Radio antennas, wireless communication systems

Abstract

To provide a radio antenna capable of forming a service area simply and at low costs and further capable of setting transmission / reception directions of electromagnetic waves.SOLUTION: A radio antenna 100 includes a cable-like waveguide 110 formed using a dielectric substance and an antenna function unit 120. The dielectric constant of the waveguide 110 is larger than the dielectric constant of the periphery of the waveguide 110 excluding the antenna function unit 120. The antenna function unit 120 includes M (M≥1) mass bodies 110c formed using a dielectric substance. Each of the M mass bodies 110c is positioned on the waveguide 110 or in the vicinity of the waveguide 110. An angle γ formed by a longer direction of a single mass body 110c and a longer direction of the waveguide 110 in the case of M=1 or an angle γ formed by a direction in which the M mass bodies 110c are arranged and the longer direction of the waveguide 110 in the case of M≥2 is larger than 0 degrees and smaller than 90 degrees.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a wireless antenna and a wireless communication system using this wireless antenna.

Background Art

[0002] A previous invention by the inventors of the present invention is disclosed in Patent Document 1. Patent Document 1 discloses a wireless antenna capable of forming a service area simply and at low cost, and a wireless communication system using this wireless antenna. The wireless antenna according to the previous invention includes a cable-shaped waveguide formed of a dielectric and one or more lumps formed of a dielectric. The dielectric constant of the waveguide is larger than the dielectric constant around the waveguide. The lumps are located on the waveguide. One end of the waveguide is connected to a signal generation device that generates a signal having a frequency of, for example, millimeter waves (30 GHz to 300 GHz) or quasi-millimeter waves (no clear definition, but approximately 20 GHz to 30 GHz). Electromagnetic waves are radiated from the lumps, and the communication terminal receives these electromagnetic waves.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention is a new approach to the previous invention, and specifically aims to provide a wireless antenna capable of forming a service area simply and at low cost, and further capable of setting the transmission and reception directions of electromagnetic waves, and a wireless communication system using this wireless antenna.

Means for Solving the Problems

[0005] The technical matters described herein are not intended to explicitly or implicitly limit the invention described in the claims, nor are they an indication of tolerance for such limitations by persons other than those who benefit from the present invention (for example, the applicant and the patentee), but are merely described to facilitate understanding of the gist of the present invention. The outline of the present invention from other viewpoints can be understood, for example, from the claims at the time of filing of this patent application. The wireless antenna of the present invention has a dielectric waveguide and an antenna functional part. The dielectric waveguide has a dielectric constant greater than that of the surrounding dielectric constant excluding the antenna functional part. The antenna functional part includes one or more blocks formed of a dielectric. The blocks are located on or near the dielectric waveguide. The blocks are sites for radiating and absorbing electromagnetic waves. Electromagnetic wave transmission and reception are realized between the blocks and the communication terminal. The dielectric waveguide may have a branching structure. The dielectric waveguide may be connected to a medium capable of propagating electromagnetic waves. The characteristic matter of the effort for the prior invention is that the angle formed by the longitudinal direction of the block and the longitudinal direction of the waveguide is greater than 0 degrees and less than 90 degrees, or the angle formed by the direction in which two or more blocks are arranged and the longitudinal direction of the waveguide is greater than 0 degrees and less than 90 degrees.

Effect of the Invention

[0006] According to the present invention, since the electromagnetic wave radiation part or absorption part is realized by the blocks on or near the dielectric waveguide, a service area can be formed simply and at low cost. Furthermore, the electromagnetic wave transmission and reception direction is set according to the longitudinal direction of the block or the direction in which two or more blocks are arranged.

Brief Description of the Drawings

[0007]

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Mode for Carrying Out the Invention

[0008] Embodiments of the present invention will be described with reference to the drawings. The wireless communication system 1 of the embodiment shown in FIG. 1 includes a wireless antenna 100 of the embodiment, a communication terminal 200, and a signal generation device 800. As shown in FIG. 1, the wireless antenna 100 has a configuration including an elongated cable-shaped waveguide 110 formed of a dielectric and N (where N is a predetermined integer satisfying N≧1) antenna function units 120. The waveguide 110 may have a linear shape, or may have a shape that meanders slightly as shown in FIG. 1, in other words, a shape having a bend that does not adversely affect the low-loss propagation of the waveguide 110 described later, or may have a branching structure. The branching structure of the waveguide 110 will be described later. In the local region of the waveguide 110 where the i-th (where i∈{1,…,N}) antenna function unit 120 is located, it is assumed that the waveguide 110 has a linear shape. Each of the N antenna function units 120 includes one or more lumps 110c formed of a dielectric. There is no limit to the number of lumps 110c included in each antenna function unit 120. Therefore, the number of lumps 110c included in a certain one antenna function unit 120 may be the same as or different from the number of lumps 110c included in any other one antenna function unit 120. Each lump 110c may be formed of the same dielectric as the waveguide 110 or a different dielectric from the waveguide 110. Each lump 110c is located on the waveguide 110. In this case, the lump 110c protrudes like a protrusion from the waveguide 110. Alternatively, each lump 110c is located in the vicinity of the waveguide 110 away from the waveguide 110. Alternatively, let the number of lumps 110c included in the i-th antenna function unit 120 be n i (where n i is n i a predetermined integer satisfying n i=1 N ≧1), and T = Σ iAs such, among the T blocks 110c, t blocks 110c (where t is a predetermined integer satisfying 1 ≦ t < T) are located on the waveguide 110, and the remaining T - t blocks 110c are located near the waveguide 110 away from the waveguide 110. In this embodiment, one end of the waveguide 110 is connected to a signal generation device 800 that generates a signal having a frequency of millimeter wave (30 GHz to 300 GHz) or quasi-millimeter wave (no clear definition, but approximately 20 GHz to 30 GHz). There is no limitation on the type of this signal, and it may be an analog signal, a digital signal, a discrete-time signal, or a continuous-time signal. In the example shown in FIG. 1, the other end of the waveguide 110 is not connected to anything and is open, but it may be short-circuited, connected to an antenna (for example, a linear antenna, an aperture antenna, etc.), or terminated.

[0009] As shown in FIG. 2, which is a cross-sectional view perpendicular to the longitudinal direction of the waveguide 110 at an arbitrary position in the longitudinal direction of the waveguide 110 (excluding the part where the antenna functional part 120 exists), the waveguide 110 has a cross-section with a constant shape and size. In this example, the cross-sectional shape of the waveguide 110 is rectangular. Therefore, the elongated rectangular parallelepiped-shaped waveguide 110 has two long side surfaces 111a, 111b that face each other in a direction perpendicular to the longitudinal direction of the waveguide 110, and two short side surfaces 113a, 113b that face each other in a direction perpendicular to the longitudinal direction of the waveguide 110. The long side surfaces 111a, 111b are the side surfaces whose width (that is, the length in the direction perpendicular to the longitudinal direction of the waveguide 110) is equal to the length of the long side of the rectangular cross-section, and the short side surfaces 113a, 113b are the side surfaces whose width is equal to the length of the short side of the rectangular cross-section. Thus, the waveguide 110 in the embodiment has a uniform structure except for the part where the antenna functional part 120 exists, that is, the shape and size of the cross-section are both constant at any position (excluding the part where the antenna functional part 120 exists), and the material is constant at any position (excluding the part where the antenna functional part 120 exists). Note that although the cross-sectional shape of the waveguide 110 is rectangular in FIG. 2, it is not limited to such a structure, and may be, for example, square or circular.

[0010] The permittivity of the waveguide 110 is greater than the permittivity of the surroundings of the waveguide 110 excluding the antenna functional unit 120. In the example shown in FIG. 2, the surroundings of the waveguide 110 is air, and the permittivity of air is approximately 1, so the permittivity of the waveguide 110 is greater than 1. Therefore, when there is no antenna functional unit 120, the electromagnetic field of the signal from the signal generation device 800 input to one end of the waveguide 110 concentrates on the waveguide 110 with a high permittivity and is transmitted with low loss toward the other end of the waveguide 110, reaching the other end of the waveguide 110.

[0011] The shape of each block 110c is, for example, a polygonal prism, a cylinder, a sphere, or a part of any of them. When the total number T of the blocks 110c is 2 or more, the shape commonly held by a part of the T blocks 110c (that is, p blocks, where p satisfies 1 ≦ p < T) may be the same as or different from the shape commonly held by another part (that is, q blocks, where q satisfies 1 ≦ q < T - p) or all (that is, q blocks, where q satisfies q = T - p) of the T blocks 110c. Alternatively, when T ≧ 2, any two different blocks 110c among the T blocks 110c may have different shapes. Further, when the total number T of the blocks 110c is 2 or more, the size commonly held by a part of the T blocks 110c (that is, p blocks, where p satisfies 1 ≦ p < T) may be the same as or different from the size commonly held by another part (that is, q blocks, where q satisfies 1 ≦ q < T - p) or all (that is, q blocks, where q satisfies q = T - p) of the T blocks 110c. Alternatively, when T ≧ 2, any two different blocks 110c among the T blocks 110c may have different sizes.

[0012] Hereinafter, the number n of the blocks 110c included in any i-th antenna functional unit 120 iThis will be described by rewriting it as M. When M = 1, one block 110c has a shape with a longitudinal direction along the side surface of the waveguide 110, and the angle γ formed by the longitudinal direction of this block 110c and the longitudinal direction of the waveguide 110 is greater than 0 degrees and less than 90 degrees. The angle γ is defined as the acute angle formed by the longitudinal direction of the block 110c and the longitudinal direction of the waveguide 110. When the waveguide 110 has a non-linear shape (for example, the meandering shape described above), the "longitudinal direction of the waveguide 110" when measuring the angle γ is defined as the extension direction of the waveguide 110 in the local region of the waveguide 110 where the i-th antenna functional unit 120 is located. (a) Apply a cylindrical coordinate system to the local region of the waveguide 110 where the i-th antenna functional unit 120 is located, and (b) the latitude line of the cylindrical coordinate system is parallel to the extension direction of the waveguide 110 in the local region, and (c) when the azimuth angle of the cylindrical coordinate system following the intersection line between the plane perpendicular to the longitudinal direction of the waveguide 110 in the local region and the side surface of the waveguide 110 (where this intersection line is a Jordan closed curve) varies from 0 radians to 2π radians, as the "shape having a longitudinal direction along the side surface of the waveguide 110", a shape along a line X on the side surface of the waveguide 110 that satisfies the following conditions can be exemplified. [Conditions] (1) The line X is a line segment (that is, a part of a straight line with a finite length and two ends) or a Jordan arc (that is, a part of a simple curve with a finite length and two ends), and (2) as the height z of the cylindrical coordinate system following the line X increases, the azimuth angle φ [unit: radian] of the cylindrical coordinate system following the line X satisfies a ≦ φ ≦ b (where φ = a corresponds to one end of the line X, φ = b corresponds to the other end of the line X, a and b satisfy 0 < b - a < π, preferably π / 4 ≦ b - a < π, and more preferably π / 3 ≦ b - a < π), and is strictly monotonically increasing or strictly monotonically decreasing, and (3) as the azimuth angle φ of the cylindrical coordinate system following the line X increases, the height z of the cylindrical coordinate system following the line X is strictly monotonically increasing or strictly monotonically decreasing. The line X is preferably included in one plane. In this case, the line X satisfies the above conditions and is a part of the intersection line between the plane intersecting the waveguide 110 obliquely and the side surface of the waveguide 110. When the cross-sectional shape of the waveguide 110 is rectangular, examples of the "shape having a longitudinal direction along the side surface of the waveguide 110" include a polygonal prism, a semi-cylindrical prism, an oblique polygonal prism (i.e., an oblique prism and a prism), and an oblique semi-cylindrical prism (i.e., an oblique prism and a semi-cylindrical prism) having a bus bar parallel to the flat side surface of the waveguide 110. FIG. 3 shows an example in which one antenna function unit 120 is present on each of two long side surfaces 111a and 111b facing each other, and each antenna function unit 120 includes a block 110c that is an oblique triangular prism. One end bottom surface of one block 110c reaches the boundary between one short side surface 113a and one long side surface 111a, and the other end bottom surface of one block 110c reaches the boundary between the other short side surface 113b and one long side surface 111a. One end bottom surface of the other block 110c reaches the boundary between one short side surface 113a and the other long side surface 111b, and the other end bottom surface of the other block 110c reaches the boundary between the other short side surface 113b and the other long side surface 111b. FIG. 4 shows an example in which one antenna function unit 120 is present on each of two long side surfaces 111a and 111b facing each other, and each antenna function unit 120 includes a block 110c that is an oblique semi-cylindrical prism. One end bottom surface of one block 110c reaches the boundary between one short side surface 113a and one long side surface 111a, and the other end bottom surface of one block 110c reaches the boundary between the other short side surface 113b and one long side surface 111a. One end bottom surface of the other block 110c reaches the boundary between one short side surface 113a and the other long side surface 111b, and the other end bottom surface of the other block 110c reaches the boundary between the other short side surface 113b and the other long side surface 111b. FIG. 5 is a modified example of the configuration shown in FIG. 4. The block 110c is a straight semi-cylindrical prism (i.e., a straight prism and a semi-cylindrical prism). One end bottom surface of one block 110c does not reach the boundary between one short side surface 113a and one long side surface 111a, and the other end bottom surface of one block 110c does not reach the boundary between the other short side surface 113b and one long side surface 111a. One end bottom surface of the other block 110c does not reach the boundary between one short side surface 113a and the other long side surface 111b, and the other end bottom surface of the other block 110c does not reach the boundary between the other short side surface 113b and the other long side surface 111b. When the cross-sectional shape of the waveguide 110 is circular, examples of the "shape having a longitudinal direction along the side surface of the waveguide 110" include a curved oblique polygonal prism and a curved oblique semi-cylindrical prism that are part of the intersection line between a plane that intersects the waveguide 110 obliquely and the side surface of the waveguide 110 along an elliptical arc. FIG. 6 shows an example in which one antenna functional unit 120 exists at each of two positions on the circumference of the waveguide 110 that are 180 degrees apart from each other, and each antenna functional unit 120 includes a block 110c that is a curved oblique semi-cylindrical body. When measuring the angle γ, the "longitudinal direction of the block 110c" is defined, for example, as the direction connecting both ends of the line X.

[0013] Alternatively, when M ≥ 2, the angle γ formed by the direction in which M blocks 110c are arranged and the longitudinal direction of the waveguide 110 is greater than 0 degrees and less than 90 degrees. Although the shape of each block 110c is not limited, for example, it is a polygonal prism, a cylinder, a sphere, or a part of any of them. The M blocks 110c are arranged, for example, along the above-mentioned line X. It is preferable that adjacent blocks 110c are in contact with each other. The angle γ is defined as the acute angle formed by the direction in which the M blocks 110c are arranged and the longitudinal direction of the waveguide 110. When measuring the angle γ, the "direction in which the M blocks 110c are arranged" is defined, for example, as the direction connecting both ends of the line X. When the waveguide 110 has a non-linear shape (for example, the above-mentioned meandering shape), when measuring the angle γ, the "longitudinal direction of the waveguide 110" is defined as the extension direction of the waveguide 110 in the local region of the waveguide 110 where the i-th antenna functional unit 120 is located. FIG. 7 shows an example having the same structure as that shown in FIG. 3 except that the block 110c shown in FIG. 3 is replaced by four hemispherical blocks 110c in the case where one antenna functional unit 120 includes four hemispherical blocks 110c.

[0014] The angle γ satisfies 0 < γ < 90 as described above, preferably satisfies 30 ≤ γ < 90, and more preferably satisfies 45 ≤ γ < 90.

[0015] The position of the antenna functional part 120 on the waveguide 110 in the longitudinal direction is preferably a position excluding both ends of the waveguide 110, and more preferably a position where mismatching is less likely to occur and mode conversion of propagation is less likely to occur. When the total number N of the antenna functional parts 120 is 2 or more, the distances measured along the longitudinal direction from one end of the waveguide 110 of any two different antenna functional parts 120 among the N antenna functional parts 120 may be different from each other, or for example, the distances measured along the longitudinal direction from one end of the waveguide 110 of some two or more different antenna functional parts 120 may be equal to each other. In the latter case, these two or more antenna functional parts 120 are located at different positions on the circumference of the waveguide 110. Further, in this latter case, considering the propagation mode of the electromagnetic wave propagating through the waveguide 110, preferably, two antenna functional parts 120 are located at positions 180 degrees apart from each other on the circumference of the waveguide 110 (see FIGS. 3, 4, and 6). When two antenna functional parts 120 are located at positions 180 degrees apart from each other on the circumference of the waveguide 110, the longitudinal direction of one block 110c in one antenna functional part 120 or the direction in which M blocks 110c are arranged, and the longitudinal direction of one block 110c in the other antenna functional part 120 or the direction in which W (where W is a predetermined integer of 2 or more) blocks 110c are arranged are, for example, in a mirror-symmetric relationship (see FIGS. 3, 4, and 6). When the waveguide 110 is, for example, an elongated rectangular parallelepiped, the mirror plane is a plane parallel to the long-side surfaces 111a and 111b and located at the same distance from the two long-side surfaces 111a and 111b.

[0016] In an example where the j-th antenna functional unit 120 (j ∈ S, S is a predetermined subset excluding the empty set of the set {1, …, N}) is located on the waveguide 110, each block 110c included in the j-th antenna functional unit 120 may be formed integrally with the waveguide 110 or may be formed separately from the waveguide 110. In the latter case, each block 110c is attached to the waveguide 110, but thereafter, it may not be removable from the waveguide 110 or may be removable from the waveguide 110. Even when each block 110c is removable from the waveguide 110, once each block 110c is attached to the waveguide 110, it is desirable that each block 110c does not move on the waveguide 110. Each block 110c is in a state of being in close contact with the waveguide 110. For this reason, when attaching the block 110c to the waveguide 110, the block 110c has a contact surface with the same shape as the local surface shape of the portion of the waveguide 110 to which the block 110c is attached. For example, if the waveguide 110 is an elongated rectangular parallelepiped, the contact surface of the block 110c is composed of at least one plane (see FIGS. 3 and 4), and if the waveguide 110 is an elongated cylinder, the contact surface of the block 110c is a part of the cylindrical surface (see FIG. 6). When using an adhesive or an adhesive agent to bring the block 110c into close contact with the waveguide 110, it is desirable that the dielectric constant of the adhesive or the adhesive agent is about the same as the dielectric constant of the waveguide 110 or about the same as the dielectric constant of the block 110c.

[0017] In an example where the k-th (k ∈ R, and R is a predetermined subset excluding the empty set of the set {1, …, N}) antenna functional unit 120 is located near the waveguide 110 away from the waveguide 110, the upper limit of the distance between the block 110c included in the k-th antenna functional unit 120 and the waveguide 110 is determined by the dielectric constant of the block 110c, the dielectric constant of the waveguide 110, the dielectric constant of the medium (examples of the medium include air or foamed plastic) between the block 110c and the waveguide 110, the intensity of the signal propagating through the waveguide 110, the shape of the cross-section of the waveguide 110, the size of the cross-section of the waveguide 110, and the like. However, here, the "distance between the block 110c and the waveguide 110" refers to the shortest of the distances between any point on the block 110c and any point on the waveguide 110. If the distance between the block 110c and the waveguide 110 is below the above upper limit, the block 110c functions as a radiation unit or a receiving unit described later. In other words, the "vicinity of the waveguide" where the block is located is the range in which the block 110c can function as a radiation unit or a receiving unit described later.

[0018] The positional relationship between the antenna functional unit 120 and the waveguide 110 may be a permanent relationship or a temporary relationship. In the case of a permanent relationship, for example, as shown in FIG. 8(a), the antenna functional unit 120 is fixed to a mounting component 310 fixed to the waveguide 110. The material of the mounting component 310 may be a dielectric or a metal. However, it is desirable to avoid the presence of an electrical conductor (for example, when the material of the mounting component 310 is metal, a part or all of the mounting component 310) between the antenna functional unit 120 and the waveguide 110. The mounting component 310 serves as a holder for holding the antenna functional unit 120 and as a spacer for keeping the distance between the antenna functional unit 120 and the waveguide 110 constant.

[0019] In the case of a temporary relationship, for example, as shown in Fig. 8(b), the antenna functional unit 120 is fixed to a cylindrical slider 320, and this slider 320 is attached to the waveguide 110. The slider 320 can move along the waveguide 110. The material of the slider 320 may be a dielectric or a metal. However, also in this example, it is desirable to avoid the presence of an electrical conductor (for example, when the material of the slider 320 is metal, a part or all of the slider 320) between the antenna functional unit 120 and the waveguide 110. The slider 320 serves as a holder for holding the antenna functional unit 120 and as a spacer for keeping the distance between the antenna functional unit 120 and the waveguide 110 constant.

[0020] As another example of a temporary relationship, an example of a form in which the antenna functional unit 120 is attached to a movable object (examples of the movable object include footwear, an object worn on the human body such as an anklet, or a transport robot), and all or part of the waveguide 110 is buried in a structure such as a floor or a passage can be cited. Fig. 8(c) shows an example in the case where the movable object is a transport robot 330. In this case, when the movable object moving on the structure approaches the waveguide 110, that is, when the antenna functional unit 120 attached to the movable object enters a range where the distance from the waveguide 110 is equal to or less than the above upper limit, the antenna functional unit 120 functions as a radiation unit or a reception unit described later. When the movable object has a receiver or a transmitter (the movable object may have electronic components such as an amplifier as necessary), communication is realized between the signal generation device 800 (as described later, not limited to the signal generation device 800, it may also be a reception device or a transceiver) and the receiver or transmitter of the movable object. According to the example in which the antenna functional unit 120 is attached to the movable object, electromagnetic wave radiation occurs only when the movable object approaches the waveguide 110, so the energy utilization efficiency is improved.

[0021] The present invention is not limited to the examples shown in FIGS. 2 to 7, and a cover 110b made of a dielectric may be disposed on the outer periphery of the waveguide 110 having N antenna functional units 120 (see FIG. 9 which is a cross-sectional view perpendicular to the longitudinal direction of the waveguide 110). The cover 110b is in close contact with the waveguide 110 and the antenna functional units 120 on the waveguide 110. Not limited to this example, the cover 110b may cover the waveguide 110 except for the antenna functional units 120, or except for the portion of the waveguide 110 where the antenna functional units 120 are located and the antenna functional units 120. The dielectric constant of the waveguide 110 and the dielectric constant of each block 110c included in the antenna functional unit 120 are larger than the dielectric constant of the cover 110b. For this reason, when there is no antenna functional unit 120, the electromagnetic field of the signal from the signal generation device 800 input to the one end of the waveguide 110 concentrates on the waveguide 110 having a large dielectric constant and is transmitted with low loss toward the other end of the waveguide 110, reaching the other end of the waveguide 110.

[0022] Each block 110c included in the i-th (i ∈ {1, …, N}) antenna functional unit 120 can function as a radiation unit that radiates electromagnetic waves (radio waves as a band). The power lost due to the radiation of electromagnetic waves in the block 110c mainly depends on the shape, size, number, and dielectric constant of the block 110c. From the viewpoint of radiating stronger electromagnetic waves, for example, it is preferable that the dielectric constant of the block 110c is the same as or larger than the dielectric constant of the waveguide 110. More preferably, from the viewpoint of loss, materials with a small dielectric tangent in the frequency band of the electromagnetic waves used are selected as the dielectrics of the waveguide 110 and the block 110c, respectively. Generally, as the dielectric constant increases, the dielectric tangent increases. Therefore, considering the radiation amount and the loss amount, the dielectric constants that the dielectrics of the waveguide 110 and the block 110c should have are determined. In this way, when the block 110c exists, the signal from the signal generation device 800 is radiated as electromagnetic waves by this block 110c. Note that "radiation" means that the power lost due to the radiation of electromagnetic waves among the power of the signal that has reached the block 110c exceeds the transmission loss that actually occurs when the block 110c does not exist. The power lost due to the radiation of electromagnetic waves in the block 110c is usually a part of the power of the signal that has reached the block 110c, and the signal with the remaining power passes through the part of the waveguide 110 where the block 110c is located. The signal that has passed through the block 110c propagates through the waveguide 110 and propagates with low loss toward the adjacent block 110c or, if there is no adjacent block 110c, toward the other end of the waveguide 110. The electromagnetic waves radiated by the block 110c are received by a wireless antenna (not shown) of a communication terminal 200 such as a mobile phone.

[0023] The waveguide 110 may have a configuration as a single product, or may have a configuration in which a plurality of waveguides having the same structure (hereinafter referred to as sub-waveguides) are connected in a row, for example. In the latter case, as the connection between the sub-waveguides, referring to optical fibers, a connection by fusion or a connection using a connector can be adopted. Alternatively, the sub-waveguides may be connected to each other by welding or soldering. The dielectric constant of one of the two adjacent sub-waveguides connected to each other may be different from the dielectric constant of the other sub-waveguide.

[0024] The waveguide 110 may have a branching structure. There is no limitation on the branching shape and the number of branches. Fig. 10 shows an example of the T-shaped waveguide 110 when the number of branches is 2. The waveguide 110 having a branching structure may have a configuration as a single product, or may have a configuration in which, for example, a plurality of sub-waveguides having the same structure are connected. In the latter case, as the connection between the sub-waveguides, for example, a connection using a branched waveguide 350 can be adopted.

[0025] In the above-described embodiment, one end of the waveguide 110 is physically connected to the signal generation device 800, but the configuration is not limited thereto. For example, as shown in Fig. 11, one end of the waveguide 110 may be connected to a part of a medium capable of propagating an electromagnetic wave, and the other part of the medium may be connected to the signal generation device 800. Examples of the medium include a line made of a material different from that of the waveguide 110 (for example, a coaxial line or a waveguide having a dielectric constant different from that of the waveguide 110), air, or an optical fiber. As can be understood from the case where the medium is air, the term "connection" does not necessarily mean only a physical connection, but means a physical aspect in which an electromagnetic wave can propagate. When the medium is the line 110a, as shown in Fig. 11(a), the line 110a and the waveguide 110 are connected to each other using, for example, a connector 360. When the medium is air, for example, as shown in Fig. 11(b), the electromagnetic wave propagation between the signal generation device 800 and the waveguide 110 is realized by the antenna device 370a attached to the signal generation device 800 and the antenna device 370b attached to one end of the waveguide 110. The antenna device 370b attached to one end of the waveguide 110 may include, for example, a repeater that amplifies the captured electromagnetic wave. However, when the alignment between the antenna device 370a attached to the signal generation device 800 and one end of the waveguide 110 is good, one end of the waveguide 110 may directly receive the signal from the signal generation device 800.

[0026] When the medium is the optical fiber 112, as shown in FIG. 11(c) for example, one end of the waveguide 110 is connected to the first optoelectronic converter 380a, the first optoelectronic converter 380a is connected to one end of the optical fiber 112, and the other end of the optical fiber 112 is connected to the second optoelectronic converter 380b of the signal generator 800. The second optoelectronic converter 380b is, for example, a laser diode, which converts the electrical signal generated by the signal generator 800 into an optical signal. The optical signal propagates through the optical fiber 112. The first optoelectronic converter 380a is, for example, a photodiode, which converts the optical signal from the optical fiber 112 into an electrical signal. Therefore, the propagation of electromagnetic waves (light in this example) is realized between the signal generator 800 and the waveguide 110. For example, if a long waveguide 110 from the signal generator 800 to the installation location of the block 110c is used under the situation where the location where the block 110c should be installed is limited to a location far from the signal generator 800, the transmission loss of the waveguide 110 cannot be ignored. Since the transmission loss of the optical fiber 112 is usually smaller than the transmission loss of the waveguide 110, the configuration shown in FIG. 11(c) is beneficial for long-distance low-loss transmission of signals. From the perspective of long-distance low-loss transmission of signals, in the configuration shown in FIG. 11(c), the above-mentioned conditions regarding the shape or arrangement of the block 110c (that is, the angle γ formed by the longitudinal direction of the block 110c and the longitudinal direction of the waveguide 110 is greater than 0 degrees and less than 90 degrees, or the angle γ formed by the direction in which two or more blocks 110c are arranged and the longitudinal direction of the waveguide 110 is greater than 0 degrees and less than 90 degrees) are not necessary, and other technical matters are as described in this specification.

[0027] The waveguide 110 typically has characteristics equivalent to those of a wideband pass filter and can transmit wideband signals. Therefore, as shown in FIG. 1, when the signal input from the signal generation device 800 to the waveguide 110 is a multi-band signal having Q bands (where Q is a predetermined integer satisfying Q≧2), electromagnetic waves of the Q bands are radiated from each block 110c. Also, the optical fiber 112 can typically transmit wideband signals. Therefore, according to the configuration shown in FIG. 11(c), the multi-band signal generated by the signal generation device 800 propagates through the optical fiber 112 as an optical signal by photoelectric conversion, and further propagates through the waveguide 110 as an electrical signal again by photoelectric conversion, and is radiated as electromagnetic waves of the Q bands from each block 110c.

[0028] In the case of a multi-band signal, since the propagation characteristics of the electromagnetic waves radiated into space from the block 110c are different for each band, the optimal position of the block 110c for radiation is different for each band. For example, electromagnetic waves in the high-frequency band are more affected by electromagnetic wave shields. Therefore, if electromagnetic waves in the high-frequency band are radiated from the same position as the optimal position for radiating electromagnetic waves in the low-frequency band, the dead zone increases due to the presence of the electromagnetic wave shield. However, by using the wireless antenna 100 and installing the block 110c at a position on the waveguide 110 that can avoid the electromagnetic wave shield (i.e., the optimal position for radiating electromagnetic waves in the high-frequency band) separately from the block 110c installed at the optimal position for radiating electromagnetic waves in the low-frequency band, preferably, further, by installing a block 110c having an appropriate shape, or by arranging a plurality of blocks 110c in an appropriate direction, the radiation direction of the electromagnetic waves in the high-frequency band is optimized, and as a result, the dead zone due to the electromagnetic wave shield can be reduced.

[0029] Figure 12 shows the radiation directivity of radio waves radiated from two blocks 110c (see Figure 3) installed on the long-side surfaces 111a and 111b of a rectangular waveguide 110 (dielectric constant: 2.1, short side: 7 mm, long side: 14 mm, length: 50 mm) surrounded by air (dielectric constant: 1). Each block 110c is an oblique triangular prism with a bottom surface that is an equilateral triangle with a side length of 5 mm. One side surface of the parallelogram of the oblique triangular prism is in contact with the long-side surface of the waveguide 110 (see Figure 3). As shown in Figure 13, taking the longitudinal direction of the waveguide 110 as the Z-axis, the normal direction of the long-side surface 111a as the X-axis, and the normal direction of the short-side surface 113a as the Y-axis, θ is the angle measured from the Z-axis in the YZ plane, and φ is the angle measured from the X-axis in the XY plane. The directivity is shown by the angle φ at θ = 60°. γ in Figure 12 is the γ shown in Figure 3. When γ = 90°, the maximum radiation directions are 0° and 180°, but when γ = 80°, the maximum radiation directions are 10° and 170°, and when γ = 75°, the maximum radiation directions are 25° and 155°. Therefore, it can be seen that the maximum radiation direction and the radiation directivity of radio waves can be changed according to the change in the angle γ.

[0030] Figures 14 and 15 show the transmission loss (S parameter: S21) and reflection characteristics (S parameter: S11) of a rectangular waveguide 110 (dielectric constant: 2.1, short side: 7 mm, long side: 14 mm, length: 50 mm) with one block 110c installed on each of the long-side surfaces 111a and 111b and surrounded by air (dielectric constant: 1). Each block 110c is an oblique triangular prism with a bottom surface that is an equilateral triangle with a side length of 5 mm. One side surface of the parallelogram of the oblique triangular prism is in contact with the long-side surface of the waveguide 110 (see Figure 3). Here, it is assumed that there is no loss (dielectric loss) caused by the dielectric tangent. From these figures, it can be seen that S21 and S11 do not change significantly even when the angle γ is changed. Therefore, it can be seen that the radiation direction can be changed according to the change in the angle γ without significantly affecting the transmission characteristics and reflection characteristics.

[0031] As described above, when the distances measured along the longitudinal direction from one end of the waveguide 110 of the two different antenna functional units 120 are equal to each other and the two antenna functional units 120 are located at positions 180 degrees apart from each other on the circumference of the waveguide 110, as can be seen from FIG. 12 for example, it can be seen that radiation is performed in two directions. When it is desired to limit the radiation direction to one direction, as shown in FIG. 16 which is a cross-sectional view along the longitudinal direction of the waveguide 110, a reflector 150 is installed above the antenna functional unit 120 that radiates electromagnetic waves in an unwanted radiation direction. In the example shown in FIG. 16(a), the waveguide 110 is surrounded by a dielectric 160 having a dielectric constant smaller than that of the waveguide 110, and the reflector 150 is installed on the outer surface of the dielectric 160. The reflector 150 may be made of metal or a dielectric having a dielectric constant different from that of the waveguide 110 or each block 110c included in the antenna functional unit 120, but preferably has a condition that the electromagnetic waves radiated from the antenna functional unit 120 are totally reflected. It is not limited to the example shown in FIG. 16(a), and as shown in FIG. 16(b), a support member 165 having a function of supporting the reflector 150 may be used (this example is useful, for example, when the dielectric 160 is air in the example of FIG. 16(a)).

[0032] Even when there is one antenna functional unit 120 at a certain part on the waveguide 110 or in the vicinity of the waveguide 110 away from the waveguide 110, electromagnetic waves are radiated not only in the first direction away from the waveguide 110 but also in the second direction opposite to the first direction from the antenna functional unit 120. When it is desired to limit the radiation direction to the first direction, as shown in FIG. 17 which is a cross-sectional view along the longitudinal direction of the waveguide 110, a reflector 150 is installed above the antenna functional unit 120 in the second direction. In the example shown in FIG. 17(a), the waveguide 110 is surrounded by a dielectric 160 having a dielectric constant smaller than that of the waveguide 110, and the reflector 150 is installed on the outer surface of the dielectric 160. The reflector 150 may be made of metal or a dielectric having a dielectric constant different from that of the waveguide 110 or each block 110c included in the antenna functional unit 120, but it has the condition that the electromagnetic waves radiated from the antenna functional unit 120 are preferably totally reflected. Not limited to the example shown in FIG. 17(a), as shown in FIG. 17(b), a support member 165 having a function of supporting the reflector 150 may be used (this example is useful, for example, when the dielectric 160 is air in the example of FIG. 17(a)).

[0033] When the waveguide 110 has two or more antenna functional units 120, the total number N of the antenna functional units 120 is determined according to the desired power lost by the radiation of electromagnetic waves. The power of the signal from the signal generation device 800 input to one end of the waveguide 110 needs to be the total power obtained by adding the actual transmission loss occurring in the part that functions as a waveguide in the waveguide 110 to the sum of the power lost by the radiation of electromagnetic waves at each antenna functional unit 120 and the other end of the waveguide 110.

[0034] Alternatively, when the power of the signal from the signal generation device 800 input to the one end of the waveguide 110 (hereinafter referred to as the input power) is predetermined, the power obtained by subtracting the actually occurring transmission loss in the portion functioning as a waveguide in the waveguide 110 from the input power is distributed to the power lost by the electromagnetic wave radiation at each antenna function unit 120 and the other end of the waveguide 110, and the degree of radiation at each antenna function unit 120 is determined according to the distributed power. For example, there may be a case where equal radiation loss is desired at each antenna function unit 120. In this case, assuming that there are N antenna function units 120, if they are called the first, second,..., i-th,..., N-th antenna function units 120 from the side closer to the signal generation device 800, the degree of radiation of the i-th antenna function unit 120 (i ∈ {1,..., N}) may be adjusted so that the power represented by a ratio of 1 / (N - i + 1) of the power of the signal reaching the site where the i-th antenna function unit 120 is located is lost by radiation. In this case, at the N-th antenna function unit 120, almost all of the power of the signal reaching here is lost by radiation, so there is almost no electromagnetic wave radiation at the other end of the waveguide 110. For example, when N = 5, the first, second, third, and fourth antenna function units 120 each radiate -7 dB (1 / 5), -6 dB (1 / 4), -4.8 dB (1 / 3), -3 dB (1 / 2) of the reached signal as electromagnetic waves, and the fifth antenna function unit 120 radiates almost all of the power of the reached signal as electromagnetic waves.

[0035] According to the above example, since the ratio of the power of the signal reaching the i-th antenna function unit 120 and the radiation loss increases as i increases, the shape, size, etc. of each block 110c included in the antenna function unit 120 are selected so that the radiation power increases at the i-th antenna function unit 120 as i increases.

[0036] In the wireless antenna 100 of the embodiment shown in FIGS. 3 to 7, if the close contact state of all the blocks 110c included in the j-th antenna functional unit 120 (j ∈ S, where S is a predetermined subset excluding the empty set of the set {1, …, N}) is not maintained in a permanent manner, the close contact state of all the blocks 110c included in the j-th antenna functional unit 120 that causes a part of the waveguide 110 to function as an electromagnetic wave radiation part can be eliminated at any time. That is, the close contact state of all the blocks 110c included in the j-th antenna functional unit 120 is continuously maintained during the period when it is necessary for a part of the waveguide 110 to function as an electromagnetic wave radiation part. However, when such a need no longer exists, the close contact state of all the blocks 110c included in the j-th antenna functional unit 120 at the part that functions as the radiation part is eliminated. The part where the close contact state is eliminated loses its function as an electromagnetic wave radiation part and functions as a waveguide. Therefore, according to the change of the service area, the position of the electromagnetic wave radiation part, that is, the position where the antenna functional unit 120 is attached to the waveguide 110, can be easily changed.

[0037] The above wireless antenna 100 can be used not only as a transmitting antenna but also as a receiving antenna. In this case, for example, a receiving device is connected to the one end of the waveguide 110 instead of the signal generating device 800. For example, electromagnetic waves emitted from a mobile phone are absorbed by the receiving section (i.e., the antenna functional section 120) and transmitted to the receiving device through the waveguide 110. The 3 dB loss is caused by the electromagnetic waves absorbed by the receiving section being distributed toward the one end and the other end of the waveguide 110. A transceiver having both transmitting and receiving functions may be connected to the one end of the waveguide 110 instead of the signal generating device 800. In addition, (1) a configuration in which a receiving device is connected to the other end of the waveguide 110 to which the signal generating device 800 is connected at the one end can also be adopted, (2) a configuration in which a receiving device is connected to the other end of the waveguide 110 to which the transceiver is connected at the one end can also be adopted, (3) a configuration in which receiving devices are connected to each of the one end and the other end of the wireless antenna 100 can also be adopted, and (4) a configuration in which transceivers are connected to each of the one end and the other end of the wireless antenna 100 can also be adopted. In particular, according to the configurations of (2), (3), and (4), the above-mentioned 3 dB loss can be eliminated by synthesizing the electromagnetic waves received by the receiving functions of the devices connected to both ends of the waveguide 110 by a synthesizer (not shown).

[0038] The technical features disclosed in the above various embodiments are not necessarily mutually exclusive. As long as there is no contradiction from a technical perspective, the technical features of one embodiment may be applied to the technical features of another embodiment.

[0039] <Addendum> The present invention has been described with reference to exemplary embodiments, and those skilled in the art will understand that various changes can be made and its elements can be replaced with equivalents without departing from the scope of the present invention. Further, many modifications can be made to adapt a particular system, device, or its components to the teachings of the present invention without departing from the essential scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed for carrying out the present invention, but is intended to include all embodiments included in the appended claims.

[0040] Furthermore, the use of terms such as "first", "second", etc. does not indicate order or importance if any, and the terms "first", "second", etc. are used to distinguish elements. The terms used herein are for the purpose of describing embodiments and are in no way intended to limit the present invention. The term "comprising" and its inflected forms, when used in this specification and / or the appended claims, disclose the presence of the recited features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The term "and / or" includes any and all combinations of one or more of the associated listed elements if any. In the claims and the specification, unless otherwise specified, "connected", "coupled", "joined", "linked", or their synonyms, and all their inflected forms, do not necessarily negate the existence of one or more intermediate elements between, for example, two that are "connected" or "coupled" to each other or "linked" to each other. In the claims and the specification, the term "any" should, if any, be understood as a term having the same meaning as the universal quantifier ∀ unless otherwise specified. For example, the expression "for any X" has the same meaning as "for all X" or "for each X".

[0041] Unless otherwise defined, all terms (including technical and scientific terms) used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, terms such as those defined in commonly used dictionaries shall be interpreted to have a meaning that coincides with their meaning in the context of the relevant art and this disclosure, and shall not be interpreted ideally or overly formally unless explicitly defined otherwise.

[0042] In the description of the present invention, it will be understood that many techniques and steps are disclosed. Each of these has individual advantages and can also be used in combination with one or more, or in some cases all, of the other disclosed techniques. Therefore, to avoid complication, this specification refrains from describing every possible combination of the individual techniques or steps. Nevertheless, the specification and claims should be read with the understanding that such combinations are fully within the scope of the present invention and the claims.

[0043] In the following claims, all corresponding structures, materials, acts, and equivalents of the functional elements combined with means or steps are intended to include structures, materials, or acts for performing functions in combination with other elements if any.

[0044] The embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Various changes and modifications are permitted without departing from the gist of the present invention. The selected and described embodiments are for explaining the principles of the present invention and its practical applications. The present invention can be used in various embodiments with various changes or modifications, and such changes or modifications are determined according to the expected uses. All such changes and modifications are intended to be included within the scope of the present invention defined by the appended claims and are intended to be given the same protection when interpreted in accordance with the breadth given fairly, legally, and equitably.

Claims

1. A wireless antenna capable of transmitting and receiving signals in the millimeter-wave band or the quasi-millimeter-wave band, comprising a cable-shaped waveguide formed of a dielectric and an antenna functional part, wherein the dielectric constant of the waveguide is greater than the dielectric constant of the surroundings of the waveguide excluding the antenna functional part, the antenna functional part includes M (where M is a predetermined integer of 1 or more) blocks formed of a dielectric, each of the M blocks is located on the waveguide or in the vicinity of the waveguide, when M = 1, the angle formed by the longitudinal direction of the one block and the longitudinal direction of the waveguide, or when M ≥ 2, the angle formed by the direction in which the M blocks are arranged and the longitudinal direction of the waveguide is greater than 0 degrees and less than 90 degrees Wireless antenna.

2. In the wireless antenna according to Claim 1, the M blocks are fixed to the waveguide Characterized by a wireless antenna.

3. In the wireless antenna according to Claim 1, the M blocks can be removed from the waveguide Characterized by a wireless antenna.

4. In the wireless antenna according to any one of Claims 1 to 3, the dielectric constant of each of the M blocks is equal to or greater than the dielectric constant of the waveguide Characterized by a wireless antenna.

5. In the wireless antenna according to any one of Claims 1 to 4, further comprising another antenna functional part, the another antenna functional part includes W (where W is a predetermined integer of 1 or more) blocks formed of a dielectric, each of the W blocks is located on the waveguide or in the vicinity of the waveguide, when W = 1, the angle formed by the longitudinal direction of the one block and the longitudinal direction of the waveguide, or when W ≥ 2, the angle formed by the direction in which the M blocks are arranged and the longitudinal direction of the waveguide is greater than 0 degrees and less than 90 degrees, when the antenna functional part and the another antenna functional part are located at positions 180 degrees apart from each other on the circumference of the waveguide, the longitudinal direction of the one block (when M = 1) or the direction in which the M blocks are arranged (when M ≥ 2) in the antenna functional part and the longitudinal direction of the one block (when W = 1) or the direction in which the W blocks are arranged (when W ≥ 2) in the another antenna functional part are in a mirror-symmetric relationship Characterized by a wireless antenna.

6. In the wireless antenna according to any one of Claims 1 to 5, the waveguide has a branched structure characterizing the wireless antenna.

7. In the wireless antenna according to any one of Claims 1 to 6, the waveguide is connected to a medium capable of propagating electromagnetic waves characterizing the wireless antenna.

8. A wireless communication system including a wireless antenna and a communication terminal, wherein the wireless antenna includes a cable-shaped waveguide formed of a dielectric and an antenna functional part, the dielectric constant of the waveguide is larger than the dielectric constant of the surroundings of the waveguide excluding the antenna functional part, the antenna functional part includes M (where M is a predetermined integer of 1 or more) lumps formed of a dielectric, each of the M lumps is located on or near the waveguide, the angle formed by the longitudinal direction of the one lump when M = 1 and the longitudinal direction of the waveguide, or the angle formed by the direction in which the M lumps are arranged when M ≥ 2 and the longitudinal direction of the waveguide is larger than 0 degrees and smaller than 90 degrees, the communication terminal receives, with the antenna of the communication terminal, the electromagnetic waves radiated from the antenna functional part, the antenna functional part receives the electromagnetic waves from the antenna of the communication terminal [[ID=!7]]characterizing the wireless communication system.

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