Antenna device

Abstract

An antenna device (10) comprises: a notch antenna (15) that is provided so as to notch an edge (12b) having a length equivalent to 1 / 4 or greater of the wavelength at the center frequency in the use frequency band of a ground conductor plate (12); a feeding point (16) that is provided so as to span the notch antenna (15) in the width direction thereof; and non-excitable monopole antennas (17a, 17b) that are provided on the ground conductor plate (12) on both sides of the notch antenna (15) in the lengthwise direction of the notch antenna (15).

Description

Antenna device

[0001] The present disclosure relates to an antenna device.

[0002] Patent Document 1 discloses an antenna device, which includes a slot antenna for vertical polarization and a notch antenna for horizontal polarization.

[0003] Japanese Patent Application Laid-Open No. 2003-332834

[0004] The antenna device disclosed in Patent Document 1 has an antenna body obtained by bending a metal plate, and is provided with a slot antenna for vertical polarization and a notch antenna for horizontal polarization. Therefore, the antenna device disclosed in Patent Document 1 needs to have a complex configuration in order to provide the polarization antennas.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an antenna device that can be equipped with a wide-coverage horizontally polarized antenna without using an antenna body obtained by bending a metal plate.

[0006] The antenna device according to the present disclosure comprises a first notch antenna arranged to cut into a first side of a ground conductor plate having a length equal to or greater than ¼ of the wavelength of the center frequency in the operating frequency band of the ground conductor plate, a first feeding point arranged to straddle the first notch antenna in its width direction, and non-excited monopole antennas arranged on both sides of the first notch antenna in the lengthwise direction on the ground conductor plate.

[0007] According to the present disclosure, a wide-coverage horizontally polarized antenna can be provided without using an antenna main body obtained by bending a metal plate.

[0008] 1A is a perspective view of an antenna device according to a first embodiment. FIG. 1B is an enlarged view of a main portion of FIG. 1A. FIG. 1B is a diagram showing an example of dimensions of each portion of the antenna device according to the first embodiment. FIG. 1C is a diagram showing a divider / combiner included in the antenna device according to the first embodiment. FIG. 1D is a diagram showing an operational effect when a non-excited monopole antenna is not included. FIG. 4A is a diagram showing a current flow during excitation. FIG. 4B is a diagram showing a radiation pattern during excitation. FIG. 1C is a diagram showing an operational effect of the antenna device according to the first embodiment. FIG. 5A is a diagram showing a current flow during excitation. FIG. 5B is a diagram showing a radiation pattern during excitation. FIG. 6A is an explanatory diagram of a case where the antenna device according to the first embodiment is used as a diversity antenna. FIG. 6A is a diagram showing a connection state between notch antennas. FIG. 6B is a diagram showing the reflection amplitude of each notch antenna and the transmission amplitude between the notch antennas. FIG. 6C is a diagram showing a radiation pattern during excitation of one notch antenna. FIG. 6D is a diagram showing a radiation pattern during excitation of the other notch antenna. FIG. 6D is a diagram showing an operational effect of a modified example of the antenna device according to the first embodiment. FIG. 9A is an overall perspective view of an antenna device according to embodiment 2. FIG. 9B is a diagram showing the effects of the antenna device according to embodiment 2. FIG. 9A is a diagram showing the flow of current during excitation. FIG. 9B is a diagram showing a radiation pattern during excitation. FIG. 9B is an overall perspective view showing a modified example of the antenna device according to embodiment 2. FIG. 11A is an overall perspective view of an antenna device according to embodiment 3. FIG. 11B is an enlarged view of a main part of FIG. 11A. FIG. 11B is a diagram showing the radiation pattern during excitation of the antenna device according to embodiment 3.

[0009] In order to explain the present disclosure in more detail, embodiments of the present disclosure will be described below with reference to the accompanying drawings.

[0010] First Embodiment An antenna device 10 according to a first embodiment will be described with reference to Figs.

[0011] First, the configuration of an antenna device 10 according to the first embodiment will be described with reference to Fig. 1 to Fig. 3. Fig. 1 is a perspective view of the antenna device 10 according to the first embodiment.

[0012] As shown in Fig. 1, the coordinate system of the antenna device 10 according to the first embodiment is a coordinate system with three orthogonal axes. The Z-axis direction is the thickness direction of the antenna device 10. The X-axis direction and the Y-axis direction are perpendicular to each other. The X-axis direction and the Y-axis direction form a horizontal plane perpendicular to the Z-axis direction. The rotation angle around the Z-axis in the X-Y plane is defined as φ, and the rotation angle around the X-axis in the Z-Y plane is defined as θ.

[0013] The antenna device 10 radiates two mutually orthogonal polarized waves and includes a substrate 11, a notch antenna 13, a feed point 14, a notch antenna 15, a feed point 16, and parasitic monopole antennas 17a and 17b.

[0014] The substrate 11 is, for example, a printed circuit board. The substrate 11 is formed in a rectangular or square shape. Fig. 1 shows an example in which the antenna device 10 has a rectangular substrate 11. The substrate 11 includes a conductive ground conductor plate 12. The ground conductor plate 12 is provided so as to cover the surface of the substrate 11. In this case, the ground conductor plate 12 is formed in a rectangular shape to match the surface of the substrate 11.

[0015] The ground conductor plate 12 has sides 12a and 12b. The sides 12a and 12b are adjacent and perpendicular to each other. The length of each side of the ground conductor plate 12 is equal to or greater than ¼ of the wavelength of the center frequency in the frequency band being used. The side 12a is the second side. The side 12b is the first side.

[0016] The notch antenna 13 is a second notch antenna. The notch antenna 13 is provided so as to cut into the side 12a of the ground conductor plate 12. That is, the notch antenna 13 is cut linearly in the Y-axis direction. The feed point 14 is a second feed point. The feed point 14 is provided so as to straddle the notch antenna 13 in its width direction. The notch antenna 13 and the feed point 14 constitute a vertically polarized antenna.

[0017] Therefore, when power is supplied to feed point 14, a current for radiation flows around notch antenna 13 on ground conductor plate 12. As a result, a vertically polarized wave is radiated from notch antenna 13. At this time, the vertically polarized wave radiated from notch antenna 13 is substantially omnidirectional in the ZY plane.

[0018] The notch antenna 15 is a first notch antenna. The notch antenna 15 is provided so as to cut into the side 12b of the ground conductor plate 12. That is, the notch antenna 15 is cut linearly in the X-axis direction. Therefore, the notch antennas 13 and 15 are provided so as to be perpendicular to each other. The feed point 16 is a first feed point. The feed point 16 is provided so as to straddle the notch antenna 15 in the width direction.

[0019] The non-excited monopole antennas 17a and 17b are each formed of, for example, a single conductive metal plate. The non-excited monopole antennas 17a and 17b are provided on both sides of the notch antenna 15 in the longitudinal direction. The non-excited monopole antennas 17a and 17b are provided so as to be perpendicular to the surface of the ground conductor plate 12. The notch antenna 15, the feeding point 16, and the non-excited monopole antennas 17a and 17b form a horizontally polarized antenna.

[0020] Therefore, when power is supplied to feed point 16, a current for radiation flows around notch antenna 13 on ground conductor plate 12 and through parasitic monopole antennas 17a and 17b. As a result, a horizontally polarized wave is radiated from notch antenna 15. At this time, the horizontally polarized wave radiated from notch antenna 15 has a wide coverage area in the ZY plane.

[0021] As a result, the antenna device 10 can radiate wide-area vertically polarized waves and wide-area horizontally polarized waves.

[0022] Fig. 2 is a diagram showing an example of dimensions of each part of the antenna device 10 according to the first embodiment. Fig. 3 is a diagram showing the distributor / synthesizer 18 included in the antenna device 10 according to the first embodiment.

[0023] 2 , when the wavelength of the center frequency of the frequency band used in the antenna device 10 is λ, the dimensions of each part are, for example, as follows: Length L1 of the substrate 11 and the ground conductor plate 12 = 1.73λ Width W1 of the substrate 11 and the ground conductor plate 12 = 0.93λ Thickness t of the substrate 11 (including the ground conductor plate 12) = 0.04λ Length L2 of the notch antenna 13 = 0.28λ Width W2 of the notch antenna 13 = 0.07λ Length L3 of the notch antenna 15 = 0.16λ Width W3 of the notch antenna 15 = 0.01λ Installation distance D of the non-excited monopole antennas 17a, 17b = 0.19λ Height H of the non-excited monopole antennas 17a, 17b = 0.20λ Width W4 of the non-excited monopole antennas 17a, 17b = 0.11λ

[0024] In order to facilitate impedance matching of the notch antennas 13 and 15, the antenna device 10 makes it possible to change the lengths L2 and L3 of the notch antennas 13 and 15, the widths W2 and W3 of the notch antennas 13 and 15, the longitudinal position of the notch antenna 13 at the feed point 14, and the longitudinal position of the notch antenna 15 at the feed point 16.

[0025] As shown in Fig. 3, the antenna device 10 has a divider / synthesizer 18. The divider / synthesizer 18 is electrically connected to the feed points 14 and 16, respectively. During radio wave transmission, a radio signal input to the antenna device 10 is divided into two by the divider / synthesizer 18. The two divided radio signals are then fed to the feed points 14 and 16, respectively. The notch antennas 13 and 15 then radiate radio waves. During radio wave reception, the radio waves received by the notch antennas 13 and 15 are combined by the divider / synthesizer 18. The combined radio signal is then output from the antenna device 10.

[0026] Next, the effects of the antenna device 10 according to the first embodiment will be described with reference to FIGS. 4 and 5. FIG.

[0027] Fig. 4 shows the effect when the non-excited monopole antennas 17a and 17b are not provided. Fig. 4A shows the current flow during excitation. Fig. 4B shows the radiation pattern during excitation. The horizontal axis of Fig. 4B indicates θ [deg] in the ZY plane, and the vertical axis of Fig. 4B indicates the directional gain [dBi]. The solid line in Fig. 4B indicates vertical polarization, and the dotted line in Fig. 4B indicates horizontal polarization.

[0028] 4A and 4B , a vertically polarized wave is radiated by a current vector generated by exciting the notch antenna 13. A horizontally polarized wave is radiated by a current vector generated by exciting the notch antenna 15. At this time, a current vector that is in opposite phase to the current vector generated around the notch antenna 13 is generated on the ground conductor plate 12, which cancels out the vertically polarized wave in the θ=90° direction.

[0029] 4B, the radiation pattern of notch antenna 15 is similar to that of a dipole antenna arranged parallel to the Y-axis, resulting in a null at θ=±90°. The 3 dB beam width is θ=96° for vertical polarization and θ=49° for horizontal polarization.

[0030] 5A and 5B are diagrams showing the effects of the antenna device 10 according to the first embodiment. FIG. 5A is a diagram showing the flow of current during excitation. FIG. 5B is a diagram showing the radiation pattern during excitation. The horizontal axis of FIG. 5B indicates θ [deg] in the ZY plane, and the vertical axis of FIG. 5B indicates the directional gain [dBi]. The solid line in FIG. 5B indicates vertical polarization, and the dotted line in FIG. 5B indicates horizontal polarization.

[0031] As shown in Figures 5A and 5B, in the antenna device 10, currents that contribute to the radiation of horizontally polarized waves from the non-excited monopole antennas 17a and 17b flow on both the left and right sides of the notch antenna 15. The horizontally polarized waves have no null in the θ±90° direction. Furthermore, the provision of the non-excited monopole antennas 17a and 17b in the antenna device 10 changes the current distribution on the ground conductor plate 12. As a result, the vertically polarized waves in the θ=90° direction are improved by approximately 10 dB. The 3 dB beam width is expanded to cover a wider area of ​​θ=238° for vertically polarized waves and a wider area of ​​θ=100° for horizontally polarized waves.

[0032] Next, a case where the antenna device 10 according to the first embodiment is used as a diversity antenna will be described with reference to Fig. 6. When the antenna device 10 according to the first embodiment is used as a diversity antenna, the notch antennas 13 and 15 are excited individually.

[0033] 6A and 6B are explanatory diagrams illustrating a case where the antenna device 10 according to the first embodiment is used as a diversity antenna. Fig. 6A is a diagram illustrating a connection state between the notch antennas 13 and 15. Fig. 6B is a diagram illustrating reflection amplitudes S11 and S22 of the notch antennas 13 and 15 and a transmission amplitude S21 between the notch antennas 13 and 15. Fig. 6C is a diagram illustrating a radiation pattern when the notch antenna 13 is excited. Fig. 6D is a diagram illustrating a radiation pattern when the notch antenna 15 is excited.

[0034] The horizontal axis of Fig. 6B represents f / f0, and the vertical axis of Fig. 6B represents the S parameter [dB]. The solid line of Fig. 6B represents the reflection amplitude S11 of notch antenna 13, the dotted line of Fig. 6B represents the reflection amplitude S22 of notch antenna 15, and the dashed-dotted line of Fig. 6B represents the passing amplitude S21 between notch antennas 13 and 15. The horizontal axis of Fig. 6C and Fig. 6D represents θ [deg] in the ZY plane, and the vertical axis of Fig. 6C and Fig. 6D represents the directional gain [dBi]. The solid line of Fig. 6C and Fig. 6D represents vertical polarization, and the dotted line of Fig. 6C and Fig. 6D represents horizontal polarization.

[0035] 6A, the antenna device 10 serving as a diversity antenna includes a switch 19. The switch 19 switches the electrical connection to the feed points 14 and 16.

[0036] 6B, the reflection amplitude S11 when notch antenna 13 is excited and the reflection amplitude S22 when notch antenna 15 is excited are −20 dB or less at the center frequency f0 of the frequency band used. Also, the passing amplitude S21 between notch antennas 13 and 15 is −18 dB. This shows that the coupling between notch antennas 13 and 15 is low.

[0037] As shown in Fig. 6C, when notch antenna 13 is excited, vertically polarized waves are dominant. At this time, vertically polarized waves and horizontally polarized waves are radiated so as to be orthogonal to each other. As shown in Fig. 6D, when notch antenna 15 is excited, horizontally polarized waves are dominant. At this time, vertically polarized waves and horizontally polarized waves are radiated so as to be orthogonal to each other.

[0038] For example, assuming that the incoming waves are distributed uniformly in all directions, the calculated correlation coefficient is 0.3 or less. It is generally known that when the correlation coefficient is 0.5 or less, diversity performance equivalent to that of a correlation coefficient of 0 can be obtained. As a result, the antenna device 10 according to the first embodiment can also function as a diversity antenna.

[0039] Although the antenna device 10 according to the first embodiment described above includes the notch antenna 13, the notch antenna 15, and the non-excited monopole antennas 17a and 17b as antennas, it may include only the notch antenna 15 and the non-excited monopole antennas 17a and 17b, as shown in Fig. 7. Fig. 7 is an overall perspective view of the antenna device 10A according to the first embodiment. As shown in Fig. 7, the antenna device 10A includes the notch antenna 15 and the non-excited monopole antennas 17a and 17b, and is thereby able to radiate horizontally polarized waves with a wide coverage area.

[0040] As described above, the antenna device 10, 10A according to the first embodiment includes the notch antenna 15 provided by cutting into the side 12b of the ground conductor plate 12, the side 12b having a length equal to or greater than one-quarter of the wavelength of the center frequency in the used frequency band, the feed point 16 provided so as to straddle the notch antenna 15 in the width direction, and the non-excited monopole antennas 17a, 17b provided on the ground conductor plate 12 on both sides of the notch antenna 15 in the length direction relative to the notch antenna 15. Therefore, the antenna device 10 can include a wide-coverage horizontally polarized antenna without using an antenna main body obtained by bending a metal plate.

[0041] Furthermore, since the antenna device 10 includes the ground conductor plate 12, a circuit pattern can be provided on the ground conductor plate 12. Therefore, the antenna device 10 can integrate the polarization antenna and the circuit.

[0042] Moreover, the antenna device 10 according to the first embodiment includes a notch antenna 13 provided by cutting into a side 12a of the ground conductor plate 12, the side 12a having a length equal to or longer than a quarter wavelength of the wavelength of the center frequency in the used frequency band, and a feed point 14 provided to straddle the notch antenna 13 in the width direction. Therefore, the antenna device 10 according to the first embodiment can radiate a wide-coverage vertically polarized wave and a wide-coverage horizontally polarized wave.

[0043] Furthermore, the antenna device 10 according to the first embodiment includes a switch 19 that switches the power supply between the feed point 14 and the feed point 16. Therefore, the antenna device 10 can also function as a diversity antenna.

[0044] Second Embodiment An antenna device 20 according to a second embodiment will be described with reference to Figures 8 to 10. Note that components having the same functions as those described in the first embodiment above will be assigned the same reference numerals, and descriptions thereof will be omitted.

[0045] First, the configuration of the antenna device 20 according to the second embodiment will be described with reference to Fig. 8. Fig. 8 is an overall perspective view of the antenna device 20 according to the second embodiment.

[0046] As shown in Figure 8, the antenna device 20 of embodiment 2 has non-excited monopole antennas 21 and 22 instead of the non-excited monopole antennas 17a and 17b of the antenna device 10 of embodiment 1 shown in Figure 1.

[0047] The non-excited monopole antennas 21 and 22 are provided on both sides of the notch antenna 15 in the longitudinal direction of the notch antenna 15. The non-excited monopole antennas 21 and 22 are provided so as to be perpendicular to the surface of the ground conductor plate 12. The non-excited monopole antennas 21 and 22 are formed, for example, by bending a single conductive metal plate into an L shape.

[0048] Specifically, the unexcited monopole antenna 21 has a flat vertical wall 21a and a horizontal wall 21b. The vertical wall 21a is disposed so as to be perpendicular to the surface of the ground conductor plate 12. The lower end of the vertical wall 21a is electrically connected to the ground conductor plate 12. The horizontal wall 21b is disposed so as to extend from the upper end of the vertical wall 21a toward the unexcited monopole antenna 22. That is, one end of the horizontal wall 21b is connected to the upper end of the vertical wall 21a. The other end of the horizontal wall 21b is positioned closer to the unexcited monopole antenna 22 than the other end, but does not extend beyond the notch antenna 15.

[0049] The unexcited monopole antenna 22 has a flat vertical wall 22a and a horizontal wall 22b. The vertical wall 22a is arranged perpendicular to the surface of the ground conductor plate 12. The lower end of the vertical wall 22a is electrically connected to the ground conductor plate 12. The horizontal wall 22b is arranged to extend from the upper end of the vertical wall 22a toward the unexcited monopole antenna 21. That is, one end of the horizontal wall 22b is connected to the upper end of the vertical wall 22a. The other end of the horizontal wall 22b is positioned closer to the unexcited monopole antenna 21 than the other end, but does not extend beyond the notch antenna 15. Therefore, a gap is formed in the Y-axis direction between the other end of the horizontal wall 21b and the other end of the horizontal wall 22b.

[0050] For example, the height H2 of the non-excited monopole antennas 21 and 22 (vertical walls 21a and 22a) is 0.13λ, and the length L4 of the non-excited monopole antennas 21 and 22 (horizontal walls 21b and 22b) is 0.07λ.

[0051] Next, the effects of the antenna device 20 according to the second embodiment will be described with reference to FIG. 9. FIG. 9 is a diagram illustrating the effects of the antenna device 20 according to the second embodiment. FIG. 9A is a diagram illustrating the flow of current during excitation. FIG. 9B is a diagram illustrating the radiation pattern during excitation. Note that the horizontal axis of FIG. 9B represents θ [deg] in the ZY plane, and the vertical axis of FIG. 9B represents the directional gain [dBi]. The solid line in FIG. 9B represents vertically polarized waves, and the dotted line in FIG. 9B represents horizontally polarized waves.

[0052] 9A and 9B, in the antenna device 20, the current contributing to the radiation of horizontally polarized waves flows in a circular pattern along the L-shaped parasitic monopole antennas 21 and 22. This improves the horizontal polarization in the θ=0° direction by approximately 5 dB. The 3 dB beamwidth increases the coverage area of ​​vertically polarized waves to θ=294° and the coverage area of ​​horizontally polarized waves to θ=237°. Furthermore, in the antenna device 20, the height H2 of the parasitic monopole antennas 21 and 22 can be made lower than the height H of the parasitic monopole antennas 17a and 17b.

[0053] Although the antenna device 20 according to the second embodiment described above includes the notch antenna 13, the notch antenna 15, and the non-excited monopole antennas 21 and 22 as antennas, it may include only the notch antenna 15 and the non-excited monopole antennas 21 and 22, as shown in Fig. 10. Fig. 10 is an overall perspective view of the antenna device 20A according to the second embodiment. As shown in Fig. 10, the antenna device 20A includes the notch antenna 15 and the non-excited monopole antennas 21 and 22, and is thereby able to radiate horizontally polarized waves with a wide coverage area.

[0054] As described above, in antenna device 20 according to embodiment 2, unexcited monopole antennas 21 and 22 are arranged with their upper ends facing each other. Therefore, antenna device 20 can radiate wide-area vertically polarized waves and wide-area horizontally polarized waves while minimizing the height of unexcited monopole antennas 21 and 22.

[0055] Third Embodiment An antenna device 30 according to a third embodiment will be described with reference to Figures 11 and 12. Note that components having the same functions as those described in the first embodiment above will be assigned the same reference numerals, and descriptions thereof will be omitted.

[0056] First, the configuration of the antenna device 30 according to the third embodiment will be described with reference to Fig. 11. Fig. 11 is a perspective view of the antenna device 30 according to the third embodiment.

[0057] As shown in Figure 11, the antenna device 30 of embodiment 3 has a dielectric substrate 31 instead of the non-excited monopole antennas 17a, 17b of the antenna device 10 of embodiment 1 shown in Figure 1.

[0058] The dielectric substrate 31 is provided on the ground conductor plate 12. Specifically, the dielectric substrate 31 is provided so as to straddle the notch antenna 15 in a direction perpendicular to the longitudinal direction of the notch antenna 15. The dielectric substrate 31 also has parasitic monopole antennas 32a and 32b.

[0059] The non-excited monopole antennas 32a and 32b are provided on the front surface of the dielectric substrate 31. The front surface of the dielectric substrate 31 is the surface facing the inside of the substrate 11 or the ground conductor plate 12. The non-excited monopole antennas 32a and 32b are provided on both sides of the notch antenna 15 in the longitudinal direction. The non-excited monopole antennas 32a and 32b are L-shaped.

[0060] That is, the lower ends of the unexcited monopole antennas 32a and 32b are electrically connected to the ground conductor plate 12. The upper ends of the unexcited monopole antennas 32a and 32b are arranged to face each other in a direction perpendicular to the longitudinal direction of the notch antenna 15. In other words, a gap is formed in the Y-axis direction between the upper ends of the unexcited monopole antennas 32a and 32b.

[0061] FIG. 11B shows an example in which the legs 31 a and 31 b of the dielectric substrate 31 are inserted into the insertion holes 12 c and 12 d of the ground conductor plate 12 , thereby electrically connecting the non-excited monopole antennas 32 a and 32 b to the ground conductor plate 12 .

[0062] For example, the installation distance D2 between the bottom ends of the unexcited monopole antennas 32a and 32b is 0.24λ, the height H3 of the unexcited monopole antennas 32a and 32b is 0.12λ, and the top length L5 of the unexcited monopole antennas 21 and 22 is 0.05λ.

[0063] Next, the effects of the antenna device 30 according to the third embodiment will be described with reference to Fig. 12. Fig. 12 is a diagram showing the radiation pattern of the antenna device 30 according to the third embodiment when excited. The horizontal axis of Fig. 12 indicates θ [deg] in the ZY plane, and the vertical axis of Fig. 12 indicates the directional gain [dBi]. The solid line in Fig. 12 indicates vertically polarized waves, and the dotted line in Fig. 12 indicates horizontally polarized waves.

[0064] As shown in FIG. 12, the 3 dB beam width is widened to θ=307° for vertically polarized waves and θ=213° for horizontally polarized waves.

[0065] The antenna device 30 according to the above-described third embodiment includes, as antennas, a notch antenna 13, a notch antenna 15, a dielectric substrate 31, and non-excited monopole antennas 32a and 32b, but may include only the notch antenna 15, the dielectric substrate 31, and the non-excited monopole antennas 32a and 32b.

[0066] As described above, in the antenna device 30 according to the third embodiment, the non-excited monopole antennas 32 a and 32 b are provided on the dielectric substrate 31. Therefore, in the antenna device 30, the non-excited monopole antennas 32 a and 32 b can be manufactured with high precision.

[0067] It should be noted that within the scope of the present disclosure, the embodiments may be freely combined, or any component in each embodiment may be modified, or any component in each embodiment may be omitted.

[0068] The antenna device according to the present disclosure is provided with a wide-coverage horizontally polarized antenna by arranging non-excited monopole antennas on both longitudinal sides of a first notch antenna that is formed by cutting into a ground conductor plate, without using an antenna body obtained by bending a metal plate, and is suitable for use in antenna devices, etc.

[0069] 10, 10A Antenna device, 11 Substrate, 12 Ground conductor plate, 12a, 12b Side, 12c, 12d Insertion hole, 13 Notch antenna, 14 Feeding point, 15 Notch antenna, 16 Feeding point, 17a, 17b Non-excited monopole antenna, 18 Splitter / combiner, 19 Switch, 20, 20A Antenna device, 21, 22 Non-excited monopole antenna, 21a, 22a Vertical wall, 21b, 22b Horizontal wall, 30 Antenna device, 31 Dielectric substrate, 31a, 31b Leg, 32a, 32b Non-excited monopole antenna.

Claims

1. An antenna device comprising: a first notch antenna cut into a first side of a ground conductor plate, the first side having a length equal to or greater than 1 / 4 of the wavelength of the center frequency in the frequency band used; a first feeding point arranged to straddle the first notch antenna in its width direction; and non-excited monopole antennas arranged on the ground conductor plate on both sides of the first notch antenna in the lengthwise direction.

2. The antenna device according to claim 1, wherein the non-excited monopole antennas are arranged so that their upper ends face each other.

3. The antenna device according to claim 1 or 2, characterized in that the non-excited monopole antenna is provided on a dielectric substrate.

4. An antenna device according to any one of claims 1 to 3, characterized in that it comprises: a second notch antenna provided by cutting into a second side of the ground conductor plate, the second side having a length equal to or greater than 1 / 4 of the wavelength of the center frequency in the operating frequency band; and a second feeding point provided so as to straddle the second notch antenna in its width direction.

5. The antenna device according to claim 4, further comprising a switch for switching the power supply between the first feed point and the second feed point.

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