JP2015177398A - Antenna, electronic equipment, and method of manufacturing antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna capable of easily and reliably adjusting reception frequencies.SOLUTION: An antenna 3 includes: a dielectric layer 3b; a first antenna electrode 3a that is arranged on a first surface 31 of the dielectric layer 3b; a second antenna electrode 3c that is arranged on a second surface 32 facing the first surface 31 in a back-to-back manner; a feeding point 4k that is arranged on the second surface 32; and a non-conducting slit 50 that is linearly extended toward the feeding point 4k from an outer peripheral edge of the second antenna electrode 3c. The antenna 3 has the length of the slit 50 set on the basis of radiation efficiency or sensitivity.

Description

  The present invention relates to an antenna, an electronic device, and a method for manufacturing the antenna.

  A technique for using a time signal from a GPS satellite and information indicating an orbital position for time adjustment and positioning of a clock is known, and Patent Document 1 describes that a GPS antenna is mounted on a wristwatch. .

  The receiving antenna described above cannot be corrected even if a deviation occurs in the electrical length of the conductor plate due to variations in the dielectric constant of the dielectric layer. When a deviation occurs in the electrical length, the electrical length of the conductor plate changes and the reception frequency is shifted. This degrades the accuracy of the GPS function.

  Therefore, Patent Document 2 proposes a planar receiving antenna provided with adjusting means for adjusting the electrical length. The adjusting means is formed of a ladder-like portion and adjusts the electrical length by cutting the crosspiece.

JP 2010-096524 A JP 2005-184756 A

However, the receiving antenna described in Patent Document 2 connects a feeding radiation electrode and a parasitic radiation electrode at the antenna outer surface.
For this reason, there exists a problem that it cannot apply to the receiving antenna used for the electronic timepiece with a GPS function.

  An object of the present invention is to propose an antenna, an electronic device, and a method for manufacturing the antenna, which can easily and reliably adjust the reception frequency.

An antenna according to a first embodiment of the present invention is disposed on a dielectric layer, a first antenna electrode disposed on the first surface of the dielectric layer, and a second surface facing away from the first surface. A second antenna electrode, a feeding point disposed on the second surface, and a non-conductive slit extending linearly from the outer periphery of the second antenna electrode toward the feeding point. To do.
Therefore, in the antenna of the present invention, the electric length of the second antenna electrode corresponding to the length of the slit can be adjusted with good antenna sensitivity and radiation efficiency.

  The antenna according to the second embodiment of the present invention is characterized in that, in the first embodiment, the length of the slit is set based on radiation efficiency or sensitivity.

The antenna according to a third embodiment of the present invention is characterized in that, in the first or second embodiment, the slit is formed in a broken line shape.
Therefore, in the antenna of the present invention, the electrical length of the second antenna electrode can be easily adjusted by connecting adjacent slits.

An antenna according to a fourth embodiment of the present invention is a beam that is formed between the slits in the second antenna electrode in the third embodiment, and the electric length of the second antenna electrode is adjusted according to trimming. It comprises a part.
Therefore, in the antenna of the present invention, it is possible to easily adjust the electrical length of the second antenna electrode by trimming the cross section between the adjacent slits.
The antenna according to the fifth embodiment of the present invention receives radio waves transmitted from GPS satellites.

An electronic apparatus according to a first embodiment of the present invention includes the antenna according to any one of the first to fourth embodiments of the present invention.
Therefore, in the present invention, it is possible to obtain an electronic device that can adjust the electrical length of the second antenna electrode according to the length of the slit with good antenna sensitivity and radiation efficiency.

The electronic device according to the second embodiment of the present invention is an electronic timepiece with a GPS function.
Therefore, according to the present invention, it is possible to obtain an electronic timepiece with a GPS function capable of adjusting the electrical length of the second antenna electrode according to the length of the slit with good antenna sensitivity and radiation efficiency.

An antenna manufacturing method according to an embodiment of the present invention includes a dielectric layer, a first antenna electrode disposed on the first surface of the dielectric layer, and a second surface disposed on the second surface facing away from the first surface. A method of manufacturing an antenna comprising two antenna electrodes and a feeding point disposed on the second surface, wherein the second antenna electrode is a non-conductive non-conductive line extending linearly from the outer periphery of the second antenna electrode toward the feeding point A slit forming step for forming a slit; and an electrical length adjusting step for adjusting an electrical length of the first antenna electrode by trimming a crosspiece of the second antenna electrode formed by the slit. To do.
Therefore, in the antenna manufacturing method according to the embodiment of the present invention, the electrical length of the second antenna electrode corresponding to the length of the slit can be adjusted with good antenna sensitivity and radiation efficiency.

It is a schematic diagram which shows the outline | summary of a GPS system. (A) The top view which shows an antenna device, (b) It is sectional drawing which shows an antenna device. It is a figure which shows the manufacturing method of an antenna device. It is the figure which trimmed the crosspiece part 57 and adjusted the electrical length of the 2nd antenna electrode 3c. It is a figure which shows the result of having compared the formation position of the linear slit 55. FIG.

An antenna, an electronic device, and an antenna manufacturing method of the present invention will be described with reference to the drawings.
As an example of a communication system that receives and uses a positioning signal or the like from a satellite such as a position information satellite, a GPS system will be taken and its outline will be described. An example of the configuration of the electronic wristwatch 1 having a GPS reception function will be described. As for the antenna, an antenna that receives radio waves from GPS satellites will be described as an example.

FIG. 1 is a schematic diagram showing an outline of a GPS system.
The GPS satellite 90 orbits a predetermined orbit above the earth and transmits a satellite signal in which a navigation message or the like is superimposed on a 1.57542 GHz microwave, for example. The GPS satellite 90 is equipped with an atomic clock, and the satellite signal includes GPS time information which is extremely accurate time information measured by the atomic clock.
Therefore, the electronic wristwatch 1 having a function as a GPS receiver can display the accurate time by receiving the satellite signal and correcting the advance or delay of the internal time. This correction is performed as a time measurement mode.

The satellite signal includes orbit information indicating the position of the GPS satellite 90 in the orbit. In other words, the electronic wristwatch 1 can also perform positioning calculation. Normally, by receiving satellite signals transmitted from four or more GPS satellites 90, orbital information and GPS time information contained therein are used. And has a function to perform positioning calculation. By the positioning calculation, the electronic wristwatch 1 can easily correct the time difference in accordance with the current position, and this correction is performed as a positioning mode.
In addition, if satellite signals are used, various applications such as displaying the current position, measuring the moving distance, and measuring the moving speed are possible. Can be digitally displayed.
The electronic wristwatch 1 is not limited to the digital display by the liquid crystal display unit 4, but may be an analog display, a combined display of digital and analog, or the like. Is also possible.

2A is a plan view showing the antenna device, and FIG. 2B is a cross-sectional view.
The first antenna electrode 3a and the second antenna electrode 3c are usually formed in a rectangular shape by a conductor such as copper, aluminum, iron, gold, silver, palladium, or an alloy thereof.
The dielectric layer 3b has a rectangular shape that is approximately the same size as the first antenna electrode 3a. Usable materials include alumina (Al ₂ O ₃ ), mullite (3Al ₂ O ₃ .2SiO ₂ ), steer. Examples include light (MgO / SiO ₂ ), forsterite (2Mg ₂ O / SiO ₂ ), zirconia (PSZ), and magnesia titanate (MgTiCO ₃ ). As characteristics of the dielectric layer 3b, the dielectric constant is desirably 8 or more and 22 or less, and the dielectric loss tangent is desirably 0.001 or less. Therefore, in order to obtain these characteristics, the size of the dielectric layer 3b in the electronic timepiece is a rectangular shape like the electronic wristwatch 1. It is desirable that one side is 2 cm to 4 cm.
The first antenna electrode 3a is disposed on the first surface 31 of the dielectric layer 3b, and the second antenna electrode 3c is disposed on the second surface 32 of the dielectric layer 3b.

When the dielectric layer 3b is circular, the diameter is desirably 2.5 cm to 3.5 cm. In any case, the thickness is desirably 0.05 mm to 1.5 mm. In the electronic wristwatch 1, the dielectric layer 3b of the antenna device uses alumina ceramic (Al ₂ O ₃ ) having a thickness of 0.5 mm, a length of 2 cm, and a width of 3 cm, and has a dielectric constant of about 9.8. have.

In the antenna device, a power feeder 4k is provided to supply power to the first antenna electrode 3a from a power feeding unit (not shown).
The power feeder (feed point) 4k is provided at a predetermined position with respect to the first antenna electrode 3a. The power feeding body 4k is a metal electrical conductor, and is inserted into the dielectric layer 3b in a state of being connected to the first antenna electrode 3a, and the inserted tip is connected to the circuit board and is passed through the power feeding body 4k. The power is supplied from the power feeding unit. At the same time, power is supplied to the second antenna electrode 3c from the power feeding unit. The second antenna electrode 3c is on the ground side and functions as a so-called ground electrode. The power supply wiring to the power supply body 4k also functions as a reception wiring for the first antenna electrode 3a.

A power feeder 4k is disposed near the center of the second antenna electrode 3c. The second antenna electrode 3c and the power feeder 4k are non-conductive. A non-conductive annular slit 51 is formed so as to surround the power feeder 4k. In the annular slit 51, the second surface 32 of the dielectric layer 3b is exposed.
A slit forming portion 55 that extends linearly toward the power feeding body 4k is provided on one (one side) of the outer peripheral edge of the second antenna electrode 3c. The slit forming part 55 adjusts the electrical length of the second antenna electrode 3c, and is provided with a gap in the form of a broken line (broken line) in the direction from the outer peripheral edge toward the power feeding body 4k. A plurality of openings 56 constituting a straight slit (slit) 50 are provided. In the opening 56, the second surface 32 of the dielectric layer 3b is exposed. The plurality of openings 56 are linearly arranged from the outer peripheral edge of the second antenna electrode 3c toward the power feeder 4k. The plurality of openings 56 are arranged at regular intervals. The shape of the plurality of openings 56 is arbitrary, such as a rectangle or a circle, but is desirably as small as possible.

  Crosspieces 57 are provided between the openings 56 adjacent to each other in the direction from the outer peripheral edge toward the power feeding body 4k and on the outer peripheral edge side of the opening 56 closest to the outer peripheral edge. The crosspiece 57 is a part of the second antenna electrode 3c. As will be described later, the plurality of openings 56 (slit forming portions 55) are trimmed manually or the like. For this reason, the opening part 56 should just be the magnitude | size which can be visually observed.

FIG. 3 is a diagram illustrating a method for manufacturing the antenna device (slit forming step).
First, the dielectric layer 3b is half-cut into a desired shape (step S1).
Next, the seed layer P is formed on both surfaces of the dielectric layer 3b by sputtering (step S2). The seed layer is any one of chromium, titanium, tungsten, and a titanium tungsten alloy.

Next, a resist R is disposed on the second surface 32 of the dielectric layer 3b (step S3). For example, a dry film resist is attached.
Then, the resist R on the second surface 32 is exposed and developed (step S4). Thereby, the resist R having a shape corresponding to the slit forming portion 55 (the plurality of openings 56) is left on the second surface 32.

Next, an electrolytic plating film Q is formed on the seed layer P on both surfaces of the dielectric layer 3b (step S5).
Then, after removing the resist R remaining on the second surface 32 (step S6), the seed layer P is etched (step S7). Thus, the first antenna electrode 3a and the second antenna electrode 3c made of the seed layer P and the electrolytic plating film Q are disposed on the dielectric layer 3b. In addition, a slit forming portion 55 (a plurality of openings 56) is also formed.
Finally, the antenna device is manufactured by dividing the dielectric layer 3b into pieces (step S8).

  Thereby, the first antenna electrode 3a is formed on the first surface 31 of the dielectric layer 3b, and the second antenna electrode 3c is formed on the second surface 32. In addition, slit forming portions 55 (a plurality of openings 56) are formed on the second surface 32.

FIG. 4 is a diagram in which the crosspiece 57 is trimmed to adjust the electrical length of the second antenna electrode.
When the antenna device functions, the electrical length of the second antenna electrode 3c is adjusted. That is, the length of the opening 56 in the slit forming portion 55 formed in the second antenna electrode 3c is adjusted (electrical length adjusting step).
Specifically, the linear slit 50 is lengthened (stretched) by connecting a plurality of openings 56 constituting the slit forming portion 55. That is, the plurality of crosspieces 57 formed between the plurality of openings 56 are removed in order from the one close to the outer peripheral edge of the second antenna electrode 3c.
Examples of the removal method (trimming) of the crosspiece 57 include grinding with a router and cutting with a laser beam.
Thus, the linear slit 50 can be lengthened by removing the crosspiece 57 in order from the one close to the outer peripheral edge of the second antenna electrode 3c. Thereby, the electrical length of the 2nd antenna electrode 3c becomes long gradually. Therefore, the reception frequency of the antenna device is lowered, and the reception frequency can be adjusted to a desired frequency (1.57542 GHz).
Moreover, since only the small crosspiece 57 is removed, the reception frequency can be adjusted easily and reliably.

  FIG. 5 is a diagram showing a result of comparing the formation positions of the linear slits 50. (A) shows the example of arrangement | positioning of the linear slit 50, (b) shows the result of antenna sensitivity and radiation efficiency.

In order to investigate the relationship between the arrangement of the linear slits 50 and the antenna sensitivity, etc., four antenna devices having different arrangement positions of the linear slits 50 were prepared.
That is, as shown in FIG. 5A, among the outer peripheral edges of the second antenna electrode 3c, the linear slit 50 is disposed at position a, disposed at position b, disposed at position c, position The one arranged in the second was prepared.
And as shown in FIG.5 (b), the antenna sensitivity and radiation efficiency of each antenna apparatus were confirmed.

  The distance L2 is the length of the linear slit 50. The column of FIG. 5B indicates the length of the distance L2 as a ratio to the distance L3 from the outer peripheral edge of the second antenna electrode 3c to the power feeder 4k. That is, the antenna sensitivity and radiation efficiency were confirmed while gradually increasing the length of the linear slit 50.

  As shown in FIG. 5 (b), it was confirmed that the antenna sensitivity and radiation efficiency of the four antenna devices with the linear slit 50 arranged at position b and at the position 2 were good. When the straight slit 50 was formed at these two positions, it was confirmed that the antenna sensitivity and radiation efficiency did not deteriorate even when the length of the straight slit 50 was increased.

As described above, the antenna device in the electronic wristwatch 1 is configured so that the linear slit 50 extends linearly from the outer peripheral edge of the second antenna electrode 3c toward the power feeder 4k, so that the antenna sensitivity and radiation efficiency are increased. The reception frequency of the antenna device can be adjusted without degrading the frequency.
Since the antenna device in the electronic wristwatch 1 includes the non-conductive linear slit 50 extending linearly from the outer peripheral edge of the second antenna electrode 3c toward the power feeding body 4k, it is easy to adjust the radiation efficiency or sensitivity of the antenna device. In particular, in the present embodiment, since the straight slit 50 is formed in a broken line shape in the slit forming portion 55, the second antenna can be obtained by trimming the crosspiece 57 of the second antenna electrode 3c provided between the straight slits 50. The electrical length of the electrode 3c is adjusted. Therefore, in this embodiment, the reception frequency of the antenna device can be adjusted easily and reliably. Therefore, the electronic wristwatch 1 having a high-performance GPS function can be realized.

  The antenna and the electronic device are not limited to the above-described embodiments, and the same effects as those of the embodiments can be obtained even in the following modifications.

  The outer case 11 of the electronic wristwatch 1 has a substantially cylindrical shape including the opening on the front surface side, but is not limited thereto, and may be a rectangular shape such as a rectangle. Also, the antenna device is not limited to a rectangular shape, and may be another shape such as a circle.

  Even when the antenna device is configured as a so-called inverted-F antenna having the same electrode configuration, the antenna function can be sufficiently exerted.

  The electronic device is not limited to the electronic wristwatch 1 but may be a travel clock, a pocket watch, a watch attached to a portable electronic device, and can be applied to a portable terminal that does not have a watch function. Further, the display unit is not limited to the liquid crystal display unit, and may be a display using a display other than liquid crystal.

  Not only the case where the linear slit 50 is extended to lower the reception frequency of the antenna 3, but also the case where the reception frequency is increased may be used.

  The straight slit 50 is not limited to being orthogonal to the outer peripheral edge of the second antenna electrode 3c, but may be configured to intersect the outer peripheral edge of the second antenna electrode 3c at an arbitrary angle.

  DESCRIPTION OF SYMBOLS 1 ... Electronic wristwatch, 3 ... Antenna, 31 ... First surface, 32 ... Second surface, 3a ... First antenna electrode, 3b ... Dielectric layer, 3c ... Second antenna electrode, 4k ... Feeding body (feeding point), 50 ... Linear slit (slit), 55 ... Slit forming part, 56 ... Opening part, 57 ... Crosspiece

Claims (8)

A dielectric layer;
A first antenna electrode disposed on a first surface of the dielectric layer;
A second antenna electrode disposed on a second surface facing away from the first surface;
A feeding point arranged on the second surface;
A non-conductive slit extending linearly from the outer peripheral edge of the second antenna electrode toward the feeding point;
An antenna comprising:   The antenna according to claim 1, wherein the length of the slit is set based on radiation efficiency or sensitivity.   The antenna according to claim 1, wherein the slit is provided in a broken line shape.   The antenna according to claim 3, further comprising a crosspiece formed between the slits in the second antenna electrode, the electric length of the second antenna electrode being adjusted according to trimming.   The antenna according to any one of claims 1 to 4, wherein the antenna receives a radio wave transmitted from a GPS satellite.   An electronic apparatus comprising the antenna according to claim 1.   6. The electronic device according to claim 5, wherein the electronic device is an electronic timepiece with a GPS function. A dielectric layer, a first antenna electrode disposed on a first surface of the dielectric layer, a second antenna electrode disposed on a second surface facing away from the first surface, and a power supply disposed on the second surface A method of manufacturing an antenna comprising points,
A slit forming step of forming a non-conductive slit in a broken line shape extending linearly from the outer peripheral edge of the second antenna electrode toward the feeding point;
An electrical length adjustment step of adjusting the electrical length of the second antenna electrode by trimming the crosspiece of the second antenna electrode formed by the slit;
A method for manufacturing an antenna, comprising:

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