Patent Grant
10218071
The present invention relates to an antenna and an electronic device.
It has become clear that periodically arranging a conductor pattern having a specific structure (hereunder denoted as a metamaterial) allows the propagation characteristics of electromagnetic waves to be controlled. The metamaterial known as the most basic components is a split ring part resonator using a C-shaped split ring part, in which a circular conductor is cut at a portion in the circumferential direction. A split ring part resonator is able to control the effective magnetic permeability by interacting with a magnetic field.
In electronic devices having a communication function, miniaturization is always desired. Accordingly, miniaturization of the antenna that performs the communication is also demanded. Therefore, techniques for miniaturization of the antenna by utilizing a split ring part resonator are being proposed.
Non-Patent Document 1 discloses a technique for miniaturizing a monopole antenna by making the effective magnetic permeance large by arranging a split ring part resonator in the vicinity of the monopole antenna.
Non-Patent Document 2 discloses a technique for miniaturizing a patch antenna by making the effective magnetic permeance large by periodically arranging a split ring part resonator in the region between the patch and the ground plane of a patch antenna.
However, in both of the antennas disclosed in Non-Patent Documents 1 and 2, it is necessary to arrange the split ring part resonator that is separately provided for the monopole antenna or the patch antenna, perpendicularly with respect to the ground plane. Split ring part resonators arranged perpendicularly with respect to the ground plane cannot be integrally manufactured with the ground plane in a normal printed substrate manufacturing process. Consequently, there is a problem in that the manufacturing costs increase.
In the antenna disclosed in Non-Patent Document 2, by applying a split ring part resonator to a patch antenna that originally has a narrow operating band, there is a problem in that the operating band becomes even narrower.
The present invention has been achieved in light of the situation mentioned above. An exemplary object of the present invention is to provide an antenna that operates over a wide band while being compact, and can also be manufactured at a low cost, and an electronic device including this antenna.
The present invention employs the following measures in order to solve the problems mentioned above.
An antenna according to an exemplary aspect of the present invention includes: a first conductor layer including a first split ring part surrounding a first opening part, the first split ring part having a first split part provided at a portion in a circumferential direction, the first split ring part being continuous in an approximate C-shape; a second conductor layer including a second split ring part opposing the first split ring part, the second split ring part surrounding a second opening part, the second split ring part having a second split part at a portion in a circumferential direction, the second split ring part being continuous in an approximate C-shape; a plurality of conductor vias provided with an interval in a circumferential direction of the first split part and the second split part, the conductor vias electrically connecting the first split ring part and the second split ring part; and a power feed line provided on a conductor layer different from the first conductor layer, the power feed line having a first end and second end, the first end being electrically connected to at least one of the conductor vias, the second end spanning the first and the second opening parts and extending to a region opposing the first split ring part.
An electronic device according to an exemplary aspect of the present invention includes at least one antenna described above.
According to the present invention, a first conductor layer and a second conductor layer, which sandwich a dielectric layer and are opposing, respectively have a first split ring part and a second split ring part that are continuous in an approximate C-shape. By connecting the first split ring part and the second split ring part by means of conductor vias, a split ring part resonator itself can be made an antenna radiator. Consequently, an antenna can be formed at a low cost from just a dielectric multilayer substrate that, at the very least, includes a plurality of layers of conductor layers sandwiching a dielectric layer. Furthermore, such an antenna operates over a comparatively wide band since it does not use a patch antenna.
Hereunder, an antenna according to exemplary embodiments of the present invention is described with reference to the attached diagrams. However, the present invention is in no way limited to these exemplary embodiments.
As shown in
The first split ring part 1 and the second split ring part 2 sandwich the dielectric layers 9A and 9B, and are arranged such that at least a portion is mutually opposing.
A rectangular opening part 5a is formed in the first split ring part 1. A rectangular opening part 5b similar to the opening part 5a is formed in the second split ring part 2. The opening parts 5a and 5b are respectively formed such that they mutually overlap when viewed from a direction orthogonal to the surface of the dielectric multilayer substrates 7.
A split part (first split part) 6a and a split part (second split part) 6b, which are slot-shaped, are formed in the first split ring part 1 and the second split ring part 2. The split part 6a and the split part 6b connect the edges of the opening part 5a and the opening part 5b on the sides adjacent to the outer edges of the first split ring part 1 and the second split ring part 2, to the outer edges of the first split ring part 1 and the second split ring part 2.
At the periphery of the opening part 5a and the opening part 5b, a plurality of conductor vias 3 are formed such that they surround the opening part 5a and the opening part 5b when seen from a top view. The plurality of conductor vias 3 pass through the dielectric layers 9A and 9B and electrically connect the first split ring part 1 and the second split ring part 2.
In this manner, it is made a configuration in which the first split ring part 1 and the second split ring part 2 sandwich the dielectric layers 9A and 9B and are mutually opposed, and are electrically connected by the conductor vias 3. The first split ring part 1 surrounds the opening part 5a, and is continuous in an approximate C-shape and has the split part 6a formed at a portion in the circumferential direction. The second split ring part 2 surrounds the opening part 5b, and is continuous in an approximate C-shape and has the split part 6b formed at a portion in the circumferential direction.
One end 4a of the power feed line 4 is connected to at least one of the conductor vias 3. The other end 4b of the power feed line 4 spans the opening part 5a and the opening part 5b when seen from a top view and extends to a region that opposes the first split ring part 1 on the opposite side, and is connected to a RF circuit (not shown in the figure).
The first split ring part 1, the second split ring part 2, and the power feed line 4 are generally formed by copper foil. However, the first split ring part 1, the second split ring part 2, and the power feed line 4 may be formed by another material as long as it is conductive. The first split ring part 1, the second split ring part 2, and the power feed line 4 may respectively be the same material, or they may be different materials.
The conductor vias 3 are, in general, formed by plating through-holes that are formed in the dielectric multilayer substrate 7 by a drill. However, the conductor vias 3 may be of any configuration as long as the layers can be electrically connected. For example, the conductor vias 3 can also be configured using laser vias formed by a laser.
In
According to the antenna 10 of the configuration described above, there is formed a LC series resonant circuit (split ring part resonator) including an inductance generated by an electric current flowing in a ring shape in the first split ring part 1 and the second split ring part 2 along the edge of the opening parts 5a and 5b, and a capacitance generated in the split parts 6a and 6b. Consequently, the antenna 10 operates as an antenna near the resonance frequency. The split ring part resonator is supplied with a high-frequency signal from the RF circuit via the power feed line 4.
The resonance frequency of the split ring part resonator can be made a low frequency by increasing the inductance by making the size of the opening parts 5a and 5b larger and making the current path longer, or by increasing the capacitance by narrowing the spacing of the split parts 6a and 6b. In particular, in the method of narrowing the spacing of the split parts 6a and 6b, while the losses become larger due to the electric field being concentrated at the split parts 6a and 6b, the operating frequency can be made a low frequency without increasing the overall size. Consequently, this method is suitable for miniaturization.
The power feed line 4 forms a transmission line by electrically coupling to the first split ring part 1 in a region where it opposes the first split ring part 1. The characteristic impedance of this transmission line can be designed by the line width of the power feed line 4, or the layer spacing between the first split ring part 1 and the power feed line 4. Consequently, by matching the characteristic impedance of the transmission line with the impedance of the RF circuit, it becomes possible to supply the signal of the RF circuit to the antenna without reflections, and hence this is preferable. However, even in a case where the characteristic impedance of the transmission line is not matched with the impedance of the RF circuit, this does have any effect on the fundamental operation of the present exemplary embodiment.
At least one antenna 10 described above can be provided for an electronic device having a communication function. In such an electronic device, it becomes possible for the whole device to be made smaller since miniaturization of the antenna 10 can be achieved.
The configuration described in the foregoing exemplary embodiment is an example, and it is possible to realize application examples such as those described herein.
In the antenna 10 of the present exemplary embodiment, the impedances of the power feed line 4 and the antenna can be matched by changing the connection position between the power feed line 4 and the split ring part resonator. The connection position of
In the foregoing, a configuration in which the capacitance is increased by narrowing the spacing of the split parts 6a and 6b is described. As an alternative method of increasing the capacitance, for example as shown in
The power feed line 4 may be connected to a plurality of conductor vias 3. For example, a configuration as shown in
In
Furthermore, in
Moreover, it is preferable for the second split ring part 2 to be continuous in a C-shape. However, even if a portion of the second split ring part 2 is not continuous, it does not have any effect on the fundamental operation of the antenna 10 of the present exemplary embodiment. For example, a configuration in which a portion of the second split ring part 2 is not continuous in order to avoid other mounted components can be considered.
In
In
In
In
The dielectric multilayer substrate 7 may be configured by any type of material and formed by any type of process as long as it is a multilayer substrate.
For example, the dielectric multilayer substrate 7 may be a printed board using a glass epoxy resin. The dielectric multilayer substrate 7 may be an interposer substrate such as a LSI. The dielectric multilayer substrate 7 may be a module substrate using a ceramic material such as LTCC. The dielectric multilayer substrate 7 may of course be a semiconductor substrate such as silicon.
Here, a case where the antenna 10 of the present exemplary embodiment is formed in the dielectric multilayer substrate 7 is described as an example. However, as long as the respective components made from a conductor are arranged and connected as mentioned above, it is not required for the space between the respective components to necessarily be filled with a dielectric material. For example, a configuration in which the respective components are manufactured from sheet metal and the interval between the respective components is partially supported by a dielectric material support member can also be considered. In this case, the sections other than the dielectric material support member are hollow, and hence the dielectric loss is reduced and the radiation efficiency of the antenna can be improved.
The antenna 20 shown in
The third split ring part 21 is such that a rectangular-shaped opening part 5c is formed in the same manner as the first split ring part 1 and the second split ring part 2. The opening parts 5a, 5b, and 5c are arranged such that they respectively overlap when seen from a top view.
A slot-shaped split part (second split part) 6c is opening partly formed such that it overlaps with the split parts 6a and 6b when seen from a top view. The opening part 5c is joined with the outer edge of the third split ring part 21 by means of the split part 6c.
The third split ring part 21 is provided with a clearance 22 in the region to which the power feed line 4 extends. The third split ring part 21 and the power feed line 4 are insulated by means of the clearance 22.
The conductor vias 3 are arranged such that they surround the opening part 5a, 5b, and 5c when seen from a top view. The conductor vias 3 electrically connect the first split ring part 1, the second split ring part 2, and the third split ring part 21. In the antenna 20 of the present second exemplary embodiment, there is formed a LC series resonant circuit (split ring part resonator) including an inductance generated by an electric current flowing in a ring shape along the edge of the opening parts 5a, 5b, and 5c, and a capacitance generated in the split parts 6a, 6b, and 6c. Consequently, it operates as an antenna near the resonance frequency.
The power feed line 4 is connected to the third split ring part 21. Consequently, the power feed line 4 is able to supply a high-frequency signal from the RF circuit to the split ring part resonator.
The present exemplary embodiment represents a configuration in which the capacitances generated at the three split parts 6a, 6b, and 6c are connected in parallel. Consequently, in the present exemplary embodiment, the capacitance can be increased from the first exemplary embodiment by the amount of the split part 6c. Therefore, compared to the antenna 10 of the first exemplary embodiment, the antenna 20 of the present exemplary embodiment is able to make the resonance frequency a low frequency.
In
In
In
In
In this case, the power feed line 4 is to be connected to the third split ring part 21 provided for the same layer as the power feed line 4.
As shown in
In the antenna 30 shown in
In
For example, as shown in
In the case of
According to the present exemplary embodiment, since the antenna can be configured by two layers, the dielectric multilayer substrate 7 can be made thinner in comparison to the antenna 10 of the first exemplary embodiment.
In the antenna 40 shown in
The split ring resonator 41 interacts with a magnetic flux that passes through the opening parts 5a and 5b, and the effective magnetic permeability of the antenna can be controlled. In particular, since the effective magnetic permeability can be made a large value near the resonance frequency of the split ring resonator 41, the operating frequency of the antenna 40 can be made a low frequency.
The split ring resonator 41 is not necessarily limited to the shape of
Furthermore, in
The antenna 50 of the present exemplary embodiment includes a first antenna 51 and a second antenna 52 at the first split ring part 1 and the second split ring part 2 of the dielectric multilayer substrate 7. As a result of such a configuration, it can be used in communication methods that require a plurality of antennas such as MIMO (Multiple Input Multiple Output) for example.
In order to obtain a high throughput with MIMO, it is known that a low correlation coefficient between the antennas is desirable. Consequently, as shown in
Here, a case based on the first exemplary embodiment is described as an example. However, a configuration based on the other exemplary embodiments can of course also be considered.
Here, a case where two antennas are provided is described as an example. However, a configuration in which more than two antennas are provided can of course also be considered.
That is to say, the antenna 60 of the present exemplary embodiment includes an RF circuit 63 in the region of the second split ring part 2. It is configured such that the signals from the RF circuit 63 are input to the power feed line 4, and functions as a wireless module. The parent substrate 68 has functions other than wireless communication. Fixing screw holes 65 are provided in order to fix the antenna 60 to this parent substrate 68, and also to make an electrical connection between the antenna 60 and the parent substrate 68. The fixing screw holes 65 are provided in an area near an opposite side to the side where the opening part 5a, 5b of at least one of the first split ring part 1 and the second split ring part 2 is provided.
In the electronic device 70 shown in
The fixing screw holes 65 and the conductive screws 67 function as electrically connecting parts, thereby electrically connecting at least one of the first split ring part 1 and the second split ring part 2 of the antenna 60 and the ground plane 69 of the parent substrate 68. Consequently, it becomes possible to make the electric potential of both elements the same.
For example, in the case of a common substrate antenna such as a reverse F antenna, an antenna current flows to the whole ground plane of the antenna. Therefore, when the ground plane of the antenna and the ground plane of the parent substrate are electrically connected, the path of the antenna current changes, and hence the antenna characteristics become highly variable. In contrast, in the antenna 60 of the present exemplary embodiment, the antenna current is concentrated at the periphery of the opening parts 5a and 5b, and the antenna current at the position of the fixing screw holes 65 is comparatively small. Consequently, even in a case when it is connected to the parent substrate 68, the effect on the antenna current is small, and it becomes possible to suppress changes to the antenna characteristics.
In
Here, a case where two fixing screw holes 65 are provided is described as an example. However, there may be one fixing screw hole 65, or three or more.
Here, a case where the fixing screw holes 65 and the conductive screws 67 serve as electrically connecting parts is described as an example. However, the configuration of the electrically connecting parts is not necessarily limited to this, as long as they are provided in an area near an opposite side to the side where the opening part 5a, 5b of at least one of the first split ring part 1 and the second split ring part 2 is provided. For example, as shown in
In
In
Here, a case based on the third exemplary embodiment is described as an example. However, a configuration based on the other exemplary embodiments can of course also be considered.
The first split ring part 1 and the second split ring part 2 of the antenna 80 of the present exemplary embodiment have a first spacing 81a and a second spacing 81b formed such that they overlap with each other in plan view. In the same manner, the first split ring part 1 and the second split ring part 2 have a second first spacing 82a and a second second spacing 82b formed such that they overlap with each other in plan view.
A first chip component 83 is connected to the second spacing 81b so as to connect to both sides of the second split ring part 2, which is divided by the second spacing 81b. In the same manner, a second chip component 84 is connected to the second second spacing 82b so as to connect to both sides of the second split ring part 2, which is divided by the second second spacing 82b.
In the antenna 80 of the present exemplary embodiment, the impedances formed by the first chip component 83 and the second chip component 84 are further added in series to the split ring resonator of the antenna 30 of the third exemplary embodiment. Consequently, it becomes possible to change the resonance frequency of the split ring resonator.
For example, in a case where chip inductors are used as the first chip component 83 and the second chip component 84, the inductances are added in series to the split ring resonator. Consequently, the resonance frequency can be made a low frequency according to the values of the inductances.
For example, in a case where chip capacitors are used as the first chip component 83 and the second chip component 84, the capacitances are added in series to the split ring resonator. Consequently, the resonance frequency can be made a high frequency according to the values of the capacitances. Therefore, by appropriately selecting the impedances of the first chip component 83 and the second chip component 84, it becomes possible to easily adjust the operating frequency of the antenna 80.
If zero ohm resistances are used as the first chip component 83 and the second chip component 84, a series impedance is not added to the split ring resonator. As a result, the resonance frequency of the split ring resonator does not change. Consequently, in a case where it is not necessary to adjust the operating frequency of the antenna 80, zero ohm resistances may be selected as the first chip component 83 and the second chip component 84.
Here, a case where the first chip component 83 is connected to the second spacing 81b is described as an example. However, the first chip component 83 may be connected to one of the first spacing 81a and the second spacing 81b, or to both.
In the same manner, in
For example, as shown in
As shown in
Here, a case where two spacings are provided for each of the first split ring part 1 and the second split ring part 2 is described as an example. However, a single spacing may be provided for each of the first split ring part 1 and the second split ring part 2. For example, as shown in
As a result of such a configuration, the operating frequency of the antenna 80 can be adjusted in exactly the same manner as the case of
As the shape of the first split ring part 1 and the second split ring part 2, for example a configuration such as shown in
In the configuration of
Here, a case based on the third exemplary embodiment is described as an example. However, a configuration based on the other exemplary embodiments can of course also be considered. For example, as shown in
Naturally, the foregoing exemplary embodiments and the plurality of modified examples can be combined within a scope in which the contents thereof do not conflict. Furthermore, in the foregoing exemplary embodiments and the modified examples, the functions and the like of the respective components have been described in detail. The functions thereof can be changed to any type within a scope that satisfies the present invention.
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2011-182325, filed Aug. 24, 2011, and Japanese Patent Application No. 2012-024848, filed Feb. 8, 2012, the disclosure of which is incorporated herein in its entirety by reference.
The present invention can be applied to an antenna and an electronic device including an antenna. An antenna to which the present invention is applied, and an electronic device including this antenna, while being compact in size, operate over a broad band, and can be manufactured at a low cost.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-182325 | Aug 2011 | JP | national |
| 2012-024848 | Feb 2012 | JP | national |
The present application is a Continuation Application of U.S. patent application Ser. No. 14/239,527, filed on Feb. 18, 2014, which is based on International Application No. PCT/JP2012/071433, filed on Aug. 24, 2012, which is based on Japanese Patent Application No. 2011-182325, filed on Aug. 24, 2011, and Japanese Patent Application No. 2012-024848, filed on Feb. 8, 2012, the entire contents of which are incorporated herein by reference.
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| Number | Date | Country | |
|---|---|---|---|
| 20170040689 A1 | Feb 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14239527 | US | |
| Child | 15299125 | US |
