JPH10126149A - Surface mounted antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the surface mounted antenna which efficiently sends/ receives an electromagnetic wave. SOLUTION: A 1st loop radiation conductor film 13, which is circulated on an upper side of a dielectric base 11 to form two ends 13a, 13b opposite to each other having a 1st gap inbetween, is formed on the upper side of the rectangular prism shaped dielectric base 11 having upper and lower square sides. A 2nd loop radiation conductor film 15 which is circulated within a horizontal plane to form two ends 15a, 15b opposite to each other having a 2nd gap inbetween whose direction differs from a direction of the 1st gap of the loop of the 1st loop radiation conductor film 13 by 90 deg. within the horizontal plane is formed in the inside of the dielectric base 11. A ground conductor film 16 is formed on the lower side of the dielectric base 11, two feeding conductor films 18, 19 which are connected to the two ends 13a, 13b of the 1st loop radiation conductor film 13, extending in parallel respectively and two feeding conductor films 21, 22 which are connected to the two ends 15a, 15b of the 2nd loop radiation conductor film 15, extending in parallel are formed on the side faces of the dielectric base 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount antenna mounted on a circuit board incorporated in a portable communication device or the like.

[0002]

2. Description of the Related Art As an antenna used in a portable communication device, an antenna which is small in size, high in gain, low in cost and easy to mount is required. On the other hand, conventional linear antennas such as dipole antennas and monopole antennas have a large volume, which hinders the miniaturization of communication devices. It is difficult to use it for portable communication devices and the like that are required to be used.

Some antennas have been proposed to solve such a problem. FIG.
It is a perspective view showing the antenna proposed in 83639 gazette. A through hole 112 having a radiating conductor film formed on an inner wall is formed in a dielectric substrate 111 constituting the antenna 110.
Are formed. A surface electrode 113 is formed on the front surface of the dielectric substrate 111, and a connector external conductor plate 114 is mounted on the back surface.
And the connector external conductor plate 114 are connected to the through hole 11.
2 are electrically connected by the radiation conductor film formed on the inner wall. Further, a coaxial connector 115 is attached to a surface of the connector outer conductor plate 114 opposite to a surface to which the dielectric substrate 111 is attached, and an outer conductor and an inner conductor of the coaxial connector 115 are a connector outer conductor. The plate 114 and the radiation conductor film in the through hole 112 are electrically connected to each other.

[0004] The antenna 110 thus configured is
When the coaxial connector 115 is connected to a connector provided on the communication device main body, the coaxial connector 115 is disposed outside the communication device main body. Electromagnetic waves are radiated from the radiation conductor film formed on the inner wall of the hole 112.

FIG. 12 is a perspective view showing an antenna proposed in Japanese Patent Application Laid-Open No. 7-221537. Antenna 1
A through hole 122 having a radiation conductor film formed on an inner wall is formed in the dielectric substrate 121 constituting the substrate 20 in a long side direction of the dielectric substrate 121. Further, a side surface electrode 123 is formed on the entire surface of one end surface of the dielectric substrate 121, and a power supply electrode 124 is formed on a central portion of the other end surface.
The side surface electrode 123 and the power supply electrode 124 are
22 are electrically connected by a radiation conductor film formed on the inner wall. Further, on the surface of the dielectric substrate 121 on which the power supply electrode 124 is formed, side electrodes 125 and 126 are formed so as to sandwich the power supply electrode 124.

[0006] The antenna 120 thus configured is mounted on a circuit board built in the communication device main body, and is transmitted from the communication device main body via the power supply electrode 124 to the antenna 12.
0 is supplied with high-frequency power, and electromagnetic waves are emitted from the radiation conductor film on the inner wall of the through hole 122.

[0007]

The antennas 110 and 120 as shown in FIGS. 11 and 12 are omnidirectional in a plane extending perpendicularly to the direction in which the through-hole in which the radiation conductor film is formed extends. . When such an antenna is mounted on, for example, a mobile phone, the mobile phone generally transmits and receives vertically polarized electromagnetic waves. Therefore, the antenna is provided in a direction in which a through hole of the antenna extends and a longitudinal direction of the mobile phone body. Is implemented in the mobile phone so that Therefore, when the longitudinal direction of the mobile phone is held perpendicular to the ground, the antenna can transmit and receive electromagnetic waves most efficiently.

In a mobile phone, a speaker is provided at an upper end and a microphone is provided at a lower end. When a mobile phone is actually used by a human, a line connecting an ear and a mouth is not perpendicular to the ground. Rather close to parallel, the mobile phone is held substantially parallel to the ground. Therefore, there is a problem that it may be difficult to efficiently transmit and receive vertically polarized electromagnetic waves.

As a method of solving this problem, an antenna as shown in FIGS. 11 and 12 is mounted on a mobile phone such that a through hole of the antenna is held perpendicular to the longitudinal direction of the mobile phone. Conceivable. However, considering the standby state of a mobile phone, since the mobile phone is generally held vertically in a pocket such as clothes, the through-holes are arranged perpendicularly to the longitudinal direction of the mobile phone as described above. In this case, in the standby state, there is a problem that the through-hole becomes horizontal and the reception efficiency of the electromagnetic wave is reduced.

In view of the above circumstances, an object of the present invention is to provide a surface mount antenna capable of efficiently transmitting and receiving electromagnetic waves.

[0011]

According to the present invention, there is provided a surface mount antenna having the following objects. (1) A dielectric substrate having an upper surface and a lower surface extending horizontally. (2) A dielectric substrate formed on the lower surface of the dielectric substrate. (3) A predetermined first conductive film formed on the upper surface of the dielectric substrate.
A first loop radiating conductor film surrounding the upper surface so as to form two ends facing each other with a gap therebetween; (4) a first loop radiating conductor film formed inside the dielectric substrate; A second loop that goes around in the horizontal plane so that two ends facing each other with a second gap different from the direction of the first gap with respect to the loop are formed.
Loop radiation conductor films (5) are connected to two ends of the first loop radiation conductor film, respectively, and extend in parallel with each other, and one of the two first radiation conductor films is connected to the ground conductor film. (6) are connected to the two ends of the second loop radiating conductor film, respectively, and extend in parallel with each other via the side surface of the dielectric substrate, and one of the two ends is connected to the ground conductor film. It is characterized by comprising two connected second power supply conductor films.

In the surface mount antenna according to the present invention, since the first loop radiation conductor film and the second loop radiation conductor film having different gap directions with respect to the loop are provided, the first loop radiation conductor film is formed by the first loop radiation conductor film. The polarization direction of the transmitted and received electromagnetic wave is different from the polarization direction of the electromagnetic wave transmitted and received by the second loop radiation conductor film. Therefore, one antenna can transmit and receive electromagnetic waves having different polarization directions.

Here, in the surface-mounted antenna according to the present invention, the first loop radiating conductor film and the second loop radiating conductor film are arranged in a direction of the first gap with respect to the loop of the first loop radiating conductor film; It is preferable that the direction of the second gap with respect to the loop of the second radiation conductor film is formed so as to be different from each other by 90 ° in the horizontal plane. As described above, when the first loop radiation conductor film and the second loop radiation conductor film are formed, even if the electromagnetic waves are vertically polarized waves or horizontally polarized waves, the electromagnetic waves can be efficiently received.

Here, in the surface-mounted antenna of the present invention, it is preferable that the first and second feeding conductor films also serve as electrodes when the surface is mounted on the circuit board. Since the power supply conductor film also serves as an electrode when surface-mounted on the circuit board, the surface-mounted antenna can be easily mounted on the circuit board.

[0015]

Embodiments of the present invention will be described below. FIG. 1 is a perspective view of a surface mount antenna according to an embodiment of the present invention, FIG. 2 is a top view thereof, and FIG.
FIG. 4 is a cross-sectional view, FIG. 4 is a bottom view thereof, FIG. 5 is a view showing a side surface on which the first feeder conductor film of the surface mount antenna shown in FIG. 1 is formed, and FIG. FIG. 9 is a diagram illustrating a side surface of the antenna on which a second feed conductor film is formed.

The surface mount antenna 10 shown in FIG. 1 includes a rectangular parallelepiped dielectric substrate 11 having a square upper surface and a lower surface. The first loop radiating conductor film 13 is formed on the upper surface of the dielectric substrate 11 along four sides of the upper surface.
Are formed. This first loop radiation conductor film 13
2 makes a round on the upper surface so as to form two ends 13a and 13b facing each other across the first gap 12 as shown in FIG. 2, and the length of this loop is determined by the resonance of the electromagnetic wave to be transmitted and received. It is adjusted to the same length as the wavelength. Further, inside the dielectric substrate 11, a second loop radiating conductor film 15 that circles in a horizontal plane in a square shape is formed. The second loop radiating conductor film 15 has two ends 15 facing each other with the second gap 14 interposed therebetween, as shown in FIG.
a and 15b are formed so as to make a round in a horizontal plane, and the direction of the second gap 14 with respect to the loop of the second loop radiation conductor film 15 is, as shown in FIG. The direction of the first gap 12 with respect to the loop of the membrane 13 is adjusted so as to differ by 90 degrees in the horizontal plane. The length of the loop of the second loop radiation conductor film 15 is determined by the dielectric substrate 11 of the electromagnetic wave to be transmitted and received.
The length is adjusted to be the same as the resonance wavelength within. A ground conductor film 16 is formed on the lower surface of the dielectric substrate 11 as shown in FIG. 4, and this ground conductor film 16 has a shape in which a part of each of two sides is cut out. Have. On one of the four side surfaces of the dielectric substrate 11, two first power supply conductor films 18 and 19 having a gap 17 therebetween are formed as shown in FIG. As shown in FIG. 6, two second power supply conductor films 21 and 22 having a gap 20 therebetween are formed on another side surface. Two first power supply conductor films 1 shown in FIG.
8, 19 are respectively connected to the two ends 13a, 13b of the first loop radiation conductor film 13 as shown in FIG. 1 and extend in parallel with each other via the side surfaces of the dielectric substrate 11,
One of the two power supply conductor films 18 and 19 is connected to the ground conductor film 16, and the other power supply conductor film 18 reaches the lower surface of the dielectric substrate 11. Further, the ground conductor film 16 side of the two power supply conductor films 18 and 19 also serves as power supply electrodes 18a and 19a, respectively, which are electrodes at the time of surface mounting on a circuit board. On the other hand, FIG.
Like the first power supply conductor films 18 and 19, the second power supply conductor films 21 and 22 are connected to the two ends 15a and 15b of the second loop radiation conductor film 15, respectively, as shown in FIG. Extending parallel to each other via the side surface of the dielectric substrate 11, one of the two power supply conductor films 21 and 22 is connected to the ground conductor film 16 and the other power supply conductor film is connected to the ground conductor film 16. The film 21 reaches the lower surface of the dielectric substrate 11. Further, the ground conductor film 16 side of the two power supply conductor films 21 and 22 also serves as the power supply electrodes 21a and 22a which are electrodes at the time of surface mounting on the circuit board.

In the surface-mounted antenna 10 thus configured, a first loop radiating conductor film 13 and a second loop radiating conductor film 15 whose gap directions are different from each other by 90 degrees in a horizontal plane are formed. Therefore, the polarization directions of the electromagnetic waves received by the first and second loop radiation conductor films 13 and 15 are different from each other by 90 degrees in the horizontal plane. Therefore, this surface-mounted antenna 10 can efficiently receive electromagnetic waves regardless of whether the electromagnetic waves are vertically polarized waves or horizontally polarized waves.

In the surface-mounted antenna 10, the vicinity of the grounding conductor film 16 of the first power supply conductor films 18 and 19 and the vicinity of the grounding conductor film 16 of the second power supply conductor films 21 and 22 serve as power supply electrodes. Since they are also used, they are easily mounted on a circuit board by soldering or the like. In addition, this surface mount type antenna 1
At 0, the first and second loop radiation conductor films 13 and 15
The direction of the gap of the first loop radiation conductor film 13 and the second
Are formed in directions different from each other by 90 degrees in the horizontal plane, but the directions of the gaps may be different from each other, for example, by 45 degrees, provided that the directions of the gaps are different. One antenna can receive electromagnetic waves having different polarization directions.

The surface mount antenna 1 shown in FIG.
0 will be described with reference to FIGS. 1 and 7 to 10. FIG. 7 shows the surface mount antenna 1 shown in FIG.
FIG. 8 is a top view showing the length and width of the dielectric substrate and the dimensions of the first loop radiating conductor film. FIG. 8 is a cross-sectional view of the surface-mounted antenna 10 shown in FIG. FIG. 9 is a diagram showing the length and width of the dielectric substrate and the dimensions of the second loop radiating conductor film. FIG. 9 is a diagram showing a side surface of the surface-mounted antenna 10 on which the first feeding conductor film is formed. FIG. 1 is a diagram showing the thickness of a dielectric substrate, the dimensions of a first power supply conductor film, and FIG.
0 is a diagram illustrating a side surface of the surface-mounted antenna 10 on which the second feeder conductor film is formed, and illustrates a thickness of the dielectric substrate;
It is a figure showing the size of the 2nd feeding conductor film.

First, a material for the dielectric substrate 11 is selected.
The material of the dielectric substrate 11 is preferably a material having a relative dielectric constant of about 10 to 100 and stable in a frequency band of transmitted and received electromagnetic waves, for example, Sr (Ni _1/3 Nb).
_2/3 ) O ₃ ceramics are preferred. This material has a relative dielectric constant of 31 and a Q value of 1800 when the frequency of the transmitted and received electromagnetic waves is 3.8 GHz.

Next, the dimensions of the first and second loop radiation conductor films, the first and second feed conductor films, and the dielectric substrate are determined. This dimension can be determined as follows. Assuming that the loop lengths of the first and second loop radiation conductor films 13 and 15 are respectively λ ₁ and λ ₂ , λ ₁ and λ ₂ can be represented by the following equations. λ ₁ = λ ₀ / √ (ε _reff-1 ) (1) λ ₂ = λ ₀ / √ (ε _reff-2 ) (2) where λ ₀ ; wavelength of electromagnetic wave in vacuum ε _{reff- 1} , ε _reff-2 ; effective relative permittivity Here, the effective relative permittivity ε _reff-1 in equation (1) is _{obtained by forming} the first loop radiating conductor film 13 on the upper surface of the dielectric substrate 11. The electromagnetic wave radiated from the first loop radiating conductor film 13 is radiated perpendicularly to the surface of the dielectric substrate 11 on which the first loop radiating conductor film 13 is formed. Considering that an electric field is generated outside, it can be expressed by the following equation.

The _{ε reff-1 = (ε r} +3) / 4 ...... (3) However, epsilon _r: relative dielectric constant of the dielectric substrate and (2) the effective relative permittivity epsilon _reff-2 in the expression, the 2
Is formed inside the dielectric substrate 11, and electromagnetic waves radiated from the second loop radiation conductor film 15 are applied to the first loop radiation conductor film 15 of the dielectric substrate 11. Taking into account the fact that the electric field is emitted perpendicular to the bent surface and an electric field is generated inside and outside the second loop radiating conductor film 15, it can be expressed by the following equation.

Ε _reff-2 = (ε _r +1) / 2 (4) where ε _r is the relative permittivity of the dielectric substrate. Therefore, the effective relative permittivity obtained by the formulas (3) and (4) By _substituting ε _reff-1 and ε _reff-2 into equations (1) and (2), respectively, the first and second loop radiating conductor films 1 are obtained.
The lengths λ ₁ and λ ₂ of 3, 15 can be obtained.

If the resonance frequency of the electromagnetic wave is 1.9 GHz, λ ₁ = 54.16 mm and λ ₂ = 39,47 mm. As shown in FIGS. 7 and 8, in order to form the first and second loop radiation conductor films 13 and 15, the length of each side of the first loop radiation conductor film 13 is set to 13.54 mm. The length of each side of the second loop radiation conductor film 15 may be 9.87 mm. Here, the alternate long and short dash lines shown in FIGS. 7 and 8 indicate the center lines of the respective sides of the first and second loop radiation conductor films 13 and 15, respectively. The impedance of the one-wavelength loop antenna is generally high impedance of 100Ω or more. However, it is necessary to adjust the width of the loop radiation conductor film and the gap width of the gap between the two ends of the loop radiation conductor film. As a result, the impedance can be reduced and the power supply efficiency can be improved. For example, to set the impedance to 50Ω, the width of the loop radiation conductor film may be set to 1 mm and the gap width may be set to 0.6 mm as shown in FIGS.

From the dimensions of the radiation conductor film determined in this manner, the length and width of the dielectric substrate 11 are both set to 14.54 mm as shown in FIGS. Further, regarding the thickness of the dielectric substrate 11, the first loop radiation conductor film 13
, The distance from the second loop radiating conductor film 15 to the ground conductor film 16, and the distance from the second loop radiating conductor film 15 to the ground conductor film 16, each having a resonance wavelength of an electromagnetic wave having a resonance frequency of 1.9 GHz. The thickness of the dielectric substrate 11 is set to 7.09 mm corresponding to a quarter wavelength in the substrate.
As shown in FIG. 9 and FIG.

Also, a desired line impedance can be obtained by adjusting the width of the power supply conductor film and the gap width of the gap between the power supply conductor films. For example, in order to set the line impedance to 50Ω, as shown in FIGS. 9 and 10, the width of the feed conductor film is 1.16 mm and the gap width is 0.6 m.
m. Next, the dielectric substrate 11 having the dimensions described above is used.
Is prepared. As shown in FIG. 1, a loop radiating conductor film is also formed inside the dielectric substrate 11, so that the length, width and thickness are 14.54 mm and 14.54, respectively.
mm, 7.09 mm dielectric body, and
A laminate of the dielectric elements is referred to as a dielectric substrate 11.

Next, the pattern of the first loop radiation conductor film 13 having the dimensions shown in FIG. 7 is formed on the upper surface of one of the two prepared dielectric bodies using a copper paste. Printing by thick film printing method. Also, the pattern of the second loop radiation conductor film 15 having the dimensions shown in FIG. 8 is formed on the upper surface of the other dielectric element body, and the pattern of the ground conductor film 16 is formed on the lower surface thereof using a copper paste by a thick film printing method. To print. Further, a pattern of the first and second power supply conductor films having dimensions as shown in FIGS. 9 and 10 is printed on the side surface of each dielectric element by a thick film printing method using a copper paste. Thereafter, the dielectric elements on which the respective patterns are printed are stacked, dried and fired in a reducing atmosphere.

Thus, the surface mount antenna 10 is manufactured.

[0029]

As described above, according to the surface mount antenna of the present invention, electromagnetic waves can be transmitted and received efficiently.

[Brief description of the drawings]

FIG. 1 is a perspective view of a surface mount antenna according to an embodiment of the present invention.

FIG. 2 is a top view of the surface-mounted antenna according to one embodiment of the present invention.

FIG. 3 is a diagram illustrating a surface mount antenna according to an embodiment of the present invention;
It is -A 'sectional drawing.

FIG. 4 is a bottom view of the surface-mounted antenna according to one embodiment of the present invention.

FIG. 5 is a diagram illustrating a side surface of the surface-mounted antenna illustrated in FIG. 1 on which a first feeding conductor film is formed.

FIG. 6 is a diagram illustrating a side surface of the surface-mounted antenna illustrated in FIG. 1 on which a second feeding conductor film is formed.

FIG. 7 is a diagram showing the length and width of a dielectric substrate and the dimensions of a first loop radiation conductor film.

FIG. 8 is a diagram showing dimensions of a second loop radiation conductor film.

FIG. 9 is a diagram illustrating the thickness of a dielectric substrate and the dimensions of a first power supply conductor film.

FIG. 10 is a diagram showing the thickness of a dielectric substrate and the dimensions of a second power supply conductor film.

FIG. 11 is a perspective view showing an antenna proposed in Japanese Patent Application Laid-Open No. 7-283639.

FIG. 12 is a perspective view showing an antenna proposed in Japanese Patent Application Laid-Open No. 7-221537.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Surface mount type antenna 11 Dielectric substrate 12, 14, 17, 20 Gap 13, 15 Loop radiation conductor film 13a, 13b, 15a, 15b End 16 Ground conductor film 18, 19, 21, 22 Feeding conductor film 18a, 19a, 21a, 22a Feeding electrode

Continued on the front page (72) Inventor Naohisa Goto 6-15-1-A514 Dobashi, Miyamae-ku, Kawasaki-shi

Claims (3)

[Claims] A dielectric substrate having an upper surface and a lower surface extending horizontally; a grounding conductor film extending in a planar shape formed on a lower surface of the dielectric substrate; and a predetermined conductor formed on an upper surface of the dielectric substrate. A first loop radiating conductor film making a round on the upper surface so as to form two ends facing each other with the first gap interposed therebetween; and the first loop radiating conductor formed inside the dielectric substrate A second loop radiating conductor film that circles in a horizontal plane such that two ends facing each other across a second gap different from the direction of the first gap with respect to the loop of the film are formed; Two first power supply conductor films connected to each of two ends of the first loop radiation conductor film and extending in parallel with each other and one of which is connected to the ground conductor film; Two of the loop radiation conductor films Two second power supply conductor films connected to the respective ends and extending in parallel with each other via the side surfaces of the dielectric substrate and one of which is connected to the ground conductor film. Surface mounted antenna. 2. The method according to claim 1, wherein the first loop radiation conductor film and the second loop radiation conductor film have a direction of the first gap with respect to a loop of the first loop radiation conductor film and the second loop radiation conductor film.
The surface-mounted antenna according to claim 1, wherein the second gap is formed so that the directions of the second gap with respect to the loop of the loop radiation conductor film are different from each other by 90 degrees in a horizontal plane. 3. The surface mount antenna according to claim 1, wherein the feed conductor film also serves as an electrode when the surface is mounted on a circuit board.