment will be omitted.

FIG.15AandFIG.15Bare cross-sectional views respectively illustrating an antenna device of the communication device according to the twelfth embodiment before and after the antenna device is fixed to the housing. In the eleventh embodiment, the vertical portion15A of the antenna device and the conductor pillar15E embedded in the housing80are connected to each other with the conductor pillar15D formed of the pogo pin interposed therebetween. In contrast, in the twelfth embodiment, the vertical portion15A on the antenna device side and the conductor pillar15E on the housing80side are connected to each other by solder15G. The solder15G electrically connects the vertical portion15A and the conductor pillar15E, and mechanically fixes the antenna device to the housing80.

Next, an excellent effect of the twelfth embodiment will be described. In the twelfth embodiment, the linear antenna15is constituted by the vertical portion15A, the solder15G, and the conductor pillar15E. Since the conductor pillar15E in the housing80operates as a part of the linear antenna15, the linear antenna15in the present embodiment is longer than the linear antenna15in the case where the linear antenna15is configured only by the vertical portion15A. As a result, it is possible to obtain an excellent effect that the gain of the linear antenna15is improved.

Further, in the twelfth embodiment, since the antenna device is fixed to the housing80by the solder15G, the antenna device can be positioned and fixed with high accuracy with respect to the housing80in a reflow process of the solder.

It will be appreciated that the embodiments described above are illustrative only, and that partial substitutions or combinations of the configurations described in different embodiments may be possible. Similar actions and effects according to a similar configuration of the plurality of embodiments will not be successively described for each embodiment. Further, the present invention is not limited to the above-described embodiments. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.10COMPOSITE ANTENNA11POWER FEEDING ELEMENT12POWER FEEDING POINT OF POWER FEEDING ELEMENT13PARASITIC ELEMENT14VIA CONDUCTOR15LINEAR ANTENNA15A VERTICAL PORTION15B HORIZONTAL PORTION15C CONDUCTOR PILLAR15D CONDUCTOR PILLAR (CONDUCTOR PORTION) ON HOUSING SIDE15E CONDUCTOR PILLAR (CONDUCTOR PORTION) EMBEDDED IN HOUSING15F CONDUCTOR MEMBER (CONDUCTOR PORTION)15G SOLDER16POWER FEEDING POINT OF LINEAR ANTENNA17VIA CONDUCTOR20POWER FEEDING LINE21MAIN LINE22BRANCH LINE23,24BRANCH POINT30SUBSTRATE31,32GROUND PLANE40SWITCH ELEMENT45RADIO FREQUENCY INTEGRATED CIRCUIT ELEMENT46BASEBAND INTEGRATED CIRCUIT ELEMENT50ANTENNA MODULE51TRANSMISSION/RECEPTION SELECTION SWITCH52POWER AMPLIFIER53LOW-NOISE AMPLIFIER54TRANSMISSION/RECEPTION SELECTION SWITCH55ATTENUATOR56PHASE SHIFTER57POWER DIVIDER58TRANSMISSION/RECEPTION SELECTION SWITCH59UP/DOWN CONVERSION MIXER60INTERMEDIATE FREQUENCY AMPLIFIER71FIRST GROUP72SECOND GROUP73,74,75,76MAIN BEAM80HOUSINGEI RADIATION ELECTRIC FIELD BY ELECTRIC CURRENTEM RADIATION ELECTRIC FIELD BY MAGNETIC CURRENTIs ELECTRIC CURRENT SERVING AS WAVE SOURCEMs MAGNETIC CURRENT SERVING AS WAVE SOURCE