JP6386944B2 - Conductive pattern antenna - Google Patents

Description

  The present invention relates to a conductive pattern antenna disposed on a substrate.

  Conventionally, as an antenna disposed on a substrate on which an electronic component is mounted, for example, the antennas disclosed in Patent Documents 1 and 2 are known. The antenna disclosed in Patent Document 1 is a small and high gain helical antenna with reduced line coupling. Further, the antenna disclosed in Patent Document 2 has a coiled antenna formed by opposing two substrates to reduce manufacturing errors.

JP 2011-188020 A JP 2011-55200 A

  However, the antenna disclosed in Patent Document 1 has a problem of requiring a large ground plane as compared with the antenna pattern in order to improve the performance as an antenna. Further, the antenna disclosed in Patent Document 2 has a structure in which an inductance in which windings are concentrated in one place is formed, and thus there is a problem that the radiation efficiency of electromagnetic waves is lowered.

  The present invention has been made in view of these problems, and provides a conductive pattern antenna that does not require a large ground plane and that improves the radiation efficiency of electromagnetic waves without concentrating the windings in one place. For the purpose.

The conductive pattern antenna according to the present invention includes a conductive pattern extending in a longitudinal direction of both ends of a substrate, a first through hole provided at a front end portion of the conductive pattern and leading to a back surface of the substrate, and the first through hole A back surface conductive pattern extending in a reverse direction to a position overlapping the conductive pattern and the substrate from the back surface; a second through hole communicating with the surface of the substrate provided at a tip of the back surface conductive pattern; A surface conductive pattern extending in the same direction as the conductive pattern from the surface of the two through holes; an antenna of coiled portions formed at both ends of the substrate; and a differential feed point for supplying power to the conductive pattern It is a summary to comprise.

  According to the conductive pattern antenna of the present invention, the radiation efficiency of electromagnetic waves can be increased without requiring a large ground plane and without concentrating the windings in one place.

It is a figure which shows the top view (surface) of the conductive pattern antenna 100 of 1st Embodiment. It is the figure which represented the conductive pattern antenna 100 with the circuit symbol. It is a figure which shows the top view (back surface) of the conductive pattern antenna. It is a figure which shows the top view (back surface) of the conductive pattern antenna 200 of 2nd Embodiment. It is a figure which shows the top view (back surface) of the conductive pattern antenna 300 of 3rd Embodiment. It is a figure which shows the top view (surface) of the conductive pattern antenna 400 of 4th Embodiment. It is a figure which shows the top view (surface) of the conductive pattern antenna 500 of 5th Embodiment. It is a figure which shows notionally VSWR of the conductive pattern antenna 500. FIG. It is a figure which shows the example of the board | substrate shape and antenna arrangement | positioning of a conductive pattern antenna.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same components in a plurality of drawings, and the description will not be repeated.

[First Embodiment]
FIG. 1 shows a plan view of a conductive pattern antenna 100 according to the first embodiment of the present invention. The conductive pattern antenna 100 is an antenna composed of antennas 110 and 120 formed at both ends in the longitudinal direction of the substrate 1 having a rectangular plane, for example.

  The both ends in the longitudinal direction of the substrate 1 are both outer portions of the central portion of the substrate 1 separated by a broken line in the example shown in FIG. Electronic components such as various chip-shaped passive elements and ICs are mounted on the central portion of the substrate 1. FIG. 1 shows the surface of the substrate 1. You may make it mount an electronic component in the same center part of the back surface side of the board | substrate 1. FIG.

  The conductive pattern antenna 100 includes differential feed points 10 and 20, conductive patterns 11 and 21, first through holes 12 and 22, back conductive patterns 13 and 23, second through holes 14 and 24, and surface conductivity. Patterns 15 and 25 are provided. The differential feeding points 10 and 20 feed high-frequency signals to the antennas 110 and 120 formed at both ends of the substrate 1. The differential feeding points 10 and 20 are provided near the substrate edge of the substrate 1 near the center of the substrate 1. A high frequency signal is input to the differential feed points 10 and 20 from the high frequency signal source 30 in a differential manner (differential input voltage).

  The conductive pattern 11 is connected to the differential feeding points 10 and 20, respectively, and extends in the longitudinal direction of both ends from the vicinity of the substrate edge near the center of the substrate 1 at both ends of the substrate 1. The longitudinal direction in this example is a direction (short side direction) orthogonal to the above-described longitudinal direction of the substrate 1.

  In this example, the conductive pattern antenna 100 is a dipole antenna including an antenna 110 and an antenna 120 formed symmetrically at both ends of the substrate 1. FIG. 2 shows the configuration. The conductive pattern antenna 100 can be referred to as a dipole antenna with an inductor added.

  In the following description, only the configuration of one antenna 110 will be described. The configuration of the other antenna 120 can be described in the same manner as the antenna 110 if the reference number is 20th as shown in FIG. Further, the reference numerals 110 and 120 of the antenna are not changed in other embodiments described later.

  The first through hole 12 is a through hole that is provided at the tip of the conductive pattern 11 and communicates with the back surface of the substrate 1. A metal film is formed on the wall surface of the through hole, and the conductive pattern 11 on the front surface of the substrate 1 and the back surface conductive pattern 13 on the back surface are electrically connected. In addition, since the board | substrate 1 is a double-sided board in this example, it is called the through hole. The through hole is referred to as a via hole when the substrate 1 is a multilayer substrate.

  The back surface conductive pattern 13 is a conductive pattern that extends from the back surface of the first through hole 12 in the direction opposite to the longitudinal direction (short side direction). A second through hole 14 is provided at the tip of the tip of the back surface conductive pattern 13 extended.

  The second through hole 14 is a through hole that is provided at the tip of the back surface conductive pattern 13 and communicates with the surface of the substrate 1. Similar to the first through hole 12, the second through hole 14 electrically connects the back surface conductive pattern 13 on the back surface of the substrate 1 and the surface conductive pattern 15 on the surface. The surface conductive pattern 15 is a conductive pattern that extends from the surface of the second through hole 14 in the same direction as the conductive pattern 11 (in the direction of the first through hole 12).

  The first through hole 12, the back surface conductive pattern 13, the second through hole 14, and the front surface conductive pattern 15 may each include two or more. In the example shown in FIG. Three are identified by a subscript alphabet. The description from here is also made with reference to FIG.

  The high-frequency signal input to the differential feeding point 10 of one antenna 110 includes a conductive pattern 11 (FIG. 1), a first through hole 12a (FIG. 1), a back surface conductive pattern 13a (FIG. 3), and a second through hole 14a. (FIG. 3), front surface conductive pattern 15a (FIG. 1), first through hole 12b (FIG. 1), back surface conductive pattern 13b (FIG. 3), second through hole 14b (FIG. 3), front surface conductive pattern 15b (FIG. 1). ), The first through hole 12c (FIG. 1), the back surface conductive pattern 13c (FIG. 3), the second through hole 14c (FIG. 3), and the front surface conductive pattern 15c (FIG. 1) in this order and radiated as electromagnetic waves. . That is, the current of the high frequency signal flows in the above transmission order. The same applies to the other antenna 120.

  The resonance frequency of the conductive pattern antenna is determined by the total length of the antenna 110 and the inductance component. The total length of the antenna 110 is generally set to a length of one quarter (λ / 4) of the wavelength λ of the resonance frequency. The total length of the antennas 110 and 120 is set to a half length of the wavelength λ of the resonance frequency.

  According to the configuration of the conductive pattern antenna 100 described above, a high-frequency signal is supplied to the conductive pattern antenna 100 with a differential input voltage, so that a ground plane is unnecessary. Further, the antenna length and the inductance component can be set to desired values by repeatedly connecting the front surface conductive pattern and the back surface conductive pattern corresponding to the coil winding.

  In addition, the conductive pattern antenna 100 includes a coiled portion composed of the conductive pattern 11, the back surface conductive pattern 13, and the surface conductive pattern 15, and a conductive pattern that does not form a coil of the surface conductive pattern 15c on the tip side of the coiled portion. It comprises. Since the surface conductive pattern 15c is present, the windings are not concentrated in one place, so that the radiation efficiency of electromagnetic waves can be increased.

  Thus, the conductive pattern antenna 100 does not require a large ground plane and can improve the radiation efficiency of electromagnetic waves. In addition, since the antennas 110 and 120 are formed by repeatedly connecting the front surface conductive pattern and the back surface conductive pattern, the size of the substrate 1 can be reduced.

  The tips of the antennas 110 and 120 of the conductive pattern antenna 100 are the surface conductive patterns 15c and 25c. The conductive pattern antenna 200 according to the second embodiment of the present invention in which the conductive pattern is further extended will be described.

[Second Embodiment]
FIG. 4 is a plan view (back surface) of the conductive pattern antenna 200 of the second embodiment in which the antenna length of the conductive pattern antenna 100 is extended. The conductive pattern antenna 200 of the present embodiment is similar to the conductive pattern antenna 100 (FIG. 1) in that a fourth first through hole 12d and a fourth back conductive pattern 13d are added to the front end of the surface conductive pattern 15c. ) Is different.

  The added back surface conductive patterns 13d and 23d are conductive patterns facing the front surface conductive patterns 15c and 25c with the substrate 1 in between, respectively. Moreover, the front-end | tips are the open ends 16 and 26, and the tip is not connected anywhere.

  The influence on the antenna characteristics can be changed depending on whether or not the conductive pattern at the tip is opposed to another conductive pattern across the substrate 1. For example, when all the conductive patterns are opposed to each other with the substrate 1 interposed therebetween as in the present embodiment, the inductance component of the antenna 110 can be set large.

  Further, in the case where there is no back surface conductive pattern facing the front surface conductive pattern 15 and the substrate 1 like the conductive pattern antenna 100, the entire length of the antenna 110 is extended without greatly increasing the inductance component of the antenna 110. be able to.

  In this way, the degree of freedom in designing the conductive pattern antenna can be increased by setting one end of the outermost back surface conductive pattern or the front surface conductive pattern at both ends to an open end. Whether the outermost conductive pattern is the front conductive pattern or the back conductive pattern depends on the size of the substrate 1 and the like.

  Next, a description will be given of a conductive pattern antenna 300 according to a third embodiment of the present invention that can easily adjust the resonance frequency of the antenna.

[Third Embodiment]
FIG. 5 shows a plan view (back surface) of a conductive pattern antenna 300 according to the third embodiment in which the resonance frequency of the conductive pattern antenna 200 can be easily adjusted. The conductive pattern antenna 300 of the present embodiment is the above in that the outermost backside conductive patterns 13d and 23d at both ends of the substrate 1 are composed of a plurality of short conductive patterns 17a to 17f and 27a to 27f. Different from the embodiment.

  In the extending direction of the short-shaped conductive pattern 17a connected to the outermost second through hole 14d, a second short-shaped conductive pattern 17b is arranged with an interval of approximately the same size as the conductive pattern 17a. ing. Thereafter, similarly, conductive patterns 17c, 17d, 17e, and 17f having the same short shape are arranged at intervals. The same applies to the antenna 120 side.

  When it is desired to lower the resonance frequency of the conductive pattern antenna 300, the conductive patterns 17a and 17b are made conductive. For conduction, solder may be deposited between the conductive patterns 17a and 17b, or a metal foil may be pasted with a conductive adhesive.

  The resonance frequency of the conductive pattern antenna 300 can be lowered by sequentially connecting the short conductive patterns 17a to 17f to extend the entire length of the antenna 110. Further, the lowered resonance frequency can be raised by removing the solder or metal foil between the short conductive patterns.

  In the present embodiment, the conductive pattern having a plurality of short shapes has been described as an example of the back surface conductive pattern 13d. The conductive pattern formed of a plurality of short shapes may be the surface conductive pattern 15. Whether the plurality of short-shaped conductive patterns arranged on the outermost side of the substrate 1 is arranged on the front surface or the back surface depends mainly on the size of the substrate 1.

  As described above, the conductive pattern antenna 300 in which one of the outermost back surface conductive pattern or the front surface conductive pattern at both ends is a plurality of short conductive patterns arranged in the longitudinal direction of both ends is the resonance of the antenna. There is an effect that the frequency can be easily adjusted.

  Next, a conductive pattern antenna 400 according to a fourth embodiment of the present invention having a matching circuit will be described.

[Fourth Embodiment]
FIG. 6 is a plan view (surface) of the conductive pattern antenna 400 of the fourth embodiment. The conductive pattern antenna 400 of this embodiment is different from the above-described embodiment in that it includes matching circuits 18 and 28 disposed between the differential feeding points 10 and 20 and the conductive patterns 11 and 21.

  The matching circuits 18 and 28 match (match) the output impedance of the high-frequency signal source 30 with the input impedances of the antennas 110 and 120.

  By providing the matching circuits 18 and 28, it becomes possible to efficiently transmit the power of the high-frequency signal source 30 to the antennas 110 and 120. That is, by arranging the matching circuits 18 and 28 between the differential feeding points 10 and 20 and the conductive patterns 11 and 21, it is possible to improve the radiation efficiency of the antenna.

  Next, a conductive pattern antenna 500 according to a fifth embodiment of the present invention capable of expanding the frequency band of the conductive pattern antenna will be described.

[Fifth Embodiment]
In FIG. 7, the top view (surface) of the conductive pattern antenna 500 of 5th Embodiment is shown. The conductive pattern antenna 500 of the present embodiment is a conductive pattern antenna in which the total length of the antenna is different between the antennas 110 and 120 at both ends.

  The total length of the antenna 110 is a length obtained by adding all the lengths of the conductive pattern 11, the back surface conductive pattern 13a, the front surface conductive pattern 15a, the back surface conductive pattern 13b, and the front surface conductive pattern 15b. On the other hand, the total length of the antenna 120 is the length of the conductive pattern 21, the back surface conductive pattern 23a, the front surface conductive pattern 25a, the back surface conductive pattern 23b, the front surface conductive pattern 25b, the back surface conductive pattern 23c, and the front surface conductive pattern 25c. This is the total length.

  The total length of the antenna 120 is longer than the antenna 110 by the total length of the back surface conductive pattern 23c and the front surface conductive pattern 25c. Therefore, the resonance frequency of the antenna 120 is lower than that of the antenna 110.

  FIG. 8 conceptually shows the frequency characteristics of the antennas 110 and 120. In FIG. 8, the horizontal axis represents frequency, and the vertical axis represents VSWR (Voltage Standing Wave Ratio). The VSWR is an index representing the relationship between the traveling wave and the reflected wave on the high-frequency transmission line, and shows a small value when the reflected wave is small.

  As shown in FIG. 8, the resonance frequency of the antenna 120 having a long total length is lower than that of the antenna 110 (characteristics indicated by broken lines in FIG. 8). In addition, the resonance frequency of the antenna 110 having a short overall length is higher than that of the antenna 120 (characteristic indicated by a dashed line in FIG. 8).

  When a high frequency signal is differentially input to the conductive pattern antenna 500, the frequency characteristic of the conductive pattern antenna 500 becomes close to the combined characteristics of the antennas 110 and 120 as shown by a solid line in FIG. Thus, the frequency bandwidth of the conductive pattern antenna can be widened by making the total length of the antenna formed on one end and the other end of the both ends different.

  FIG. 7 shows an example in which the high-frequency signal source 30 is arranged at a position near the antenna 110. This is a notation for easy understanding that the total length of the antenna is different, and the position of the differential feeding point. There is no need to move.

  As described above, according to the conductive pattern antennas 100 to 500, the radiation efficiency of electromagnetic waves can be increased without requiring a large ground plane. Further, it is possible to provide a conductive pattern antenna that can be reduced in size as compared with the prior art.

  In addition, although the shape of the board | substrate 1 was demonstrated to the example of the rectangle, this invention is not limited to this board | substrate shape. The shape of the substrate 1 may be any outer shape. For example, the outer shape of the substrate 1 may be circular as shown in FIG. A region indicated by hatching in FIG. 9A is a region where an antenna is formed.

  Further, as shown in FIG. 9B, the antenna may be formed in a direction rotated 90 degrees with respect to the above example. In this case, the longitudinal direction of both ends is the same as the longitudinal direction of the substrate, and is different from the above example.

  The material of the substrate 1 may be anything. For example, the conductive pattern antenna of the present invention is configured using a flexible substrate in which an electric circuit is formed on a base material obtained by bonding a thin and soft base film (such as polyimide) having an insulating property and a conductive metal such as copper foil. May be.

  As described above, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the gist thereof.

1: substrate 10, 20: differential feeding point 11, 21: conductive pattern 12, 22: first through hole 13, 23: back surface conductive pattern 14, 24: second through hole 15, 25: front surface conductive pattern 16, 26 : Open ends 17 and 27: Short conductive pattern 100: Conductive pattern antenna 110: Antenna 120: Antenna

Claims (5)

A conductive pattern extending in the longitudinal direction of both ends of the substrate;
A first through hole provided at a tip of the conductive pattern and leading to a back surface of the substrate;
A back surface conductive pattern extending in a reverse direction from the back surface of the first through hole to a position overlapping with the conductive pattern across the substrate ;
A second through hole that communicates with the surface of the substrate provided at the tip of the back surface conductive pattern;
A surface conductive pattern extending in the same direction as the conductive pattern from the surface of the second through hole;
An antenna of a coiled portion formed at both ends of the substrate including:
A conductive pattern antenna comprising: a differential feeding point that feeds power to the conductive pattern. The conductive pattern antenna according to claim 1,
One end of the outermost backside conductive pattern or the frontside conductive pattern at both ends is an open end. The conductive pattern antenna according to claim 1,
One of the backside conductive pattern or the surface conductive pattern at the outermost side of the both end portions is a plurality of short-shaped conductive patterns arranged in the longitudinal direction of the both end portions. The conductive pattern antenna according to any one of claims 1 to 3,
A conductive pattern antenna comprising a matching circuit disposed between the differential feeding point and the conductive pattern. The conductive pattern antenna according to any one of claims 1 to 4,
The conductive pattern antenna characterized in that the total antenna length of the conductive pattern, the back surface conductive pattern, and the front surface conductive pattern differs between the antennas formed at one and the other of the both end portions. .

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