JP4234616B2 - Antenna device and manufacturing method thereof - Google Patents

Description

  The present invention relates to an antenna device in which an antenna electrode made of an electrode film is formed on a dielectric substrate, and a manufacturing method thereof.

  Conventionally, in order to reduce the size of an antenna device and a communication device, for example, many dielectric antennas have been proposed in which an antenna electrode made of an electrode film is formed on the surface of a dielectric substrate (for example, Patent Document 1, Patent Document 2 and (See Patent Document 3).

  These dielectric antennas 200 have an antenna electrode 204 formed by printing a conductor paste on the surface or inside of a dielectric substrate 202, as typically shown in FIG. In order to obtain the antenna device 200 that operates at a desired frequency, the electrical length of the antenna electrode 204 needs to be set to λ / 4 or λ / 2 of the operating frequency.

  When the electrical length of the antenna electrode 204 varies due to variations in the printed size of the conductive paste and the dielectric constant of the dielectric substrate 202, the frequency of the antenna device 200 is reduced by, for example, partially cutting the pattern of the formed antenna electrode 204. Need to optimize.

  For example, as shown in FIG. 13, when the pattern shape of the antenna electrode 204 is a band shape, the frequency can be increased by partially cutting the pattern from the open end 204a of the antenna electrode 204. Further, the frequency can be lowered by adding a capacitance to the open end 204a of the antenna electrode 204 using a chip capacitor or the like.

JP-A-9-162633 Japanese Patent Laid-Open No. 10-32413 Japanese Patent Laid-Open No. 10-41722

  However, when the frequency is lowered by the antenna electrode 204, it is necessary to extend the electrode length, which causes a problem that the size of the dielectric substrate becomes large.

  In addition, when a capacitor is added to the open end 204a of the antenna electrode 204 using a chip capacitor or the like, there is a problem that the number of steps for mounting the capacitor increases.

  The present invention has been made in view of such problems, and provides an antenna device that can arbitrarily adjust the resonance frequency of the antenna device and the impedance of the antenna electrode while reducing the size of the antenna device, and a method of manufacturing the antenna device. The purpose is to do.

The antenna device according to the present invention is an antenna device in which a strip-shaped antenna electrode is formed on a dielectric substrate, wherein the antenna electrode has a certain width and has a feeding point, and the main body. formed in a portion integral with and possess an adjustment portion having a width different from the width of the body portion, the distance from the feeding point to said adjusting portion, the length of the width and the adjustment portion of the adjustment section characterized that you have at least the resonance frequency is adjusted.

  In this case, when forming the antenna electrode on the dielectric substrate, the distance from the feeding point of the adjustment portion of the antenna electrode, the width of the adjustment portion, and the length of the adjustment portion are adjusted to at least the antenna device. The resonance frequency is set to a desired frequency. In this case, the impedance of the antenna electrode is also changed.

  Here, when the width of the adjustment portion of the antenna electrode is made larger than the width of the main body portion, the resonance frequency of the antenna electrode changes depending on the position of the adjustment portion. When the adjustment portion is positioned near the center of the antenna electrode, the resonance frequency hardly changes. The resonance frequency increases near the feeding point, and the resonance frequency decreases near the open end.

  The effect of the width of the adjustment portion varies depending on the position of the adjustment portion. In the vicinity of the feeding point, the wider one increases the resonance frequency, and in the vicinity of the open end, the wider one decreases the resonance frequency.

  The effect of the length of the adjustment part (ratio of the length of the adjustment part and the length of the main body part) becomes significant when the adjustment part is positioned near the feeding point. When the length of the adjustment part is increased, the resonance frequency is increased. Go up. The amount of change becomes smaller as the adjustment portion is positioned closer to the open end of the antenna electrode, and there is almost no change in frequency when the end face of the adjustment portion is an open end.

  Reducing the overall length of the antenna electrode naturally increases the resonance frequency, but positioning the adjustment part near the open end has the effect of lowering the resonance frequency. The resonance frequency can be adjusted. In other words, it is not necessary to increase the length of the antenna electrode even when the resonance frequency is lowered.

  On the other hand, when the width of the adjustment portion is made smaller than the width of the main body portion, the resonance frequency of the antenna electrode changes depending on the position of the adjustment portion. When the adjustment portion is positioned near the open end, the resonance frequency hardly changes, and the resonance frequency is lowered as it is closer to the feeding point.

  The effect of the width of the adjustment portion is that the resonance frequency decreases as the width decreases, but the amount of change is large near the feeding point and hardly changes near the open end.

  Even if the length of the adjustment portion (the ratio between the length of the adjustment portion and the length of the main body portion) is changed, the resonance frequency hardly changes or changes, but the amount of change is small.

  As described above, in the present invention, in the initial design stage, for example, the resonance frequency can be lowered without increasing the total length of the antenna electrode. Thus, a small antenna device can be manufactured.

  In addition, since the impedance of the antenna electrode is also changed by optimizing the dimensions and the like of the adjustment portion, the antenna can be connected without connecting an impedance matching circuit or an impedance matching element between the feeding point and the external circuit. Impedance matching with an external circuit can be performed by the electrode itself. This leads to simplification of the circuit configuration, and leads to miniaturization of electronic equipment and communication equipment mounted with the antenna device.

  Of course, in the present invention, a desired resonance frequency can be obtained when the antenna electrode is formed on the dielectric substrate. However, in order to eliminate manufacturing variations, a trimming process may be performed on the antenna electrode. In this case, trimming may be performed on the adjustment portion, not the main body portion, and can be easily performed. The antenna electrode may have a meander shape.

The manufacturing method according to the present invention includes a band-shaped main body portion having a certain width and having a feeding point , and an adjustment portion formed integrally with the main body portion and having a width different from the width of the main body portion. And an antenna electrode having at least a resonance frequency adjusted to a predetermined frequency by a distance from the feeding point to the adjustment portion, a width of the adjustment portion, and a length of the adjustment portion on the dielectric substrate. It is characterized by forming.

  Thereby, it is possible to arbitrarily adjust the resonance frequency of the antenna device and the impedance of the antenna electrode while reducing the size of the antenna device.

  As described above, according to the antenna device and the manufacturing method thereof according to the present invention, it is possible to arbitrarily adjust the resonance frequency of the antenna device and the impedance of the antenna electrode while reducing the size of the antenna device.

  Embodiments of an antenna device and a manufacturing method thereof according to the present invention will be described below with reference to FIGS.

  As shown in FIG. 1, an antenna device 10A according to the first embodiment includes a dielectric substrate 12 formed by laminating and firing a plurality of plate-like dielectric layers, and the dielectric substrate 12 The antenna electrode 14 is formed on the upper surface. The antenna electrode 14 is formed in, for example, a belt shape by an electrode film.

  In the antenna device 10A according to the first embodiment, as shown in FIG. 1, an input / output terminal 16 made of an electrode film is formed on the rear end surface 12a of the dielectric substrate 12, and the input / output terminal 16 and The rear end of the antenna electrode 14 is electrically connected to the strip line electrode 18 formed in the dielectric substrate 12 via the via hole 20. The strip line electrode 18 and the via hole 20 constitute an input portion 22 of the antenna electrode 14. In addition, a portion of the antenna electrode 14 to which the via hole 20 is connected becomes a feeding point 14a.

  Specifically, as shown in FIG. 2, the dielectric substrate 12 is configured by laminating, for example, first to tenth dielectric layers S1 to S10 in order from the top. These first to tenth dielectric layers S1 to S10 are composed of one or a plurality of layers, for example.

  The antenna electrode 14 and the strip line electrode 18 are formed in a planarly separated region on the dielectric substrate 12, and the antenna electrode 14 is formed on the upper surface of the first dielectric layer S1 and is stripped. The line electrode 18 is formed on the sixth dielectric layer S6. The one end 18a of the strip line electrode 18 and the feeding point 14a of the antenna electrode 14 are electrically connected through the via hole 20 formed in the first to fifth dielectric layers S1 to S5, and the strip line electrode 18 The other end and the input / output terminal 16 (see FIG. 1) are directly connected.

  As shown in FIG. 1, the antenna electrode 14 in the antenna device 10A according to the first embodiment includes a main body portion 30 having a width W1, and an adjustment portion 32 having a width W2 larger than the width W1. . Although FIG. 1 shows an example in which one adjustment portion 32 is formed, two adjustment portions 32A and 32B may be formed as in the antenna device 10Aa according to the first modification shown in FIG. Alternatively, although not shown, three or more adjustment portions may be formed.

  Further, in FIG. 1, the protruding width W3 of the adjustment portion 32 from the main body portion 30 may be the same on both sides, or the protruding widths on both sides may be different.

  In the following description, as shown in FIG. 1, a configuration in which one adjustment portion 32 is formed in the main body portion 30 will be described. First, the resonance frequency of the antenna device 10A and the impedance of the antenna electrode 14 are adjusted by appropriately setting the distance L1 from the feeding point 14a of the adjustment portion 32, the width W2 of the adjustment portion 32, and the length L2 of the adjustment portion 32. be able to.

  Here, one experimental example is shown. In this experimental example, the reflection characteristics of the comparative example and Examples 1 to 3 are observed. The antenna electrode according to the comparative example and the first to third embodiments will be described. As illustrated in FIG. It is a 7 mm strip.

  As shown in FIG. 5, the antenna electrode 14 of the antenna device 10A1 according to the first embodiment includes a strip-shaped main body portion 30 having a length of 11 mm and a width W1 = 0.7 mm, a width W2 = 2.2 mm, and a length L2 =. And a distance L1 from the feeding point 14a to the adjustment portion 32 is 0.5 mm.

  As shown in FIG. 6, the antenna electrode 14 of the antenna device 10A2 according to the second embodiment includes a strip-shaped main body portion 30 having a length of 11 mm and a width W1 = 0.7 mm, a width W2 = 2.2 mm, and a length L2 =. The distance L1 from the feeding point 14a to the adjustment portion 32 is 4 mm.

  As shown in FIG. 7, the antenna electrode 14 of the antenna device 10 </ b> A <b> 3 according to the third embodiment includes a band-shaped main body portion 30 having a length of 10 mm and a width W1 = 0.7 mm, a width W2 = 2.2 mm, and a length L2 =. And a distance L1 from the feeding point 14a to the adjustment portion 32 is 7 mm.

  The experimental results are shown in FIG. In FIG. 8, the solid line A indicates the reflection characteristic of the comparative example, and the broken line B indicates the reflection characteristic of the first embodiment. An alternate long and short dash line C indicates the reflection characteristic of Example 2, and an alternate long and two short dashes line D indicates the reflection characteristic of Example 3.

  From FIG. 8, all of Examples 1 to 3 have a resonance frequency higher than that of the comparative example, and Example 1 has the highest resonance frequency. The resonance frequency of the second embodiment is located between the resonance frequency of the first embodiment and the resonance frequency of the third embodiment. Example 3 has the lowest resonance frequency.

  Thus, the resonance frequency of the antenna device 10A can be adjusted by the distance L1 from the feeding point 14a of the adjustment portion 32, the width W2 of the adjustment portion 32, and the length L2 of the adjustment portion 32.

  Further, from the result of FIG. 8, the presence of the adjustment portion 32 in the main body portion 30 causes the resonance frequency of the antenna device 10 </ b> A to be higher than that in the case of only the band-shaped antenna electrode 14. This is because the presence of the wide adjustment portion 32 reduces the impedance of the antenna electrode 14 and increases the resonance frequency.

  As described above, when the width W2 of the adjustment portion 32 is larger than the width W1, the resonance frequency of the antenna electrode 14 changes depending on the position of the adjustment portion 32. When the adjustment portion 32 is positioned near the center of the antenna electrode 14, the resonance frequency hardly changes, the resonance frequency increases near the feeding point 14a, and the resonance frequency decreases near the open end 14b.

  The effect of the width W2 of the adjustment portion 32 varies depending on the position of the adjustment portion 32. In the vicinity of the feeding point 14a, the wider the width W2, the higher the resonance frequency, and in the vicinity of the open end 14b, the wider the width W2, the lower the resonance frequency.

  The effect of the length L2 of the adjustment portion 32 (the ratio between the length L2 of the adjustment portion 32 and the length of the main body portion) becomes significant when the adjustment portion 32 is positioned in the vicinity of the feeding point 14a. Increasing the length L2 increases the resonance frequency. The amount of change becomes smaller as the adjustment portion 32 is positioned closer to the open end 14b of the antenna electrode 14. When the end face of the adjustment portion 32 is the open end 14b, there is almost no change in frequency.

  If the total length of the antenna electrode 14 is shortened, the resonance frequency naturally increases. However, if the adjustment portion 32 is positioned in the vicinity of the open end 14b, the resonance frequency is reduced, so the length of the antenna electrode 14 is reduced. Can be adjusted to a desired resonance frequency. In other words, even when the resonance frequency is lowered, it is not necessary to increase the total length of the antenna electrode 14.

  In addition, since the impedance of the antenna electrode 14 is changed by optimizing the dimensions and the like of the adjustment portion 32, an impedance matching circuit and an element for impedance matching need not be connected between the feeding point 14a and the external circuit. In addition, impedance matching with an external circuit can be performed by the antenna electrode 14 itself. This leads to simplification of the circuit configuration, and leads to downsizing of electronic devices and communication devices in which the antenna device 10A is mounted.

  When manufacturing the antenna device 10A according to the first embodiment, the antenna paste is printed on the main surface of the dielectric layer S1 located in the upper layer of the dielectric substrate 12 in step S1 of FIG. The electrode 14 is formed. As shown in FIG. 1, the antenna electrode 14 includes a main body portion 30 having a width W1 and an adjustment portion 32 having a width W2 larger than the width W1.

  In forming the antenna electrode 14, it is possible to obtain a desired resonance frequency by optimizing the size and position of the adjustment portion 32.

  Thereafter, in step S2, a plurality of dielectric layers S1 to S10 including the dielectric layer S1 on which the antenna electrode 14 is formed are stacked to produce a stacked body. Thereafter, in step S <b> 3, the multilayer body is baked to obtain the dielectric substrate 12.

  Thereafter, in step S4, the adjustment portion 32 of the antenna electrode 14 formed on the dielectric substrate 12 is trimmed to finely adjust the deviation of the resonance frequency and the like due to manufacturing variations, so that the first embodiment is implemented. The antenna device 10A according to the embodiment is completed. In this case, since it is only necessary to trim not the main body portion 30 but the adjustment portion 32 having a large width as shown in FIG. Of course, this trimming process is arbitrarily performed and is not an essential process.

  Thus, in the antenna device 10A according to the first embodiment, the antenna electrode 14 includes the main body portion 30 having the width W1 and the adjustment portion 32 having the width W2 larger than the width W1, and thus the antenna device. The resonance frequency of the antenna device 10A and the impedance of the antenna electrode 14 can be arbitrarily adjusted while reducing the size of 10A.

  Next, a second modification of the antenna device 10 according to the first embodiment will be described with reference to FIG.

  As shown in FIG. 11, the antenna device 10Ab according to the second modification has substantially the same configuration as the antenna device 10A according to the first embodiment described above, but the antenna electrode 14 has a meander shape. It is different in point.

  This antenna device 10Ab has six adjustment portions 32a to 32f, and is formed along the longitudinal direction of the antenna device 10Ab. Then, by optimizing the dimensions and positions of one or more of the adjustment portions 32a to 32f, the resonance frequency and impedance of the antenna device 10Ab can be adjusted to desired values.

  Next, an antenna device 10B according to a second embodiment will be described with reference to FIG.

  As shown in FIG. 12, the antenna device 10B according to the second embodiment has substantially the same configuration as the antenna device 10A according to the first embodiment described above (see FIG. 1). Is different in that the width W2 is smaller than the width W1 (the width of the main body portion 30).

  In this case, the resonance frequency of the antenna electrode 14 changes depending on the position of the adjustment portion 32. When the adjustment portion 32 is positioned in the vicinity of the open end 14b, the resonance frequency hardly changes, and the resonance frequency decreases as it approaches the feeding point 14a.

  The effect of the width W2 of the adjustment portion 32 is that the smaller the width W2, the lower the resonance frequency, but the amount of change is large near the feeding point 14a and hardly changes near the open end 14b.

  Even if the length of the adjustment portion 32 (ratio between the length of the adjustment portion 32 and the length of the main body portion) is changed, the resonance frequency hardly changes or changes, but the change amount is small.

  Thus, also in the antenna device 10B according to the second embodiment, the resonance frequency can be lowered, for example, without increasing the total length of the antenna electrode 14 in the initial design stage. When obtaining the above, it is possible to manufacture the antenna device 10B that is smaller than the conventional antenna device.

  Of course, the antenna device and the manufacturing method thereof according to the present invention are not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention.

1 is a perspective view showing an antenna device according to a first embodiment. It is a disassembled perspective view which shows the antenna apparatus which concerns on 1st Embodiment. It is a top view which shows the 1st modification of the antenna device which concerns on 1st Embodiment. It is a top view which shows the antenna apparatus which concerns on a comparative example. 1 is a plan view showing an antenna device according to Example 1. FIG. 6 is a plan view showing an antenna apparatus according to Embodiment 2. FIG. FIG. 6 is a plan view illustrating an antenna device according to a third embodiment. It is a figure which shows the reflective characteristic of a comparative example and Examples 1-3. It is a process block diagram which shows the manufacturing method of the antenna device which concerns on this Embodiment. It is explanatory drawing which shows the example of the trimming to an adjustment part. It is a top view which shows the antenna apparatus which concerns on a 2nd modification. It is a perspective view which shows the antenna device which concerns on 2nd Embodiment. It is a perspective view which shows the dielectric antenna which concerns on a prior art example.

Explanation of symbols

10A, 10A1 to 10A3, 10Aa, 10Ab, 10B ... Antenna device 12 ... Dielectric substrate 14 ... Antenna electrode 14a ... Feed point 16 ... Input / output terminal 30 ... Main body part 32, 32A, 32B, 32a-32f ... Adjustment part W1 ... Width of main body W2 ... Width of adjustment part L1 ... Distance from feeding point to adjustment part L2 ... Length of adjustment part

Claims (5)

In an antenna device in which a strip-shaped antenna electrode is formed on a dielectric substrate,
The antenna electrode has a band-shaped main body portion having a certain width and having a feeding point , and an adjustment portion formed integrally with the main body portion and having a width different from the width of the main body portion. And
Wherein a distance from the feed point to the adjustment portion, the length of the width and the adjustment portion of the adjustment portion, an antenna apparatus characterized that you have been adjusted at least resonant frequency. The antenna device according to claim 1 , wherein
The antenna device, wherein the resonance frequency and the impedance of the antenna electrode are adjusted by a distance from the feeding point to the adjustment portion, a width of the adjustment portion, and a length of the adjustment portion. The antenna device according to claim 1 or 2 ,
An antenna device, wherein at least a resonance frequency is adjusted by trimming the adjustment portion. It has a constant width, and a belt-shaped body portion having a feed point is formed in a body portion integrally, and having an adjustment portion having a width different from the width of the body portion, and wherein An antenna electrode having at least a resonance frequency adjusted to a predetermined frequency according to a distance from a feeding point to the adjustment portion, a width of the adjustment portion, and a length of the adjustment portion is formed on a dielectric substrate Device manufacturing method. In the manufacturing method of the antenna device according to claim 4 ,
After forming the antenna electrode on the dielectric substrate,
A method of manufacturing an antenna device, wherein the frequency is adjusted by trimming the adjustment portion of the antenna electrode.

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