Communication module and electromagnetic flux control member

Abstract

The present invention provides a communication module that is compact and can achieve favorable gain. A communication module according to the present invention includes: 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 reverse side from 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 to and refracted by the first surface and are emitted from and refracted by the second surface. If A° is defined as the angle between the advancing direction of the electromagnetic waves before being incident to and refracted by the first surface and the advancing direction of the electromagnetic waves that are incident to and refracted by the first surface and advance within the electromagnetic flux control member, and B° is defined as the angle between the advancing direction of the electromagnetic waves advancing within the electromagnetic flux control member and the advancing direction of the electromagnetic waves emitted from and refracted by the second surface, then A / B is from 1 to 2.

Description

Communication module and electromagnetic flux control member

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

[0002] There are known communication modules that include a wave source that emits electromagnetic waves and a component for controlling the electromagnetic waves emitted from the wave source. For example, a communication module disclosed in Patent Document 1 includes 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.

[0003] Japanese Patent Application Laid-Open No. 2004-274656

[0004] FIG. 1 is a schematic diagram illustrating a horn antenna 1, which is a type of communication module, and the electromagnetic waves controlled by the horn antenna 1. As shown in FIG. 1, the horn antenna 1 includes a wave source 10 for generating electromagnetic waves and a horn portion 20. In addition to the horn portion 20, the horn antenna 1 also includes a lens antenna 30. The horn portion 20 of the horn antenna 1 described above has a certain length and size. This results in a large horn antenna 1. It is believed that the communication module can be made smaller by removing the horn portion 20 from the horn antenna 1. However, this may result in insufficient control of the direction of the electromagnetic waves, resulting in reduced gain.

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

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

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

[0008] Fig. 1 is a diagram showing a horn antenna having a lens antenna. Fig. 2A is a diagram showing a communication module according to an embodiment, and Figs. 2B and 2C are diagrams showing an electromagnetic flux control member. Fig. 3A is a graph showing the relationship between the angle and gain of an electromagnetic wave emitted from a horn antenna, and Fig. 3B is a graph showing the relationship between the angle and gain of an electromagnetic wave emitted from a waveguide. Fig. 4 is a diagram showing an electromagnetic flux control member according to an embodiment. Fig. 5 is a diagram showing an electromagnetic flux control member according to a comparative example.

[0009] [Communication Module] Fig. 2A is a cross-sectional view that schematically illustrates communication module 2 according to the present embodiment and the traveling direction of electromagnetic waves in communication module 2. Communication module 2 has primary radiator 100 and electromagnetic flux control member (lens antenna) 300. The cross section of Fig. 2A is a cross section that includes central axis CA1 of the electromagnetic wave emitted from primary radiator 100 and central axis CA2 of electromagnetic flux control member 300. Here, central axis CA1 of the electromagnetic wave refers to the electromagnetic wave at the center of the three-dimensional electromagnetic wave emitted from primary radiator 100.

[0010] Electromagnetic flux control member 300 has first surface 310 which is a concave surface, and second surface 320 which is a convex surface opposite first surface 310. In communication module 2, first surface 310 is a surface facing primary radiator 100.

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

[0012] In this communication module 2, the electromagnetic wave emitted from primary radiator 100 at an angle of 60° to 70° from central axis CA1 of the electromagnetic wave is incident on and refracted by first surface 310, and is then emitted and refracted by second surface 320. When the angle between the traveling direction of the electromagnetic wave before being incident on and refracted by first surface 310 and the traveling direction of the electromagnetic wave incident on and refracted by first surface 310 and traveling within electromagnetic flux control member 300 is A°, and the angle between the traveling direction of the electromagnetic wave traveling within electromagnetic flux control member 300 and the traveling direction of the electromagnetic wave emitted and refracted by second surface 320 is B°, A / B is between 1 and 2. Communication module 2 in which the electromagnetic wave is controlled in this manner can achieve a good gain. Details of the gain will be described later, showing simulations. Hereinafter, A° and B° will also be referred to as the angle change at first surface 310 and the angle change at second surface 320, respectively, as appropriate.

[0013] The communication module 2 may be used as a transmitting module or a receiving module.

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

[0015] On the other hand, when the communication module 2 is used as a receiving module, electromagnetic waves emitted from a distant transmitter enter and are refracted at the second surface 320, exit and are refracted at the first surface 310, and are converged on the primary radiator 100 and received.

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

[0017] (Primary Radiator) The primary radiator 100 may function as a transmitter that transmits electromagnetic waves, or as a receiver 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 30 GHz to 3 THz (wavelength of approximately 10 mm to approximately 0.1 mm), and more preferably 30 GHz to 300 GHz. Examples of the primary radiator 100 include a waveguide, a patch antenna, etc. The primary radiator 100 has an exit surface from which the electromagnetic waves are emitted. Examples of the exit surface of the primary radiator may include a virtual plane including an opening from which the electromagnetic waves of the tubular part of a waveguide are emitted to the outside, the exit surface from which the electromagnetic waves of a patch antenna are emitted, etc.

[0019] (Electromagnetic Flux Control Member) Electromagnetic flux control member 300 has first surface 310, which is a concave surface, and second surface 320, which is a convex surface opposite first surface 310. Electromagnetic flux control member 300 having such first surface 310 and second surface 320 has a meniscus lens shape.

[0020] In the present embodiment, the curvature of second surface 320 may be greater than the curvature of first surface 310, or the curvature of first surface 310 may be greater than the curvature of second surface 320, or the curvature of second surface 320 may be the same as the curvature of first surface 310. In the present embodiment, electromagnetic flux control member 300 as a whole has the function of controlling electromagnetic waves like a convex lens. That is, when communication module 2 functions as a transmitter, electromagnetic waves radially emitted from primary radiator 100 are incident on first surface 310 of electromagnetic flux control member 300 and are controlled in a converging direction when emitted from second surface 320. In the present embodiment, the electromagnetic waves controlled in a converging direction are emitted from second surface 320 as substantially parallel electromagnetic waves. On the other hand, when communication module 2 functions as a receiver, substantially parallel electromagnetic waves emitted from a distant transmitter are incident on second surface 320 and are controlled in a converging direction when emitted from first surface 310. In this embodiment, the electromagnetic waves controlled in the converging direction are converged onto the primary radiator 100 .

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

[0022] At least one of first surface 310 and second surface 320 of electromagnetic flux control member 300 may be provided with an anti-reflection structure for suppressing reflection of electromagnetic waves.

[0023] As described above, electromagnetic flux control member (lens antenna) 300 in communication module 2 according to the present embodiment does not control electromagnetic waves to a certain extent by the horn portion, as in the case of a lens antenna of a horn antenna, but it can increase gain. Figures 3A and 3B are graphs illustrating this. Figure 3A is a graph showing the relationship between the angle from the central axis CA1 of the electromagnetic wave and the gain when receiving an electromagnetic wave (270 GHz) emitted from a horn antenna such as that shown in Figure 1. Meanwhile, Figure 3B is a graph showing the relationship between the angle from the central axis CA1 of the electromagnetic wave and the gain when receiving an electromagnetic wave (270 GHz) emitted from a waveguide, which is an example of a primary radiator. In Figures 3A and 3B, the outer curve (black curve) shows the measurement results in a plane of φ=0° including the central axis CA1, and the inner curve (gray curve) shows the measurement results in a plane of φ=90° including the central axis CA1. 3A and 3B, angles in the clockwise direction from the central axis CA1 of the electromagnetic wave are indicated by positive values, and angles in the counterclockwise direction are indicated by negative values.

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

[0025] 3A and 3B , from the viewpoint of increasing gain, electromagnetic flux control member 300 is preferably disposed so that electromagnetic waves emitted from primary radiator 100 at a large emission angle are incident on first surface 310. Specifically, as shown in FIG. 4 , when a plane including the emission surface of primary radiator (e.g., waveguide) 100 and perpendicular to central axis CA1 of the electromagnetic waves emitted from primary radiator 100 is defined as reference plane 101, the shortest distance between reference plane 101 and the outer edge of first surface 310 is defined as ODe, and the shortest distance between reference plane 101 and the center of first surface 310 is defined as ODc, ODe / ODc is preferably 0 to 0.9, more preferably 0.3 to 0.8, and even more preferably 0.4 to 0.75. When ODe / ODc is as described above, electromagnetic waves in a large angular range are more likely to be incident on first surface 310, thereby increasing gain.

[0026] From the viewpoint of increasing the refractive index of electromagnetic waves, electromagnetic flux control member 300 preferably has the following dielectric constant: That is, the dielectric constant of electromagnetic flux control member 300 can be determined as the average value of measured values ​​at a frequency of 250 to 300 GHz and room temperature, and is preferably 6 to 12.

[0027] Examples of materials that form the electromagnetic flux control member 300 include resin, ceramic, glass, etc. Examples of resin include polypropylene, polycycloolefin, polytetrafluoroethylene, and modified polyphenylene ether. Examples of ceramic include CaTiO ３ , SrTiO ３ , BaTiO ３, ZnO. Examples of materials for 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 by, for example, injection molding. From the viewpoint of facilitating injection molding of electromagnetic flux control member 300, it is preferable that electromagnetic flux control member 300 be configured as follows. That is, as shown in FIG. 4 , when Te is the distance between the outer edge of first surface 310 and the outer edge of second surface 320 in the direction along central axis CA2 of electromagnetic flux control member 300, and Tc is the distance between the center of first surface 310 and the center of second surface 320 of electromagnetic flux control member 300, Te / Tc is preferably 0.2 to 0.7, and more preferably 0.3 to 0.6. Note that when the outer edge of first surface 310 is located inside the outer edge of second surface 320 in a plan view, Te is the distance between the outer edge of first surface 310 and second surface 320 in the direction along central axis CA2 of electromagnetic flux control member 300. Similarly, when the outer edge of the second surface 320 is located inside the outer edge of the first surface 310 when viewed in a plane, 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 electromagnetic flux control member 300 is injection molded, electromagnetic flux control member 300 is injection molded using a mold having a cavity with a shape complementary to electromagnetic flux control member 300. In such a mold, the molding material is filled from the portion corresponding to the outer edge of electromagnetic flux control member 300, and then flows sequentially to the center of electromagnetic flux control member 300 and the portion corresponding to the outer edge opposite the outer edge. With Te / Tc as described above, the molding material can easily flow smoothly sequentially from the outer edge, to the center, and to the outer edge opposite the outer edge of electromagnetic flux control member 300, thereby improving the dimensional accuracy of the obtained electromagnetic flux control member 300.

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

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

[0032] [Simulation] A simulation was performed to determine the relationship between the angular change in electromagnetic waves caused by electromagnetic flux control members 300, 300a and the resulting gain using a communication module 2 of the example (see FIG. 2A ) and a communication module 2a of the comparative example shown in FIG. 5 . The communication module 2 of the example used electromagnetic flux control member 300, which has a meniscus lens shape and includes first surface 310, which is concave, and second surface 320, which is convex, as described above. In contrast, the communication module 2a of the comparative example used electromagnetic flux control member 300a, which has first surface 310a facing primary radiator 100, which is flat, and second surface 320a, which is opposite first surface 310a, which is convex, as shown in FIG. 5 . That is, electromagnetic flux control member 300a of communication module 2a of the comparative example has a plano-convex lens shape. The electromagnetic flux control members of the communication modules of the example and the comparative example are both circular in plan and bottom views.

[0033] Specifically, as shown in Table 1, gain was simulated for each of Examples 1 to 5 and Comparative Examples 1 and 2, in which the value of angle change A° at the first surface and the value of angle change B° at the second surface were changed by changing the curvature of the first surface and the curvature of the second surface. More specifically, in Examples 1 and 2, the change in gain when A° and B° were changed and A / B was changed was simulated for electromagnetic waves emitted from the primary radiator 100 at angles of 60°, 65°, and 70° from the central axis CA1 of the electromagnetic waves. In Example 5, the change in gain when A° and B° were changed and A / B was changed was simulated for electromagnetic waves emitted from the primary radiator 100 at angles of 60°, 65°, and 69° from the central axis CA1 of the electromagnetic waves. Furthermore, for Examples 3 and 4 and Comparative Examples 1 and 2, a simulation was performed to determine the change in gain when A° and B° were changed and A / B was changed for electromagnetic waves emitted from primary radiator 100 at angles of 60° and 65° from the central axis CA1 of the electromagnetic waves. The simulation results are shown in Table 1. Table 1 also shows ODe, ODc, ODe / ODc, Te, Tc, Te / Tc, the diameter of the electromagnetic flux control member, and the dielectric constant for each Example and Comparative Example. Table 1 also shows the maximum gain ratio for each Example. For Example 1, the maximum gain ratio was calculated by (maximum gain of Example 1) / (maximum gain of Comparative Example 1). For Examples 2 to 5, the maximum gain ratio was calculated by (maximum gain of each of Examples 2 to 5) / (maximum gain of Comparative Example 2).

[0034]

[0035] As can be seen from Table 1, in Examples 1 to 5, the ratio of angle change, A / B, was within the range of 1 to 2, and the maximum gain was 60 or more in all cases. In contrast, in Comparative Examples 1 and 2, A / B exceeded 2, and the maximum gain was less than 60. Thus, it can be seen that a good gain can be obtained when A / B is 1 to 2.

[0036] The reason for this is presumed to be as follows. That is, a low A / B of 1 to 2 means that the difference in angle change between the first surface 310 and the second surface 320 is small, and no large angle change occurs in controlling the electromagnetic wave. Specifically, in the Example, the angle of incidence of the electromagnetic wave on the first surface is small compared to the Comparative Example, and the refraction of the electromagnetic wave is small. As a result, it is presumed that the Fresnel reflection on the first surface is small in the Example compared to the Comparative Example, and therefore the gain is good. Note that the reason for this good gain is a presumption and does not limit the present invention.

[0037] Furthermore, from Table 1, from the viewpoint of obtaining a good gain, A / B, which is the ratio of the angle change at the first surface to the angle change at the second surface of an 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] Furthermore, as can be seen from Table 1, in Examples 1 to 5, ODe / ODc was within the range of 0 to 0.9, and the maximum gain was all equal to or greater than 60. In contrast, in Comparative Examples 1 and 2, ODe / ODc exceeded 0.9, and the maximum gain was less than 60. This is thought to be because when ODe / ODc is 0 to 0.9, electromagnetic waves in a large angular range are more likely to be incident on first surface 310.

[0039] This application claims priority from Japanese Patent Application No. 2023-214176, filed December 19, 2023. The contents of the specification and drawings of this application are incorporated herein by reference in their entirety.

[0040] The communication module and electromagnetic flux control member according to the present invention are useful for communication using electromagnetic waves.

[0041] REFERENCE SIGNS LIST 1 Horn antenna 2, 2a Communication module 10 Wave source 20 Horn portion 30 Lens antenna 100 Primary radiator 101 Reference surface 300, 300a Electromagnetic flux control member 310, 310a First surface 320, 320a Second surface

Claims

1. A communications module comprising: an electromagnetic flux control member having a first surface which is concave and a second surface which is convex opposite to the first surface; and a primary radiator facing the first surface, wherein an electromagnetic wave emitted from the primary radiator at an angle of 60° to 70° from a central axis CA1 of the electromagnetic wave is incident on and refracted at the first surface, and is emitted and refracted at the second surface, wherein an angle between the traveling direction of the electromagnetic wave before being incident on and refracted at the first surface and the traveling direction of the electromagnetic wave which is incident on and refracted at the first surface and travels within the electromagnetic flux control member is A°, and an angle between the traveling direction of the electromagnetic wave traveling within the electromagnetic flux control member and the traveling direction of the electromagnetic wave which is emitted and refracted at the second surface is B°, A / B is between 1 and 2.

2. The communications module described in claim 1, wherein Te is the distance between the outer edge of the first surface and the outer edge of the second surface of the electromagnetic flux control member in a direction along a central axis CA2 of the electromagnetic flux control member, and Tc is the distance between the center of the first surface and the center of the second surface of the electromagnetic flux control member, and Te / Tc is 0.2 to 0.

7.

3. The communications module described in claim 1, wherein a plane including the emission surface of the primary radiator and perpendicular to the central axis CA1 of the electromagnetic wave emitted from the primary radiator is taken as a reference plane, the shortest distance between the reference plane and the outer edge of the first surface is taken as ODe, and the shortest distance between the reference plane and the center of the first surface is taken as ODc, and ODe / ODc is between 0 and 0.

9.

4. An electromagnetic flux control member for use in a communication module according to any one of claims 1 to 3.

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