Patent Grant
12142827
The present disclosure relates to an antenna module and a communication device mounted with the antenna module and more particularly to a structure of an antenna module that improves antenna characteristics.
In Japanese Unexamined Patent Application Publication No. 2018-148290 (Patent Document 1), an antenna device in which a plurality of tabular radiation elements (patch antennas) are formed on a rectangular substrate is disclosed.
In such patch antennas as disclosed in Patent Document 1, a tabular ground electrode is provided so as to face the radiation elements and radio waves are radiated by way of electromagnetic field coupling between the radiation elements and the ground electrode.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2018-148290
Such an antenna device as disclosed in Japanese Unexamined Patent Application Publication No. 2018-148290 (Patent Document 1) is used in a portable terminal such as a cellular phone or a smartphone, for instance. For such a portable terminal, there are still great demands for reduction in size and thickness and further reduction in size of an antenna device built in the portable terminal is required accordingly. In recent years, particularly, there has been a tendency in which a region in a casing where the antenna device can be placed is restricted with enlargement of screens of smartphones and thus the antenna device may be placed in a narrow region on a side face of the casing, for instance.
In order to attain desired antenna characteristics in a patch antenna, ideally, it is necessary to provide a ground electrode having a sufficiently large area, compared with a radiation element. In case where the antenna device is placed in such a restricted narrow region as described above, however, it may be impossible to ensure the sufficiently large area of the ground electrode, compared with the radiation element. Meanwhile, it may be impossible to attain a symmetrical shape of the ground electrode, depending on an installation site of the antenna device or positional relation thereof with peripheral instruments. There is a fear, as recognized by the present inventors, that such restrictions on the size and shape of the ground electrode may cause turbulence of electric lines of force between the radiation elements and the ground electrode and may influence antenna characteristics such as gain, frequency band, or directivity.
The present disclosure has been made in order to solve such problems, as well as other problems, and aims at maintaining satisfactory antenna characteristics in an antenna module in which a patch antenna is formed and in which the size and/or shape of the ground electrode is restricted.
An antenna module according to a first aspect of the present disclosure includes a dielectric substrate including a plurality of dielectric layers that are laminated, and a radiation element, a ground electrode, and peripheral electrodes that are disposed in or on the dielectric substrate. The radiation element is configured to radiate radio waves in a first polarization direction. The ground electrode is positioned so as to face the radiation element. The peripheral electrodes are arranged in a plurality of layers between the radiation element and the ground electrode and are electrically connected to the ground electrode. The peripheral electrodes are symmetrically positioned with respect to at least one of a first direction parallel to the first polarization direction or a second direction orthogonal to the first polarization direction.
An antenna module according to a second aspect of the present disclosure includes a dielectric substrate including a plurality of dielectric layers that are laminated, and a first radiation element, a second radiation element, a ground electrode, and peripheral electrodes that are disposed in or on the dielectric substrate. The first radiation element and the second radiation element are positioned so as to adjoin each other. The ground electrode is positioned so as to face the first radiation element, and the second radiation element. The peripheral electrodes are arranged in a plurality of layers between the first radiation element and the ground electrode and a plurality of layers between the second radiation element and the ground electrode and are electrically connected to the ground electrode. The peripheral electrodes are symmetrically positioned with respect to at least one of a first direction parallel to a polarization direction of radiated radio waves or a second direction orthogonal to the polarization direction, for each of the first, radiation element and the second radiation element.
A circuit board according to a third aspect of the present disclosure is a device to feed radio frequency signals to a radiation element and includes a dielectric substrate including a plurality of dielectric layers that, are laminated, a ground electrode, and peripheral electrodes. The radiation element radiates radio waves in a first polarization direction. The ground electrode is positioned to face the radiation element. The peripheral electrodes are arranged in a plurality of layers between the radiation element and the ground electrode and are electrically connected to the ground electrode. The peripheral electrodes are symmetrically positioned with respect to at least one of a first direction parallel to the first polarization direction or a second direction orthogonal to the first polarization direction.
In the antenna module and the circuit board according to the present disclosure, the peripheral electrodes electrically connected to the ground electrode are placed in the plurality of layers of the dielectric substrate between the radiation element and the ground electrode. Further, the peripheral electrodes are placed at the positions that are symmetrical with respect to at least either of the first direction parallel to the polarization direction of the radiation element and the second direction orthogonal to the first direction. By the placement of the peripheral electrodes at the positions that are symmetrical with respect to the radiation element, the electric lines of force generated in the radiation element can be homogenized in this manner and therefore the deterioration in the antenna characteristics on condition that the size and/or shape of the ground electrode is restricted can be suppressed.
Hereinbelow, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, identical components or corresponding components are provided with identical reference characters and description thereof will not be iterated.
(Basic Configuration of Communication Device)
In reference to
In
The RFIC 110 includes switches 111A to HID, 113A to 113D, and 117, power amplifiers 112AT to 112DT, low-noise amplifiers 112/AR to 112DR, attenuators 114A to 114D, phase shifters 115A to 115D, a signal synthesizer/branching filter 116, a mixer 118, and an amplifier circuit 119.
For transmission of the radio frequency signals, the switches 111A to 111D and 113A to 113D are switched to states that select the power amplifiers 112AT to 112D7 and the switch 117 is connected to a transmitting-side amplifier in the amplifier circuit 119. For reception of the radio frequency signals, the switches 111A to HID and 113A to 113D are switched to states that select the low-noise amplifiers 112AR to 112DR and the switch 117 is connected to a receiving-side amplifier in the amplifier circuit 119.
The signals transferred from the BBIC 200 are amplified by the amplifier circuit 119 and are up-converted by the mixer 118. Transmission signals that are the up-converted radio frequency signals are branched into four parts by the signal synthesizer/branching filter 116, are passed through four signal paths, and are respectively fed into the different feed elements 121. Then, directivity of the antenna device 120 can be adjusted via individual phase adjustments made by the phase shifters 115A to 115D provided respectively in the signal paths.
Reception signals that are the radio frequency signals received by the feed elements 121 are respectively passed through the four different signal paths and are multiplexed by the signal synthesizer/branching filter 116. The multiplexed reception signals are down-converted by the mixer 118, are amplified by the amplifier circuit 119, and are transferred to the BBIC 200.
The RFIC 110 is formed as a one-chip integrated-circuit component including an above-described circuit configuration, for instance. Alternatively, circuitry components (switch, power amplifier, low-noise amplifier, attenuator, and phase shifter) corresponding to each of the feed elements 121 in the RFIC 110 may be separately, or in sub groups, formed as one-chip integrated-circuit component for the corresponding feed element 121.
With reference to
In reference to
The dielectric substrate 130 is a low temperature co-fired ceramics (LTCC) multilayer substrate, a multilayer resin substrate that is formed of a lamination of a plurality of resin layers made of resin such as epoxy or polyimide, a multilayer resin substrate that is formed of a lamination of a plurality of resin layers made of liquid crystal polymer (LCP) having a lower permittivity, a multilayer resin substrate that is formed of a lamination of a plurality of resin layers made of fluorine-based resin, or a ceramics multilayer substrate other than LTCC, for instance.
The dielectric substrate 130 has a substantially rectangular shape arid has the feed element 121 placed in a layer (upside layer) near to a top surface 131 (surface facing in the positive direction along the Z axis) thereof. The feed element 121 may be embodied so as to be exposed on a surface of the dielectric substrate 130 or may be placed within an inner layer in the dielectric substrate 13C as shown in the example of
In a layer (downside layer) closer to a bottom surface 132 (surface facing in the negative direction along the Z axis) than the feed element 121 in the dielectric substrate 130, the tabular (or flat) ground electrode GND2 is placed so as to face the feed element 121. The ground electrode GND1 is placed in a layer between the feed element 121 and the ground electrode GND2.
A layer between the ground electrode GND1 and the ground electrode GND2 is used as a wiring region. In the wiring region, a wiring pattern 170 is placed, the wiring pattern 170 forming the feeder wiring to feed the radio frequency signals to the radiation element, stubs and filters to be connected to the feeder wiring, connection wiring to be connected to other electronic components, and the like. Once again “wiring” should be construed and a one or more electrically conductive paths, and not necessarily a “wire” of any particular gauge. Unnecessary coupling between the feed element 121 and the wiring pattern 170 can be suppressed by formation of the wiring region in the dielectric layer opposed to the feed element 121 with respect to the ground electrode GND1 in this manner.
Below the bottom surface 132 of the dielectric substrate 130, the RFIC 110 is mounted with solder bumps 100 interposed therebetween. The RFIC 110 may be connected to the dielectric substrate 130 with use of multi-pole connectors instead of solder connection.
The radio frequency signals are fed from the RFIC 110 through the feeder wiring 140 to a feeding point SP1 of the feed element 121. The feeder wiring 140 rises from the RFIC 110 through the ground electrode GND2 and extends in the wiring region. Further, the feeder wiring 140 rises from immediately below the feed element 121 through the ground electrode GND1 and is connected to the feeding point SRI of the feed element 121.
In the example structure of
The peripheral electrodes 150 are formed in end portions of the dielectric substrate 130 and in a plurality of dielectric layers between the feed element 121 and the ground electrode GND1. In the antenna module 100, the peripheral electrodes 150 are placed along sides of the rectangular feed element 121 in plan view from the normal direction (positive direction along the Z axis) with respect to the dielectric substrate 130. The peripheral electrodes 150 placed along the sides are placed at positions that are symmetrical with respect to the polarization direction (Y-axis direction) of the feed element 121 and a direction (X-axis direction) orthogonal to the polarization direction.
In plan view of the dielectric substrate 130, the peripheral electrodes 150 are placed 30 as to be overlaid in a direction of the lamination (i.e., a footprint of one peripheral electrode 150 at least partially overlaps ail others). That is, the peripheral electrodes 150 form a virtual conductor wall along the sides of the dielectric substrate 130. The peripheral electrodes 150 adjoining in the direction of the lamination are electrically connected to each other by connecting conductors 151, sometimes referred to as vias 151. In this context, a “via” is a vertical structure extending between peripheral electrodes 150 and may be provided with an electrically conductive material so as to make an electrical connection between them. In this context the term “via” is a connecting conductor. Further, the peripheral electrodes 150 at bottom are electrically connected to the ground electrode GND1 by the connecting conductors 151. That is, the peripheral electrodes 150 substantially have a configuration equivalent to a configuration in which end portions of the ground electrode GND1 are extended in the direction of the lamination. Incidentally, the peripheral electrodes 150 need not have an identical shape, and respective sizes of the electrodes may be increased with approximation to the ground electrode GND1 in the direction of the lamination of the dielectric substrate 130, for instance.
In the antenna module 100, the connecting conductors 151 formed in the dielectric layers adjoining in the direction of the lamination are preferably placed so that successive connecting conductors 151 do not to overlap in plan view from the normal direction with respect to the dielectric substrate 130. Moreover, as seen from a side view, cross-section, a set of connecting conductors 151 are staggered so a first connecting conductor 151 is on a first side, a next connecting conductor 151 is on the other side, and then the next connecting conductor 151 after that is on the first side, and so on. Electrical conducting material (copper, typically) forming the connecting conductors 151 exhibits smaller compressibility than dielectric material, when being pressurized. Therefore, when the dielectric substrate 130 is pressed for pressure bonding of the dielectric layers in case where all the connecting conductors 151 in the layers are placed at the same positions in plan view from the normal direction with respect to the dielectric substrate 130, portions made of the connecting conductors 151 exhibit a smaller rate of decrease in thickness, compared with other dielectric portions, which may cause a variation in thickness in the entire dielectric substrate 130. Thus accuracy in thickness of the dielectric substrate 130 having undergone forming can be increased by placement of the connecting conductors 151 in the dielectric layers adjoining in the direction of the lamination in different positions as described above.
Electrical connections between the peripheral electrodes 150 themselves, and between the peripheral electrodes 150 and the ground electrode GND1 are not limited to direct connections through the connecting conductors 151 and may include a configuration in which some or all of the connections are attained by capacitance coupling.
From a patch antenna including such a tabular radiation element, radio waves are radiated by way of electromagnetic field coupling between the radiation element and the ground electrode. In order to attain desired antenna characteristics, the ground electrode has a sufficiently large area, compared with the radiation element.
On the other hand, for portable terminals such as cellular phones or smartphones in which patch antennas are used, there are still great demands for reduction in size and thickness, so that further reduction in size of antenna devices built in the portable terminals is required.
In a situation where the antenna device is placed in a limited space in a casing, however, it may be impossible to ensure the sufficiently large area of the ground electrode, compared with the radiation element. Meanwhile, it may be impossible to attain a symmetrical shape of the ground electrode, depending on an installation site of the antenna device or positional relation thereof with peripheral instruments. There is a concern that such restrictions on the size and shape of the ground electrode may cause turbulence of electric lines of force between the radiation element and the ground electrode and may influence the antenna characteristics such as gain, frequency band, or directivity.
In a case where the ground electrode GND1 has a sufficiently large area compared with the feed element 121, electric lines of force are given and received on a surface of the ground electrode GND1 facing the feed element 121. In case where the sufficient area of the ground electrode GND1 cannot be ensured, however, a portion of the electric lines of force may go around onto a back surface of the ground electrode GND1, as illustrated in
In the antenna module 100 of Embodiment 1, the peripheral electrodes 150 electrically connected to the ground electrode GND1 are placed in the layers between the feed element 121 and the ground electrode GND1, as in
The peripheral electrodes 150 are placed at positions that are symmetrical with respect to the polarization direction of the radio waves and/or the direction orthogonal to the polarization direction. Thus symmetry of the electric lines of force generated between the feed element 121 and the ground electrode GND1 can be improved, so that the variation in the polarization direction can be suppressed.
With a free space wavelength of the radio waves radiated from the feed element 121 defined as λo, the peripheral electrodes 150 are preferably provided on condition that a length (distance LG in
The antenna module 100A of
Therefore, the antenna module 100A has a configuration in which the feed element 121 is placed with a tilt of 45° around the Z axis with the surface center CP of the feed element 121 as the center in order that the distances from the surface center CP of the feed element 121 to the end portions of the ground electrode GND1 in the polarization direction may be ensured so as to be as long as possible. That is, the feeding point SP1 is placed at a position offset from the surface center CP of the feed element 121 by equal distances in the negative direction along the X axis and the positive direction along the Y axis. In the antenna module 100A, therefore, the polarization direction is a direction (direction along a chain line CL1 in
In the antenna module 100A, the feed element 121 is made to protrude from an extent of the ground electrode GND1 (that is, an extent of the dielectric substrate 130) as a result of the tilting of the feed element 121 and thus four corner portions of the square feed element 121 are cut off so that the feed element 121 is substantially shaped like an octagon.
In the antenna module 100A, peripheral electrodes 150A that are substantially shaped like right triangles are placed along sides of the feed element 121 that extend along the polarization direction and sides thereof that are orthogonal to the polarization direction and in layers between the feed element 121 and the ground electrode GND1. The peripheral electrodes 150A are placed so as to have hypotenuses facing in a first direction parallel to the polarization direction or in a second direction orthogonal to the polarization direction. Such placement of the peripheral electrodes 150A at positions that are symmetrical with respect to the polarization direction of the radio waves and/or the direction orthogonal to the polarization direction increases the degree of the coupling between the feed element 121 and the ground electrode GND1 and improves the symmetry of electric lines of force generated between the feed element 121 and the ground electrode GND1, so that the deterioration in the antenna characteristics can be suppressed.
Though the peripheral electrodes 150A substantially shaped like the right triangle are illustrated in
(Comparison of Antenna Characteristics)
With use of
In an antenna module 100#1 of Comparative example 1, in reference to
In both of the antenna module 100A and the antenna module 100#1 of Comparative example 1, a dimension of the ground electrode GND1 along the Y-axis direction is smaller than a dimension thereof along the X-axis direction and a shape of the ground electrode is asymmetrical with respect to the polarization direction passing through the surface center CP of the feed element 121. Accordingly, a current distribution in the ground electrode of the antenna module 100#1 is shaped like a distorted ellipse having a minor axis along the Y-axis direction. In the antenna module 100A of Embodiment 1, by contrast, the peripheral electrodes 150A are placed at the positions that are symmetrical with respect to the polarization direction and the direction orthogonal to the polarization direction. Accordingly, it is observed that a current distribution in the ground electrode is closer to a true circle, compared with Comparative example 1, and that symmetry of currents is improved.
Thus the symmetrical placement of the peripheral electrodes electrically connected to the ground electrode enables suppression of the electric lines of force that are generated between the radiation element and the ground electrode and that go around onto the back surface and improvement in the symmetry of the electric lines of force even if the area of the ground electrode cannot be made sufficiently large, compared with the radiation element, and/or even if the ground electrode is asymmetrical with respect to the polarization direction passing through the surface center of the feed element. Thus, the deterioration in the antenna characteristics on condition that the size and/or shape of the ground electrode is restricted can be suppressed.
(Modification)
In such a configuration as well, the degree of the coupling between the feed element 121 and the ground electrode GND1 can be increased, so that the antenna characteristics can be improved. Further, dielectrics surrounded by the feed element 121, the ground electrode GND1, and a conductor wall of the peripheral electrodes 150B are reduced in amount, compared with the configuration of the antenna module 100 illustrated in
In Embodiment 1, the configuration in which the radiation element is singularly provided has been described. In Embodiment 2, a configuration in which peripheral electrodes are used in an array antenna provided with a plurality of radiation elements will be described.
The dielectric substrate 130A includes a first substrate 1301 and a second substrate 1302 that differ in the normal direction each other and that are tabular and curving portions 135 to connect the first substrate 1301 and the second substrate 1302.
The first substrate 1301 is a rectangular flat plate having the normal direction along the Z-axis direction and has four feed elements 121 arrayed thereon along the Y-axis direction. The RFIC 110 is placed on a back surface side of the first substrate 1301.
The second substrate 1302 is a flat plate having the normal direction along the X-axis direction and has four feed elements 121 arrayed thereon along the Y-axis direction. In the second substrate 1302, cutout portions 136 are formed in portions to be connected to the curving portions 135 and protruding portions 133 that protrude in the positive direction along the Z axis from the cutout, portions 136 are formed. At least a portion of each of the feed elements 121 arrayed on the second substrate 1302 is formed on the protruding portions 133.
Such a configuration is used for an instrument that is shaped like a thin plate, such as a smartphone for instance, and that radiates radio waves in two directions from a main surface side and a side surface side. In the antenna module 100D, the first substrate 1301 corresponds to the main surface side and the second substrate 1302 corresponds to the side surface side. On the second substrate 1302 placed on the side surface side in this configuration, the ground electrode GND1 having a sufficient area may not be ensured due to a restriction on a dimension of the instrument along a direction of thickness that is, the Z-axis direction. Additionally, the cutout portions 136 for connection to the curving portions 135 make the shape of the ground electrode GND1 asymmetrical with respect to the polarization direction passing through the surface center of each of the feed elements 121 and further make the shape of the ground electrode GND1 different for each of the feed elements 121. Then the antenna characteristics of the feed elements 121 of the array antenna become heterogeneous and thus the characteristics of the entire array antenna may be deteriorated.
In Embodiment 2, therefore, the antenna characteristics of the plurality of feed elements forming the array antenna are homogenized by application of such peripheral electrodes as described in Embodiment 1 to the array antenna, so that the antenna characteristics of the entire array antenna are improved.
More specifically, each of the feed elements 121 has the feeding point SP1 (that is, the polarization direction) placed with a tilt, of 45° with respect to the Z axis and further has an octagonal shape resulting from deletion of four corners. The peripheral electrodes 150A are placed at positions facing sides of the feed element 121 that extend along the polarization direction and sides thereof that extend along the direction orthogonal to the polarization direction and in layers between the feed element 121 and the ground electrode GND1. With such a configuration, the antenna characteristics can be homogenized by the peripheral electrodes even if a variation among the ground electrodes corresponding to the feed elements is brought about by restrictions on the sizes and/or shapes of the ground electrodes.
With regard to the return losses, solid lines LN20 and LN20# denote the feed element 121-1 and dashed lines LN21 and LN21# denote the feed element 121-2. With regard to the antenna gains, peak gains of a main lobe ML1 among the main lobe ML1 and side lobes SL1 and SL2 of radio waves radiated in the X-axis direction are illustrated. Regarding the antenna gains, a solid line LN25 denotes the antenna module 100D of Embodiment 2 and a dashed line LN26 denotes the antenna module 100#2 of Comparative example 2.
In the antenna module 1002 of Comparative example 2, in reference to
It is thus observed that the antenna module 100D (solid lines LN25) of Embodiment 2 is larger in the antenna gains in a pass band as well, compared with the antenna module 100#2 (dashed line LN26) of Comparative example 2, and improves the antenna characteristics.
As described above, the placement of the peripheral electrodes at the positions that are symmetrical with respect to the polarization direction and/or the direction orthogonal to the polarization direction for each of the radiation elements enables decrease in the variations in the antenna characteristics among the radiation elements and improvement in the antenna characteristics of the entire antenna module, even if the sizes and/or shapes of the ground electrodes with respect to the radiation elements are restricted in the antenna module in which the array antenna is formed.
(Modification 1)
In the antenna module 100D of Embodiment 2 illustrated in
Thus the commonality of the adjoining peripheral electrodes increases an area of the peripheral electrodes that receives the electric lines of force emitted from the feed elements and therefore enables suppression of the electric lines of force that go around onto the back surface of the ground electrode GND1. As a result, the deterioration in the antenna characteristics such as deterioration in the antenna gains, narrowing of the frequency band width, or the variation in the polarization direction can be further suppressed.
Though the commonality of some of the peripheral electrodes may deteriorate symmetry of a distribution of the electric lines of force in each feed element, sizes, shapes, and/or the like of the peripheral electrodes provided with no commonality may be appropriately adjusted in such a case.
(Modification 2)
In Modification 1, a configuration in which the peripheral electrodes for the adjoining feed elements are integrated by the separate connection electrodes has been described.
An antenna module 100D2 of Modification 2 illustrated in
In Embodiment 1 and Embodiment 2, the configurations in which radio waves having the single polarization direction are radiated from one radiation element have been described. In Embodiment 3, an example of a configuration with application of the peripheral electrodes to a so-called dual-polarization antenna module in which radio waves having two different polarization directions can be radiated from one radiation element will be described.
The feed element 121-2 is placed so as to be turned by 180° with respect to the adjoining feed element 121-1. The feed element 121-4 is placed so as to be turned by 180° with respect to the adjoining feed element 121-3. Radio frequency signals having inverted phases are fed to identical feeding points of the feed elements that are placed so as to be turned by 180° with respect to each other. The phases of the radio waves radiated from each feed element and having each polarization direction can be made to coincide by such phase adjustment. Further, cross polarization discrimination (XPD) can be improved by placement of the feed elements, placed so as to adjoin, with turning by 180°.
In the antenna module 100E as well, the peripheral electrodes 150A are placed at the positions that are symmetrical, with respect to the polarization direction and the direction orthogonal to the polarization direction, for each of the feed elements 121-1 to 121-4. Thus the variations in the antenna characteristics among the feed elements that are associated with the restrictions on the size and/or shape of the ground electrode GND1 can be decreased and the antenna characteristics of the entire antenna module can be improved.
In the dual-polarization antenna module as well, as described above, the antenna characteristics can be improved, even in presence of restrictions on the ground electrode, by the placement of the peripheral electrodes at the positions that are symmetrical with respect to the polarization direction and/or the direction orthogonal to the polarization direction for each of the radiation elements.
Though the example in which the peripheral electrodes are applied to the dual-polarization array antenna has been described in above description, the peripheral electrodes may be applied to the dual-polarization antenna module having a single radiation element as described in Embodiment 1.
In the embodiments described above, the configurations in which the radio waves radiated from the radiation elements have a single frequency band have been described. In Embodiment 4, a configuration with application of such peripheral electrodes as described above to a so-called dual-band antenna module In which radio waves having two different frequency bands can be radiated from each radiation element will be described.
The passive elements 122 are placed in layers between the feed elements 121A and the ground electrode GND1. Feeder wiring from the RFIC 110 is connected through the passive elements 122 to the feeding points SP1 and SP2 of the feed elements 121A. A dimension of the passive elements 122 in the polarization direction is greater than a dimension of the feed elements 121A in the polarization direction. Accordingly, a resonant frequency of the passive elements 122 is lower than a resonant frequency of the feed elements 121A. Feeding of radio frequency signals corresponding to the resonant frequency of the passive elements 122 causes the passive elements 122 to radiate radio waves that are lower in frequency band than from the feed elements 121A. That is, the antenna module 100F is the dual-band antenna module capable of radiating radio waves having two different frequency bands.
The feed elements 121A and the passive elements 122 are placed so that the polarization direction is tilted by 45° with respect to the Z-axis direction, due to the restriction on the size of the ground electrode GND1. Further, the passive elements 122 have an octagonal shape resulting from deletion of four corner portions that protrude from the ground electrode GND1.
Herein, the feed elements 121A on a higher-frequency side function as antennas by way of electromagnetic field coupling with the passive elements 122. Meanwhile, the passive elements 122 function as antennas by way of electromagnetic field coupling with the ground electrode GND1. For the ground electrode GND1, as with Embodiment 2 and Embodiment 3, a sufficient area is not ensured with respect to the passive elements 122 and a shape that is asymmetrical with respect to the polarization direction passing through a surface center of a passive element 122 is further provided.
In the antenna module 100F, therefore, the peripheral electrodes 150A are placed at positions facing sides of the passive elements 122 that extend along the polarization direction and sides thereof that, extend along the direction orthogonal to the polarization direction and in layers between the passive elements 122 and the ground electrode GND1. Thus the variations in the antenna characteristics among the passive elements 122 can be decreased and the antenna characteristics of the entire antenna module can be improved.
In the antenna module 100F, though an example of a configuration in which the feed elements and the passive elements are provided as the radiation elements has been described, both the two radiation elements may be feed elements.
(Modification 3)
(Modification 4)
The area for the peripheral electrodes is preferably increased in order that the electric lines of force going around onto the back surface of the ground electrode may be suppressed with use of the peripheral electrodes. On the other hand, in case where other elements such as stubs or filters are formed in the dielectric substrate, a layout of those elements may be restricted by increase in the size of the peripheral electrodes.
In Embodiment 5, a configuration that may attain both ensuring of freedom of layout in the dielectric substrate and reduction in the electric lines of force going around onto the back surface of the substrate will be described.
In reference to
With use of
In
As illustrated in
A graph of
In a region with the angles greater than 100° and a region with the angles less than −100°, the gains of the antenna module 100G are slightly greater than the gains of the antenna module 100A. This indicates enhancement of going around onto the back surface of the dielectric substrate. That is, the case with the antenna module 100G attains the directivity within a targeted specification range in general, though exhibiting a slight reduction, compared with the antenna module 100A.
As described above, the antenna module 100G of Embodiment 5 is slightly inferior in the antenna characteristics to the antenna module 100A illustrated in
Which of the configuration of the antenna module 100A and the configuration of the antenna module 100G is to be adopted is appropriately selected in accordance with the required antenna characteristics and presence or absence of elements to be provided in the antenna module.
In the embodiments and modifications that have been described above, the configurations in which the radiation elements and the ground electrode are placed on the same dielectric substrate have been described. The radiation elements, however, may have a configuration in which the radiation elements are formed on a dielectric substrate differing from a dielectric substrate where the other elements are formed.
A bottom surface of the dielectric substrate 130B is placed so as to face a top surface of the dielectric substrate 130C in the circuit board 300. The feeder wiring 140 is connected to the feed element 121 through a connection terminal 161 placed between the dielectric substrate 130B and the dielectric substrate 130C. A solder bump, a connector, or a connecting cable is used as the connection terminal 161.
Thus freedom of instrument placement in a communication device can be increased by the configuration in which the circuit board to be provided with the RFIC and the dielectric substrate to toe formed with the radiation element are formed as separate substrates. For instance, a configuration in which the circuit board is placed on a motherboard and in which the radiation element are placed in a casing may be adopted.
It is to be understood that the embodiments disclosed herein are exemplary in all respects and are not restrictive. A scope of the present disclosure is intended to be designated by the claims instead of the description of embodiments described above and to encompass all modifications within purport and a scope that are equivalent to the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-177383 | Sep 2019 | JP | national |
The present application is a continuation application of International Patent Application No. PCT/JP2020/026388, filed Jul. 6, 2020, which claims priority to Japanese Patent Application No. 2019-177383, filed Sep. 27, 2019, the entire contents of each of which being incorporated herein by reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 20150214625 | Sawa | Jul 2015 | A1 |
| 20150315397 | Toyoda | Nov 2015 | A1 |
| 20160315397 | Sawa | Oct 2016 | A1 |
| 20190098750 | Woo | Mar 2019 | A1 |
| Number | Date | Country |
|---|---|---|
| 109546326 | Mar 2019 | CN |
| 110224222 | Sep 2019 | CN |
| 2018-148290 | Sep 2018 | JP |
| 2016153459 | Sep 2016 | WO |
| Entry |
|---|
| International Search Report and Written Opinion mailed on Sep. 24, 2020, received for PCT Application PCT/ JP2020/026388, Filed on Jul. 6, 2020, 11 pages including English Translation. |
| Chinese Office Action issued Jul. 18, 2022, in Chinese Application No. 202080067617.9. |
| Office Action issued Dec. 7, 2022 in German Patent Application No. 11 2020 003 999.4, 6 pages. |
| Chinese Office Action issued Dec. 21, 2022, in corresponding Chinese Patent Application 202080067617.9, 9pp. |
| Number | Date | Country | |
|---|---|---|---|
| 20220216605 A1 | Jul 2022 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2020/026388 | Jul 2020 | WO |
| Child | 17703984 | US |
