JP2004120296A - Antenna and antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna which is small in size and performs wide-band multi-frequency operations, and and also to provide an antenna device. <P>SOLUTION: The antenna is provided with a spiral conductor pattern 2. When the shape of the spiral is decided by a length in the axial direction of the spiral, two lengths in the radial direction vertical to the axis of the spiral and perpendicular to each other, and the number of turns, the antenna has two different lengths in the radial direction. Also, at least one of the two lengths in the radial direction is made longer than the length in the axial direction of the spiral. Also, a capacitance plate 3 to give a capacitance in-between a ground is provided to the terminal end of the spiral conductor pattern 2. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an antenna and an antenna device suitable for mobile communication, wireless LAN, Bluetooth, and the like.
[0002]
[Prior art]
2. Description of the Related Art At present, wireless communication devices called by names such as mobile telephones and PHS (Personal Handy-phone System: registered trademark) have become widespread among general users, and there is a demand for a small and lightweight mobile communication device.
[0003]
By the way, regarding an antenna element for transmitting and receiving radio waves in a wireless communication device, there is a close relationship between the total length of the conductor line and the wavelength of the radio waves. For this reason, simply shortening the conductor line increases the resonance frequency, making it difficult to wirelessly communicate radio waves of a desired frequency with good efficiency. Therefore, various techniques have been developed to reduce the overall shape of the antenna element while maintaining the required resonance frequency.
[0004]
For example, there is a method of reducing the height of the antenna using a meander line or helical line antenna.
[0005]
In a dielectric antenna, the antenna conductor is formed on the surface or inside of the dielectric, thereby reducing the antenna size by using the wavelength shortening effect of the dielectric.
[0006]
Further, in a region where the frequency is lower than that of the mobile phone, a loaded antenna is used. In a loaded antenna, a capacitance plate for taking a capacitance between the antenna and the ground is placed at the top of the antenna, or a coil for increasing inductance is loaded at the center of the antenna. Since these form a series LC circuit with the ground, the resonance length can be shortened.
[0007]
On the other hand, there is an increasing demand for providing various systems having different frequencies, such as PDC, GPS, and IMT2000, in the same mobile phone, and accordingly, it is necessary to use an antenna to cope with these systems. On the other hand, when a multi-frequency antenna is miniaturized using a dielectric, the antenna can be built in. Therefore, there is a high need for a small dielectric antenna that can handle multiple frequencies.
[0008]
FIG. 12 shows a conventional example of a multi-frequency antenna. FIG. 12A is a perspective view showing the appearance, and FIG. 12B is a sectional view thereof.
[0009]
FIG. 12 shows a dual-frequency antenna in which circular patch antennas having different sizes are stacked. Details of such a multi-frequency compatible patch antenna are as shown in, for example, "Illustrations and Antennas" by Naohisa Goto, IEICE (1995).
[0010]
In FIG. 12, a lower large patch antenna 101 transmits and receives a low frequency, and an upper small patch antenna 102 transmits and receives a high frequency. 103 is a ground, 106a and 106b are dielectrics, and 107a and 107b are conductor discs. Reference numeral 104 denotes a power supply line, which also serves as an internal conductor of the coaxial cable 108. The outer conductor 110 of the coaxial cable is connected to the ground 103.
[0011]
The upper patch antenna 102 is fed by the feed line 104. On the other hand, the lower patch antenna 101 is not directly fed with power, but is fed with an electromagnetic field between the hole of the patch and the feed line 104. 105 is a short pin.
[0012]
With such a configuration, it is possible to share the two frequencies.
[0013]
[Problems to be solved by the invention]
However, antennas used in mobile communication, wireless LAN, Bluetooth, and the like have a problem in that the patch antenna itself is large in the above-described configuration, and the size becomes large because two patch antennas are overlapped. There is.
[0014]
For example, when an antenna is operated at 800 MHz of the PDC, the wavelength is long because the frequency is low, and the antenna length is long. For this reason, even in the case of a dielectric antenna using a dielectric, the size and weight of the antenna are large.
[0015]
Furthermore, when trying to increase the number of frequencies, the conventional method has a problem that the size is further increased since another antenna is added to the outside.
[0016]
Further, the patch antenna has a problem that the band is narrow, and the same problem also occurs at a frequency added by increasing the number of frequencies.
[0017]
As described above, there is a problem in terms of size, weight, and bandwidth in using a low-frequency compatible antenna or a multi-frequency compatible antenna as a built-in antenna of a portable terminal.
[0018]
Therefore, an object of the present invention is to provide an antenna having a small size and capable of performing a wideband multi-frequency operation. That is, it is an object of the present invention to provide a small-sized, multi-frequency, wide-band antenna that can be built in a portable device.
[0019]
[Means for Solving the Problems]
The antenna according to the first configuration of the present invention is an antenna including a spiral-shaped conductor formed by combining strip-shaped conductors located on a substantially rectangular parallelepiped surface and forming a substantially spiral shape as a whole. The length is different in two directions perpendicular to each other in a plane perpendicular to the axis of the helix.
[0020]
The helical conductor may have at least one of a length in two directions orthogonal to each other in a plane perpendicular to the axis of the substantially spiral, longer than a length in a direction parallel to the axis of the substantially spiral. .
[0021]
In addition, it is preferable that a capacitance plate for providing a capacitance between the terminal and the ground is connected to the terminal end of the spiral conductor.
[0022]
Further, it is preferable that the terminal end of the helical conductor is branched into two branches and the two branches have different lengths.
[0023]
Further, the helical conductor may be formed on a surface of a dielectric or magnetic material.
[0024]
Further, the spiral conductor may be a conductor film formed by printing, vapor deposition, plating, or sheet metal bonding.
[0025]
Further, the helical conductor may be formed inside a dielectric or magnetic material.
[0026]
Further, it is preferable that the helical conductor is constituted by approximately one to two turns.
[0027]
The dielectric or magnetic body may have a through hole or a counterbore.
[0028]
The antenna according to the second configuration of the present invention includes a substantially linear conductor portion extending in one direction as an antenna conductor, and each of the two end portions of the conductor portion being connected at a right angle to the one direction, and And two substantially linear conductors that are substantially parallel.
[0029]
In the second configuration, the antenna conductor may be formed on the surface or inside of a dielectric or magnetic material.
[0030]
An antenna conductor, an excitation electrode, and a ground electrode are provided on or in the surface of or inside a dielectric or magnetic material, and the antenna conductor is connected to and contacted with the ground electrode, and is closer to the ground electrode than near the center of the antenna conductor. , A part of the antenna conductor may be located near the excitation electrode.
[0031]
An antenna conductor, an excitation electrode, and a ground electrode are provided on or in the surface of or inside the dielectric or magnetic material. The antenna conductor is connected to and connected to the ground electrode, and is closer to the ground electrode than near the center of the antenna conductor. In the above, a part of the antenna conductor is located in the vicinity of the excitation electrode, and the antenna conductor is substantially linear conductor portion extending in one direction, and in each of both ends of the conductor portion, the one direction May be composed of two substantially straight conductors which are connected at substantially right angles and are substantially parallel to each other.
[0032]
An antenna device according to the present invention is characterized in that the antenna of the first or second configuration is mounted on the non-ground area on a substrate having a ground area and a non-ground area.
[0033]
Next, the operation of the present invention will be described. In order to obtain a fundamental wave in a small shape, an antenna having a helical structure is used, and dimensions are different in two directions perpendicular to the axis of the helix, and the helix is made up of less than one turn to one and a half turns. By doing so, the effect of the folded antenna is obtained for the harmonic, and even if the frequency is shifted, the folded antenna is formed even partially, so that a wide band can be obtained.
[0034]
In addition, as the longer dimension of the two directions perpendicular to the axial direction of the helix is increased, the band of the folded antenna becomes wider with respect to the frequency change, and a broadband harmonic is obtained. Further, in order to widen the band of the third harmonic, the spiral is composed of one and a half to two turns. By doing so, the phases of the currents are aligned with respect to the third harmonic, and the antenna functions as a folded antenna.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0036]
(Embodiment 1) FIG. 1 shows a first embodiment of the antenna of the present invention. Reference numeral 1 denotes a rectangular parallelepiped ceramic block having a relative dielectric constant of 6.7, which has a length of 23 mm, a width of 6 mm, and a height of 5 mm. Since the dielectric has a wavelength shortening effect, ceramic is used in this example to reduce the size of the antenna, but resin may be used. Since a magnetic material has a wavelength shortening effect similarly to a dielectric, a magnetic material may be used.
[0037]
On the surface of the ceramic block 1, a conductor pattern printed with a conductor such as silver is formed. Reference numeral 2 denotes a spiral conductor pattern printed around the ceramic block 1, and reference numeral 3 denotes a capacitor plate electrically connected to the tip of the spiral and printed on the upper surface of the ceramic block 1.
[0038]
The spiral conductor pattern 2 is printed so that the direction perpendicular to the axis of the spiral (the horizontal direction in the drawing) is the longitudinal direction of the ceramic block 1. Reference numeral 4 denotes an excitation electrode printed on the back surface of the ceramic block 1 (on the other side in the drawing), and reference numeral 5 denotes a fixed electrode for fixing provided on the back surface. 6 shows the whole of this antenna.
[0039]
If a dielectric or magnetic material is not used, it is difficult to reduce the size of the antenna because the effect of shortening the wavelength due to the dielectric constant or magnetic permeability of the material cannot be obtained. Instead of using 1, a three-dimensional spiral antenna can be formed in space with a sheet metal or the like.
[0040]
(Embodiment 2) FIG. 2 is a perspective view showing an antenna device according to Embodiment 2 of the present invention, and is a mounting example of an antenna 6 of the present invention. Reference numeral 7 denotes a glass epoxy substrate having dimensions of 186 × 43 × 0.7 mm. Reference numeral 8 denotes a copper foil adhered to the surface of the glass epoxy substrate 7 and is hereinafter referred to as a ground. The size of the ground 8 is 43 × 170 mm. The antenna 6 is set 9 mm away from the ground 8.
[0041]
The antenna 6 is soldered to a non-ground area on the glass epoxy board 7. Reference numeral 10 denotes an excitation electrode wiring adhered on the glass epoxy substrate 7 with a copper foil, and reference numeral 9 denotes a fixed electrode wiring. The excitation electrode wiring 10 is soldered to the excitation electrode 4 of the antenna 6, and the fixed electrode wiring 9 is soldered to the fixed electrode 5 of the antenna 6 or a part of the spiral conductor pattern 2.
[0042]
Reference numeral 13 denotes a coaxial cable that excites the antenna 6. The inner conductor is soldered to the matching circuit wiring 11 made of a conductor foil on the glass epoxy substrate 7, and the outer conductor is soldered to the ground 8. The matching circuit wiring 11 constitutes a matching circuit together with the chip capacitor 14 and the chip inductor 12.
[0043]
When the antenna 6 is arranged near the ground, the matching is deteriorated. Further, the radiation efficiency of the antenna is not always maximized at the resonance frequency of the antenna. Therefore, adjustment is performed by a matching circuit so that resonance, matching, and efficiency are improved at a required frequency.
[0044]
FIG. 10 shows a matching circuit. Although the circuit of FIG. 10A is used in the first embodiment of FIG. 2, when two resonances are taken at different frequencies, the configurations of FIGS. 10B and 10C may be suitable. . In FIG. 10, 30 is a transmitting / receiving antenna, 31 is a power supply, 32 is a series capacitor, and 33 is a ground inductor to ground. 34 is a ground, and 35 is a series inductor.
[0045]
As a result of measuring the return loss with this configuration, a matching state with a return loss of 5 dB or less was obtained in the entire range of 824 to 960 MHz and 1710 to 1990 MHz. In addition, as a result of measuring the efficiency, an efficiency of −3.5 dB or more at 824 to 960 MHz and an efficiency of −3 dB or more at 1710 to 1990 MHz were obtained.
[0046]
The reason why the antenna 6 can perform a wideband multi-frequency operation will be described below. Since the antenna 6 is printed on the side surface of the rectangular parallelepiped ceramic, the folded portion of the spiral is adjacent to the two surfaces in the longitudinal direction perpendicular to the axis of the spiral conductor at an angle close to parallel.
[0047]
FIG. 3 shows the current distribution in the fundamental wave and the harmonic wave. In a monopole antenna, for example, if the fundamental wave is 900 MHz, the tip of the antenna is an open end, and the feeding point is located at a position separated by 1/4 wavelength. In that case, in the fundamental wave, the current on the monopole antenna has the same direction at any position.
[0048]
FIG. 3A shows the direction of the current at the fundamental wave of 900 MHz. As the frequency increases, the current distribution on the antenna changes as shown in FIGS. 3 (b), 3 (c) and 3 (d). Here, FIG. 3B shows the current distribution at 1710 MHz, FIG. 3C shows the current distribution at 1800 MHz, and FIG. 3D shows the current distribution at 1990 MHz. The current direction 15 is indicated by solid and dashed arrows.
[0049]
As can be seen from FIG. 3, in this frequency band, the antenna has a folded antenna configuration, and a current flows in the same direction on the corresponding conductor surface. Even if the frequency slightly shifts, a partially folded antenna is formed at some place, so that a wideband characteristic can be obtained. At this time, since the spiral forms a bent antenna with a harmonic wave, the spiral is preferably about one turn, or less than one turn to one and a half turns. Since the current density is small at the tip of the antenna, even a little more than one turn does not hinder the bent antenna.
[0050]
In addition, since the bent portion is closer and the longer one is easier to form a bent antenna, in many cases, one of two orthogonal axes in a plane perpendicular to the axis of the spiral is longer than the axial direction of the spiral. Should be longer.
[0051]
By the way, the main antenna 6 of FIG. Since the harmonic wave has a wide band without the capacitance plate 3, the capacitance plate is not necessarily required, but the fundamental wave can be broadened with the capacitance plate.
[0052]
In FIG. 1, the entire surface of the ceramic block 1 is the capacitance plate 3. However, if the entire capacitance plate and the helical portion are located close to each other, an image current flows due to electromagnetic correlation, and the efficiency of the antenna is reduced. Since there is a possibility of deterioration, it is possible to use only a part of the ceramic block 1 instead of the entire surface of the ceramic block 1.
[0053]
FIG. 4 shows an equivalent circuit of the present antenna. Series capacitance of the equivalent circuit C ₁ represents the capacitance between the ground 8 of capacitive plates 3 and 2 in Figure 1. Parallel circuit of the inductance L ₁ and the capacitance C ₂ is an equivalent circuit of the spiral conductor patterns 2 parts of FIG. Here, the inductance L ₁ represents an inductance to make the spiral conductive pattern 2, the capacitance C ₂ represents a line-to-line capacitance of the spiral conductor patterns 2.
[0054]
The capacitive plates 3, it is possible to decrease the resonance frequency of the antenna, so that even lower the line-to-line capacitance C ₂ of the antenna, the resonance can be taken at a low frequency.
[0055]
Incidentally, the line-to-line capacitance C ₂ is large, but lowers the resonance frequency of the helical antenna (helical antenna), at the same time, narrowing the bandwidth at resonance. Therefore, by lowering the line capacitances C _2, it can increase the bandwidth at resonance.
[0056]
C ₂ is a line capacitances of the spiral conductor pattern 2, but the bandwidth of the fundamental wave, in particular, come into play is the capacitance between the start and end points of the spiral. Therefore, by increasing the distance between the starting point and the ending point of the spiral, it is possible to widen the band with respect to the fundamental wave.
[0057]
In the example of FIG. 1, the resonance frequency is lowered by the capacitance plate 3 and the distance between the start point and the end point of the spiral is increased, so that the fundamental wave is broadened. Along with these, the spiral consists of about a little less than one turn.
[0058]
In the example of FIG. 1, resonance occurs at a fundamental loss of 800 MHz to 1 GHz and a double wave of 1700 to 2 GHz MHz with a return loss of -5 dB. The antenna dimensions are length 22 × width 5 × 4 mm (height from the substrate surface). In order to reduce the weight, a through-hole or a counterbored portion may be provided vertically on a 22 × 4 mm surface of the ceramic block 1, that is, a surface perpendicular to the axis of the spiral.
[0059]
The change of the effective permittivity due to the through hole and the counterbore is not so large. If the hole penetrates the capacitance plate, the capacitance of the capacitance plate changes, but the electrical characteristics of the antenna can be sufficiently adjusted by adjusting the thickness and length of the helix. Although the weight of the entire ceramic block is about 4 g, the weight becomes 1 g when the through-hole is opened except for a thickness of 1 mm, and the weight is reduced.
[0060]
(Embodiment 3) FIG. 5 is a perspective view showing Embodiment 3 of the present antenna. In this example, there is no capacity plate. Instead of a capacitance plate, an extension 17 of a helical conductor is added. The extension 17 may be on the same side as the helical conductor, but in this example is attached to a different side to keep away from the beginning of the helix. The spiral conductor is kept for one to one and a half turns including the extension. Note that a capacitance plate (not shown) may be connected to the tip of the extension portion 17 of the spiral conductor.
[0061]
(Embodiment 4) FIG. 6 is a perspective view showing Embodiment 4 of the present antenna. In order to prevent a decrease in antenna efficiency due to a video current, a conductor pattern in which most of the spiral conductor pattern 20 is separated from the capacitor plate 19 is formed. Thereby, the opposing surfaces of the spiral conductor pattern 20 are parallel. The capacitance plate 19 uses only a part of one surface of the ceramic block.
[0062]
(Fifth Embodiment) FIG. 7 is a perspective view showing a fifth embodiment of the present invention.
[0063]
In this antenna 44, an antenna lead, an excitation electrode 45, and a fixed electrode 46 are formed on the surface of a ceramic block 43.
[0064]
Further, the antenna conductor has a bifurcated branch of 42a and 42b at the tip of the antenna together with the spiral conductor pattern 41. Since the forked branches 42a and 42b have different electrical lengths, two antennas having different lengths are combined, and the antenna bandwidth is increased. In addition, a conductor plate may be attached to the tip of the two branches 42a, 42b as a capacitance plate.
[0065]
(Embodiment 6) FIG. 8 is a perspective view showing Embodiment 6 of the present invention, in which a spiral conductor pattern 41 takes one and a half turns to two turns.
[0066]
In this configuration, as shown in FIG. 8, the antenna becomes just a folded antenna at the third harmonic, and the current direction is aligned in each half turn of the spiral as indicated by the arrow of the current direction 16. Therefore, wideband antenna characteristics can be obtained with the third harmonic. When the spiral conductor pattern is about one and a half turns, relatively wide-band resonance is obtained for both the harmonic and the harmonic.
[0067]
(Embodiment 7) FIG. 9 is a perspective view showing an antenna to which the same principle is applied other than the spiral antenna according to Embodiment 7 of the present invention.
[0068]
In the seventh embodiment, a fundamental wave antenna lead 21 and multiple harmonic antenna leads 22 and 23 are formed on the same surface of a resin block 26 by plating. The harmonic wave antenna conductors 22 and 23 are substantially parallel, and both are orthogonal to the fundamental wave antenna conductor 21.
[0069]
For the fundamental wave, the harmonic wave antenna conductors 22 and 23 function as transmission lines, and the fundamental wave antenna conductor 21 functions as an antenna.
[0070]
On the other hand, for the harmonic wave, the harmonic wave antenna conductors 22 and 23 function as bent antennas, and work together with the fundamental wave antenna conductor 21 as an antenna.
[0071]
Reference numeral 24 denotes a power supply conductor connected from the power supply electrode 25 to the harmonic wave antenna conductor 22. The power supply conductor 24 itself also functions as an antenna with respect to the fundamental wave and the harmonic wave. Here, since the feed wire 24 is orthogonal to both the fundamental wave antenna wire 21 and the overtone wave antenna wires 22 and 23, the feed wire 24 forms an antenna without forming a transmission line therewith.
[0072]
Numeral 28 is a capacitance wire for reducing the antenna by forming a parallel capacitance with the feed wire 24 as an antenna and increasing the reactance. However, the capacitive conductor 28 may not be provided. 27 is a fixed electrode.
[0073]
Further, although not illustrated in FIG. 9, there may be a capacitance plate connected to the harmonic antenna wire 23 as in the first embodiment which is a spiral antenna.
[0074]
This antenna is also mounted in the same manner as in the case of FIG. When there is a capacitor plate, a capacitor is formed between the capacitor and the ground, as in the second embodiment, to lower the resonance frequency of the antenna.
[0075]
(Eighth Embodiment) FIG. 11 is a perspective view showing an antenna device according to an eighth embodiment. In mounting an antenna similar to that of the seventh embodiment shown in FIG. An example is shown in which the characteristic excitation structure is adopted and implemented.
[0076]
Reference numerals 52 and 60 denote excitation electrodes, and power is supplied to the excitation wiring 54 as a conductor pattern on the glass epoxy substrate 56 by the coaxial cable 55. The outer conductor of the coaxial cable 55 is electrically connected to the ground 57. Although omitted in FIG. 11, a matching circuit composed of a chip inductor and a chip capacitor is used as in the case of FIG.
[0077]
Reference numeral 51 denotes an excitation lead wire of the antenna, which is fed by the excitation electrode 60 by capacitive coupling. Reference numeral 59 denotes a ground electrode, and 58 denotes a ground wiring on the glass epoxy substrate 56. Since the antenna current passes through the excitation wiring 54 and the ground wiring 58, the antenna becomes a combination of two antennas passing through the excitation wiring 54 and the ground wiring 58, the antenna length increases, and the resonance frequency decreases.
[0078]
【The invention's effect】
As described above, in a helical antenna in which the length in two directions perpendicular to the axis of the helix (crossing) is not the same size, a broadband harmonic wave can be formed in about one to one and a half turns in a helix. can get. In addition, a broadband third harmonic can be obtained in one and a half to two turns.
[0079]
Further, by loading the capacitance plate with this structure, the bandwidth of the fundamental wave can be improved.
[0080]
Further, according to the same principle, even in an antenna having a single U-shaped conductor without a spiral structure, a wide band can be obtained in a harmonic wave.
[0081]
An antenna and an antenna device having any conductor shape can be manufactured in a small size.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an antenna according to a first embodiment of the present invention.
FIG. 2 is a perspective view showing an antenna device according to a second embodiment of the present invention.
FIG. 3 is a perspective view showing a frequency change of a current distribution on a spiral conductor pattern in the antenna according to the first embodiment of the present invention. 3A shows a case of 900 MHz, FIG. 3B shows a case of 1710 MHz, FIG. 3C shows a case of 1800 MHz, and FIG. 3D shows a case of 1990 MHz.
FIG. 4 is a diagram showing an equivalent circuit for the antenna according to the first embodiment of the present invention.
FIG. 5 is a perspective view showing an antenna according to a third embodiment of the present invention.
FIG. 6 is a perspective view showing an antenna according to a fourth embodiment of the present invention.
FIG. 7 is a perspective view showing an antenna according to a fifth embodiment of the present invention.
FIG. 8 is a perspective view showing an antenna according to a sixth embodiment of the present invention.
FIG. 9 is a perspective view showing an antenna according to a seventh embodiment of the present invention.
FIG. 10 is a diagram showing an equivalent circuit of a matching circuit used in the present invention. 10 (a), 10 (b), and 10 (c) all show configuration examples of the matching circuit.
FIG. 11 is a perspective view showing an antenna device according to an eighth embodiment of the present invention.
FIG. 12 is a view showing a conventional antenna. FIG. 12A is a perspective view showing the appearance, and FIG.
[Explanation of symbols]
1,43 ceramic block 2,20,41 spiral conductor pattern 3,19 capacitance plate 4,45,52,60 excitation electrode 5,27,46 fixed electrode 6,44 antenna 7,56 glass epoxy substrate 8,34,57 ground REFERENCE SIGNS LIST 9 fixed electrode wiring 10 excitation electrode wiring 11 matching circuit wiring 12 chip inductor 13, 55 coaxial cable 14 chip capacitor 15, 16 current direction 17 extension portion 21 fundamental wave antenna conductor 22, 23 overtone antenna conductor 24 power supply conductor 25 power supply electrode 26 resin block 28 volume conductor 30 transmitting and receiving antenna 31 power source 32 series capacitor 33 grounded inductor 35 series inductor 42a, 42b 2 branches 51 excitation conductors 54 excitation wiring or 58 ground wiring 59 ground electrodes _C 1, _{C 2} capacitance _{L 1} inductance

Claims (14)

In an antenna including a spiral conductor that is formed by combining strip-shaped conductors located on a surface of a substantially rectangular parallelepiped and has a substantially spiral shape as a whole, the spiral conductors are orthogonal to each other in a plane perpendicular to the axis of the substantially spiral. An antenna having different lengths in two directions. The helical conductor has a length in at least one of two directions perpendicular to each other in a plane perpendicular to the axis of the spiral, and at least one of the lengths is longer than a length in a direction parallel to the axis of the spiral. The antenna according to claim 1, wherein: The antenna according to claim 1, wherein a capacitor plate that provides a capacitance between the terminal and the ground is connected to a terminal of the spiral conductor. 4. 4. The antenna according to claim 1, wherein the terminal end of the helical conductor is bifurcated and the two branches have different lengths. The antenna according to any one of claims 1 to 4, wherein the spiral conductor is formed on a surface of a dielectric or a magnetic material. The antenna according to claim 5, wherein the spiral conductor is a conductor film formed by printing, vapor deposition, plating, or sheet metal bonding. The antenna according to any one of claims 1 to 4, wherein the spiral conductor is formed inside a dielectric material or a magnetic material. The antenna according to any one of claims 1 to 7, wherein the spiral conductor has approximately one to two turns. The antenna according to any one of claims 5 to 8, wherein the dielectric or magnetic body has a through hole or a counterbore. A substantially straight conductor portion extending in one direction as the antenna conductor, and two substantially straight conductors connected at substantially right angles to the one direction and substantially parallel to each other at both ends of the conductor portion, respectively. An antenna comprising: The antenna according to claim 10, wherein the antenna conductor is formed on or inside a dielectric or magnetic material. An antenna conductor, an excitation electrode, and a ground electrode are provided on the surface or inside of a dielectric or magnetic material, and the antenna conductor is connected to and connected to the ground electrode, and on the ground electrode side from near the center of the antenna conductor, The antenna according to claim 1, wherein a part of the antenna conductor is located near the excitation electrode. An antenna conductor, an excitation electrode, and a ground electrode are provided on the surface or inside of a dielectric or magnetic material, and the antenna conductor is connected to and connected to the ground electrode, and on the ground electrode side from near the center of the antenna conductor, The antenna according to claim 11, wherein a part of the antenna conductor is located near the excitation electrode. 14. An antenna device, wherein the antenna according to claim 1 is mounted on the non-ground area on a substrate having a ground area and a non-ground area.

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