JP2007266915A - Tag antenna for uhf band and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tag antenna for UHF bands, which has a small size and a small printing area and has easiness of performing impedance matching. <P>SOLUTION: As shown in (A), a pair of main constituent elements 2R, 2L which is symmetric to a Y-axis is arranged. As shown in (B), auxiliary constituent elements 3R, 3L are provided in contact with an inside of each of the pair of the forging main constituent elements and further auxiliary constituent elements 4R, 4L are provided in contact with an inside of the elements 3R, 3L. Meshes 5 are put in these auxiliary constituent elements to form frame-shaped constituent elements. As shown in (C), a pair of the auxiliary constituent elements 4R, 4L is tied by a loop constituent element 6, while a ground point E is grounded and besides a high-frequency circuit 7 is connected with a feeding point S. For example, when scheming the antenna so as to receive and transmit an electric wave of 953 MHz, the antenna becomes 50.4 mm×16.8 mm in size, which is extremely small and light. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a small antenna suitable for use as a tag antenna, which transmits and receives UHF band radio waves, and a method of manufacturing the same.

As the tag antenna, for example, a bow tie type dipole antenna is used.
A tag antenna usually has a flexible electrical insulating film as a substrate, and its constituent elements are printed using silver paste.
JP 2004-180217 A JP 2006-31766 A

The tag antenna is still in its infancy since it has been put to practical use, so it is in the process of research and improvement. In order to make this more widespread, reduction in size, weight, cost reduction, and ease of adjustment are desired.
The present invention has been made in view of the circumstances described above, and the object is as follows.
Compared to the conventional bow tie dipole antenna, it is smaller, lighter, and less expensive.
The present invention also provides a tag antenna that can be easily matched.

However, the downsizing of antennas has technical significance different from that of general equipment.
In other words, in general machinery and equipment, the goal is to reduce the size without reducing the strength.
The antenna must be small without changing the antenna performance, in particular without increasing the tuning frequency.

The basic principle of the present invention created to achieve the above object will be briefly described with reference to FIG. 1 corresponding to one embodiment thereof.
As shown in FIG. 1A, a pair of main components 2R and 2L that are symmetrical with respect to the Y-axis are arranged on the surface of the substrate 1 assuming orthogonal coordinate axes X and Y. In the present invention, the main constituent element means a constituent element having the greatest influence on the impedance of the antenna device.
As shown in FIG. 1B, frame-shaped auxiliary component elements 3R, 3L and frame-shaped auxiliary component elements 4R, 4L are arranged inside the main component elements 2R, 2L, respectively.
Further, the auxiliary constituent elements 3R and 3L are connected by a loop constituent element 6.
If comprised as mentioned above, since the main component element has C and L, it can adjust the shape and can take impedance matching easily,
The electrical length can be obtained by the auxiliary component, and the material cost for printing the conductive pattern is reduced because the area is smaller than the electrical length.

As a specific configuration based on the above-described principle, the tag antenna for UHF band according to the invention of claim 1 (see FIG. 1) sets orthogonal coordinates X and Y on the substrate surface,
A grounding point (E) and a feeding point (S) are arranged symmetrically with respect to the Y axis, positioned on the X axis,
A pair of main components (2R, 2L) having a length in the Y-axis direction and a width in the X-axis direction and symmetrical with respect to the X-axis are symmetrically arranged with respect to the Y-axis. Is located outside the
In addition, one or more pairs of substantially rectangular auxiliary components (3R and 3L, 4R and 4L) are disposed inside each of the pair of main components,
A mesh (5) is provided on at least one pair of auxiliary components to form a frame-shaped component;
Among the auxiliary components arranged symmetrically with respect to the Y-axis, the innermost pair of auxiliary components are connected by a loop-shaped component (6) passing through the grounding point and the feeding point. It is characterized by being.

The configuration of the tag antenna for the UHF band according to the invention of claim 2 is:
(See Fig. 5) Set Cartesian coordinates X, Y on the board surface,
A grounding point (E) and a feeding point (S) are arranged symmetrically with respect to the Y axis, positioned on the X axis,
A pair of main components (8R, 8L) having a length in the Y-axis direction and a width in the X-axis direction and symmetrical with respect to the X-axis are symmetrical with respect to the Y-axis, and the grounding point and the feeding point Is located outside the
In addition, one or more pairs of substantially rectangular auxiliary components (10R and 10L, 11R and 11L) are disposed on the outside of the pair of main components, and / or A pair of substantially rectangular auxiliary components (9R, 9L) are disposed inside and in contact with each of the pair of main components,
Furthermore, at least one pair of the auxiliary components is provided with a mesh (5) to form a frame-shaped component,
Of the plurality of pairs of constituent elements arranged symmetrically with respect to the Y-axis, the innermost pair of constituent elements (8R, 8L) are mutually connected in a loop shape through the grounding point and the feeding point. It is connected by (6), It is characterized by the above-mentioned.

The configuration of the UHF band tag antenna according to the invention of claim 3 is in addition to the configuration requirements of the invention of claim 1 or claim 2,
(See FIG. 2) The loop component (6) has an elongated cut-out annular portion, and its longitudinal direction is parallel to the X-axis.

The structure of the manufacturing method of the tag antenna for UHF band according to the invention of claim 4 is as follows:
(See FIG. 2) When manufacturing a tag antenna for UHF band according to claim 1 or claim 2,
The pair of main components (2R and 2L) is characterized in that the impedance is adjusted by deleting the corner portion (P portion drawn by phantom lines) while maintaining symmetry with respect to the Y-axis.

The structure of the UHF band tag antenna manufacturing method according to the invention of claim 5 is as follows:
(See FIG. 2) When manufacturing the tag antenna for UHF band according to claim 3,
The electrical length of the antenna device is adjusted by adjusting the effective length of the loop constituent element (6) in the X-axis direction.

When the tag antenna for the UHF band according to the invention of claim 1 is applied, it can be configured smaller than a conventional tag antenna that transmits and receives radio waves of the same frequency, and impedance matching is easy. .
The small size not only has the advantage of being easy to use, but also has the advantage of reducing the material cost for printing the antenna pattern.

Even when the UHF band tag antenna according to the invention of claim 2 is applied, it can be configured in a small size as in the invention of claim 1, and it is easy to achieve impedance matching.
In order to achieve the same object, any one of claims 1 and 2 can be arbitrarily selected, which increases the degree of freedom in design and manufacture, and thus has a great industrial production value.

  When the tag antenna for UHF band according to the invention of claim 3 is applied together with the invention of claim 1 or claim 2, the electrical length can be increased without increasing the area of the antenna device. .

  When the invention method of claim 4 is applied, impedance matching of the UHF band tag antenna according to the invention of claim 1 or claim 2 can be more easily achieved.

By applying the inventive method of claim 5, the electrical length of the UHF band tag antenna according to the invention of claim 3, that is, the tuning frequency can be easily adjusted,
For example, semi-finished products of the same use can be mass-produced and stocked, and after receiving a firm order, the frequency can be adjusted quickly and easily before shipment.

  In order to understand the configuration of the tag antenna for the UHF band according to the present invention, the configuration method will be described with reference to FIG. Paragraph numbers 0016 to 0021 are descriptions of the process of design thinking, and do not limit the configuration method or the configuration procedure of the present invention.

(Refer FIG. 1 (A)) The rectangular board | substrate 1 is an electrically insulating thin sheet | seat.
Orthogonal coordinates X and Y are set on the substrate surface. O is the coordinate origin.
A ground point E and a feeding point S are set in the vicinity of the coordinate origin O so as to be positioned symmetrically with respect to the coordinate origin O and on the X axis. At this stage, the grounding point E and the feeding point S are fictitious points with no substance.
Next, a pair of main component 2R and main component 2L are arranged.

The pair of main components is preferably symmetric with respect to the Y axis, and is preferably symmetric with respect to the X axis.
Each main component has a length in the Y-axis direction and a width in the X-axis direction. That is, it is a strip shape in the vertical direction in the figure. However, when implementing the present invention, the main component does not necessarily have to be rectangular.
The necessary condition of the main component is to have a length in the X-axis direction and a width in the Y-axis direction, that is, to have an area, and may be a triangle or a semicircle. In the accompanying drawings of the present invention, the portions shown with spots are conductive thin plates (so-called conductive patterns).

This is an arrangement place of the pair of auxiliary component 3R and auxiliary component 3L indicated by phantom lines in contact with the inside of the main component 2R and the main component 2L.
The pair of auxiliary components are positioned symmetrically with respect to the Y axis. It is desirable that the X axis is also symmetric.
Assume that a pair of auxiliary component 4R and auxiliary component 4L are arranged inside the auxiliary component 3R and auxiliary component 3L in the same manner as described above.

(See FIG. 1B) A mesh 5 is put in each of the two pairs of auxiliary components (3R, 3L, 4R, 4L) to form a frame-shaped component as illustrated in the figure.
In electrical engineering in general, it is defined as “one branch that forms one closed circuit inside a network” (Maglow Hill Science and Technology Dictionary). However, with respect to components, mesh is
An opening that does not significantly affect the electrical length of the element is assumed. In the present embodiment, one mesh 5 is put in the auxiliary component 4R and the auxiliary component 4L, and two meshes are put in each of the auxiliary component 3R and the auxiliary component 3L.

Of the three pairs of constituent elements (the total of the main constituent elements and the auxiliary constituent elements) drawn with a solid line in FIG. 1B, the pair of auxiliary constituent elements 4R and 4L located on the innermost side In the meantime, “A loop component planned area 6 ′ passing through the ground point E and the feeding point S is assumed.
Then, as shown in FIG. 1C, a loop component 6 having an elongated cut-off circular detour portion is provided in the middle.

The ground point E is grounded and the output terminal of the high-frequency circuit 7 is connected to the feeding point S.
FIG. 2 is an explanatory diagram of a method for adjusting a tag antenna for UHF band according to the present invention.
For the main component 2R and the main component 2L, when the area of the main component 2R and the main component 2L is reduced by scraping away the corner portion of the original shape, the C and L of the main component change, and the impedance changes. Can be adjusted. By utilizing this phenomenon, impedance matching can be performed quickly and easily.

The loop component 6 forms a notched annular portion that is elongated in the X-axis direction, and when the length dimension in the X-axis direction is adjusted, the electrical length of the UHF band tag antenna changes. By utilizing this phenomenon, the tuning frequency can be adjusted quickly and easily. It is also possible to easily adjust the electrical length by providing a ladder-like pattern drawn in phantom lines at both ends in the X-axis direction of the loop constituent element 6 in advance and scraping it.
There are two possible forms for implementing the impedance matching and tuning frequency adjustment described above.

In the prototype stage, the approximate geometric dimensions can be designed and calculated as will be described later with reference to FIG. 4, but the details of the antenna performance must be adjusted by reworking the prototype.
In such a case, the practical value of being able to perform impedance matching and tuning frequency adjustment quickly and easily as described above is great.

When an antenna manufacturer receives an order from a wireless device manufacturer, there are many examples in which a plurality of products having different detailed specifications are ordered.
When producing such "similar types of tag antennas", if a single semi-finished product consisting of basic antenna patterns is mass-produced and stocked, we received an order for tag antennas with slightly different specifications. In this case, it is possible to respond quickly and to enjoy the advantages such as cost reduction by mass production.

3A and 3B are performance graphs of the tag antenna according to the embodiment shown in FIG. 2, wherein FIG. 3A shows impedance characteristics and FIG. 3B shows directivity.
The tag antenna of this example is designed to be used near 0.953 GHz,
8.14 + j295Ω was obtained at 0.953 GHz.
It can be seen that the directivity characteristics can be completely satisfied as a tag antenna.

FIG. 4 shows a design example related to the basic shape tag antenna shown in FIG. The given frequency is 953 MHz and the design target is
Zin = 8.3 + j288 [Ω].
It is a small size that can fit in 16.8 mm x 50.4 mm.
Moreover, the dimensions of the main component are 16.8 mm × 7.35 mm, and the amount of silver paste used for printing is very small.

FIG. 5 is a process explanatory view illustrating an embodiment different from the above of the tag antenna for the UHF band according to the present invention.
It is the same as in the above embodiment (FIG. 1) that the orthogonal coordinate axes X and Y are assumed on the surface of the substrate 1 and the ground point E and the feeding point S are set.
(See FIG. 5A) A pair of main component elements 8R and 8L are arranged symmetrically with respect to the Y axis.

Auxiliary component installation planned areas 10R and 10L drawn by dotted lines are set outside the pair of main component elements.
Furthermore, while setting auxiliary component installation planned areas 11R and 11L drawn with chain lines on the outside of each of the outside,
An installation planned area for the pair of auxiliary component 9R and auxiliary component 9L is set inside each of the pair of main components.

Frame-shaped auxiliary component elements 9R, 9L, 10R, 10L, 11R, and 11L with mesh 5 are formed in each of the three pairs of auxiliary component installation scheduled areas.
These three pairs of auxiliary components are required to be symmetrical about the Y axis. It is desirable to make the X axis as symmetrical as possible.
In the embodiment shown in FIG. 5, the pair of auxiliary component 9R and auxiliary component 9L located inside the main component can be omitted.

The innermost constituent element among the four pairs of main constituent elements and auxiliary constituent elements shown in FIG. 5A is connected by the loop constituent element 6.
In this example, the pair of auxiliary component 9R and auxiliary component 9L are located on the innermost side, and these are connected by the loop component 6. The loop component 6 is the same member as the loop component 6 in the embodiment of FIG. 2 and passes through the ground point E and the feeding point S.
Although not shown, the ground and the high-frequency circuit 7 are connected in this example as in FIG.

In order to assist the understanding of the configuration of the UHF band tag antenna according to the present invention, the design procedure is drawn, (A) is a schematic diagram showing the arrangement of the main component and the auxiliary component installation planned area, (B) is Schematic diagram showing a frame-shaped auxiliary component and a loop component arrangement planned area, (C) is an antenna pattern composed of a pair of main components, two pairs of auxiliary components, and loop components for a high frequency circuit and a ground. Schematic diagram showing the connected state 1C is an explanatory diagram of an operation for obtaining impedance matching and an operation for adjusting an electrical length in the embodiment of FIG. 2 shows the antenna performance of the UHF band tag antenna according to the embodiment shown in FIG. 2, wherein (A) is an impedance characteristic graph drawn with frequency (GHz) on the horizontal axis and ohms on the vertical axis, and (B) is directed. Sex graph The top view showing the size of the main part in one embodiment of the UHF band tag antenna concerning the present invention 1A and 1B show a UHF band tag antenna according to an embodiment further different from the above-mentioned FIG. 1 and FIG. 2, wherein FIG. 1A is a schematic plan view illustrating a design procedure in phantom lines, and FIG. Plan view

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Board | substrate 2R ... Main component 2L ... Main component 3R ... Auxiliary component 3L ... Auxiliary component 4R ... Auxiliary component 4L ... Auxiliary component 5 ... Mesh 6 ... Loop component 6 '... Loop component planned area 7 ... High-frequency circuit 8R ... Main component 8L ... Main component 9R ... Auxiliary component 9L ... Auxiliary component 10R ... Auxiliary component 10L ... Auxiliary component 11R ... Auxiliary component 11L ... Auxiliary component

Claims (5)

Set Cartesian coordinates X, Y on the board surface,
A grounding point (E) and a feeding point (S) are arranged symmetrically with respect to the Y axis, positioned on the X axis,
A pair of main components having a length in the Y-axis direction and a width in the X-axis direction and symmetrical with respect to the X-axis are arranged outside the grounding point and the feeding point symmetrically with respect to the Y-axis. Has been
In addition, one or a plurality of pairs of substantially rectangular auxiliary components are arranged in contact with each of the pair of main components and inside thereof,
A mesh is provided on at least one pair of the auxiliary components to form a frame-shaped component,
Among the auxiliary components arranged symmetrically with respect to the Y-axis, the innermost pair of auxiliary components are connected by a loop-shaped component passing through the grounding point and the feeding point. Characteristic tag antenna for UHF band. Set Cartesian coordinates X, Y on the board surface,
A grounding point (E) and a feeding point (S) are arranged symmetrically with respect to the Y axis, positioned on the X axis,
A pair of main constituent elements having a length in the Y-axis direction and a width in the X-axis direction and symmetrical with respect to the X-axis are arranged symmetrically with respect to the Y-axis and outside the grounding point and the feeding point. Has been
In addition, one or more pairs of substantially rectangular auxiliary components are disposed on the outside of the pair of main components, and / or each of the pair of main components. One or more pairs of substantially rectangular auxiliary components are arranged on the inner side of the
Further, at least one pair of the auxiliary components is provided with a mesh to form a frame-shaped component,
Among the plural pairs of constituent elements arranged symmetrically with respect to the Y-axis, the innermost pair of constituent elements are connected to each other by a loop-shaped constituent element (6) passing through the grounding point and the feeding point. A tag antenna for UHF band, characterized in that   The tag antenna for UHF band according to claim 1 or 2, wherein the loop constituent element has an elongated cutout annular portion, and a longitudinal direction thereof is parallel to the X axis. When manufacturing a tag antenna for UHF band according to claim 1 or claim 2,
A method of manufacturing a tag antenna for a UHF band, wherein the impedance is adjusted by deleting a corner portion while maintaining symmetry with respect to the Y axis of a pair of main constituent elements. When manufacturing the tag antenna for UHF band according to claim 3,
A method of manufacturing a tag antenna for a UHF band, wherein the electrical length of the antenna device is adjusted by adjusting the effective length of the loop constituent element in the X-axis direction.

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