JP2003069331A - Surface-mounted antenna and communication apparatus mounting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an omnidirectional surface-mounted antenna with a broad band width and a high radiation gain, that uses a substrate with a high dielectric constant so as to attain downsizing and facilitate impedance matching. SOLUTION: The surface-mounted antenna comprises a substrate made of a high dielectric constant material having a dielectric constant εr of 6 or more, a ribbon-shaped radiation electrode having one end which is grounded and the other end which is open, a grounding electrode connected or capacitance- coupled to one end of the radiation electrode, and a current feeding electrode in a portal shape formed on a side surface separate from the radiation electrode with a gap. The area ratio of the grounding electrode at the bottom side of the substrate is a required minimum value of 30% or below, the current-feeding electrode has a current-feeding portion at one end, a grounding portion at the other end, and a portion substantially in alignment with the radiation electrode between them, and the length of the aligning portion, a gap width or a portal shape being able to be properly set as a channel shape, a meandered shape or a crank shape such that capacitance owned by the current-feeding electrode and inductance can be adjusted for easily achieving impedance matching.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small antenna having a dielectric or magnetic material such as ceramics or resin as a substrate, and more particularly to a surface mount antenna having an impedance matching function provided to a feeding electrode and a communication device equipped with the same. .

[0002]

2. Description of the Related Art GPS (Global Positi
oning System) and wireless LAN (Local Area Network)
Surface mount antennas are used. The miniaturization of mobile terminal devices is rapidly progressing, and surface mount antennas are also required to be small in size and low in height, have good radiation efficiency, have no directivity, and have a wide band. However, the characteristics of the conventional surface mount antenna deteriorate as the size and height of the antenna are reduced, so that it is not always satisfactory to realize a sufficiently small and low height.

Generally, the radiation electrode length of this type of antenna is 1 /
It is set to correspond to 4 wavelengths. This is a quarter wavelength
This is because the radiation efficiency of the antenna is maximized.
It is essential that the battery can be used for as long as possible by charging.
This is especially important for essential mobile terminal devices. On a dielectric substrate
When the radiation electrode is placed on the _r
It is known to be inversely proportional to the square root of
It is called the shortening effect. If the wavelength shortening effect is used,
The radiating electrode of the antenna can be shortened, and the antenna can be made small and low in height.
Wear. The lower the propagation frequency of the antenna,
Compact antenna by using a material with a large dielectric constant
Can be converted. However, in reality, high permittivity
There is a limit to the use of materials, and in practice the dielectric constant is about 4
Rate ε_rDielectric substrates with
Yes. This is the relative permittivity ε_rBecomes larger than this
This is because the problem of pedestal matching occurs. High relative permittivity
The surface-mounted antennas of the
Since the dance is likely to change significantly, the size of the
It was difficult to solve the problem of dance alignment.

For example, as shown in FIG.
The surface-mounted antenna described in Japanese Patent Publication No. 9-219610 is a radiating electrode 92 that is bent in an approximately L shape or an approximately U shape on an upper surface 91 of a substantially rectangular parallelepiped base body 90, and has one end open and the other end grounded.
And a feeding electrode 94 formed on the upper surface of the base body 90 via a gap 96 for exciting the radiation electrode 92.
One end of is connected to the power supply line 99. As shown in FIG. 22, the equivalent circuit includes the radiation resistance R and the inductance L of the radiation electrode 92, the capacitance C formed between the radiation electrode 92 and the ground conductor, and the radiation electrode 92 and the feeding electrode 94. It is a parallel resonant circuit composed of the formed capacitance Ci '. In this antenna, high-frequency power from a transmission circuit (not shown) is transmitted to the feeding electrode 94 via the feeding line 99 of the circuit board and input to the resonance circuit formed by the radiation electrode 92 and the ground conductor, It resonates in parallel and is radiated as an electromagnetic wave from the radiation electrode 92. Impedance matching is required to prevent voltage reflection at the feeding point 98.

Various types of impedance matching means have been proposed for matching the input impedance of the feeding electrode 94 viewed from the transmitting circuit side, that is, the input impedance at the feeding point 98 with the characteristic impedance (50Ω). For example, in the antenna shown in FIG. 21, the radiation electrode 92 and the feeding electrode 94 are capacitively coupled, and the radiation electrode 92 and the feeding electrode 94 are so arranged as to cancel the inductance L of the radiation electrode 92 as shown in the equivalent circuit of FIG. Capacitance between
Is set. However, in the conventional antenna shown in FIG. 21, the feeding electrode and the radiating electrode are not directly connected but only by capacitance coupling, and the inductance is not used for impedance matching. For this reason, if this antenna is made small and its height is low, it is not possible to make it an antenna with high characteristics in which impedance matching is easy. Also GPS and wireless LAN
Antennas used for such purposes are basically required to be omnidirectional, and it is also necessary to improve radiation efficiency and gain and expand bandwidth. Conventionally, consideration and consideration for this point have not been sufficient.

When impedance mismatch occurs, a new matching circuit may be inserted between the transmission / reception circuit and the antenna. However, the addition of the new matching circuit causes a problem that the antenna device becomes large. is there. Regarding the impedance matching circuit, Japanese Patent Laid-Open No. 2000-286615 discloses a small antenna in which a base has a laminated structure and a matching circuit is built in between layers. However, this not only complicates the structure of the antenna, but also causes an increase in manufacturing cost. WO01 / 24316A1 discloses that the upper surface of the substrate is
An antenna that has one radiating electrode (feeding side radiating electrode) and second radiating electrode (non-feeding side radiating electrode), is in a multiple resonance state between the two radiating electrodes, and has a matching circuit electrode on the side surface of the base body. Is disclosed. In this antenna, the first radiating electrode (feeding side radiating electrode) and the matching electrode are directly connected at the impedance matching position, but the feeding electrode does not have capacitance, and impedance matching is performed exclusively by operating the inductance. I am trying to The electrode structure having such a matching circuit corresponds to the conventional inverted F antenna, and is an antenna structure which is originally easy to achieve impedance matching.

Japanese Unexamined Patent Publication No. 8-186431 and Japanese Unexamined Patent Publication No. 11-340726 disclose impedance matching techniques in a unidirectional antenna having a structure in which a radiation conductor is formed on the upper surface of a base and a ground conductor is formed on the entire bottom surface of the base. is doing. However, such an antenna is not suitable for applications that require non-directionality such as GPS and wireless LAN. This can also be understood from the configuration in which the power supply conductor provided on the upper surface of the base is surrounded by the radiation conductor, and the coupling of the capacitance is large. Moreover, it is not suitable for use in GPS, etc., because it is not considered to be compact, radiation efficiency, gain and bandwidth.

[0008]

In the prior art, it has not been possible to obtain a device having a small size, a low profile, easy impedance matching, and high antenna characteristics. Also, G
An antenna used for PS, wireless LAN, and the like basically needs non-directionality, and it is also necessary to improve radiation efficiency and gain and expand bandwidth. Conventionally, consideration and consideration in this respect have not been sufficient. An object of the present invention is an antenna that can be easily impedance-matched and downsized even when a material having a relatively high dielectric constant is used, and is particularly suitable for GPS, wireless LAN, etc., and has high gain, wide band, and omnidirectional. The object of the present invention is to provide a surface mount antenna having a property. Another object of the present invention is to provide a communication device for a mobile phone, a headphone, a personal computer, a notebook computer, a digital camera, etc., which is equipped with this surface mount antenna.

[0009]

As a result of earnest research in view of the above-mentioned object, a material having a relatively high dielectric constant was used when an impedance matching function was provided by forming a power supply electrode with a structure having an inductance in addition to a capacitance. The inventors have found that a small surface-mounted antenna having an omnidirectional property can be obtained even if impedance matching is easy, and the present invention has been made.

A first surface mount antenna according to the present invention is a substrate made of a dielectric or magnetic material, a radiation electrode provided on at least an upper surface of the substrate, and directly connected to one end of the radiation electrode or by capacitive coupling. So that the ground electrode provided on the base body and a power supply electrode provided on at least a side surface of the base body so as to face the radiation electrode through a gap, and the power supply electrode has a power supply point at one end. Each has a ground point at the other end, has an impedance matching section by capacitance and inductance between the feeding point and the ground point, and the area ratio of the ground electrode on the bottom surface of the substrate is 30% or less. Is characterized by.

A second surface mount antenna according to the present invention is a substrate made of a dielectric or magnetic material, a radiation electrode provided on at least an upper surface of the substrate, and either directly connected to one end of the radiation electrode or capacitively coupled. So that the ground electrode provided on the base body and a power supply electrode provided on at least a side surface of the base body so as to face the radiation electrode through a gap, and the power supply electrode has a power supply unit at one end. It is characterized in that it has a grounded portion at the other end, and has a gate-like shape having a parallel portion arranged between the two and the radiation electrode with a gap therebetween.

A third surface mount antenna according to the present invention is a substrate made of a dielectric or magnetic material, a radiation electrode provided on at least the upper surface of the substrate, and either directly connected to one end of the radiation electrode or capacitively coupled. And a power supply electrode provided on at least a side surface of the base so as to face the radiation electrode with a gap therebetween, the power supply electrode facing the base. The two L-shaped electrodes provided on the side surface and one I-shaped electrode provided on the end surface of the base are connected, and one L-shaped electrode has a power feeding portion at one end, The other L-shaped electrode has a ground portion at one end, the I-shaped electrode is a parallel portion, and thus the power feeding electrode is in a gate shape.

In the present invention, the feeding electrode includes first and second electrodes provided on opposite side surfaces of the base,
One I-shaped electrode provided on the end surface of the base is connected to the first electrode, the first electrode has a feeding portion at one end, and the second electrode has a ground portion at one end. It is preferable that the electrode is a parallel portion, the feeding electrode is in the shape of a gate, and the ground electrode portion formed on the end face or the end face of the base and the opposite side face is formed. The feeding electrode and the radiation electrode are at least partially in a meandering shape, a U shape, and an L shape.
It is preferable to have one of a letter shape and a crankshaft shape. It is preferable that the power feeding electrode is provided on a side surface of the base through a gap on the open end side of the radiation electrode. At this time, it is preferable to dispose a power feeding portion near the open end of the radiation electrode. In a preferred embodiment of the present invention, at least a part of the radiation electrode extends continuously and / or stepwise from the one end of the base body to the other end in the longitudinal direction while substantially narrowing the width. In another preferred embodiment of the present invention, the radiation electrode extends continuously and / or stepwise from the one end of the base body toward the other end in the longitudinal direction while substantially narrowing the width, and at the other end of the radiation electrode. It is bent like a letter. In another preferred embodiment of the present invention, the radiation electrode is formed so as to reach the upper surface via a side surface different from the side surface on which the power feeding electrode is formed. At this time, when the radiation electrode provided on the upper surface of the base is projected onto the lower surface of the base, it is preferable that there is no overlapping ground electrode. In the antenna of the present invention, it is preferable that the radiating electrode and / or the feeding electrode have rounded corners. In the antenna of the present invention, a second ground electrode facing the other end of the radiation electrode via a gap may be provided on the base body. A dielectric material having a relative permittivity ε _r of 6 to 50 can be used for the antenna substrate of the present invention.

A surface mount antenna according to a preferred embodiment of the present invention is a substrate made of a dielectric or magnetic material, a strip-shaped radiation electrode provided on the substrate, and either directly connected to one end of the radiation electrode or capacitively coupled. And a power supply electrode provided on at least a side surface of the base so as to be located with a desired gap from the radiation electrode, the radiation electrode being the base. An electrode portion formed in one side surface in the longitudinal direction and an L-shaped electrode portion formed on the upper surface of the base are connected to each other to have a generally U-shaped shape, and the power supply electrode is A feed portion and a ground portion extending substantially vertically on the other side surface of the base body; and a parallel portion extending between the feed portion and the ground portion substantially parallel to the radiation electrode through the gap, The ground on the bottom surface of the substrate The area ratio of the electrodes is 30% or less, and it is characterized in that the capacitance and the inductance can be adjusted by correcting the shapes and the positional relationships of the feeding electrode and the radiating electrode, and thus impedance matching can be performed.

A communication device of the present invention comprises an antenna device in which the surface-mounted antenna is mounted in a region of a circuit board where there is no ground conductor, and the radiation electrode extends in the longitudinal direction. It is characterized in that the feeding electrode is arranged on the side of the ground conductor side by side with the edge portion of the conductor via a gap. In a preferred embodiment of the present invention, the ground electrode portion located on the side opposite to the ground conductor of the circuit board on the surface mount type antenna is located on the corner side of the circuit board, and the ground electrode portion and the conductor of the circuit board are lined. Connected by strip conductors.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail with reference to the embodiments shown in the drawings. First, the reason why impedance matching becomes difficult will be described. A radiation electrode on the substrate,
When the ground electrode, the feeding electrode, etc. are arranged, a capacitance is generated between the electrodes. Increasing the capacitance between the feed electrode and the radiating electrode lowers the input impedance,
Causes impedance mismatch. Since the capacitance increases in proportion to the relative permittivity ε _r , impedance mismatch becomes noticeable when a high permittivity material is used to lower the propagation frequency. Therefore, the relative permittivity ε
Dielectric substrates with a low _r of around 4 are used. The invention allows, but is not limited to, the use of dielectric materials having a relative permittivity ε _r of 6 or more, preferably 20 to 50 or more.

According to the present invention, even if the capacitance between the radiation electrode and the feeding electrode is increased by using a material having a high dielectric constant for the substrate, the inductance of the feeding electrode is increased by increasing the length of the feeding electrode. The increment is canceled to achieve impedance matching. Conventionally, the feeding electrode of this type of antenna has a configuration that provides only capacitance on an equivalent circuit, but has a shape that can obtain inductance in addition to capacitance according to the present invention. Specifically, it is possible to adjust the capacitance by forming the feeding electrode in a strip shape to easily obtain the inductance and arranging a part of the feeding electrode in parallel with the radiation electrode through the gap. Also, by using one end of the strip-shaped power supply electrode as the power supply part and the other end as the ground part, the parallel component L ₂ and the series components L ₁ and C _i are provided as shown in FIG. 2 to facilitate impedance matching design. And the development period was shortened.

Since the surface mount antenna has various forms depending on the application, the impedance matching condition needs to satisfy the wide range of requirements. As mentioned above,
The feeding electrode of the present invention can be regarded as a combination of the parallel component L ₂ and the series components L ₁ and C _i . By forming the power feeding electrode in a meandering shape, a U-shape, an L-shape, a crankshaft shape, or a combination thereof, the inductance and the capacitance can be arbitrarily set without being limited to the impedance matching condition. For example, the capacitance and the inductance can be made substantially the same, or one of them can be made large. The inductance is proportional to the length of the feed electrode, and the capacitance is a function of the facing length of the feed electrode and the radiating electrode. Therefore, when impedance matching is performed using the power supply electrode of the present invention, first, it is determined which of L ₁ , L ₂ and C _{i in} the equivalent circuit should be increased or decreased. Next, L ₁ and L ₂ are proportional to the length of the feed electrode, and C _i is a function of the facing length between the feed electrode and the radiation electrode. The shape of the electrode can be easily set.

In the antenna structure according to one embodiment of the present invention, the radiation electrode is provided on at least the upper surface of the base, one end of which is grounded and the other end is an open end. This antenna structure looks like an inverted F-type antenna in which a feeding electrode is connected near the ground end of the radiating electrode, but in the present invention, the radiating electrode and the feeding electrode are separated and capacitively coupled. It is different from the inverted F type structure. It should be noted that when the power feeding electrode is formed on one side surface of the base body, there is no print misalignment when the electrode is formed by printing, manufacturing is easy, and the characteristics are stable. In the present invention, by appropriately setting the distance and the parallel length between the radiation electrode and the feeding electrode and / or the leg length and the shape of the feeding electrode,
Impedance matching is facilitated. Thereby, the bandwidth BW can be arbitrarily selected. Since BW∝1 / Q and Q = R√ (C / L), C based on the degree of capacitive coupling and electrode length
Alternatively, the bandwidth BW can be expanded by controlling C / L. For example, if the power feeding portion side of the power feeding electrode is arranged near the open end of the radiation electrode, the radiation end is regarded as an inductor and a large inductance component (L) can be taken. If the design is performed at the same resonance frequency, the capacitance (C) can be reduced accordingly and the Q value can be increased. Therefore, the bandwidth can be increased.

The surface-mounted antenna of the present invention is characterized by having almost no grounding electrode for soldering on the bottom surface because it has excellent omnidirectionality. When the ground electrode is formed on the entire back surface, the omnidirectionality of the antenna is lost due to capacitance coupling with the radiation electrode on the top surface. Specifically, the ratio of the total area of the ground electrode on the bottom surface / the total area of the bottom surface is preferably 30% or less, more preferably 20% or less.
Also on the bottom. It is preferable that there is substantially no ground electrode in the region below the radiation electrode provided on the upper surface, and the second ground electrode can be arranged to face the open end of the radiation electrode via a gap. . In this case, since the capacitive coupling with the opposing ground electrode is strong, even if the power supply electrode is arranged in the vicinity, the influence is relatively small. Therefore, when the propagation frequency is adjusted significantly, the frequency is mainly adjusted by adjusting the degree of coupling between the radiation electrode and the second ground electrode, and by adjusting the degree of coupling between the radiation electrode and the feeding electrode. Fine tune the frequency.

In the present invention, the relative permittivity ε of the substrate is_rIs 6 to 50
Is preferred. This relative permittivity ε _rIs the temperature of the dielectric
It is decided in consideration of the coefficient, the processing accuracy of the substrate, etc.
However, if the material, processing accuracy, etc. improve, naturally the upper limit value will also increase.
Be lifted. Such a relative permittivity ε_rSubstrate with
Is, for example, 22.22 wt% MgO, 5.13 wt% CaCO₃, 48.
14 wt% TiO₂And 24.51% by weight of ZnO
The element body is fired and 36.6 mol% MgO, 3.4
Mol% CaO, 40 mol% TiO₂And from 20 mol% ZnO
Dielectric ceramic (relative permittivity ε_r: 21)
be able to. Using a high dielectric substrate, the radiation electrode
Radiation efficiency is reduced. To suppress the decrease in radiation efficiency
, The radiation electrode and ground to enhance the radiation to the free space
A substrate that constitutes an electrode or is a composite of high-dielectric and low-dielectric
Use the body.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a surface mount antenna according to a first embodiment of the present invention. This antenna 1A
Is a radiation electrode 2 disposed on the upper surface of a rectangular parallelepiped base body 1,
The ground electrode 3 is connected to one end of the radiation electrode 2, and the feeding electrode 4 is formed on the side surface of the radiation electrode 2 with a predetermined gap G1. The other end of the radiation electrode 2 is an open end 20. Antenna 1A has a configuration similar to an inverted F antenna, except that feed electrode 4
Is different from the inverted-F antenna in that it is through the gap G1.
No electrodes other than the soldering electrodes are arranged on the bottom surface 1a of the base 1, and the antenna is mounted in a region on the circuit board where there is no ground conductor, so that a substantially uniform radiated electric field pattern can be obtained in any direction. The omnidirectionality shown is obtained. Feeding electrode 4
Has a gate-shaped (U-shaped) shape in which a strip-shaped electrode is bent at two places, and has a parallel portion 41 that faces the edge portion 23 of the radiation electrode 2 substantially in parallel. The feeding electrode 4 has a feeding point 40 connected to a feeding line of a transmission / reception circuit (not shown) at a feeding portion 43 at one end, and a grounding end 42 connected to a ground conductor at a grounding portion 44 at the other end. The power feeding part 43 and the grounding part 44 of the power feeding electrode 4 mainly generate an inductance, and the radiation electrode 2 and the parallel part 41
Mainly produces capacitance. Therefore, the surface mount antenna according to the present invention has the equivalent circuit shown in FIG.

The inductances L ₁ and L ₂ are the legs 4 of the feeding electrode.
3 and 44, the capacitance C _i is formed between the radiation electrode 2 and the parallel part 41 of the feed electrode 4. Therefore, leg 4
Set the length and shape of 3, 44 and parallel part 41 appropriately to L ₁ , L ₂
By changing C _i and C _i ,
The input impedance Z _in seen from 2 can be matched to 50 Ω. Thus, in addition to the capacitance between the radiation electrode 2 and the power feeding electrode 4, it is an important feature of the present invention that the impedance of the power feeding electrode 4 can be manipulated to uniquely match the input impedance. The same applies to the following embodiments, but the positions of the feeding point 40 and the grounding point 42 may be reversed right and left. Further, the parallel portion 41 may be aligned with the radiation electrode 2 via a gap, and does not need to be parallel.

FIG. 3 is a perspective view showing a surface mount antenna according to the second embodiment, FIG. 4 is a developed view of the radiation electrode thereof, and FIG. 5 is a view showing an equivalent circuit of this antenna.
The surface-mounted antenna 1B of this embodiment is for GPS, and has a rectangular parallelepiped base body 1, a radiation electrode 2 formed on the upper surface 1c and the adjacent side surface 1d, and a ground electrode 3 connected to one end of the radiation electrode 2. And a feeding electrode 4 formed in a gate shape from the longitudinal side surface 1b to the upper surface 1c of the base 1. Feeding electrode 4 is side 1b
It may be provided only on the side surface. The arrangement and shape of the gate-shaped power supply electrode 4 are determined by balancing impedance matching and widening the band. The radiation electrode 2 of this embodiment has a shape extending from one end of the substrate 1 continuously and / or stepwise in the longitudinal direction while substantially narrowing the width. As shown in the exploded view of Figure 4,
The radiation electrode 2 includes a radiation electrode portion 21 provided on the upper surface 1c of the base 1.
And the radiation electrode portion 22 formed continuously on the adjacent side surface 1d, the width of the radiation electrode portion 22 is slightly narrowed toward the tip. Thus, by forming the radiation electrode 2 having a gradually narrowed width not only on the upper surface 1c of the base 1 but also on the adjacent side surface 1d, it is possible to induce multiple resonance, reduce the size, and become more omnidirectional. . The ground electrode 3 and the radiation electrode 2 may be connected by non-contact capacitive coupling. The ground electrode 3 may be provided on four surfaces surrounding the one end surface 1e of the base 1. The ground electrode 3 formed on the bottom surface 1a also serves as a soldering electrode and is connected to the ground conductor of the circuit board. The power feeding electrode 4 also has a ground electrode portion 50 on the bottom surface 1a of the base body 1, and the ground electrode portion 50 acts as an electrode for soldering to the circuit board.

In the present embodiment, the feeding electrode 4 is a gate type (U-shaped) having a width of 1 mm and an equivalent length of 10 mm. Figure 6 (a) ~ (c)
Shows various shapes of the feeding electrode 4. FIG. 6 (a) shows an example of the U-shaped feeding electrode 4, and the inductances L ₁ and L ₂ generated in the left and right legs are substantially equal. The shapes shown in FIGS. 6B and 6C are examples in which the left and right legs have different lengths, and the inductance is adjusted by the length of the conductor. In FIG. 6B, the right leg has a meandering shape and L ₁ <L ₂ . Further, in FIG. 6 (c), the left leg has a crank shape and the right leg has a meandering shape, and L ₁ > L ₂ . When adjusting using the inductance, L ₁ is increased to increase the input impedance, and conversely, L ₂ is increased to decrease the input impedance.

The central parallel portion 41 of the feeding electrode 4 is one of the features of the present invention. C and C _i can be arbitrarily set by the central parallel portion 41. Ie capacitance
C _i is approximately proportional to the length W of the parallel portion 41 and inversely proportional to the distance G ₁ between the parallel portion 41 and the radiation electrode 2. Therefore, when increasing C _i , the parallel part 41 is lengthened or the parallel part 41 and the radiation electrode are
Reduce the distance G ₁ from 2. When decreasing C _i , the opposite is true. In this way, C _i can be adjusted by changing the length W of the parallel portion 41 and the distance G ₁ between the parallel portion 41 and the radiation electrode 2.

This embodiment is also characterized by the radiation electrode 2. The basic shape of the radiation electrode 2 was gradually reduced as it approached the open end 20 side, without making the electrode length in the direction perpendicular to the flow of the high frequency current (longitudinal direction of the substrate 1), that is, the width constant. It has a shape. The high-frequency current supplied from the power supply source via the power supply electrode 4 resonates at a frequency determined by the capacitance formed between the inductance of the radiation electrode 2 and the ground, and is radiated as space electromagnetic energy. At this time, it becomes a current distribution mode in which the ground electrode 3 and the open end 20 serve as nodes and antinodes. If the width of the radiation electrode 2 is constant, there is only one current distribution mode, but if the width of the radiation electrode 2 is not constant, the antenna has a plurality of inductances Lr ₁ , Lr ₂ , as shown in FIG. Lr ₃ ,…, and capacitance C
A resonance circuit composed of r ₁ , Cr ₂ , Cr ₃ , ... Is equivalently formed. Since the resonance frequencies of the resonance circuits are very close to each other, a plurality of resonances exist continuously, and as a result, a wide-band resonance characteristic is obtained.

FIG. 7 shows a surface mount antenna according to the third embodiment of the present invention. The same parts as those in the above-mentioned embodiment are designated by the same reference numerals, and their description will be omitted. Similar to the above-described embodiment, the radiation electrode 24 has a substantially trapezoidal shape extending continuously and / or stepwise from the one end of the substrate 1 toward the other end in the longitudinal direction while substantially narrowing the width, and the feeding electrode 4 is the substrate. It is provided over the side surface 1b and the upper surface 1c of the 1. In this embodiment, since the feeding electrode 4 is U-shaped, the distance between the parallel portion 41 and the radiation electrode 24 is not constant and the capacitance is small. As described above, the radiation electrode 24 and the power feeding electrode 4 do not have to be parallel to each other, as long as they are partially aligned. This is called almost parallel. The stepwise narrowing of the radiation electrode means, for example, a stepwise narrowing step.

FIG. 8 shows a surface mount antenna according to a fourth embodiment of the present invention. The same parts as those in the above-mentioned embodiment are designated by the same reference numerals, and their description will be omitted. The radiation electrode 25 has a microstrip shape, one end of which is grounded and the other end 20 is open. In each of the above examples, the dielectric substrate 1
Although the radiation electrode 2 is provided over the entire length of the upper surface 1c of the above, the length of the radiation electrode may be selected to be 1/4 wavelength of the desired frequency and is not necessarily provided over the entire length of the substrate 1. In this embodiment, the radiation electrode 25 is shorter than the base 1. This allows
An adjustment allowance can be taken to lower the propagation center frequency. Further, even if the end of the base 1 has a defect such as a dimensional defect or a chip, there is no problem in forming the radiation electrode 25.

FIG. 9 shows a surface mount antenna according to a fifth embodiment of the present invention. The same parts as those in the above-mentioned embodiment are designated by the same reference numerals, and their description will be omitted. Open end of radiation electrode 26
The second ground electrode 5 so as to face 20 through the gap G2
Are formed. This causes the open end 20 of the radiating electrode 26 to
A large and stable capacitance is formed between the ground conductor and the ground conductor, and the frequency can be adjusted significantly. Fine adjustment for power supply electrode
The inductance and capacitance of 4 may be used.
Gap G2 between the open end 20 of the radiation electrode 26 and the second ground electrode 5
Due to the capacitance, the desired frequency can be obtained even if the radiation electrode 26 is short (small inductance). Therefore, the surface mount antenna having such a structure is suitable for miniaturization. Although the power feeding electrode 4 is formed from the side surface 1b to the upper surface 1c of the base 1, it may be provided only on the side surface 1b depending on conditions. This is common to the above-mentioned embodiments. When the power supply electrode 4 is provided only on the side surface 1b, it is not necessary to pay attention to the accuracy of the joints when forming it by screen printing or the like, and the number of steps is reduced, which is also preferable in manufacturing.

10 to 12 show surface mount antennas according to the sixth to eighth embodiments of the present invention. A perspective view is shown on the left side of the drawing, and a development view is shown on the right side. In these examples, the strip-shaped radiation electrode 2 is formed from the side surface 1d to the upper surface 1c of the base 1. In the sixth embodiment shown in FIG. 10, an L-shaped electrode portion 27 is provided at the end of the upper surface 1c of the base 1 and the adjacent side surface 1
An L-shaped electrode 28 is continuously formed at d. Feeding electrode 4
Is a gate-shaped (U-shaped) shape having leg portions 43 and 44 respectively serving as a feeding end and a grounding end and a central parallel portion 41, and is a side surface 1b of the base 1.
Are formed side by side on the open end side of the L-shaped electrode portion 27.
In the seventh embodiment shown in FIG. 11, at the end of the upper surface 1c of the base 1,
The L-shaped electrode portion 27 is provided, and the L-shaped electrode 29 is continuously formed on the adjacent side surface 1d. Also shown in FIG.
In the eighth embodiment, the L-shaped electrode portion 27 is provided at the end of the upper surface 1c of the base 1.
Is provided, and the I-shaped electrode 30 is continuously formed on the adjacent side surface 1d. Regarding the shape of the feeding electrode 4, the seventh and eighth embodiments are substantially the same as the sixth embodiment. The electrode 51 is a soldering electrode for fixing the antenna to the circuit board, but in the examples of FIGS. 11 and 12, a soldering electrode 52 is added to increase the bonding strength with the circuit board. The electrodes 51 and 52 are not connected to the ground conductor of the circuit board. In the examples of FIGS. 10 to 12, the radiation electrode is L-shaped in order to increase the inductance. In the example of FIG. 11, the bent portions of the L-shaped radiation electrode portion 29 and the gate-shaped feeding electrode 4 are rounded.
Only the radiation electrode may have the curvature R. When the substrate 1 is made low in height, as shown in FIG. 12, when the soldering electrode 52 is directly connected to the radiation electrode 30 via the connection electrode 31, the antenna characteristic is stable without a great change.

As shown in FIG. 11, when the bent portion of the L-shaped electrode portion 29 has a roundness R, the radiation gain is improved. In a conventional radiation electrode having a substantially L-shaped, U-shaped, meander-shaped, or crank-shaped bent portion, the straight portion and the bent portion have unequal widths and are connected in an angular shape. This means that the impedance changes discontinuously, and a part of the traveling wave is reflected due to the discontinuity. For this reason, the reflection loss of the input high frequency was large, and the gain was reduced.
In order to solve this problem, it was found that if the bent portion is rounded, the line becomes almost equal in width, and impedance discontinuity can be avoided. Alternatively, it has been found that it is also effective to perform chamfering with the corners cut off.
When the generation of the reflection loss at the bent portion is suppressed, the transmission loss of the resonance current flowing through the radiation electrode of the antenna is reduced and the gain is improved.

13 and 14 show surface mount antennas according to the ninth and tenth embodiments of the present invention. The same parts as those in the above-mentioned embodiment are designated by the same reference numerals, and their description will be omitted. These examples are characterized by the radiation electrode 33 and the feeding electrode 4. The radiation electrode 33 is mainly provided on the upper surface 1c of the base body 1 and substantially continuously and / or stepwise from one end connected to the ground electrode 3 to the other end in the longitudinal direction as in the example shown in FIG. The radiation electrode portion 33a extends while narrowing the width, and the radiation electrode portion 33b bent in a U shape or a U-turn shape at the left end portion. With such a radiation electrode 33, a trapezoidal radiation electrode portion 33a can obtain a broadband resonance characteristic, and a bent radiation electrode portion 33b can supplement the inductance. The electrode 51 is a soldering electrode for fixing the antenna to the circuit board, and is provided in a necessary minimum amount. In this embodiment, a gap of about 0.2 to 0.5 mm is provided between the outer circumference of the radiation electrode 33 and the ridgeline of the base 1. Due to this gap, electrode printing becomes easy, and printing deviation does not easily occur. In addition, electrode peeling due to deformation or chipping of the edge of the substrate 1 can be prevented. By preventing print misalignment and electrode peeling, variations in propagation frequency can be suppressed. In the configuration in which the radiation electrode 33 is provided only on the upper surface 1c of the base 1, the capacitance coupling with the ground conductor of the circuit board is reduced as compared with the configuration in which the radiation electrode is also provided on the side surface, and thus a high gain can be obtained.

As shown in FIG. 13, the gate-shaped feed electrode 4 provided on the side surface 1b faces the open end 20 of the radiation electrode portion 33b.
The power feeding electrode 4 shown in FIG. 14 has a power feeding end 43 at one end and a side surface 1b.
An L-shaped electrode portion 41 provided on the side surface 1d, an I-shaped electrode portion 42 provided on the end surface 1f, and an L-shaped electrode portion 45 provided on the side surface 1d having a ground end 44 at one end. The gate-shaped power supply electrode 4 includes electrode portions 41, 42, 45 provided on the two side faces 1b, 1d and the end face 1f.
And has a U-shaped parallel portion 41, and the parallel portion 41 faces the U-shaped radiation electrode 33b. With such a feeding electrode 4,
Capacitance coupling can be performed over almost the entire U-shaped portion of the radiation electrode 33, which is advantageous for downsizing the antenna. Further, for the same capacitance value, the gap with the radiation electrode 33 can be widened, and the variation of the capacitance value and the variation of the propagation frequency due to the print misalignment can be reduced. FIG. 15 shows a surface mount antenna of Example 11. In this example, the structure of the feeding electrode 4 is different from that of the other examples. That is, the power feeding electrode 4 includes an F-shaped electrode portion 41 having a power feeding end 43 and a grounding end 44 provided on the side surface 1b of the base body 1 and an end face.
1f and linear electrode portions 42 and 45 formed on the side surface 1d. The power feeding electrode of this embodiment is capable of widening the band by using multiple resonance at the same time as impedance matching. It is also possible to combine the antenna configurations of the respective embodiments described above, and various other embodiments can be configured within the scope of the present invention.

FIG. 16 shows a surface mount antenna of the twelfth embodiment. The strip-shaped radiation electrode 133 is formed on the upper surface 1c and the crankshaft-shaped electrode portion 133d formed on the side surface 1d in the longitudinal direction.
It is composed of an L-shaped electrode portion 133c and has a generally U-shape. In this way, the radiation electrode 133 is formed from the upper surface 1c to the side surface 1d of the substrate 1.
Since it extends up to the bent shape, the total length can be increased. As a result, the size of the antenna base 1 can be reduced in the same bandwidth. The positional relationship between the power feeding portion 143 and the grounding portion 144 of the power feeding electrode 104 is opposite to that of the above-described embodiment, the power feeding point 140 is located in substantially the center of the base, and the power feeding portion 143 is located near the open end of the radiation electrode 133. I am trying to do it. Further, the L-shaped electrode portion 133c formed on the upper surface 1c does not overlap with the ground electrode 32 when projected on the lower surface 1a. As a result, the improved bandwidth and omnidirectionality make it a well-balanced GPS antenna. Also the radiation electrode 13
The open end of 3 and the parallel portion 141 of the feeding electrode 104 are close to each other. The wide parallel portion 141 facilitates impedance matching and slightly improves the gain. In the present embodiment, the parallel portion 141 has a wide width and a shape close to a rectangle, but the shape of the feeding electrode 104 can be variously changed depending on the mounting position on the circuit board side, the arrangement of the conductor pattern, the radiation electrode structure, and the like. . Even if the specifications of the circuit board and the radiation electrode 133 are changed, the power feeding electrode is placed between the power feeding point 140 and the grounding point 142.
By appropriately setting the layout, shape, size, etc. of 104, impedance matching can be easily achieved by appropriately adjusting the inductance and capacitance.

FIG. 17 shows input impedances obtained by simulation for the surface mount antenna (present invention) of FIG. 1 and the surface mount antenna of FIG. 21 (conventional example).
The relationship between Z _in and the relative permittivity ε _r of the substrate is shown. In the present invention, the increase in capacitance associated with the use of a high-dielectric constant substrate can be appropriately canceled by the inductance, and a high-dielectric material having a relative dielectric constant ε _{r of up} to about 50 can be used. Compared with the conventional case where the relative permittivity ε _r is about 4, it is possible to use a dielectric material having ε _r that is 5 times or more, which is very effective in miniaturizing the antenna. Note that the upper limit of the input impedance Z _in will further increase if a stable dielectric material is developed in a high temperature range or if processing technology is improved. It is also expected that the upper limit will be raised when a composite material of a high dielectric material and a low dielectric material is developed.

Next, a structure for mounting the above surface mount antenna on a circuit board will be described. FIG. 18 shows a state in which the antenna 1B shown in FIG. 3 is mounted on the circuit board 6. In FIG. 18, parts other than the antenna are omitted. The antenna 1B is arranged on the exposed portion 65 of the circuit board 6 where there is no ground conductor so as to be aligned in the longitudinal direction with the edge portion 63 of the ground conductor 62 with a slight gap. At that time, the feeding electrode 4 is connected to the ground conductor 62.
Located on the side, the open end 20 of the radiation electrode 2 is located far from the ground conductor 62. One end of the gate-shaped power supply electrode 4 is connected to the power supply line 61, and the other end is connected to the ground conductor 62. As a result, the high-frequency signal supplied from the power supply 60 is supplied to the power supply electrode 4 via the power supply line 61, and flows from the power supply end 40 to the radiation electrode 2 side via the parallel portion 41 and the ground end 42. It is divided into a current flowing toward the ground conductor 62, and impedance matching is performed and the radiation electrode 2 is excited. As a result, the electromagnetic wave is radiated into the space from the open end 20 of the radiation electrode 2.

Conventionally, the antenna was often arranged vertically to the edge of the ground conductor 62. In this case, it goes without saying that the dead space becomes large and the degree of freedom in design is small. However, in the present invention, the antenna is slightly separated from the edge of the ground conductor 62, and by arranging the antenna in parallel with it,
The area substantially occupied by the antenna (including the dead space) is markedly reduced, and the flexibility and density of the mounting layout are increased, so that the space of the antenna device can be saved. The left and right arrangement of the feeding portion 43 and the grounding portion 44 of the feeding electrode 4 may be changed according to the arrangement of the feeding line 61 and the ground conductor 62 of the substrate 6, but at least the feeding electrode 4 is arranged on the feeding line 61 side, It is necessary to make the ground conductor 62 and the antenna base body 1 parallel to each other in order to obtain the effect of the present invention with a small occupied area. In order to be omnidirectional, the antenna of the present invention is preferably mounted on the exposed portion 65 without the ground conductor 62. By mounting the circuit board 6 on which the antenna is mounted in a mobile phone, a personal computer, or the like schematically shown in FIG. 19, it can be used as a communication device having a GPS or a wireless LAN function.

FIG. 20 shows an example in which the antenna shown in FIG. 16 is mounted on a circuit board 6 different from that shown in FIG. The same parts as those in FIG. 18 are designated by the same reference numerals. The antenna 1L is mounted on the exposed portion 65 of the circuit board 6 where the ground conductor 62 is not formed, and
The edge portion 63 and the antenna base 1 are arranged so as to be aligned with a slight gap. The power feeding electrode 4 is formed on the side surface 1b of the base body 1 on the ground conductor 62 side, and the power feeding end 14 of the power feeding electrode 104 is formed.
0 is connected to the power supply line 61, and the ground end 142 is connected to the ground conductor 62. Of the ground electrode 32 connected to the radiation electrode 133, the portion located on the corner side of the circuit board 6 is the ground conductor of the circuit board 6.
62 and the linear electrode 66 are connected. The linear electrode 66 acts as an inductance and facilitates miniaturization of the antenna base body 1. Further, in the same substrate 1, the bandwidth can be expanded by using a material having a lower dielectric constant. The metal regions 51 'and 53' are provided for fixing the antenna base 1 to the circuit board 6 by soldering.

Antenna characteristic tests were conducted on Example 2 shown in FIG. 3, Example 7 shown in FIG. 11 and Example 12 shown in FIG. An antenna characteristic test was conducted by using Comparative Example 1 as the same antenna as shown in FIG. 3 except that a part of the radiation electrode 2 was formed into a meandering shape as shown in FIG. The antenna base is made of a ceramic dielectric having a relative permittivity εr of 21, and the base size is 15 in Example 2 and Comparative Example 1.
mm × width 3 mm × thickness 3 mm, and in Examples 7 and 12, length 10 mm
× width 3 mm × thickness 2 mm. The center frequency of the propagation frequency
Bandwidth BW (MHz), average gain (dBi) and directivity at a voltage standing wave ratio of 2 (VSWR = 2) were measured at 1.575 GHz ± 1 MHz.
VSWR is measured by connecting the power supply terminal provided at one end of the antenna mounting board and the input terminal of the network analyzer via a coaxial cable (characteristic impedance 50 Ω), and looking at the antenna from the network analyzer side at the power supply terminal. Scattering Parameter (Scattering Paramete
Based on this value, VSWR was calculated by measuring r). In addition, when measuring the gain, connect the signal generator to the power supply terminal of the antenna under test (transmission side) in the anechoic chamber and receive the power radiated from the antenna with the reference antenna for reception. did. Let the received power coming from the antenna under test be Pa, and let the received power measured by the reference antenna for transmission having a known gain Gr be Pr,
The gain Ga of the antenna under test is represented by Ga = Gr × Pa / Pr. Regarding the directivity, by mounting the antenna element under test on the rotary table and performing the above-mentioned gain measurement while rotating the antenna under test, as shown in FIG. 18, X, Y
And the gain with respect to the rotation angle when rotated about the Z axis were measured. Further, as shown in FIG. 19, the metal dependence of the characteristics was examined on the assumption that it is mounted on a communication device such as a mobile phone. The measurement results are shown in Table 1.

[0041]

[Table 1]

From the above results, it was found that the antennas of Examples 2, 7 and 12 can easily achieve impedance matching while having a substrate having a relatively high relative dielectric constant. Further, the antennas of Examples 2, 7 and 12 are different from those of Comparative Example 1 in Examples 2 and 7
Although the bandwidth was a little narrow, a high radiation gain was obtained, and there was little decrease in gain due to metal proximity, and stable antenna characteristics were obtained. In Example 7, although the substrate size was reduced to about 2/3, the bandwidth and the gain were good.
Regarding the omnidirectionality, the gains of all three axes were close to a circle, and omnidirectional characteristics with no directivity were obtained. From the above, the bandwidth of the antennas of Examples 2, 7, and 12, particularly Example 12 is
Good results with good balance in radiation gain, directivity and metal dependence were obtained. It is considered that the reason for the low radiation gain in Comparative Example 1 is that impedance matching is not easy and the radiation electrode is formed in a meandering shape in order to obtain matching inductance. Further, as described above, it was found that the size of the substrate can be reduced to about 10 mm in length × 3 mm in width × 2 mm in thickness or less by adopting the radiation electrode as shown in FIGS. .

As another embodiment of the present invention, the base body is not limited to a rectangular parallelepiped, but may have an appropriate shape. The material is magnetic
It may be a resin body or a laminated substrate of these. Further, it is effective to trim the parallel portion 23a or the base formed at the open end of the side of the radiation electrode for widening the bandwidth or adjusting the frequency. The radiation electrode may have various shapes such as a trapezoidal shape, a stepped shape, a curved shape, a meandering shape, a part meandering shape, and a crank shape, but the width may be reduced continuously and / or stepwise in the longitudinal direction. It is desirable to have an elongated shape. Further, it is not always necessary to form the ground electrode continuously on one end side of the radiation electrode, and it is sufficient that the ground electrode is finally grounded without discontinuous capacitance coupling. Further, the first or second ground electrode may have at least its end face covered and connected to the ground face so as to be grounded, but in order to obtain the effect of suppressing the emission of the electric field from the end face of the base body, It is advisable to form the end face so as to cover the end face and the four faces around it. The antenna of the present invention can be expected to have the maximum characteristics if it is mounted in a region of the circuit board where there is no ground conductor, but it may be mounted on the ground conductor even if the characteristics are sacrificed to some extent depending on the design. The antenna configurations of the above embodiments may be combined, and various modifications may be made within the scope of the present invention.

[0044]

As described above, according to the present invention, impedance matching when a high dielectric material, which has been a problem in the past, is used for a substrate becomes easy, and it is small and lightweight, has a high gain, a wide band and is omnidirectional. It is possible to obtain a surface-mounted antenna having excellent properties. Further, when used for GPS, wireless LAN, etc., it becomes a communication device in which the characteristics of the antenna are sufficiently extracted.

[Brief description of drawings]

FIG. 1 is a perspective view of a surface mount antenna showing a first embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram of the antenna of the first embodiment.

FIG. 3 is a perspective view of a surface mount antenna showing a second embodiment of the present invention.

4 is a development view of the radiation electrode of FIG.

FIG. 5 is an equivalent circuit diagram of the antenna of the second embodiment.

FIG. 6 is another embodiment of the power supply electrode according to the present invention.

FIG. 7 is a perspective view of a surface mount antenna showing a third embodiment of the present invention.

FIG. 8 is a perspective view of a surface mount antenna showing a fourth embodiment of the present invention.

FIG. 9 is a perspective view of a surface mount antenna showing a fifth embodiment of the present invention.

FIG. 10 is a perspective view and a developed view of a surface mount antenna showing a sixth embodiment of the present invention.

FIG. 11 is a perspective view and a developed view of a surface mount antenna showing a seventh embodiment of the present invention.

FIG. 12 is a perspective view and a development view of a surface mount antenna showing an eighth embodiment of the present invention.

FIG. 13 is a perspective view and a development view of a surface mount antenna showing a ninth embodiment of the present invention.

FIG. 14 is a perspective view and a development view of a surface mount antenna showing a tenth embodiment of the present invention.

FIG. 15 is a perspective view and a developed view of a surface mount antenna showing an eleventh embodiment of the present invention.

FIG. 16 is a perspective view and a developed view of a surface mount antenna showing a twelfth embodiment of the present invention.

FIG. 17 is a relationship between relative permittivity and input impedance.

FIG. 18 is a mounting view showing a state in which the antenna of the present invention is mounted on a circuit board.

FIG. 19 is a conceptual diagram of mounting the antenna of the present invention on a communication device.

FIG. 20 is a mounting view showing a state in which another antenna of the present invention is mounted on another circuit board.

FIG. 21 is a perspective view showing an example of a conventional surface mount antenna.

FIG. 22 is an equivalent circuit diagram of the conventional antenna.

23 is a development view showing a radiation electrode of the surface-mounted antenna of Comparative Example 1. FIG.

[Explanation of symbols]

1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1
I, 1J, 1K, 1L: Surface mount antenna 1, 90: Dielectric substrate 2, 21, 24, 25, 26, 27, 33, 92: Radiation electrode 22, 28, 29, 30: Side radiation electrode, 31 : Connection electrodes 20, 97: Open end 23 of the radiation electrode: Side 23a of the radiation electrode: Parallel parts 32, 51, 52, 53 formed on the sides of the radiation electrode: Fixing electrodes 38, 39: Extension electrodes 3, 32 , 93: ground electrode 4, 94: power supply electrode, 95: power supply terminal electrode 40, 98: power supply point 41, 141: parallel part (parallel part) of power supply electrode 42: ground point 43, 143: leg part serving as power supply end (Power feeding part) 44, 144: Leg part (grounding part) serving as a grounding end 5: Second ground electrode 6: Circuit board, 10: Ridge line of base 60: Power feeding power source, 61, 99: Power feeding line, 62: Grounding Conductor 63: Ground conductor boundary line, 64: Ground conductor extension,
5: Exposed portion of circuit board 66: Linear conductor

Continued front page    (72) Inventor Hidetoshi Hagiwara             Hitachi Metals, 70-2 Minamieicho, Tottori City, Tottori Prefecture             Tottori Factory Co., Ltd. F-term (reference) 5J046 AA02 AA04 AA07 AA12 AB13                       PA07                 5J047 AA02 AA04 AA07 AA12 AB13                       FD01

Claims (17)

[Claims] 1. A base made of a dielectric or magnetic material, a radiation electrode provided on at least an upper surface of the base, and a ground provided on the base so as to be directly connected or capacitively coupled to one end of the radiation electrode. A surface mount antenna comprising an electrode and a feeding electrode provided on at least a side surface of the base so as to face the radiation electrode through a gap, the feeding electrode having one end having a feeding point at the other end. Each has a grounding point, has an impedance matching section by capacitance and inductance between the feeding point and the grounding point, and the area ratio of the grounding electrode on the bottom surface of the base is
Surface mount antenna characterized by less than 30%. 2. A base made of a dielectric or magnetic material, a radiation electrode provided on at least an upper surface of the base, and a ground provided on the base so as to be directly connected to one end of the radiation electrode or capacitively coupled. A surface mount antenna comprising an electrode and a feeding electrode provided on at least a side surface of the base so as to face the radiation electrode through a gap, wherein the feeding electrode has one end and a feeding part at the other end. A surface-mounted antenna having a ground portion and a parallel-shaped portion between the radiation electrode and the radiation electrode, the parallel portion being arranged between the two. 3. A base made of a dielectric or magnetic material, a radiation electrode provided on at least an upper surface of the base, and a ground provided on the base so as to be directly connected to one end of the radiation electrode or capacitively coupled. A surface mount antenna comprising an electrode and a feeding electrode provided on at least a side surface of the base so as to face the radiation electrode through a gap, wherein the feeding electrode is provided on an opposite side surface of the base. The two L-shaped electrodes provided are connected to one I-shaped electrode provided on the end face of the base body, and one L-shaped electrode has a feeding portion at one end and the other L-shaped electrode. The surface-mounted antenna, wherein the V-shaped electrode has a ground portion at one end, the I-shaped electrode is a parallel portion, and thus the power feeding electrode is in a gate shape. 4. The surface mount antenna according to claim 1, wherein the feeding electrode has first and second electrodes provided on opposite side surfaces of the base, and an end surface of the base. Is connected to one I-shaped electrode provided on the first electrode, the first electrode has a feeding portion at one end, the second electrode has a ground portion at one end, and the I-shaped electrodes are parallel to each other. The surface mount antenna is characterized in that the power supply electrode has a gate shape, and further has a ground electrode portion formed on the end face or the end face of the base and the opposite side face. 5. The surface mount antenna according to claim 1, wherein the feed electrode has at least a part of a meander shape, a U shape, an L shape, or a crankshaft shape. A surface mount antenna, comprising: 6. The surface mount antenna according to claim 1, wherein the feeding electrode is provided on a side surface of the base body with a gap on the open end side of the radiation electrode. Surface mount antenna. 7. The surface mount antenna according to claim 1, wherein the feed electrode has a feed portion arranged near an open end of the radiation electrode. 8. The surface-mounted antenna according to claim 1, wherein at least a part of the radiation electrode is continuous and / or stepped from one end of the base to the other end in the longitudinal direction. A surface-mounted antenna characterized in that it extends while substantially narrowing its width. 9. The surface mount antenna according to claim 1, wherein the radiation electrode reaches the upper surface via a side surface different from the side surface on which the feeding electrode is formed. Surface mount antenna. 10. The surface mount antenna according to claim 1, wherein there is substantially no ground electrode at least in a region below the open end of the radiation electrode provided on the upper surface of the base. Surface mount antenna characterized by. 11. The surface mount antenna according to claim 1, wherein the radiating electrode has a meander-shaped, U-shaped, L-shaped or crankshaft-shaped bent portion. Surface mount antenna. 12. The surface mount antenna according to claim 1, wherein the radiating electrode and / or the feeding electrode has a rounded corner. 13. The surface mount antenna according to claim 1, further comprising a second ground electrode facing the other end of the radiation electrode with a gap. Surface mount antenna. 14. A substrate made of a dielectric or magnetic material, a strip-shaped radiation electrode provided on the substrate, and a ground electrode provided on the substrate so as to be directly connected to one end of the radiation electrode or capacitively coupled. A surface mount antenna comprising: the radiation electrode and a feeding electrode provided on at least a side surface of the base body so as to be located via a desired gap, wherein the radiation electrode is long on one side surface of the base body. Has a generally U-shaped shape in which an electrode portion formed in a direction and an L-shaped electrode portion formed on the upper surface of the base body are connected to each other, and the power supply electrode is the other side surface of the base body. A feed portion and a ground portion extending substantially vertically above, and a parallel portion extending between the feed portion and the ground portion substantially parallel to the radiation electrode through the gap, Area ratio of ground electrode is 30% or less There, the feeding electrode and the adjusted capacitance and inductance by modifying the shape and positional relationship of the radiation electrode, with the surface-mounted antenna, characterized in that it is possible to perform impedance matching. 15. The surface mount antenna according to claim 14, wherein the feeding portion of the feeding electrode is located near an open end of the radiation electrode, and the ground portion is a base end portion opposite to the ground electrode. Surface mount antenna characterized by being located in the vicinity. 16. A communication device comprising an antenna device in which the surface-mounted antenna according to claim 1 is mounted in a region of a circuit board where there is no ground conductor, wherein the radiation electrode is arranged in a longitudinal direction. The communication device, wherein the extending base is aligned with an edge of a ground conductor of the circuit board via a gap, and the power feeding electrode is disposed on the ground conductor side. 17. The communication device according to claim 16, wherein:
The ground electrode located on the side opposite to the ground conductor of the circuit board on the surface-mounted antenna is arranged on the corner side of the circuit board, and the ground electrode and the conductor of the circuit board are linear conductors. A communication device characterized by being connected by.