JP2006148688A - Antenna structure and wireless radio providing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control directivity by a simple constitution. <P>SOLUTION: In an antenna structure 1 disposing a dielectric substrate 2 providing a radiation electrode 3 on a rectangular substrate 4, the radiation electrode 3 is designed to perform a wireless communication with circularly polarized electric wave by providing a configuration of the radiation electrode 3 to be shrunk and separated, in which a length of any one of edges of the rectangular substrate 4 is shorter than one wave length of the electric wave of a predetermined frequency band for the wireless communication. In the rectangular substrate 4, a ground electrode 5 is formed approximately all over the substrate 4 except for a slit 10 for directivity control. The slit 10 for directivity control is a slit which is extended and formed toward a disposing area of the dielectric substrate 2 from a pair of respective edges 5A, 5B side in the substrate 4 opposing to each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antenna structure that performs wireless communication using circularly polarized waves, and a wireless communication device including the antenna structure.

  FIG. 9A is a schematic perspective view showing an example of the antenna structure, and FIG. 9B is a schematic plan view of the antenna structure of FIG. 9A viewed from above. It is shown. The antenna structure 1 includes a dielectric base 2, a radiation electrode 3, a mounting substrate 4, and a ground electrode 5 as described below. That is, in this example, the dielectric substrate 2 has a rectangular parallelepiped shape and is mounted on the mounting substrate 4. A radiation electrode 3 is formed on the square upper surface of the dielectric substrate 2. The radiation electrode 3 has a square shape, and the length of one side of the square radiation electrode 3 is about ½ of the wavelength λ of the frequency band used for wireless communication. The two corners at the diagonal positions are notched so as to be degenerated and separated, and the radiation electrode 3 is configured to be able to perform radio communication of circularly polarized radio waves. A ground electrode (not shown) is formed on almost the entire bottom surface of the dielectric substrate 2, and the dielectric substrate 2, the radiating electrode 3 and the ground electrode shown in this example constitute a circularly polarized microstrip antenna. is doing.

  A feeding electrode 6 is formed on the side surface of the dielectric substrate 2. One end side of the feeding electrode 6 is disposed so as to be spaced from the radiation electrode 3 and is electromagnetically coupled to the radiation electrode 3 via a capacitor. The other end of the power supply electrode 6 is joined to a power supply conductor pattern 7 formed on the mounting substrate 4, and a high frequency circuit for wireless communication provided in, for example, a wireless communication device via the power supply conductor pattern 7. 8 is connected. The mounting substrate 4 is a rectangular substrate made of a dielectric, and a ground electrode 5 is provided on the upper surface of the mounting substrate 4 over almost the entire surface avoiding the region where the power supply conductor pattern 7 is formed.

  In such an antenna structure 1, for example, when a signal for transmission is supplied from the high-frequency circuit 8 for wireless communication to the power supply electrode 6 via the power supply conductor pattern 7, the signal is transmitted to the power supply electrode 6 and the radiation electrode. It is transmitted to the radiation electrode 3 by electromagnetic coupling via a capacitance between the three. The radiation electrode 3 is excited by this signal supply, whereby circularly polarized radio waves are radiated and the signal is transmitted wirelessly. When a radio wave arrives at the radiation electrode 3 and the radiation electrode 3 is excited and receives a signal, the received signal is transmitted from the radiation electrode 3 to the power supply electrode 6 by electromagnetic coupling between the radiation electrode 3 and the power supply electrode 6. The high frequency circuit 8 for wireless communication is supplied through the power supply electrode 6 and the power supply conductor pattern 7.

JP 2000-183637 A JP 2004-134860 A JP 2001-274719 A

The radio wave radiated from the radiation electrode 3 is affected by the ground electrode 5 of the mounting substrate 4. In particular, when the length of any one side of the ground electrode 5 is one wavelength or less in the frequency band for wireless communication, the influence of the ground electrode 5 on the radio wave is large. For example, in the antenna structure 1 shown in FIG. 9, the ground electrode 5 has a rectangular shape, and due to this shape, for example, the directivity of the radiation electrode 3 in the YZ plane along the short side (on the short side side) The directivity) is as shown by the solid line A in the graph of FIG. 9C representing the antenna gain characteristics, and the directivity of the radiation electrode 3 in the XZ plane along the long side (the directivity on the long side). 9) is indicated by a solid line B in the graph of FIG. 9D showing the antenna gain characteristics, and there is a difference between the directivity on the short side and the directivity on the long side. For example, in FIG. 9C and FIG. 9D, when attention is paid to a portion where the antenna gain which is a standard for good radio communication is α, the directivity on the short side is an angle range of θ ₀ , and the directivity on the long side is The angle is in the angle range of θ ₁ , and the directivity on the short side is wider than the directivity on the long side.

  By the way, there arises a problem that as the antenna directivity becomes a wide angle, it is easily affected by noise from the lateral direction. For this reason, if the directivity on the short side is wide-angle, for example, in a system that regulates the directivity in the lateral direction by standards, such as ETC (Electronic-Toll-Collection (automatic toll collection system)), May be inappropriate. Therefore, in order to suppress the wide angle of the directivity on the short side, a means such as changing the shape of the ground electrode 5 to a square shape can be considered, but the shape of the ground electrode 5, that is, the mounting substrate 4 is considered. The degree of design freedom with respect to the shape of the mounting substrate 4 is very low, and the shape of the mounting substrate 4 cannot be changed.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an antenna structure capable of adjusting the directivity of a radiation electrode with a simple configuration regardless of the shape of the ground electrode, and the antenna structure. It is providing the radio | wireless communication apparatus provided with.

  In order to achieve the above object, the present invention has the following configuration as means for solving the above problems. In other words, the antenna structure of the present invention is an antenna structure in which a dielectric substrate provided with a radiation electrode is disposed on a rectangular substrate, and the radiation electrode has a form of degenerate separation so that a circularly polarized radio wave is generated. Wireless communication is performed, and the length of any one side of the rectangular substrate is configured to be equal to or less than one wavelength of radio waves in a predetermined frequency band for wireless communication. The ground electrode is formed on almost the entire surface of the substrate avoiding the directivity control slit, and the directivity control slit is disposed on each side of the pair of substrates facing each other. It is characterized by the fact that it is formed as a slit extending toward the region.

  The antenna structure according to the present invention is an antenna structure in which a dielectric substrate provided with a radiation electrode is disposed on an elliptical substrate, and the radiation electrode has a form of degenerate separation so that a circularly polarized radio wave is generated. Wireless communication is performed, and the major axis of the elliptical board is configured to have a wavelength equal to or less than one wavelength of radio waves in a predetermined frequency band for wireless communications, and the elliptical board has directivity control. A ground electrode is formed on almost the entire surface of the substrate avoiding the slits for directivity, and the slits for directivity control are formed from the edge of the substrate in the direction along the major axis or minor axis of the elliptical substrate. It is also characterized by a slit that extends toward the arrangement region. Furthermore, the wireless communication device of the present invention is characterized in that an antenna structure having a configuration unique to the present invention is provided.

  According to this invention, the ground electrode has a configuration in which the directivity control slit is formed to extend from the edge side of the substrate toward the region where the dielectric substrate is disposed. By providing the directivity control slit on the edge side of the ground electrode, the ground current flowing through the edge portion of the ground electrode where the directivity control slit is provided flows while bypassing the slit. . For this reason, the current path length of the ground current at the edge portion of the ground electrode where the directivity control slit is provided is longer than that when the directivity control slit is not provided. As a result, the electrical length (electrical length) becomes longer at the edge portion of the ground electrode where the slit for directivity control is provided, and the size of the edge portion of the ground electrode is electrically increased. can do.

  Generally, as the size of the ground electrode becomes smaller, it becomes easier for radio waves to wrap around to the ground electrode side, thereby widening the directivity. On the other hand, by forming a slit as described above to electrically increase the size of the ground electrode, the wraparound of radio waves to the ground electrode side is suppressed, and widening of directivity is suppressed. Can do.

  For example, when the ground electrode (substrate) has a rectangular shape, the directivity on the short side of the ground electrode (substrate) is easier to widen than the directivity on the long side. When suppression of widening of the directivity on the short side is required, a directivity control slit is formed on each short side of the ground electrode facing each other. Thereby, widening of the directivity on the short side of the ground electrode can be suppressed as described above. Thus, by adjusting the formation position, the number of slits, and the slit length (slit depth) of the directivity control slit provided on the ground electrode, the ground electrode is rectangular (rectangular or square). Even in the case of an elliptical shape, it is possible to control the narrowing (widening) of directivity regardless of the shape of the ground electrode.

  The ground electrode has not only one or more directivity control slits extending from each side of the first set of the rectangular substrate facing each other, but also the second electrode of the substrate facing each other. In the case of having a configuration in which one or more directivity control slits are extended from each side of the set, the ground electrode is compared to the case where no directivity control slit is provided. The directivity on the side of the first group and the directivity on the side of the second group of (substrate) can be reduced. In addition, the total value of the slit lengths of the directivity control slits provided on each side of the one set of the first set and the second set is equal to each side of the other set. Is larger than the total value of the slit lengths of the directivity control slits provided in each, the directivity on the side of the group with the larger total value is greater than the directivity on the side of another group. Can also be greatly reduced.

  Furthermore, in the configuration where the slit for directivity control is formed by cutting the substrate into a slit shape, the slit is formed not only on the ground electrode but also on the substrate, so the slit is formed only on the ground electrode. The effect of suppressing the widening of directivity by the directivity control slit is greater than when no slit is formed in the substrate. That is, when a slit is provided in the ground electrode, the direction of the ground current flowing through the ground electrode portion on one slit side edge of the side edges on both sides of the slit and the slit side edge on the other side The directions of the ground currents flowing through the ground electrode portions are opposite to each other. When the ground currents on both sides of the slit are electromagnetically coupled, a part of the ground currents on both sides of the slit cancel each other according to the magnitude of the coupling, and the electrical length due to the provision of the slits Extension effect is suppressed. The magnitude of the coupling of the ground current on both sides of the slit is greatly related to the capacitance value between the side edges on both sides of the slit. The larger the capacitance value, the stronger the coupling of the ground current on both sides of the slit. The effect of extending the electrical length is reduced.

  In general, since the relative permittivity of the dielectric constituting the substrate is larger than 1, the capacitance between both side edges of the slit is larger when the substrate is in the slit portion than when the substrate is not in the slit portion. Will grow. In other words, when there is no substrate in the slit portion, the capacity between both side edges of the slit is smaller than when the substrate is in the slit portion. For this reason, by forming a slit by cutting out the substrate, the coupling of the ground current on both sides of the slit becomes weak, and the effect of extending the electrical length by the slit can be greatly obtained. That is, the effect of suppressing the widening of the directivity by the directivity control slit can be greatly obtained by cutting the substrate to form the directivity control slit.

  In a wireless communication apparatus provided with an antenna structure having a specific configuration in the present invention, it is easy to have a narrow-angle directivity, and thus a narrow-angle directivity such as ETC is desired. A wireless communication device can be easily provided.

  Embodiments according to the present invention will be described below with reference to the drawings. In the description of the embodiment described below, the same components as those of the antenna structure shown in FIG. 9 are denoted by the same reference numerals, and redundant description of common portions is omitted.

  1A is a schematic perspective view showing the antenna structure of the first embodiment, and FIG. 1B is a schematic plan view of the antenna structure of FIG. 1A as viewed from above. It is shown by the figure. In the first embodiment, the mounting board 4 is a rectangular board made of a dielectric, and the length L of the long side of the mounting board 4 is a predetermined frequency band for wireless communication. The length of the radio wave is one wavelength or less. In other words, the length of any one side of the mounting substrate 4 is equal to or shorter than one wavelength of radio waves in a predetermined frequency band for wireless communication.

  A ground electrode 5 is formed on almost the entire top surface of the mounting substrate 4. When the ground electrode 5 has a rectangular shape as shown in FIGS. 9A and 9B, the directivity on the short side by the radiation electrode 3 (that is, Y− including the direction along the short side) as described above. The directivity in the Z plane is easier to widen than the directivity on the long side (that is, the directivity in the XZ plane including the direction along the long side). In the first embodiment, the following unique configuration is provided to suppress widening of the directivity on the short side.

  That is, in the first embodiment, the dielectric substrate 2 including the radiation electrode 3 is disposed at the center of the upper surface of the mounting substrate 4, and the ground electrode 5 on the upper surface of the mounting substrate 4 includes Directivity control slits 10 are formed to extend from the short sides of the mounting substrate 4 facing each other toward the region where the dielectric substrate 2 is disposed. In the first embodiment, three directivity control slits 10 are formed on each of the opposing short sides 5A and 5B of the ground electrode 5 (mounting substrate 4), as shown in FIG. The three directivity control slits 10 on the left side 5A side and the three directivity control slits 10 on the right side 5B side are symmetrical with respect to the center line along the Y direction of the mounting substrate 4. Each of the positions is arranged and formed. In the first embodiment, all directivity control slits 10 are formed by cutting the mounting substrate 4 into a slit shape. Furthermore, all the slits 10 for directivity control have the same slit width and slit length.

  In the first embodiment, as described above, since the ground electrode 5 is provided with the slits 10 for directivity control on the short sides 5A and 5B side, the ground flowing through the short sides 5A and 5B of the ground electrode 5 is provided. For example, as shown by a solid line I in FIG. 1B, the current is passed through the slit 10 to be energized. For this reason, the current path length of the ground current at the short sides 5A and 5B of the ground electrode 5 is longer than that when the slit 10 is not provided. The length becomes longer. Thus, when the electrical length on the short side 5A, 5B side of the ground electrode 5 is increased, the size on the short side 5A, 5B side of the ground electrode 5 is increased in terms of electrical appearance. Is prevented from widening.

2A shows a result obtained by simulating the directivity on the short side of the ground electrode in the antenna structure 1 of the first embodiment by a solid line A, and FIG. 2B shows the ground in the antenna structure 1. The solid line B indicates the result of obtaining the directivity on the long side of the electrode by simulation. When the slit 10 is not provided on the short sides 5A and 5B side of the ground electrode 5, the directivity on the short side in the antenna gain α is within the angle range of θ ₀ shown in FIG. In this first embodiment, since the slit 10 is provided on the short side 5A, 5B side of the ground electrode 5, the short side 5A, 5B side of the ground electrode 5 is provided. When the size can be increased in terms of electrical appearance, the directivity on the short side in the antenna gain α is in the angle range of θ ₀ ′ shown in FIG. 2A, and the slit 10 is not provided. In comparison, it can be seen from the simulation that widening is suppressed. Further, as is clear from the comparison between FIG. 2A and FIG. 2B, the directivity at the antenna gain α can be controlled to be substantially the same on both the short side and the long side. I understand.

  In the first embodiment, in order to suppress widening of the directivity on the short sides 5A and 5B side of the ground electrode 5, an example in which the directivity control slit 10 is provided on the short sides 5A and 5B side. Although shown, for example, the wide angle of the directivity on the short sides 5A and 5B may be left as it is, but there is a demand for further promoting the narrowing of the directivity on the long sides 5C and 5D. . In this case, the directivity control slit 10 is not provided on the short sides 5A and 5B, but the directivity is formed on the long sides 5C and 5D so as to extend toward the region where the dielectric substrate 2 is disposed. A control slit is provided.

  The second embodiment will be described below. In the description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and duplicate descriptions of common portions are omitted.

  In the second embodiment, the configuration that can suppress the wide angle of the directivity on the short side of the mounting substrate 4 and can meet the demand for further narrowing the directivity on the long side of the mounting substrate 4. It has. In other words, in the second embodiment, as shown in the schematic plan view of FIG. 3, the ground electrode 5 is directed to the opposing short sides 5A and 5B as in the first embodiment. In addition to the slits 10 for controlling the directivity, the slits 11 for controlling the directivity are also formed on the opposing long sides 5C and 5D. In this second embodiment, two directivity control slits 11 are formed by cutting the mounting substrate 4 in a slit shape on each of the opposing long sides 5C and 5D of the ground electrode 5. . In addition, all the slits 11 for controlling directivity have the same slit length and slit width. Further, the total value of the slit lengths of all the directivity control slits 11 is smaller than the total value of the slit lengths of all the directivity control slits 10. In the second embodiment, the configuration other than the configuration related to the directivity control slit 11 is the same as that of the first embodiment.

  In the second embodiment, the directivity control slit 10 is provided on the short sides 5A and 5B side of the ground electrode 5, so that the directivity of the short sides 5A and 5B is reduced as in the first embodiment. Widening of the angle can be suppressed. Also, by providing the directivity control slit 11 on the long sides 5C and 5D side of the ground electrode 5, the path length of the ground current passing through the long sides 5C and 5D of the ground electrode 5 becomes long, and the ground electrode 5 The electrical length of the long sides 5C and 5D can be increased. Thereby, the size of the long sides 5C and 5D side of the ground electrode 5 is increased in terms of electrical appearance, and the narrowing of the directivity on the long sides 5C and 5D side can be promoted.

  In the second embodiment, the total value of the slit lengths of the directivity control slits 10 formed on the short sides 5A and 5B of the ground electrode 5 (each side of the first set) is , Larger than the total slit length of the directivity control slits 11 formed on the long sides 5C and 5D (each side of the second set). For this reason, the formation of the directivity control slit 11 can of course achieve the effect of promoting the narrowing of the directivity on the long side, but the directivity is more than this effect. The effect of suppressing the wide angle of the directivity on the short side by the control slit 10 is stronger.

  In this second embodiment, the total slit length of all the directivity control slits 10 is used in order to exert a strong effect of suppressing the wide angle of the directivity on the short side by the directivity control slit 10. The value was larger than the total value of the slit lengths of the directivity control slits 11 on all the long sides. For example, the narrow angle of the directivity on the long sides by the directivity control slit 11 is reduced. When it is desired to exert a strong promotion effect, the total slit length of the directivity control slits 11 on all long sides is set to the total slit length of the directivity control slits 10 on all short sides. Make it larger than the value.

  The third embodiment will be described below. In the description of the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and a duplicate description of the common portions is omitted.

  In the third embodiment, as shown in the schematic plan view of FIG. 4, the mounting substrate 4 has a square shape, and the ground electrode 5 is formed on almost the entire upper surface of the square mounting substrate 4. Has been. When the ground electrode 5 has a square shape, the directivity on the side of the first set of sides 5A and 5B facing the ground electrode 5 shown in FIG. 4 and the side of the second set of ground electrode 5 facing each other. The directivity on the 5C and 5D side is almost the same. On the other hand, there is a case where it is desired that the directivity on the sides 5A and 5B side of the ground electrode 5 be narrower than the directivity on the sides 5C and 5D while the mounting substrate 4 is square.

  In the third embodiment, a configuration for meeting such a demand is provided. That is, in this third embodiment, the directivity control slits 10 are respectively formed on the sides 5A and 5B on the side of the ground electrode 5 where narrowing of directivity is desired. The slit 10 is formed by cutting out the mounting substrate 4, and the slit 10 can promote the narrowing of the directivity on the sides 5 </ b> A and 5 </ b> B of the ground electrode 5.

  In the third embodiment, an example in which slits 10 for directivity control are provided on the pair of sides 5A and 5B facing each other of the ground electrode 5 is shown. When not only the directivity on the sides 5A and 5B side of the first set, but also the narrowness of the directivity on the sides 5C and 5D side of the second set facing the ground electrode 5 is desired, Not only is the directivity control slit 10 provided on the sides 5A and 5B of the ground electrode 5, but also the directivity control slit is provided on the sides 5C and 5D of the ground electrode 5. When it is desired to make the degree of directivity narrowing on the sides 5A and 5B side substantially the same as the degree of directivity narrowing on the sides 5C and 5D, directivity control provided on the sides 5A and 5B side. The slit forming conditions such as the number of slits to be formed and the slit length are the same as those for the directivity control slits provided on the sides 5C and 5D.

  Further, when the directivity on the sides 5A and 5B side of the ground electrode 5 is desired to be narrower than the directivity on the sides 5C and 5D side, for example, as shown in the plan view of FIG. The total value of the slit lengths of all the directivity control slits 10 on the 5A, 5B side is larger than the total value of the slit lengths of all the directivity control slits 11 on the sides 5C, 5D side. The number of slits 10 and 11 for directivity control, the slit length, and the slit width are set.

  Furthermore, when the directivity on the sides 5C and 5D side of the ground electrode 5 is desired to be narrower than the directivity on the sides 5A and 5B, all directivity control on the sides 5C and 5D is used. The directivity control slits 10 and 11 are formed so that the total value of the slit lengths of the slits 11 is larger than the total slit length of all the directivity control slits 10 on the sides 5A and 5B. Set the number, slit length, and slit width.

  The fourth embodiment will be described below. The fourth embodiment relates to a wireless communication device. The wireless communication device of the fourth embodiment is characterized in that any one of the antenna structures 1 shown in the first to third embodiments is provided. There are various configurations of the wireless communication device other than the configuration related to the antenna, and any configuration may be adopted here, and the description thereof is omitted. Further, since the configuration of the antenna structure 1 has been described in each of the first to third embodiments, redundant description thereof will be omitted.

  In addition, this invention is not limited to the form of each 1st-4th embodiment, Various embodiment can be taken. For example, in each of the first to fourth embodiments, the directivity control slits 10 and 11 are formed by cutting the mounting substrate 4 into a slit shape. As shown in the perspective view of FIG. 7A and the plan view of FIG. 7B, the slit 10 may be formed only in the ground electrode 5 and the slit may not be formed in the mounting substrate 4.

  In the first to fourth embodiments, the directivity control slits 10 are arranged symmetrically on the left side 5A side and the right side 5B side of the ground electrode 5, respectively. As shown in FIG. 6A, the directivity control slit 10 on the left side 5A side of the ground electrode 5 and the directivity control slit 10 on the right side 5B side may be arranged asymmetrically.

  In the first to fourth embodiments, the number of directivity control slits 10 on the left side 5A side of the ground electrode 5 and the number of directivity control slits 10 on the right side 5B side are as follows. For example, when it is desired to make the directivity on the right side 5B side narrower than the directivity on the left side 5A side, as shown in FIG. 6B, for directivity control on the right side 5B side. The number of slits 10 is increased more than the number of directivity control slits 10 on the left side 5A side, or the slit length of the directivity control slit 10 on the right side 5B side is set for directivity control on the left side 5A side. The total slit length of the directivity control slit 10 on the right side 5B side is longer than the total slit length of the directivity control slit 10 on the left side 5A side. To do. On the other hand, when the directivity on the left side 5A side is desired to be narrower than the directivity on the right side 5B side, the number of directivity control slits 10 and the slit length are adjusted to adjust the directivity on the left side 5A side. The total value of the slit length of the slit 10 for property control is made larger than the total value of the slit length of the slit 10 for directivity control on the right side 5B side.

  Similarly to the above, the directivity on the upper side 5C side and the directivity on the lower side 5D side can also be controlled by adjusting the number of formed directivity control slits 11 and the slit length.

  Furthermore, the shape of the mounting substrate 4 is not limited to the shape shown in FIG. 1 or FIGS. 3 to 7. For example, the mounting substrate 4 may have a rectangular shape with rounded corners. Moreover, the shape where the corner | angular part was cut and chamfered by the plane may be sufficient.

  Further, the mounting substrate 4 may have an elliptical shape as shown in FIG. Also in this case, as in the first to third embodiments, there is provided a directivity control slit that extends from the edge of the mounting substrate 4 toward the region where the dielectric substrate 2 is disposed. Thus, the widening of directivity by the radiation electrode 3 can be controlled. For example, as shown in FIG. 8, when the slit 10 for directivity control is extended from the edge of the mounting substrate 4 toward the arrangement region of the dielectric substrate 2 in the direction along the elliptical long axis. Can suppress the widening of directivity in the YZ plane including the elliptical minor axis direction. In addition, when a slit for directivity control is extended from the edge of the mounting substrate 4 toward the arrangement region of the dielectric substrate 2 in the direction along the elliptical minor axis, the major axis direction of the elliptical shape is It is possible to promote narrowing of directivity in the included XZ plane.

  Furthermore, in each of the first to fourth embodiments, the radiation electrode 3 has a square shape. However, the radiation electrode 3 may be in any form that can perform depolarized separation and perform circularly polarized radio communication, It is not limited to a square shape. Furthermore, although the dielectric base 2 has a rectangular parallelepiped shape, for example, the dielectric 2 may have another shape such as a cylindrical shape. Furthermore, in each of the first to fourth embodiments, the circularly polarized microstrip antenna composed of the dielectric substrate 2, the radiation electrode 3, and the ground electrode is of a one-point capacity feeding type, but the circularly polarized microstrip antenna The strip antenna may be of a two-point capacity feeding method, and the circularly polarized microstrip antenna may be of a direct feeding method in which power is fed directly using a feeding pin. Further, in each of the first to fourth embodiments, the dielectric substrate 2 is disposed at the center of the mounting substrate 4. However, the dielectric substrate 2 is disposed at other portions of the mounting substrate 4. May be. Since the length of any one side of the mounting substrate 4 is one wavelength or less in the frequency band for wireless communication, the dielectric substrate 2 is oriented regardless of the location of the mounting substrate 4. The effects described in the first to fourth embodiments can be obtained by providing the slit for controlling the sex.

It is a figure for demonstrating the antenna structure of the example of 1st Embodiment. It is a graph for demonstrating the effect acquired from the structure of the antenna structure of the example of 1st Embodiment. It is a figure for demonstrating the antenna structure of the example of 2nd Embodiment. It is a figure for demonstrating the antenna structure of the example of 3rd Embodiment. It is a figure showing the modification of the antenna structure of the example of 3rd Embodiment. It is a model figure for demonstrating other example embodiments. It is a model figure for demonstrating another example of another embodiment. It is a model figure for demonstrating another example of another embodiment. It is a figure for demonstrating one example of an antenna structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna structure 2 Dielectric base 3 Radiation electrode 4 Mounting board 5 Ground electrode 8 High frequency circuit for radio | wireless communication 10, 11, 12 Slit for directivity control

Claims (5)

  An antenna structure in which a dielectric substrate provided with a radiation electrode is disposed on a rectangular substrate, and the radiation electrode is configured to degenerate and separate and performs radio communication of circularly polarized radio waves. The length of any one side of the shaped substrate is configured to be one wavelength or less of a radio wave in a predetermined frequency band for wireless communication, and a rectangular substrate is avoided with a slit for directivity control. A ground electrode is formed on almost the entire surface of the substrate, and the directivity control slits are extended from each side of the pair of substrates facing each other toward the region where the dielectric substrate is disposed. An antenna structure characterized by a slit.   The ground electrode is formed with one or more directivity control slits extending from each side of the first set of the substrate facing each other to extend toward the region where the dielectric substrate is disposed, and facing the substrate. One or more directivity control slits are extended from each side of the second set, and the slit lengths of the directivity control slits provided on the respective sides of the first set. 2. The antenna structure according to claim 1, wherein the total value is different from the total value of the slit lengths of the directivity control slits provided on each side of the second set.   An antenna structure in which a dielectric substrate provided with a radiation electrode is disposed on an elliptical substrate, and the radiation electrode is configured to degenerate and separate and performs radio communication of circularly polarized radio waves. The major substrate has a configuration in which the major axis is equal to or less than one wavelength of radio waves in a predetermined frequency band for wireless communication, and an elliptical substrate is almost the same as a substrate that avoids a directivity control slit. A ground electrode is formed on the entire surface, and the slit for directivity control is formed to extend from the edge of the substrate toward the region where the dielectric substrate is disposed in the direction along the major axis or minor axis of the elliptical substrate. An antenna structure characterized by comprising a slit.   4. The antenna structure according to claim 1, wherein the directivity control slit is formed by cutting a substrate into a slit shape.   A wireless communication device comprising the antenna structure according to any one of claims 1 to 4.

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