JP2000059241A - Small receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid giving bad influence to the antenna of an incorporated receiving part though the housing of a wrist watch, etc., is metallic. SOLUTION: A ring-shaped step part 11a is formed at the conductive main body base 11 of a wrist watch main body 1 and a ring-forming antenna part 2 is mounted to the part 11a. The part 2 is provided with a C-shaped loop element 22 formed on a dielectric substrate 21, the element 22 is provided with a cutting off part 23 and the base 11 can be used as a ground plane. Thus, the base 11 is made conductive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized receiver provided with an antenna capable of receiving circularly polarized waves, and is particularly suitable for a portable receiver of a satellite communication system.

[0002]

2. Description of the Related Art In recent years, it has been possible to reduce the size of a transceiver due to the development of technology. Particularly, in the case of a receiver, a receiver that can be worn on an arm or the like has been proposed. As one of them, Japanese Patent Application Laid-Open No. 9-247006 proposes a first receiver incorporated in a wristwatch. In addition, since an antenna is indispensable for a receiver, a wristwatch body having a built-in receiver is provided with an antenna. In the conventional wristwatch-type receiver, the antenna is provided in the band of the wristwatch, so that the flexibility of the band is lost, and the performance of the antenna is deteriorated because the band is closely attached to the human body. It was easy to do. Therefore, the first receiver is provided with the antenna by forming the wristwatch main body by coating the resin which is a nonconductive material with the antenna as a core material.

Further, as a receiver incorporated in a wristwatch, there is known a second receiver proposed in Japanese Patent Application Laid-Open No. H6-197063. The antenna in this receiver is a loop antenna provided along the surface of the lid located at the top of the case in which the watch body is built. The case is made of resin so as not to affect the loop antenna. By positioning the rotor of the step motor of the watch made of ferromagnetic material near the inside of the loop portion of the loop antenna, Improves efficiency and stability.

[0004]

However, in the first receiver incorporated in the above-mentioned conventional wristwatch, the wristwatch body, which is generally made of metal, must be made of resin and an antenna must be embedded. However, there has been a problem that special and complicated components are required.
In addition, since the wristwatch body is attached in close contact with the human body, there is a problem that the performance of the antenna embedded in the wristwatch body is likely to deteriorate. Further, the second receiver incorporated in the above-mentioned conventional wristwatch also has a problem that the loop antenna is adversely affected unless the case is made non-conductive. Furthermore, a part made of a ferromagnetic material is required inside the loop antenna, and there is a problem that it cannot be applied to a wristwatch or the like that does not have a part made of a ferromagnetic material. Furthermore, both the antenna in the first receiver and the loop antenna in the second receiver are antennas that receive linearly polarized waves, and cannot receive circularly polarized waves. However, there is a problem that it cannot be applied to a communication system that performs communication.

Accordingly, the present invention provides a compact receiver having an antenna capable of receiving circularly polarized waves without deteriorating the performance of the antenna even if the housing is made of metal and requiring no special parts. It is intended to be.

[0006]

In order to achieve the above object, a small-sized receiver according to the present invention comprises a housing in which a receiving unit and other functional units are built, and a ring-shaped housing formed in the housing. A ring-shaped antenna portion mounted on the step portion and capable of receiving a circularly polarized wave, which is mounted so as to be substantially flush with the surface of the housing, wherein a reception signal received by the antenna portion is received by the reception portion. And the antenna section has a dielectric substrate and a cut portion formed on the dielectric substrate so as to be arranged to face the ground plane with a predetermined space therebetween.
And a mold loop element.

In the above-mentioned small receiver, the angle formed between the feeding point provided in the C-type loop element and the cutting portion is approximately ± 35 ° to ± 45 ° or approximately ± 135 °.
± 145 °. Further, in the above-mentioned small receiver, when the free space wavelength is λ, the circumference of the C-shaped loop element may be approximately 1.0λ to 1.5λ. Furthermore, in the small receiver, the ground plane may be the conductive casing or a ground conductor formed on the back surface of the dielectric substrate. Furthermore, in the small receiver, when a free space wavelength is λ, a distance between the C-type loop element and the ground plane may be approximately 0.05λ to 0.26λ.

According to the present invention, since the housing can be used as the ground plane of the antenna, it is possible to prevent the performance of the antenna from deteriorating even if the housing is made conductive. Further, since the housing is a ground plane, even if the housing is in close contact with a human body, it is possible to prevent the antenna portion from being adversely affected. Further, since the C-shaped loop element constituting the antenna unit is an antenna capable of receiving circularly polarized waves, for example,
A GPS signal from a PS satellite can be received, and the small receiver of the present invention can be used as a receiver for a portable navigation system.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an exploded perspective view showing an example of the configuration of an embodiment of a small receiver according to the present invention. However, this configuration example is an example in which a receiving unit is incorporated in a wristwatch. In FIG. 1, reference numeral 1 denotes a wristwatch main body, and the wristwatch main body 1 includes a conductive main body base 11 and a band 12. A clock circuit and a receiving unit are incorporated in the main body base 11. The band 12 is for wearing the wristwatch main body 1 on an arm. Further, a display unit 13 on which clock information and received information are displayed is provided on the front surface of the main body base 11. Furthermore, a ring-shaped ring-shaped step 11a is formed on the front surface of the main body base 11, and an insertion hole 14 having a small diameter is formed in the ring-shaped step 11a.

The ring-shaped step portion 11a formed around the display portion 13 has a ring-shaped antenna portion 2 formed thereon.
Is fitted. When the antenna unit 2 is fitted to the ring-shaped step 11a, the height of the upper surface of the antenna unit 2 and the display unit 1
The height of the upper surface of the third member 3 is substantially the same. The antenna unit 2 includes a ring-shaped dielectric substrate 21 and a C-shaped loop element 22 formed on the upper surface of the dielectric substrate. The C-shaped loop element 22 has a cut portion 23 in which a loop is partially cut in order to receive a circularly polarized wave. The dielectric substrate 21 is made of, for example, ceramic, and is located at a predetermined angle from the cut portion 23.
A power supply pin 24 is provided from a power supply point 24a. The C-shaped loop element 22 is formed by evaporating a conductive material on the dielectric substrate 21,
Processing a metal thin plate into a C-shaped loop element to form a dielectric substrate 21
It is formed by sticking on top.

Feeding pin 24 derived from antenna section 2
Is inserted into the insertion hole 14 when the antenna portion 2 is fitted to the ring-shaped step portion 11a. In this case, the power supply pin 24 is coated with an insulating paint or covered with an insulating tube so that the power supply pin 24 does not contact the conductive main body base 11. In this manner, the power supply pin 24 is inserted into the insertion hole 14.
, An equivalent coaxial line is formed by the feed pin 24 and the insertion hole 14. FIG. 2 shows the appearance of the small receiver of the present invention when the antenna section 2 is fitted and fixed to the ring-shaped step section 11a of the main body base 11 in this way.
As shown in FIG. 2, the height of the upper surface of the antenna unit 2 and the height of the upper surface of the display unit 13 substantially match, and the appearance is improved. Also, the main body base 11 is
You may apply coloring according to.

When the receiving unit built in the main body base 11 is a GPS receiving unit, when the clock information is displayed on the display unit 13, the year, month, day, day of the week, hour, minute, second Are displayed, and when the display information is displayed on the display unit 13 by operating the display switching button (not shown), the antenna unit 2
Latitude calculated from the circularly polarized GPS signal received at
Longitude, speed, map information, and the like are displayed. Thereby, the small receiver of the present invention can be used as a receiver of the navigation system. The main body base 11 is usually made of metal and functions as a ground plane of the antenna section 2. However, when the main body base 11 is made non-conductive, a ground is provided on the back surface of the dielectric substrate 21. A conductor may be formed to serve as a ground plane.

Next, the antenna section 2 capable of receiving circularly polarized waves in the small receiver of the present invention will be described with reference to FIG. 3A is a top view of the loop antenna, and FIG. 3B is a front view thereof. 3A and 3B, reference numeral 101 denotes a C-shaped loop element in which a cut portion 106 is formed, 103 denotes a ground plane arranged in parallel with the C-shaped loop element 101, and 104 denotes a C-shaped loop element. A coaxial line 107 for transmitting a received signal is a power supply pin which functions as a center conductor of the coaxial line 104 having one end connected to the power supply point 105. Further, the angle between the feeding point 105 and the cutting unit 106 is Φa. When the angle Φa is a predetermined angle, the C-shaped loop element 101 can transmit and receive circularly polarized waves by the action of the cutting section 106. FIG. 3 (a)
In the example shown in (1), right-hand circularly polarized waves can be transmitted and received.

Here, the distance between the ground plane 103 and the C-shaped loop element 101 is h, the angle between the feeding point 105 and the cutting section 106 is Φa, and the length of the cutting section 6 is Δg
And the circumferential length of the C-shaped loop element 101 is C. When the free space wavelength is λ, for example, C
= 1.31λ, h = 0.15λ, Φa = 40 °, Δg
= 0.018λ. The loop antenna thus configured is a high-gain and wide-band antenna. Furthermore, since this loop antenna is small and low-profile, it is suitable to be applied to a GPS antenna or a BS antenna mounted on a mobile object or portable.

The distance h between the ground plane 103 and the C-shaped loop element 101 can be in the range of approximately 0.05λ to 0.26λ, and the angle Φa formed between the feeding point 105 and the cutting portion 106 is approximately 35. ° to 45 °, and the length Δg of the cut portion 106 is approximately 0.01λ to 0.02.
λ, and the circumferential length C of the C-shaped loop element 101 can be in the range of approximately 1.0λ to 1.5λ. In addition, approximately 135 ° to 14 ° counterclockwise from the feeding point 105.
Even if the cutting portion 106 is provided at a position of 5 ° (angle Φa), a right-handed circularly polarized wave loop antenna can be obtained. Further, approximately 35 ° to 45 ° counterclockwise from the feeding point 105.
When the cutting section 106 is provided at the position of °, a loop antenna capable of transmitting and receiving left-hand circularly polarized waves can be obtained.

That is, the angle Φa formed by the cutting portion 106 formed in the C-shaped loop element 101 with respect to the feeding point 105 is
± 35 ° to ± 45 ° or approximately ± 135 ° to ± 145 °
If so, a loop antenna capable of transmitting and receiving right-handed circularly polarized waves or left-handed circularly polarized waves can be obtained. Further, the antenna input impedance versus frequency characteristic of the loop antenna shown in FIG. 3 is at least 1.5 times as wide as that of a general loop antenna, so that the dimensional tolerance in manufacturing and the performance of materials used vary. Can be widened.

In the antenna section 2 provided in the small receiver of the present invention, the C-shaped loop element 10 shown in FIG.
1 corresponds to a C-shaped loop element 22 formed on a dielectric substrate 21 by a microstrip line. Accordingly, the antenna section 2 has the same electrical characteristics as the loop antenna shown in FIG. 3, but the wavelength on the C-shaped loop element 22 is shortened in accordance with the relative permittivity of the dielectric substrate 21. The height from the element 22, the cut portion 23, and the ground plane is set to a length according to the wavelength reduction ratio. The ground plane 103 shown in FIG. 3 corresponds to the main body base 11, and the power supply pin 107 and the coaxial line 104 correspond to the power supply pin 24 and the insertion hole 14 formed in the main body base 11. In the above description, the small receiver of the present invention is mounted on a wristwatch. However, the present invention is not limited to this, and may be incorporated in a decorative article worn by a broach or the like.

[0018]

As described above, according to the present invention, since the housing can be used as the ground plane of the antenna section, it is possible to prevent the performance of the antenna section from deteriorating even if the housing is made conductive. it can. Further, since the housing is a ground plane, even if the housing is in close contact with a human body, it is possible to prevent the antenna portion from being adversely affected. Further, since the C-shaped loop element constituting the antenna section is an antenna capable of receiving circularly polarized waves, it can receive GPS signals from, for example, GPS satellites. It can be a receiver for the system.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an example of a configuration of an embodiment of a small receiver according to the present invention.

FIG. 2 is a diagram showing an appearance of a small receiver according to an embodiment of the present invention.

FIG. 3 is a diagram showing a principle configuration of an antenna unit provided in the small receiver according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wristwatch main body 2 Antenna part 11 Main body base 11a Ring-shaped step part 12 Band 13 Display part 14 Insertion hole 21 Dielectric substrate 22, 101 C-shaped loop element 23, 106 Cutting part 24, 107 Feeding pin 24a, 105 Feeding point 103 Ground Plain 104 coaxial line

Continued on the front page (72) Inventor Motoki Oshima 4-7-4 Kitamachi, Warabi City, Saitama Prefecture Inside the Antena Co., Ltd. Warabi Plant (72) Inventor Yasuhiro Momose 3-5-3 Yamato, Suwa City, Nagano Prefecture Seiko -Epson Corporation F term (reference) 5J046 AA00 AA03 AB11 SA06 TA04 5J047 AA00 AA03 AB11 FC01 FC05 FC06 5K016 AA08 BA06 BA18 CA03 HA01 HA09 JA03

Claims (6)

[Claims] 1. A housing in which a receiving unit and other functional units are built, and a ring-shaped step formed in the housing is mounted so as to be substantially flush with the surface of the housing. A ring-shaped antenna unit capable of receiving a circularly polarized wave to be attached, wherein a reception signal received by the antenna unit is guided to the reception unit, and the antenna unit is separated from the dielectric substrate by a predetermined distance. And a C-type loop element having a cut portion formed on the dielectric substrate so as to face the ground plane with a C-type loop element interposed therebetween. 2. An angle between a feeding point provided in the C-type loop element and the cutting portion is approximately ± 35 ° to ± 45 °.
2. The small receiver according to claim 1, wherein the angle is approximately ± 135 ° to ± 145 °. 3. 3. The small receiver according to claim 1, wherein when a free space wavelength is λ, a circumference of the C-shaped loop element is approximately 1.0λ to 1.5λ. . 4. The small receiver according to claim 1, wherein the ground plane is formed by the conductive casing. 5. The small receiver according to claim 1, wherein the ground plane is a ground conductor formed on a back surface of the dielectric substrate. 6. When the free-space wavelength is λ, the distance between the C-type loop element and the ground plane is approximately 0.0.
2. The small receiver according to claim 1, wherein the range is 5λ to 0.26λ.