JP2004023507A - Multi-frequency band antenna and multi-frequency omnidirectional antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-frequency band antenna capable of receiving a radio wave with a plurality of frequency bands. <P>SOLUTION: A feeding line 2 is provided to a middle of a lower side face of a dielectric board, and a metallic plate 3 is stacked on an upper side face. An F1 slot 4a, an F2 slot 4b, and an F3 slot 4c with different resonance frequencies are formed on the metallic plate 3 nearly at an interval of λg/2 with respect to each frequency band from an upper open end 2a of the feeding line 2. Further, the length of the F1 slot 4a to F3 slot 4c is selected respectively to be λ/2, and the λ is based on values with respect to the frequencies F1, F2, F3. The F1 slot 4a resonated with a signal with the frequency F1, the F2 slot 4b resonated with a signal with the frequency F2, and the F3 slot 4c resonated with a signal with the frequency F3 respectively emit a radio wave. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multi-frequency band antenna and a multi-frequency omnidirectional antenna corresponding to a plurality of frequency bands.
[0002]
[Prior art]
In recent years, for example, aircraft, ships, trains, automobiles, and the like are increasingly equipped with a plurality of wireless communication devices and receiving a plurality of radio waves having different frequency bands. For example, an automobile is equipped with a car navigation system and a mobile radio, and receives traffic information such as traffic congestion, accidents, traffic regulations, and parking lots from a VICS (Vehicle Information and Communication System). It receives a plurality of radio waves having different frequency bands, such as receiving radio waves for mobile radio.
[0003]
[Problems to be solved by the invention]
In the case where a plurality of radio waves having different frequency bands are received by the wireless communication device as described above, conventionally, antennas corresponding to the respective frequency bands are separately provided. However, in a mobile body such as an automobile, the installation area of the antenna is small, and it is not preferable to install a plurality of antennas.
[0004]
The present invention has been made to solve the above problems, and has as its object to provide a multi-frequency band antenna and a multi-frequency omnidirectional antenna capable of receiving radio waves in a plurality of frequency bands.
[0005]
[Means for Solving the Problems]
A multi-frequency band antenna according to the present invention includes a feed line having an open end, and a plurality of slots having different resonance frequencies provided on the feed line at approximately λg / 4 of each frequency band from the open end. And characterized in that: Specifically, a dielectric substrate, a feed line provided at one end of the dielectric substrate with an open end, a metal plate provided on the other surface of the dielectric substrate, The plate is provided with a plurality of slots having different resonance frequencies provided at a position of approximately λg / 4 in each frequency band from the open end of the feeder line.
With the above configuration, a single antenna can receive radio waves in a plurality of frequency bands.
[0006]
The multi-frequency omnidirectional antenna according to the present invention is characterized in that the multi-frequency band antenna is arranged on multiple surfaces.
By arranging the multi-band antenna composed of a plurality of slots on multiple surfaces as described above, it is possible to make the antenna non-directional.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0008]
(1st Embodiment)
FIG. 1 is a plan view of a multi-band antenna according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA of FIG.
In FIG. 2, reference numeral 1 denotes a rectangular dielectric substrate, for example, in which a power supply line 2 is provided in the center of the lower surface, and a metal foil or metal plate 3 is laminated on the upper surface. As the feeder line 2, for example, a microstrip line or a triplate line is used, and the upper end is an open end 2a.
[0009]
As shown in FIG. 1, the metal plate 3 has a plurality of slots having different resonance frequencies on the feeder line 2, for example, F1 slots 4a, F2 slots 4b, and F3 having lengths corresponding to the frequencies F1 to F3. The slot 4c is formed at a position of approximately λg / 4 in each frequency band from the open end 2a of the feed line 2. The frequencies F1 to F3 can be selected and used from, for example, a VHF band, a UHF band, and an SHF band.
[0010]
The length of each of the F1 slot 4a to the F3 slot 4c is set to approximately λ / 2. In this case, λ uses a value based on the frequencies of F1, F2, and F3.
[0011]
Then, the signals of F1, F2, and F3 are sequentially switched and supplied to the power supply line 2, and power is supplied to the F1 slots 4a to 4c. In this case, the signals of F1, F2, and F3 may be superimposed on the power supply line 2 and supplied.
[0012]
By feeding power to the F1 slot 4a to F3 slot 4c through the feed line 2, the F1 slot 4a resonates with the signal of the frequency F1, the F2 slot 4b resonates with the signal of the frequency F2, and the F3 slot 4c changes the frequency of the frequency F3. Resonates with this signal and radiates radio waves on both upper and lower sides.
[0013]
By providing a plurality of slots 4a to 4c having different resonance frequencies on one feeder line 2 as described above, radio waves in different frequency bands can be radiated from each of the slots 4a to 4c, thereby forming a multi-frequency band antenna 10. Can be.
[0014]
In the first embodiment, the case where radio waves are radiated from both upper and lower surfaces of the F1 slot 4a to the F3 slot 4c has been described. However, a reflector is disposed at a predetermined interval on the power supply line 2 side, and the F1 slot 4a Radio waves emitted downward from the F3 slot 4c may be reflected upward by the reflector. In such a configuration, radio waves are radiated only from one surface of the antenna, and the antenna gain can be improved.
[0015]
In the first embodiment, the case where the dielectric substrate 1 is provided has been described. However, the configuration in which the positional relationship between the power supply line 2 and each of the slots 4a to 4c is maintained at a preset position is particularly advantageous. The body substrate 1 need not be provided.
[0016]
(2nd Embodiment)
FIG. 3 is a plan view of a multi-band antenna according to the second embodiment of the present invention.
The second embodiment is different from the first embodiment shown in FIG. 1 in that an F3 anti-resonance circuit 6 is provided at the center of the F3 slot 4c having the longest slot length. As shown in FIG. 4, the F3 anti-resonance circuit 6 has a high-frequency coil 7 and a capacitor 8 connected in parallel to the center of the F3 slot 4c to resonate at a frequency F3. In this case, both ends of the high-frequency coil 7 and the capacitor 8 are connected to the metal plates 3 on both sides of the F3 slot 4c by soldering or the like.
[0017]
There is a characteristic that the F1 slot 4a and the F2 slot 4b whose other slot lengths are short are easily coupled to the F3 slot 4c of the low frequency band having the longest slot length, but the F3 slot 4c has the F3 anti-resonance as described above. By providing the circuit 6, the coupling between the F1 slot 4a and the F2 slot 4b can be prevented. That is, the F3 anti-resonance circuit 6 is in a parallel resonance state with respect to the frequency F2 and has a high impedance, so that it does not affect the F3 slot 4c. On the other hand, at frequencies other than F3, in this case, at frequencies of F1 and F2, the impedance of the F3 anti-resonance circuit 6 becomes low, and the length of the F3 slot 4c becomes apparently almost half. As a result, the coupling of the F1 slot 4a and the F2 slot 4b to the F3 slot 4c can be prevented.
[0018]
In the first embodiment, the case where the F3 anti-resonance circuit 6 is provided in the F3 slot 4c having the longest slot length has been described. However, the anti-resonance circuit is provided in other slots, and interference with other frequency band slots is provided. May be prevented.
[0019]
In the first and second embodiments, the case where a linear slot is used has been described. In addition, for example, an X-shaped cross slot 9 as shown in FIG. May be configured.
[0020]
(Third embodiment)
FIG. 6 is a plan view of the multi-band antenna according to the third embodiment of the present invention.
In the third embodiment, a shared slot 11 having the same length as the F3 slot 4c is provided at the upper end side of the F1 slot 4a in the first embodiment shown in FIG. In this case, the F1 slot 4a, the F2 slot 4b, and the F3 slot 4c are arranged at a position of λg of each frequency band from the common slot 11. On the shared slot 11, F1 resonance circuits 12a and 12b are arranged at positions corresponding to both ends of the F1 slot 4a, and F2 resonance circuits 13a and 13b are provided at positions corresponding to both ends of the F2 slot 4b.
[0021]
The F1 resonance circuits 12a and 12b are formed by connecting a high-frequency coil and a capacitor in series to resonate in series at a frequency F1. The F1 resonance circuits 12a and 12b are laid over an F1 slot 4a and both ends thereof are connected to the metal plate 3 by soldering or the like. . The F2 resonance circuits 13a and 13b are connected in series to a frequency F2 by connecting a high-frequency coil and a capacitor in series. The F2 resonance circuits 13a and 13b are connected across the F2 slot 4b by soldering or the like at both ends. . The power supply line 2 has an upper end extending to the end of the common slot 11 and a leading end (not shown) connected to the metal plate 3 by a short pin (short stub) to form a short end 2b. In this case, the short pin is inserted through the dielectric substrate 1 to connect between the tip of the feeder line 2 and the metal plate 3.
[0022]
In the above configuration, the shared slot 11 is in a state where the F1 resonance circuits 12a and 12b resonate and are short-circuited (short-circuited) with respect to the frequency of F1, and have an apparent length equal to the length of the F1 slot 4a. For the frequency of, the F2 resonance circuits 13a and 13b resonate and become short-circuited, and have an apparent length equal to the length of the F2 slot 4b. Further, the shared slot 11 does not resonate at the frequency of F3 in any of the F1 resonance circuits 12a and 12b and the F2 resonance circuits 13a and 13b, and thus has the same length as the F3 slot 4c.
[0023]
As a result, the shared slot 11 operates in the same frequency band with respect to any of the F1 slot 4a, the F2 slot 4b, and the F3 slot 4c, and emits radio waves from the two slots, thereby improving the antenna gain.
[0024]
In the third embodiment, the case where the F1 resonance circuits 12a and 12b and the F2 resonance circuits 13a and 13b are provided on the shared slot 11 has been described. However, when the frequencies of F1, F2, and F3 are separated to some extent, It is possible to use a high-pass circuit using a capacitor instead of a resonance circuit.
[0025]
Further, in the third embodiment, the case where the shared slot 11 is combined with the slots 4a to 4c of F1 to F3 has been described. However, even when the shared slot 11 is provided alone without providing the slots 4a to 4c. A waveband antenna can be configured.
[0026]
(Fourth embodiment)
FIG. 7 is a plan view of a multi-band antenna according to the fourth embodiment of the present invention.
This fourth embodiment is different from the first embodiment shown in FIG. 1 in that the F1 slot 16a, the F2 slot 16b, and the F3 slot 16c corresponding to the F1 slot 4a, the F2 slot 4b, and the F3 slot 4c are provided above the F1 slot 4a. Are provided so as to be symmetrical. In this case, the F1 slot 16a, the F2 slot 16b, and the F3 slot 16c are not supplied with power without providing a power supply line. The intervals between the corresponding slots, that is, the intervals between the F1 slots 4a and 16a, the F2 slots 4b and 16b, and the F3 slots 4c and 16c are set to approximately λg in each frequency band.
[0027]
According to the above configuration, the unpowered F1 slot 16a, F2 slot 16b, and F3 slot 16c are coupled to the corresponding F1 slot 4a, F2 slot 4b, and F3 slot 4c to emit radio waves. Gain can be improved.
[0028]
(Fifth embodiment)
Next, a multi-band antenna according to a fifth embodiment of the present invention will be described.
In the first embodiment shown in FIG. 1, the dielectric substrate 1 and the metal plate 3 are formed in a rectangular shape. However, the multi-band antenna 10A according to the fifth embodiment has a dielectric material as shown in FIG. The substrate 1 and the metal plate 3 are formed in a substantially triangular shape. That is, the slots 4a to 4c have the longest length of the F3 slot 4c, and then become shorter in the order of the F2 slot 4b and the F1 slot 4a, so that the width of the dielectric substrate 1 and the metal plate 3 on the F3 slot 4c side is increased. , F1 slots 4a are formed in a triangular shape so that the width on the side thereof is gradually reduced.
By forming the dielectric substrate 1 and the metal plate 3 in a triangular shape as described above, the multi-frequency band antenna 10A can be downsized. Further, the dielectric substrate 1 and the metal plate 3 are not limited to a triangular shape, and may be formed in, for example, a trapezoidal shape.
[0029]
(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described.
In the sixth embodiment, a plurality of triangular multi-frequency band antennas 10A shown in the fifth embodiment of FIG. 8 are used to form a triangular protruding shape as shown in FIG. 21. Further, the multi-frequency omnidirectional antenna 21 may be formed on a multi-sided surface such as a quadrangular pyramid by the triangular multi-frequency band antenna 10A.
[0030]
Further, the rectangular multi-frequency band antenna 10 shown in the first embodiment may be formed on, for example, four surfaces as shown in FIG. 10 to form a rectangular cylindrical multi-frequency omnidirectional antenna 21A. Further, the rectangular multi-band antenna 10 may be formed on three or five or more surfaces.
[0031]
In addition, the dielectric substrate 1 and the metal plate 3 shown in the first embodiment are formed in a cylindrical shape as shown in FIG. 11, and a plurality of slots 4a to 4c are formed along the outer peripheral surface of the metal plate 3 to form a cylindrical shape. Multi-frequency omnidirectional antenna 21B. In this case, for each of the slots 4a to 4c, the feeder line 2 is formed on the inner surface of the dielectric substrate 1.
[0032]
(Seventh embodiment)
Next, a multi-frequency omnidirectional antenna according to a seventh embodiment of the present invention will be described.
[0033]
The multi-frequency omnidirectional antenna according to the seventh embodiment differs from the triangular pyramid-shaped multi-frequency omnidirectional antenna 21 shown in the sixth embodiment in FIG. A partition 22 made of a conductive material, that is, a metal plate, is provided inside 10A so as to partition between the slots 4a, 4b, and 4c. Then, a through hole 23 is provided in the center of the partition wall 22, and the power supply line 24 is inserted into the through hole 23. In this case, the through hole is formed to be larger than the diameter of the power supply line 24, and the space between the partition wall 22 and the power supply line 24 is maintained in an insulated state. Note that an insulating material may be provided between the partition wall 22 and the power supply line 24. The feed line 24 is provided in common for each multi-frequency band antenna 10A arranged as described above, and the feed line 2 for each multi-frequency band antenna 10A is omitted.
[0034]
As described above, the slots 4a, 4b, and 4c are partitioned by the partition walls 22 to form a waveguide structure, so that the feed line 24 and the slots 4a, 4b, and 4c are coupled by the waveguide structure. You. Thus, power can be supplied from the power supply line 24 to each of the slots 4a, 4b, and 4c.
[0035]
FIG. 12 shows a case where the present invention is applied to the triangular pyramid-shaped multi-frequency omnidirectional antenna 21. However, the present invention is also applied to a quadrangular pyramid or a multifaceted multi-frequency omnidirectional antenna having a larger size than FIG. be able to.
[0036]
Also, in the rectangular cylindrical multi-frequency omnidirectional antenna 21A shown in FIG. 10 or the cylindrical multi-frequency omnidirectional antenna 21B shown in FIG. 11, the multifrequency omnidirectional antenna 21B shown in FIG. Similarly to the above, a conductive partition may be provided between the upper and lower opening surfaces and each slot, and power may be supplied from the power supply line 24 disposed at the center thereof.
[0037]
In each of the above embodiments, the case where three slots 4a to 4c are provided has been described. However, the same applies to the case where two slots are provided or the case where four or more slots are provided. Of course, it can be implemented.
[0038]
【The invention's effect】
As described above in detail, according to the present invention, a plurality of slots having different lengths are provided on a substrate to resonate at respective target frequencies, and a common power supply line is provided for each slot to supply power. Thus, one antenna can receive radio waves in a plurality of frequency bands. In addition, by arranging the multi-frequency band antenna including the plurality of slots on multiple surfaces, it is possible to make the antenna non-directional.
[Brief description of the drawings]
FIG. 1 is a plan view of a multi-band antenna according to a first embodiment of the present invention.
FIG. 2 is a sectional view taken along line AA in FIG.
FIG. 3 is a plan view of a multi-band antenna according to a second embodiment of the present invention.
FIG. 4 is a diagram showing details of an anti-resonance circuit portion in the embodiment.
FIG. 5 is a diagram illustrating an example in which a cross slot is used as a slot of an antenna to cope with circular polarization.
FIG. 6 is a plan view of a multi-band antenna according to a third embodiment of the present invention.
FIG. 7 is a plan view of a multi-band antenna according to a fourth embodiment of the present invention.
FIG. 8 is a plan view of a multi-band antenna according to a fifth embodiment of the present invention.
FIG. 9 is a perspective view of a multi-frequency omnidirectional antenna according to a sixth embodiment of the present invention.
FIG. 10 is a perspective view showing an example of a case where a rectangular cylindrical multi-frequency omnidirectional antenna is configured in the embodiment.
FIG. 11 is an exemplary perspective view showing an example in which a cylindrical multi-frequency omnidirectional antenna is configured in the embodiment;
FIG. 12 is a sectional view of a multi-frequency omnidirectional antenna according to a seventh embodiment;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Dielectric board 2 ... Feeding line 2a ... Open end 2b ... Short end 3 ... Metal plate 4a ... F1 slot 4b ... F2 slot 4c ... F3 slot 6 ... Anti-resonance circuit 7 ... High frequency coil 8 ... Capacitor 9 ... Cross slot 10 , 10A Multi-band antenna 11 Shared slots 12a and 12b F1 resonance circuits 13a and 13b F2 resonance circuit 16a F1 slot 16b F2 slot 16c F3 slot 21 Multi-frequency omnidirectional antenna 21A square prism Multi-frequency omni-directional antenna 21B: cylindrical multi-frequency omni-directional antenna 22: partition wall 23: through hole 24: feed line

Claims (8)

A power supply line having an open end, and a plurality of slots having different resonance frequencies provided at a position of approximately λg / 4 in each frequency band from the open end on the power supply line. Band antenna. A dielectric substrate, a power supply line provided at one end of the dielectric substrate with an open end, a metal plate provided on the other surface of the dielectric substrate, and the power supply line connected to the metal plate. And a plurality of slots having different resonance frequencies provided at a position of approximately λg / 4 in each frequency band from the open end of the multi-band antenna. 3. The multi-frequency band antenna according to claim 1, wherein an anti-resonance circuit that anti-resonates in a frequency band used for the slot is provided to reduce interference with other frequency band slots. 4. The multi-frequency band antenna according to claim 1, wherein each slot is constituted by a cross slot to correspond to a circularly polarized wave. A dielectric substrate, a power supply line provided on one surface of the dielectric substrate and having a short end, a metal plate provided on the other surface of the dielectric substrate, and a power supply line provided on the metal plate. A common slot provided near the short end of the target frequency band and resonating at the lowest frequency of the target frequency band, and a resonance circuit arranged at a position having a slot length corresponding to a desired frequency band in the common slot, A multi-frequency band antenna, wherein the common slot is short-circuited at a position corresponding to a desired frequency band. A dielectric substrate, a power supply line provided on one surface of the dielectric substrate and having a short end, a metal plate provided on the other surface of the dielectric substrate, and a power supply line provided on the metal plate. A common slot that is provided near the short-circuited end and resonates at the lowest frequency of the target frequency band; And a resonance circuit disposed in the shared slot at a position having a slot length corresponding to each of the frequency bands. 7. A multi-frequency omnidirectional antenna, wherein the multi-frequency band antenna according to claim 2 is arranged on multiple sides. 8. The multi-frequency omnidirectional antenna according to claim 7, wherein each of the slots of the multi-frequency band antenna arranged on multiple sides is partitioned by a conductive partition wall to form a waveguide structure, and is shared by a central portion of the partition wall. A multi-frequency omnidirectional antenna, wherein a power supply line is provided in an insulated state, and power is supplied to each of the multi-frequency band antennas via the waveguide structure.

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