Communication module and electromagnetic flux control member

Abstract

To provide a communication module which is small in a size and can obtain a good gain.SOLUTION: A communication module has an electromagnetic flux control member having a first surface being a concave surface, and a second surface being a convex surface opposite to the first surface, and a primary radiator facing the first surface. The electromagnetic wave emitted from the primary radiator at an angle of 60° to 70° from the central axis CA1 of the electromagnetic wave is incident and refracted at the first surface, and is emitted and refracted at the second surface. When the angle between the traveling direction of the electromagnetic wave before the electromagnetic wave is incident and refracted at the first surface and the traveling direction of the electromagnetic wave that is incident and refracted at the first surface and travels inside the electromagnetic flux control member is A°, and the angle between the traveling direction of the electromagnetic wave traveling inside the electromagnetic flux control member and the traveling direction of the electromagnetic wave that is emitted and refracted at the second surface is B°, A / B is 1 to 2.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a communication module and an electromagnetic flux control member.

Background Art

[0002] A communication module having a wave source that emits electromagnetic waves and a member for controlling the electromagnetic waves emitted from the wave source is known. For example, the communication module disclosed in Patent Document 1 has a dielectric lens and a horn, and the dielectric lens is attached to the opening of the horn. The horn and the dielectric lens control the electromagnetic waves emitted from the wave source.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] FIG. 1 is a diagram schematically showing a horn antenna 1 which is a kind of communication module and the electromagnetic waves controlled by the horn antenna 1. As shown in FIG. 1, the horn antenna 1 has a wave source 10 for generating electromagnetic waves and a horn portion 20. Further, the horn antenna 1 also has a lens antenna 30 in addition to the horn portion 20. The horn portion 20 of the horn antenna 1 as described above has a certain length and size. Therefore, the horn antenna 1 becomes large-sized. If the horn portion 20 is removed from the horn antenna 1, it is considered that the communication module can be miniaturized. However, if this is done, the communication module may have insufficient control over the direction of the electromagnetic waves and the gain may decrease.

[0005] An object of the present invention is to provide a communication module that is small in size and can obtain good gain, and an electromagnetic flux control member used in the communication module.

Means for Solving the Problems

[0006] The present invention relates to the following communication module and an electromagnetic flux control member used in the communication module. [1] A communication module having an electromagnetic flux control member having a first surface that is a concave surface and a second surface that is a convex surface on the opposite side of the first surface, and a primary radiator facing the first surface, wherein an electromagnetic wave emitted at an angle of 60° to 70° from a central axis CA1 of the electromagnetic wave emitted from the primary radiator is incident and refracted on the first surface, and emitted and refracted on the second surface, and an angle between a traveling direction of the electromagnetic wave before being incident and refracted on the first surface and a traveling direction of the electromagnetic wave that is incident and refracted on the first surface and travels inside the electromagnetic flux control member is defined as A°, and an angle between a traveling direction of the electromagnetic wave that travels inside the electromagnetic flux control member and a traveling direction of the electromagnetic wave that is emitted and refracted on the second surface is defined as B°, and A / B is 1 to 2. [2] The communication module according to [1], wherein when a distance between an outer edge of the first surface and an outer edge of the second surface of the electromagnetic flux control member along a direction of a central axis CA2 of the electromagnetic flux control member is defined as Te, and a distance between a center of the first surface and a center of the second surface of the electromagnetic flux control member is defined as Tc, Te / Tc is 0.2 to 0.7. [3] The communication module according to [1] or [2], wherein when a plane including an emission surface of the primary radiator and perpendicular to a central axis CA1 of the electromagnetic wave emitted from the primary radiator is defined as a reference plane, a shortest distance between the reference plane and an outer edge of the first surface is defined as ODe, and a shortest distance between the reference plane and a center of the first surface is defined as ODc, ODe / ODc is 0 to 0.9. [4] An electromagnetic flux control member used in the communication module according to any one of [1] to [3].

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a communication module that is small in size and can obtain good gain, and an electromagnetic flux control member used for the communication module.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0009] [Communication Module] FIG. 2A schematically shows in cross-section a communication module 2 according to the present embodiment and the traveling direction of electromagnetic waves in the communication module 2. The communication module 2 includes a primary radiator 100 and an electromagnetic flux control member (lens antenna) 300. The cross-section of FIG. 2A is a cross-section including the central axis CA1 of the electromagnetic waves emitted from the primary radiator 100 and the central axis CA2 of the electromagnetic flux control member 300. Here, the central axis CA1 of the electromagnetic waves means the central electromagnetic waves of the three-dimensional emitted electromagnetic waves from the primary radiator 100.

[0010] The electromagnetic flux control member 300 has a first surface 310 that is concave and a second surface 320 that is convex on the opposite side of the first surface 310. In the communication module 2, the first surface 310 is a surface facing the primary radiator 100.

[0011] As shown in FIG. 2A, in the communication module 2, there is no horn portion of the horn antenna between the primary radiator 100 and the electromagnetic flux control member 300, and the communication module 2 is smaller than the horn antenna 1 (see FIG. 1 for comparison).

[0012] In such a communication module 2, the electromagnetic wave emitted at an angle of 60° to 70° from the central axis CA1 of the electromagnetic wave emitted from the primary radiator 100 is incident and refracted on the first surface 310, and is emitted and refracted on the second surface 320. Let the angle between the traveling direction of the electromagnetic wave before being incident and refracted on the first surface 310 and the traveling direction of the electromagnetic wave that is incident and refracted on the first surface 310 and travels in the electromagnetic flux control member 300 be A°, and the angle between the traveling direction of the electromagnetic wave traveling in the electromagnetic flux control member 300 and the traveling direction of the electromagnetic wave that is emitted and refracted on the second surface 320 be B°. When A / B is 1 to 2. In the communication module 2 in which the electromagnetic wave is controlled in this way, a good gain can be obtained. Details about the gain will be described later while showing the simulation. Hereinafter, A° and B° will be appropriately referred to as the angle change on the first surface 310 and the angle change on the second surface 320, respectively.

[0013] The communication module 2 may be used as a transmission module or as a reception module.

[0014] When the communication module 2 is used as a transmission module, the radially spreading electromagnetic wave from the primary radiator 100 is controlled by the electromagnetic flux control member 300 to become a substantially parallel electromagnetic wave and is emitted from the second surface 320. The electromagnetic wave controlled to be substantially parallel is received by a receiving unit at a distance. The substantially parallel electromagnetic wave is an electromagnetic wave within a range of an angle of ±5° with respect to the central axis CA1 of the electromagnetic wave.

[0015] On the other hand, when the communication module 2 is used as a reception module, the electromagnetic wave emitted from a transmitting unit at a distance is incident and refracted on the second surface 320, is emitted and refracted on the first surface 310, and converges on the primary radiator 100 and is received.

[0016] Hereinafter, the details of the primary radiator 100 and the electromagnetic flux control member 300 included in the communication module 2 will be described.

[0017] (Primary radiator) The primary radiator 100 may function as a transmission unit that transmits electromagnetic waves, or may function as a reception unit that receives electromagnetic waves. It is preferable that the primary radiator 100 can transmit or receive polarized waves.

[0018] The electromagnetic waves to be transmitted or received are not particularly limited, but are preferably radio waves, and more preferably millimeter waves, quasi-millimeter waves, or terahertz waves. More specifically, the band of the electromagnetic waves is preferably from 30 GHz to 3 THz (wavelength from about 10 mm to wavelength about 0.1 mm), and more preferably 30 GHz to 300 GHz. Examples of the primary radiator 100 include waveguides, patch antennas, etc. The primary radiator 100 has an emission surface from which electromagnetic waves are emitted. Examples of the emission surface of the primary radiator may include a virtual plane including an opening through which electromagnetic waves in the tubular portion of the waveguide are emitted to the outside, an emission surface from which electromagnetic waves of the patch antenna are emitted, etc.

[0019] (Electromagnetic flux control member) The electromagnetic flux control member 300 has a first surface 310 that is concave and a second surface 320 that is convex on the opposite side of the first surface 310. The electromagnetic flux control member 300 having such a first surface 310 and second surface 320 is in the shape of a meniscus lens.

[0020] In the present embodiment, the curvature of the second surface 320 may be larger than the curvature of the first surface 310, the curvature of the first surface 310 may be larger than the curvature of the second surface 320, or the curvature of the second surface 320 may be the same as the curvature of the first surface 310. In the present embodiment, the electromagnetic flux control member 300 as a whole may have a function of controlling electromagnetic waves like a convex lens. That is, when the communication module 2 functions as a transmitting unit, the electromagnetic waves radiated radially from the primary radiator 100 enter from the first surface 310 of the electromagnetic flux control member 300 and are controlled in a converging direction when exiting from the second surface 320. In the present embodiment, the electromagnetic waves controlled in the converging direction are emitted as electromagnetic waves substantially parallel to the second surface 320. On the other hand, when the communication module 2 functions as a receiving unit, the substantially parallel electromagnetic waves emitted from a remote transmitting unit enter from the second surface 320, exit from the first surface 310, and are controlled in a converging direction. In the present embodiment, the electromagnetic waves controlled in the converging direction converge on the primary radiator 100.

[0021] In the present embodiment, when the electromagnetic flux control member 300 is viewed in plan view and bottom view, it is circular as shown in FIGS. 2B and 2C. In the present embodiment, the first surface 310 and the second surface 320 are each circular when viewed in plan view as shown in FIGS. 2B and 2C. Further, in the present embodiment, the electromagnetic flux control member 300 has a central axis CA2, and the electromagnetic flux control member 300 is rotationally symmetric (circularly symmetric) about the central axis CA2. Also, in the present embodiment, the first surface 310 and the second surface 320 are also rotationally symmetric (circularly symmetric) about the central axis CA2. That is, in the present embodiment, the central axis CA2 is the axis of rotational symmetry (axis of circular symmetry) of the electromagnetic flux control member 300. Further, in the present embodiment, such a central axis CA2 is arranged with respect to the primary radiator 100 so as to coincide with the central axis CA1 of the electromagnetic wave as shown in FIG. 2A.

[0022] An antireflection structure for suppressing reflection of electromagnetic waves may be provided on at least one of the first surface 310 and the second surface 320 of the electromagnetic flux control member 300.

[0023] As described above, the electromagnetic flux control member (lens antenna) 300 in the communication module 2 according to the present embodiment does not control electromagnetic waves that are somewhat controlled by the horn portion like the lens antenna of the horn antenna, but can increase the gain. FIGS. 3A and 3B are graphs for explaining this. FIG. 3A is a graph showing the relationship between the angle from the central axis CA1 of the electromagnetic wave and the gain when receiving the electromagnetic wave (270 GHz) emitted from the horn antenna as shown in FIG. 1. On the other hand, FIG. 3B is a graph showing the relationship between the angle from the central axis CA1 of the electromagnetic wave and the gain when receiving the electromagnetic wave (270 GHz) emitted from a waveguide which is an example of a primary radiator. In FIGS. 3A and 3B, the outer curve (black curve) shows the measurement result in the plane of φ = 0° including the central axis CA1, and the inner curve (gray curve) shows the measurement result in the plane of φ = 90° including the central axis CA1. Also, in FIGS. 3A and 3B, the angle in the clockwise direction from the central axis CA1 of the electromagnetic wave is shown as positive, and the angle in the counterclockwise direction is shown as negative.

[0024] As can be seen from FIG. 3A, in the horn antenna, substantially all electromagnetic waves are included in the angular range of -60° to +60°, and about 92% of the electromagnetic waves are included in the angular range of -45° to +45°. On the other hand, as can be seen from FIG. 3B, in the waveguide, the electromagnetic waves spread over a wider angular range, and in order to utilize about 88% of the electromagnetic waves, it is necessary to utilize the electromagnetic waves in the wide angular range of -70° to +70°, and in order to utilize about 93% of the electromagnetic waves, it is necessary to utilize the electromagnetic waves in an even wider angular range of -75° to +75°.

[0025] That is, from FIGS. 3A and 3B, from the viewpoint of increasing the gain, it is preferable that the electromagnetic wave emitted from the primary radiator 100 at a large emission angle is arranged to be incident on the first surface 310. Specifically, as shown in FIG. 4, a plane including the emission surface of the primary radiator (e.g., waveguide) 100 and perpendicular to the central axis CA1 of the electromagnetic wave emitted from the primary radiator 100 is defined as the reference plane 101. When the shortest distance between the reference plane 101 and the outer edge of the first surface 310 is ODe and the shortest distance between the reference plane 101 and the center of the first surface 310 is ODc, ODe / ODc is preferably in the range of 0 to 0.9, more preferably in the range of 0.3 to 0.8, and even more preferably in the range of 0.4 to 0.75. When ODe / ODc is as described above, electromagnetic waves in a large angular range are likely to be incident on the first surface 310, and the gain can be increased.

[0026] From the perspective of increasing the refractive index of the electromagnetic wave, the electromagnetic flux control member 300 preferably has a dielectric constant as follows. That is, the dielectric constant of the electromagnetic flux control member 300 can be obtained as the average value of the measured values at room temperature, for example, at a frequency of 250 to 300 GHz, and is preferably 6 to 12.

[0027] Examples of the material constituting the electromagnetic flux control member 300 include resins, ceramics, glass, etc. Examples of resins include polypropylene, polycycloolefin, polytetrafluoroethylene, and modified polyphenylene ether. Examples of ceramics include CaTiO3, SrTiO3, BaTiO3, and ZnO. Also, examples of the material of the electromagnetic flux control member 300 include the above-mentioned resins containing the above-mentioned ceramic powder.

[0028] The electromagnetic flux control member is manufactured, for example, by injection molding. From the perspective of facilitating the injection molding of the electromagnetic flux control member 300, it is preferably configured as follows. That is, as shown in FIG. 4, in the direction along the central axis CA2 of the electromagnetic flux control member 300, when the distance between the outer edge of the first surface 310 and the outer edge of the second surface 320 is Te, and the distance between the center of the first surface 310 and the center of the second surface 320 of the electromagnetic flux control member is Tc, Te / Tc is preferably 0.2 to 0.7, and more preferably 0.3 to 0.6. When the outer edge of the first surface 310 is inside the outer edge of the second surface 320 in a plan view, the above Te is the distance between the outer edge of the first surface 310 and the second surface 320 in the direction along the central axis CA2 of the electromagnetic flux control member 300. Similarly, when the outer edge of the second surface 320 is inside the outer edge of the first surface 310 in a plan view, the above Te is the distance between the outer edge of the second surface 320 and the first surface 310 in the direction along the central axis CA2 of the electromagnetic flux control member 300.

[0029] When the electromagnetic flux control member 300 is injection-molded, the electromagnetic flux control member 300 is injection-molded using a mold having a cavity with a shape complementary to that of the electromagnetic flux control member 300. In such a mold, the molding material is filled from a portion corresponding to the outer edge of the electromagnetic flux control member 300 and sequentially flows to the central portion of the electromagnetic flux control member 300 and a portion corresponding to the outer edge on the opposite side of the outer edge. When Te / Tc is as described above, the molding material can flow smoothly to the outer edge, the central portion, and the outer edge on the opposite side of the outer edge of the electromagnetic flux control member 300 in sequence, and the dimensional accuracy of the obtained electromagnetic flux control member 300 is improved.

[0030] (Effect) The present invention can provide a communication module that is small in size and can obtain good gain.

[0031] The electromagnetic flux control member according to the embodiment of the present invention is useful for controlling electromagnetic waves to maintain a desired maximum gain even when the central axis CA1 of the electromagnetic waves emitted from the primary radiator is slightly deviated from the central axis CA2 of the electromagnetic flux control member when installed in the communication module.

[0032] [Simulation] Using the communication module 2 of the embodiment (see Fig. 2A) and the communication module 2a of the comparative example as shown in Fig. 5, the relationship between the amount of angular change of the electromagnetic wave by the electromagnetic flux control members 300 and 300a and the resulting gain was simulated. The communication module 2 of the embodiment used a meniscus lens-shaped electromagnetic flux control member 300 having a first surface 310 that is concave and a second surface 320 that is convex as described above. In contrast, the communication module 2a of the comparative example used an electromagnetic flux control member 300a in which the first surface 310a facing the primary radiator 100 is flat and the second surface 320a on the opposite side of the first surface 310a is convex as shown in Fig. 5. That is, the electromagnetic flux control member 300a included in the communication module 2a of the comparative example has a plano-convex lens shape. Note that the electromagnetic flux control members in the communication modules of the embodiment and the comparative example are both circular when viewed in plan view and in bottom view.

[0033] Specifically, as shown in Table 1, for Examples 1 to 5 and Comparative Examples 1 and 2 in which the values of the angular change A° on the first surface and the angular change B° on the second surface were changed by changing the curvature of the first surface and the curvature of the second surface, the gain was simulated. More specifically, in Examples 1 and 2, for the electromagnetic waves emitted from the primary radiator 100 with angles of 60°, 65°, and 70° from the central axis CA1 of the electromagnetic wave, the change in gain when A° and B° were changed to change A / B was simulated. In Example 5, for the electromagnetic waves emitted from the primary radiator 100 with angles of 60°, 65°, and 69° from the central axis CA1 of the electromagnetic wave, the change in gain when A° and B° were changed to change A / B was simulated. Also, in Examples 3 and 4 and Comparative Examples 1 and 2, for the electromagnetic waves emitted from the primary radiator 100 with angles of 60° and 65° from the central axis CA1 of the electromagnetic wave, the change in gain when A° and B° were changed to change A / B was simulated. The simulation results are shown in Table 1. Also shown in Table 1 are ODe, ODc, ODe / ODc, Te, Tc, Te / Tc, the diameter of the electromagnetic flux control member, and the dielectric constant for each example and each comparative example. The ratio of the maximum gain for each example is also shown in Table 1. The ratio of the maximum gain was obtained as (the maximum gain of Example 1) / (the maximum gain of Comparative Example 1) for Example 1. For Examples 2 to 5, it was obtained as (the respective maximum gains of Examples 2 to 5) / (the maximum gain of Comparative Example 2).

[0034] [Table 1]

[0035] As can be seen from Table 1, in Examples 1 to 5, A / B, which is the ratio of the angle change, was in the range of 1 to 2, and all the maximum gains were 60 or more. On the other hand, in Comparative Examples 1 and 2, A / B exceeded 2, and the maximum gains were less than 60. Thus, it can be seen that good gains can be obtained when A / B is 1 to 2.

[0036] The reason is speculated as follows. That is, the fact that A / B is as low as 1 to 2 means that the difference in the angle change between the first surface 310 and the second surface 320 is small, and a large angle change does not occur in the control of electromagnetic waves. Specifically, in the examples, compared with the comparative examples, the incident angle of the electromagnetic wave on the first surface is small, and the refraction of the electromagnetic wave is small. It is speculated that, as a result, the Fresnel reflection on the first surface is smaller in the examples than in the comparative examples, and thus the gain is better. Note that the reason for the better gain is speculative and does not limit the present invention.

[0037] Also, from Table 1, from the viewpoint of obtaining a good gain, A / B, which is the ratio of the angle change on the first surface and the angle change on the second surface of the electromagnetic wave emitted at an angle of 60° to 70° from the central axis CA1 of the electromagnetic wave, is more preferably 1.2 to 1.9, more preferably 1.3 to 1.8, and even more preferably 1.3 to 1.6.

[0038] Also, as can be seen from Table 1, in Examples 1 to 5, ODe / ODc was in the range of 0 to 0.9, and all the maximum gains were 60 or more. On the other hand, in Comparative Examples 1 and 2, ODe / ODc exceeded 0.9, and the maximum gain was less than 60. This is presumably because when ODe / ODc is 0 to 0.9, electromagnetic waves in a large angular range are likely to be incident on the first surface 310.

Industrial Applicability

[0039] The communication module and the electromagnetic flux control member according to the present invention are useful for communication using electromagnetic waves.

Explanation of Symbols

[0040] 1 Horn antenna 2, 2a Communication module 10 Wave source 20 Horn portion 30 Lens antenna 100 Primary radiator 101 Reference plane 300, 300a Electromagnetic flux control member 310, 310a First surface 320, 320a Second surface

Claims

1. An electromagnetic flux control member having a first surface that is concave and a second surface that is convex on the opposite side of the first surface, and a primary radiator facing the first surface, Electromagnetic waves emitted at an angle of 60° to 70° from the central axis CA1 of the electromagnetic waves emitted from the primary radiator are incident and refracted on the first surface, and are emitted and refracted on the second surface, Let the angle between the traveling direction of the electromagnetic waves before being incident and refracted on the first surface and the traveling direction of the electromagnetic waves that are incident and refracted on the first surface and travel within the electromagnetic flux control member be A°, When the angle between the traveling direction of the electromagnetic waves traveling within the electromagnetic flux control member and the traveling direction of the electromagnetic waves emitted and refracted on the second surface is B°, A / B is 1 to 2, A communication module.

2. When the distance between the outer edge of the first surface and the outer edge of the second surface of the electromagnetic flux control member along the central axis CA2 of the electromagnetic flux control member is Te, and the distance between the center of the first surface and the center of the second surface of the electromagnetic flux control member is Tc, Te / Tc is 0.2 to 0.

7. The communication module according to Claim 1.

3. Using the plane perpendicular to the central axis CA1 of the electromagnetic waves emitted from the primary radiator including the emission surface of the primary radiator as a reference plane, the shortest distance between the reference plane and the outer edge of the first surface is ODe, and the shortest distance between the reference plane and the center of the first surface is ODc. When ODc is used, ODe / ODc is 0 to 0.

9. The communication module according to Claim 1.

4. An electromagnetic flux control member used in the communication module according to any one of Claims 1 to 3.

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