DIELECTRIC SUBSTRATE AND ANTENNA DEVICE
20170346180 · 2017-11-30
Inventors
Cpc classification
H01Q9/0407
ELECTRICITY
H01Q1/42
ELECTRICITY
International classification
H01Q1/52
ELECTRICITY
H01Q1/42
ELECTRICITY
Abstract
A dielectric substrate for transmitting a signal with a frequency F.sub.0 includes a dielectric and a copper film pattern arranged on a first surface of the dielectric. The copper film pattern has a first dimension L in a direction parallel to a propagation direction of an electromagnetic wave that has the frequency F.sub.0 and that propagates on the first surface, and the first dimension L is given by:
where ε.sub.r represents a relative permittivity of the dielectric, k represents a constant in a range of 0.15 to 0.70, and λ.sub.0 represents a free space wavelength of the signal.
Claims
1. A dielectric substrate for transmitting a signal with a frequency f.sub.0, the dielectric substrate comprising: a dielectric; and a copper film pattern arranged on a first surface of the dielectric, wherein the copper film pattern has a first dimension L in a direction parallel to a propagation direction of an electromagnetic wave that has the frequency F.sub.0 and that propagates on the first surface, and the first dimension L is given by:
2. The dielectric substrate according to claim 1, wherein the copper film pattern arranged on the first surface comprises a plurality of copper film patterns, and in the propagation direction of the electromagnetic wave, a distance between adjacent copper film patterns of the plurality of copper film patterns is smaller than or equal to λ.sub.0.
3. The dielectric substrate according to claim 1, wherein an antenna that radiates the signal with the frequency F.sub.0 is arranged on the first surface, and in the propagation direction of the electromagnetic wave, a distance between the antenna and the copper film pattern is smaller than or equal to 2λ.sub.0.
4. The dielectric substrate according to claim 3, wherein the antenna arranged on the first surface comprises a plurality of antennas, and the copper film pattern is arranged between the antennas.
5. The dielectric substrate according to claim 4, wherein the dielectric substrate is used in a radar device.
6. The dielectric substrate according to claim 1, wherein a transmission line for transmitting the signal with the frequency f.sub.0 is arranged on the first surface, and in the propagation direction of the electromagnetic wave, a distance between the transmission line and the copper film pattern is smaller than or equal to 2λ.sub.0.
7. The dielectric substrate according to claim 6, wherein the transmission line arranged on the first surface comprises a plurality of transmission lines, and the copper film pattern is arranged between the transmission lines.
8. The dielectric substrate according to claim 6, wherein the dielectric substrate is used in a radar device.
9. The dielectric substrate according to claim 1, wherein the copper film pattern has a second dimension in a direction orthogonal to the propagation direction of the electromagnetic wave that propagates on the first surface, and the second dimension is larger than λ.sub.0/2.
10. An antenna device comprising: an antenna that radiates signal with a frequency f.sub.0; and a dielectric substrate for transmitting the signal, the dielectric substrate having a dielectric and a copper film pattern arranged on a first surface of the dielectric, wherein the copper film pattern has a first dimension L in a direction parallel to a propagation direction of an electromagnetic wave that has the frequency f.sub.0 and that propagates on the first surface, and the first dimension L is given by:
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
[0033] Embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings. Each of the embodiments described below is an example, and the present disclosure is not limited to the embodiments. In the following description, the same or similar constituent elements are denoted by the same reference numerals.
First Embodiment
[0034]
[0035] The dielectric substrate 10 according to the present embodiment transmits signals with a frequency f.sub.0. The dielectric substrate 10 has a dielectric 101 and a copper film pattern 102. The dielectric substrate 10 may be used, for example, in a radar device.
[0036] As illustrated in
[0037] The first dimension L of the copper film pattern 102 is given by:
[0038] In equation (1), ε.sub.r represents a relative permittivity of the dielectric 101, k represents a constant in the range of 0.15 to 0.70, and λ.sub.0 represents a free space wavelength of signals transmitted on the dielectric substrate 10.
[0039] That is, in the present embodiment, the first dimension L of the copper film pattern 102 is determined by the frequency F.sub.0 of signals transmitted on the dielectric substrate 10 and the relative permittivity ε.sub.r of the dielectric 101.
[0040]
[0041] In this case, when the first dimension L of the copper film pattern 102 in the electromagnetic-wave propagation direction 103 is set to the value in equation (1), electromagnetic waves that have propagated along the respective paths 402 and 403 have phases that are opposite to each other path. Hence, when the electromagnetic waves that have propagated along the respective paths 402 and 403 propagate along one path again, that is, a path 404, the electromagnetic waves that have propagated along the respective paths 402 and 403 cancel each other out. Thus, the electromagnetic waves that propagate on the obverse surface of the dielectric substrate 10 attenuate on the path 404. As a result, the electromagnetic waves that propagate on the dielectric 101 are suppressed or reduced by the copper film pattern 102.
[0042] The present inventors analyzed the amount of attenuation of the electromagnetic waves that propagate on the obverse surface of the dielectric substrate 10 illustrated in
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[0044]
[0045] Also, in the electromagnetic-field simulation result illustrated in
[0046] In addition,
[0047] Thus, it can be understood from
[0048] As described above, in the present embodiment, the dielectric substrate 10 has the copper film pattern 102 on the obverse surface of the dielectric 101. Also, in accordance with equation (1), the first dimension L of the copper film pattern 102 in the propagation direction 103 of the electromagnetic waves on the obverse surface of the dielectric substrate 10 is set depending on the frequency f.sub.0 (i.e., the wavelength λ.sub.0) of the electromagnetic waves that propagate on the dielectric substrate 10. More specifically, the first dimension L is set so that the phases of electromagnetic waves that propagate along the path 402 above the copper film pattern 102 and the path 403 below the copper film pattern 102 after splitting thereto have opposite phases on the path 404.
[0049] With this arrangement, the dielectric substrate 10 makes it possible to suppress or reduce electromagnetic waves that propagate on the obverse surface of the dielectric substrate 10. Hence, for example, when the copper film pattern 102 is provided around an antenna or a transmission line on the dielectric substrate 10 according to the present embodiment, it is possible to suppress or reduce unwanted electromagnetic waves (unwanted radiation) from the antenna or the transmission line. Alternatively, when the copper film pattern 102 is provided between a plurality of antennas or between a plurality of transmission lines on the dielectric substrate 10 according to the present embodiment, it is possible to improve isolation between the antennas or between the transmission lines.
[0050] Also, according to the present embodiment, since the dielectric substrate 10 has the copper film pattern 102 on the obverse surface of the dielectric 101, it is possible to suppress or reduce unwanted electromagnetic waves that propagate on the obverse surface of the dielectric substrate 10. That is, in order to suppress or reduce the electromagnetic waves, the dielectric substrate 10 according to the present embodiment does not need to have an additional member, such as a conductive via as disclosed in Patent Document 1 or a radome as disclosed in Patent Document 2. Accordingly, for example, even when a control circuit or the like is mounted on a reverse surface of the dielectric substrate 10, it is possible to obtain an area for configuring the control circuit or the like. Hence, according to the present embodiment, even when a module including the dielectric substrate 10 is configured, the module can be miniaturized, and there are also an advantage in that the module can be produced at low cost.
[0051] Thus, according to the present embodiment, the dielectric substrate 10 makes it possible to suppress or reduce electromagnetic waves that propagate on the obverse surface of the dielectric substrate 10, while avoiding an increase in the structure size.
Variation of First Embodiment
[0052] The dielectric substrate 10 according to the present embodiment may have a configuration in which a ground pattern 601 is provided and a copper film pattern 102 is connected to the ground pattern 601 therearound, as illustrated in
[0053] In addition, the copper film pattern 102 on the dielectric substrate 10 according to the present embodiment has a second dimension W in a direction (a Y-axis direction) orthogonal to the electromagnetic-wave propagation direction 103, and the present embodiment is not limited to a case in which the second dimension W is substantially the same as that of the dielectric 101 (e.g., see
[0054] In addition, in the dielectric substrate 10 according to the present embodiment, a plurality of copper film patterns 102 may be arranged on the obverse surface of the dielectric 101, as illustrated in
[0055] Also, in the dielectric substrate 10 according to the present embodiment, the first dimension of the copper film pattern 102 in the electromagnetic-wave propagation direction 103 may be ununiform, as illustrated in
[0056] Also, in the dielectric substrate 10 according to the present embodiment, the copper film pattern 102 is not limited to a pattern that extends in the direction (the Y-axis direction) orthogonal to the electromagnetic-wave propagation direction 103 (the X-axis direction), as illustrated in
Second Embodiment
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[0058] The dielectric substrate 10 illustrated in
[0059] Also, in the electromagnetic-wave propagation direction 103, an arrangement distance 1201 between the copper film patterns 102A and 102B is smaller than or equal to λ.sub.0. Also, the first dimension L in a propagation direction 103 (i.e., in an X-axis direction) of electromagnetic waves on the copper film patterns 102A and 102B satisfies equation (1) noted above.
[0060] With this configuration, since electromagnetic waves can be suppressed or reduced in each of the copper film patterns 102 arranged on the obverse surface of the dielectric 101, the effect of suppressing or reducing electromagnetic waves that propagate on the obverse surface of the dielectric substrate 10 can be more enhanced than that in the first embodiment.
[0061] The shapes of the copper film patterns 102 do not necessarily have to be the same. For example, as illustrated in
Third Embodiment
[0062]
[0063] The dielectric substrate 10 illustrated in
[0064] The antenna 1501 radiates signals (radio waves) with a frequency f.sub.0. An arrangement distance 1502 between the antenna 1501 and a copper film pattern 102 (i.e., an arrangement distance in an X-axis direction in
[0065] With this configuration, when the copper film pattern 102 is provided on the obverse surface of the dielectric 101, unwanted radiation emitted from the antenna 1501 can be suppressed or reduced in the X-axis direction in
[0066] In the dielectric substrate 10 according to the present embodiment, for example, the antenna 1501 may be arranged between adjacent copper film patterns 102, as illustrated in
[0067] Also, the antenna 1501 arranged on the dielectric 101 according to the present embodiment is not limited to the configuration illustrated in
Fourth Embodiment
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[0069] The dielectric substrate 10 illustrated in
[0070] The transmission line 2001 transmits signals with a frequency f.sub.0. An arrangement distance 2002 between the transmission line 2001 and a copper film pattern 102 (i.e., an arrangement distance in an X-axis direction in
[0071] With this configuration, the copper film pattern 102 can suppress or reduce unwanted radiation emitted from the transmission line 2001 in the X-axis direction in
Fifth Embodiment
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[0073] The dielectric substrate 10 illustrated in
[0074] The following description will be given of an example in which the antenna 1501A is a transmitting antenna and the antenna 1501B is a receiving antenna. In this, in the X-axis direction in
[0075] In the present embodiment, a plurality of copper film patterns 102 may be arranged between the antenna 1501A and the antenna 1501B, as illustrated in
Sixth Embodiment
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[0077] The dielectric substrate 10 in
[0078] For example, when the copper film pattern 102 is provided between the transmission lines 2001A and 2001B, and different signals are transmitted through the transmission lines 2001A and 2001B, it is possible to suppress or reduce unwanted radiation emitted from each of the transmission lines 2001A and 2001B, and it is possible to reduce crosstalk noise.
[0079] In this case, a first dimension L of the copper film pattern 102 in an X-axis direction is determined by the frequency f.sub.0 of signals transmitted through the transmission line 2001A or 2001B (e.g., see equation (1)). For example, when the copper film pattern 102 is provided between the transmission lines 2001A and 2001B, signals with a frequency f.sub.0 are transmitted through the transmission line 2001A, and signals with a frequency f.sub.1 are transmitted through the transmission line 2001B, the copper film pattern 102 can suppress or reduce unwanted radiation emitted from the transmission line 2001A.
[0080] In the present embodiment, a plurality of copper film patterns 102 may be arranged between the transmission lines 2001A and 2001B, as in
[0081] The present disclosure can be realized by software, hardware, or software in cooperation with hardware.
[0082] Each functional block used in the description of each embodiment described above can be partly or entirely realized by an LSI such as an integrated circuit, and each process described in each embodiment may be controlled partly or entirely by the same LSI or a combination of LSIs. The LSI may be individually formed as chips, or one chip may be formed so as to include a part or all of the functional blocks. The LSI may include a data input and output coupled thereto. The LSI here may be referred to as an IC, a system LSI, a super LSI, or an ultra LSI depending on a difference in the degree of integration.
[0083] However, the technique of implementing an integrated circuit is not limited to the LSI and may be realized by using a dedicated circuit, a general-purpose processor, or a special-purpose processor. In addition, a field programmable gate array (FPGA) that can be programmed after the manufacture of the LSI or a reconfigurable processor in which the connections and the settings of circuit cells arranged inside the LSI can be reconfigured may be used. The present disclosure can be realized as digital processing or analogue processing.
[0084] If future integrated circuit technology replaces LSIs as a result of the advancement of semiconductor technology or other derivative technology, the functional blocks could be integrated using the future integrated circuit technology. Biotechnology can also be applied.
[0085] One aspect of the present disclosure can be applied to a dielectric substrate that transmits signals with a frequency F.sub.0 and that suppresses or reduces electromagnetic waves that propagate on an obverse surface of a dielectric substrate.