JP4620018B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device such as a chip antenna, and more particularly to a technique for realizing a high-gain chip antenna or the like, and particularly effective in realizing a so-called system-on-package in which an active device and an antenna are integrated. The present invention relates to an antenna device that achieves high gain.

Conventionally, a technique using a parasitic element array has been proposed as an antenna device that realizes an array configuration without using a feed line (see Non-Patent Document 1).
FIG. 6 shows the configuration of the antenna device according to the conventional technique. In the figure, 20 is a feeding microstrip antenna, 30 is a parasitic element metal, 40 is a ground plane, 50 is a microstrip line, and 60 is a high-frequency signal source.

This prior art antenna device operates as a kind of array antenna by magnetically coupling four parasitic element metals 30 to one feeding microstrip antenna 20 which is a feeding element. As a result, higher gain is achieved.
H.Legay and L.Shafai, “New stacked microstrip antenna with large bandwidth and high gain,” IEE Proc.-Microw. Antennas Propag., Vol.141, No3, pp.199-204, June 1994.

In general, when an array antenna is formed by arranging antenna elements in a package, it is necessary to form a feeding line for feeding power to each antenna element. Loss and unnecessary radiation are caused by the routing of the feeding line. Therefore, the gain cannot be increased effectively.
Regarding such a problem, according to the antenna device according to the related art using the parasitic element metal 30 shown in FIG. 6 described above, the parasitic element metal 30 is magnetically fed from the feeding microstrip antenna 20. The above-mentioned problem caused by the routing of the power supply line can be avoided without requiring a power supply line.

  However, according to the antenna device according to the prior art shown in FIG. 6, the arrangement position of the parasitic element metal 30 that can be magnetically coupled to the feeding microstrip antenna 20 is limited. There is a problem that the number cannot be increased effectively, and therefore the gain cannot be increased effectively.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an antenna device that can effectively achieve high gain while suppressing loss without requiring the feeding line. And

In order to solve the above problems, the present invention has the following configuration.
That is, the present invention is arranged in a multilayer substrate (for example, an element corresponding to the multilayer substrate 1 shown in FIG. 1) formed by laminating a plurality of insulating layers and an insulating layer forming the multilayer substrate, and a high-frequency signal is fed. A plurality of parasitic elements (for example, FIG. 1) disposed on an insulating layer forming the multilayer substrate and a magnetic coupling subordinately to the feeding element (for example, an element corresponding to the feeding element 2 shown in FIG. 1). Elements corresponding to the parasitic elements 311 to 314, 321 to 324, 331 to 334, and 341 to 344 shown in Fig. 1 and two adjacent parasitic elements among the plurality of parasitic elements are different from each other . The antenna device has a structure in which the antenna devices are alternately arranged in the insulating layer.

  According to this configuration, part of the energy radiated from the feed element excites the plurality of parasitic elements, and each of the plurality of parasitic elements radiates electromagnetic waves. Accordingly, since electromagnetic waves are radiated from a plurality of parasitic elements in addition to the feeding elements, the aperture area of the antenna is substantially enlarged, thereby increasing the gain. In addition, since a plurality of parasitic elements are subordinately coupled, it is possible to effectively increase the number of parasitic elements with respect to one feeding element, thus increasing the aperture area of the antenna. High gain can be effectively realized.

In the antenna device, for example, the plurality of parasitic elements are arranged point-symmetrically with respect to the feeding element.
In the antenna device, for example, the plurality of parasitic elements are arranged in a line from the feeding element as a base point.
In the antenna device, for example, when a group of parasitic elements located at an equal distance from the feeding element as a base is defined as one unit, a plurality of units of parasitic elements are provided.
In the antenna device, for example, at least 5 units or more of parasitic elements are provided.
In the antenna device, for example, when a plurality of parasitic elements arranged in a row are set as one set, a plurality of sets of parasitic elements are provided.
In the antenna device, for example, the adjacent two parasitic elements may form an overlapping region through an insulating layer forming the multilayer substrate.

According to the present invention, since a plurality of parasitic elements are electromagnetically coupled to the feeding element in a dependent manner, it is possible to effectively realize a high gain while suppressing a loss without requiring a feeding line. it can.
In addition, according to the present invention, an array antenna having a large area can be configured without using a feeding circuit, so that an antenna having a low loss and a high gain can be realized even in a millimeter wave band or the like.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1-5 is a figure for demonstrating embodiment of this invention.
Here, FIG. 1 and FIG. 2 are diagrams showing the configuration of the antenna device according to the present embodiment, FIG. 1 is a top view, and FIG. 2A is a cross-sectional view taken along line AB in FIG. FIG. 2B is a diagram showing a modification of the configuration shown in FIG. 1 and 2A, reference numeral 1 denotes a multilayer substrate, reference numeral 2 denotes a feeding element made of a rectangular feeding microstrip antenna, and reference numeral 300 denotes a parasitic element made of a square metal piece. Reference numeral 4 denotes a ground plane, and reference numeral 5 denotes a feeder line.

  As shown in FIG. 1 and FIG. 2A, the multilayer substrate 1 is configured by laminating dielectric substrates (insulating layers) 1A and 1B, and 1 is formed on the dielectric substrate 1A forming the lower layer of the multilayer substrate 1. One feeding element 2 is arranged. A plurality of parasitic elements 311, 312, 313, 314, 331, 332, 333, and 334 are arranged on the dielectric substrate 1 </ b> B that forms the upper layer of the multilayer substrate 1, and the dielectric substrate is on the same plane as the feeder element 2. A plurality of parasitic elements 321, 322, 323, 324, 341, 342, 343, and 344 are arranged on 1A.

The feed line 5 is formed so as to penetrate the dielectric substrate 1 </ b> A, and a high-frequency signal is fed from the high-frequency signal source (not shown) to the feed element 2 through the feed line 5.
In the following description, when a plurality of parasitic elements 311, 312, 313, 314, 321, 322, 323, 324, 331, 332, 333, 334, 341, 342, 343, 344 are collectively referred to This is called a power feeding element 300.

Here, the plurality of parasitic elements 300 are arranged point-symmetrically with respect to the feeding element 2 and are magnetically coupled to the feeding element 2 in a dependent manner.
More specifically, the parasitic elements 311, 321, 331, 341 are arranged in a row with the feeding element 2 as a base point, and are adjacent to each other among the plurality of parasitic elements 311, 321, 331, 341. Two parasitic elements are alternately arranged on different dielectric substrates.

  In the example shown in FIG. 1 and FIG. 2A, one parasitic element 311 is disposed on the dielectric substrate 1B among the two adjacent parasitic elements 311 and 321 and the other parasitic element. 321 is disposed on the dielectric substrate 1A, and these two adjacent parasitic elements form an overlapping region via the dielectric substrate 1B. The overlapping region is similarly formed for the other two parasitic elements. The area of this overlapping region is appropriately set according to the amount of electromagnetic wave energy to be transmitted between adjacent parasitic elements, or set so that the phase of the electromagnetic waves radiated from each parasitic element matches. The However, the present invention is not limited to this example, and the overlapping area may be appropriately set according to the required antenna performance.

  In the present embodiment, “adjacent two parasitic elements” mean two parasitic elements having a close magnetic coupling relationship. In this respect, in the example shown in FIG. 1 and FIG. 2A, strictly speaking, for example, there is a magnetic coupling relationship between the parasitic element 311 and the parasitic element 331, which is understood from FIG. As described above, by providing the above overlapping region, the facing area between the parasitic element 311 and the parasitic element 321 is overwhelming compared to the facing area between the parasitic element 311 and the parasitic element 331. Therefore, the magnetic coupling between the parasitic element 311 and the parasitic element 321 becomes dense. Therefore, the parasitic element 321 is adjacent to the parasitic element 311. The same applies to the other two parasitic elements.

  Of the plurality of parasitic elements 300, the parasitic elements 311, 321, 331, 341 are magnetically coupled to the feeder element 2 in a dependent manner. That is, the parasitic element 311 is magnetically coupled to the parasitic element 2, the parasitic element 321 is magnetically coupled to the parasitic element 311, and the parasitic element 341 is coupled to the parasitic element 321. Dependently magnetically coupled. Similarly, the parasitic elements 312, 322, 332, and 342, the parasitic elements 313, 323, 333, and 343, and the parasitic elements 314, 324, 334, and 344 are respectively provided with respect to the feeder element 2. Is magnetically coupled in a dependent manner.

  Here, in the configuration of the antenna apparatus shown in FIG. 1 and FIG. 2A described above, a group of parasitic elements that are equidistant from the feeding element 2 and arranged at point-symmetric positions are defined as one unit. In other words, it can be said that a plurality of parasitic elements are provided. In this example, a total of four parasitic elements arranged at four point-symmetric positions with respect to the center of the feeding element 2 are defined as one unit. Specifically, the four parasitic elements 311, 312, 313, and 314 magnetically coupled to the feeding element 2 are at the shortest equidistant distance from the feeding element 2, and these four parasitic elements are equivalent to one unit. A parasitic element is formed. Similarly, four parasitic elements 321, 322, 323, and 324, four parasitic elements 331, 332, 333, and 334, and four parasitic elements 341, 342, 343, and 344, respectively, A parasitic element for one unit is configured. Therefore, the antenna apparatus shown in FIG. 1 is a configuration example including a total of four units of parasitic elements.

  Further, the configuration of the antenna apparatus shown in FIGS. 1 and 2A can be paraphrased as follows. In other words, the configuration of this antenna apparatus is such that four pairs of parasitic elements are provided if a plurality of parasitic elements 311, 321, 331, and 341 for one column that are subordinately magnetically coupled to the feeder element 2 are taken as one set. It can be said that these four sets of parasitic elements are arranged symmetrically with respect to the feeding element.

  In this example, four sets of parasitic elements are arranged in a cross-shaped point symmetry, but the present invention is not limited to this, and one set corresponding to one row is provided for one feeding element 2. Only parasitic elements (for example, parasitic elements 311, 321, 331, 341) may be provided, and the number of parasitic groups is not limited to four, and any number of groups of parasitic elements may be used depending on the required antenna performance. An element can also be provided. Further, the number of parasitic elements constituting one set is not limited to this example, and may be set appropriately. Further, it is sufficient if the point symmetry is provided as necessary, and it is not always necessary.

  2A, the feed element 2 and the parasitic elements 321, 323, 341, and 343 (in FIG. 1, the parasitic elements 321, 322, 323, 324, 341, 342, 343, and 344). ) Is disposed on the lower dielectric substrate 1A, and parasitic elements 311, 313, 331, 333 (in FIG. 1, parasitic elements 311, 312, 313, 314, 331, 332, 333, 334) are disposed on the upper layer. Although arranged on the dielectric substrate 1B, as shown in FIG. 2B, the feeding element 2 and the parasitic elements 321, 323, 341, and 343 are arranged on the upper dielectric substrate 1B, and the parasitic element 311 is arranged. , 313, 331, 333 may be disposed on the lower dielectric substrate 1A.

Next, the operation (operation) of this embodiment will be described.
When the feeding element 2 is fed from a high-frequency signal source (not shown) via the feeding line 5, the feeding element 2 functions as a microstrip antenna and radiates electromagnetic waves. Part of the electromagnetic waves radiated from the feed element 2 excites the first unit parasitic elements 311, 312, 313, and 314 magnetically coupled to the feed element 2, and a high-frequency current is induced in these parasitic elements. . Thereby, each of the parasitic elements 311, 312, 313, and 314 emits electromagnetic waves.

  Further, a part of the electromagnetic waves radiated from the first unit parasitic elements 311, 312, 313, and 314 are transmitted to the second unit parasitic elements 321, 322, 323, and 324 that are magnetically coupled to these parasitic elements. High frequency current is induced in these parasitic elements by excitation. Thereby, each of the parasitic elements 321, 322, 323, and 324 emits electromagnetic waves. Similarly, the third unit parasitic elements 331, 332, 333, and 334 are excited by a part of the electromagnetic waves radiated from the second unit parasitic elements to emit electromagnetic waves, and the third unit parasitic elements are emitted. The parasitic elements 341, 342, 343, and 344 of the fourth unit are excited by a part of the electromagnetic waves radiated from radiate the electromagnetic waves.

  Therefore, according to the present embodiment, since a plurality of units of parasitic elements 300 are subordinately magnetically coupled to the feeding element 2, it is possible to feed power to each parasitic element without using a feeding line. Become. In addition, since the feed element 2 and each parasitic element 300 radiate electromagnetic waves, the feed element 2 and each parasitic element 300 function as a kind of array antenna element. Therefore, the aperture area of the antenna is substantially enlarged, and this makes it possible to increase the gain of the antenna.

Further, according to the present embodiment, since two adjacent parasitic elements are arranged on different dielectric substrates, the parasitic elements functioning as array antenna elements as compared with the prior art shown in FIG. The number of can be increased dramatically. Therefore, according to the present embodiment, it is not necessary to route the feeding line with respect to the plurality of parasitic elements 300 that function as array antenna elements, and it is possible to effectively realize a high gain of the antenna device while suppressing loss.
In addition, according to the present embodiment, since the plurality of parasitic elements 300 are arranged at point-symmetrical positions, the structure is symmetric in each of the front-rear direction and the left-right direction. It becomes possible to use polarized waves simultaneously.

[Example]
Next, examples of the present invention will be described.
The antenna device according to the present embodiment is assumed to be applied in the 60 GHz band, and the dielectric substrates 1A and 1B are low-temperature fired ceramic substrates (relative permittivity εr = 7) suitable for manufacturing a millimeter-wave band package. .7) was used. The substrate configuration is such that a ground plane (ground plate) 4 is arranged in the lowermost layer, the thickness of the lower dielectric substrate 1A of the multilayer substrate 1 is 0.1 mm, and the upper dielectric substrate 1B is 0.05 mm. did. In addition, the shape of the feeding microstrip antenna as the feeding element 2 is a rectangular patch with a side of 0.65 mm, and the feeding point (the place where the feeding element 2 and the feeding line 5 are connected) is the center of the feeding element 2. Was set to a point shifted by 0.22 mm. Thereby, the impedance in the connection part of the feed element 2 and the feed line 5 was matched.

Further, each parasitic element arranged on the dielectric substrate 1A on the same plane as the feeding microstrip antenna as the feeding element 2 is formed in a rectangular patch shape with a side of 0.70 mm, and the upper layer of the feeding element 2 ( The shape of each parasitic element arranged on the dielectric substrate 1B) was a rectangular patch having a side of 0.73 mm. As a result, the resonance frequency of the resonance circuit formed with the dielectric substrate was matched. By the way, if this resonance frequency is not matched, the degree of electromagnetic coupling decreases, and therefore, the loss tends to increase.
The shapes of the feeding element 2 and the parasitic element 300 are not limited to squares, and other shapes such as a rectangle, a circle, and an ellipse may be adopted.

  Further, as shown in FIG. 1 described above, when an xy coordinate system with the center position of the feed element 2 as an origin is set and the center position of the metal piece of each parasitic element is indicated by the distance from the y-axis, 1 unit The center position w1 of the parasitic element of the eye is 0.60 mm, the center position w2 of the parasitic element of the second unit is 1.05 mm, the center position w3 of the parasitic element of the third unit is 1.50 mm, 4 The center position w4 of the unit parasitic element was 2.10 mm, and the center position w5 (not shown) of the fifth unit parasitic element was 2.75 mm. Thus, the area of the overlapping region between adjacent parasitic elements was adjusted by setting the center position of each parasitic element with reference to the feeding element 2.

  FIG. 3 shows the analysis result of the antenna directivity when five units of parasitic elements 300 are arranged. That is, in this analysis example, four parasitic elements (not shown) magnetically coupled to each of the four parasitic elements 341, 342, 343, and 344 of the fourth unit in the configuration shown in FIG. Is further provided. In FIG. 3, the solid line indicates the characteristics of the H plane, and the dotted line indicates the characteristics of the E plane. As can be seen from FIG. 3, according to this embodiment, the 3 dB beam width is 40 degrees or less for both the H plane and the E plane in terms of radiation angle, and the antenna gain is 10.3 dBi.

FIG. 4 shows the analysis result of the current distribution on each antenna element (feeding element 2 and parasitic element 300). As understood from the figure, the current is distributed to the parasitic elements located at the end portions, and it can be seen that this antenna apparatus is useful for realizing the array antenna.
FIG. 5 shows changes in antenna gain when the number of parasitic element units is changed. As can be understood from the figure, in order to realize an antenna device satisfying a performance of 10 dBi or more as an antenna gain applicable to short-range communication in the millimeter wave band, it is necessary to provide a parasitic element of 5 units or more. It is valid.

  As described above, according to the above-described embodiment, the parasitic element that has the feeding microstrip antenna fed with the high-frequency signal on the dielectric substrate having the ground plane in the lower layer and is excited by at least electromagnetic coupling. In the antenna device having a metal, a parasitic element metal is disposed on an upper layer or a lower layer of the feeding microstrip antenna via at least one dielectric layer, and the metal pieces of the parasitic element are separated into at least two different layers. By alternately arranging on the dielectric substrate and configuring the array antenna by electromagnetic coupling, it is possible to configure the array antenna without requiring a power feeding circuit, thereby realizing a low-loss antenna device. Therefore, a high gain antenna can be provided even in the millimeter wave band or the like.

  Further, when a ceramic substrate is used as the dielectric substrate and four parasitic element metals are arranged at four points symmetrically on the feeder element as one unit, at least five units of parasitic elements are defined. By providing the antenna device, the antenna device can be configured with only a thin substrate having a small number of layers. Therefore, an antenna capable of realizing a high gain at a low cost can be provided.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention.
For example, in the above-described embodiment, the dielectric substrates 1A and 1B are used as the insulating layer, but the insulating layer may be formed of an air layer without being limited thereto.

  In the above-described embodiment, parasitic elements are alternately arranged on the dielectric substrate 1A and the dielectric substrate 1B. However, the present invention is not limited to this. The substrate may be configured in any way as long as two adjacent parasitic elements are disposed on different dielectric substrates.

It is an upper view which shows the structure of the antenna apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the antenna device which concerns on embodiment of this invention. It is a characteristic view which shows the antenna characteristic (directional characteristic) of the antenna apparatus which concerns on embodiment of this invention. It is a figure which shows the electric current distribution on each element in the antenna apparatus which concerns on embodiment of this invention. It is a characteristic view which shows the relationship between the unit number of the parasitic element of the antenna apparatus which concerns on embodiment of this invention, and antenna gain. It is a figure which shows the structure of the conventional parasitic element array.

Explanation of symbols

1 ... Multilayer substrate 1A, 1B ... Dielectric substrate (insulating layer)
DESCRIPTION OF SYMBOLS 2 ... Feeding element 4 ... Ground plane 5 ... Feeding line 311 to 314, 321-324, 331-334, 341-344 ... Parasitic element

Claims (7)

A multilayer substrate formed by laminating a plurality of insulating layers;
A feeding element that is disposed on an insulating layer forming the multilayer substrate and fed with a high-frequency signal; and
A plurality of parasitic elements that are arranged in an insulating layer that forms the multilayer substrate and are magnetically coupled to the feeder elements in a dependent manner;
Two antenna elements adjacent to each other among the plurality of parasitic elements are alternately arranged on two different insulating layers.   The antenna device according to claim 1, wherein the plurality of parasitic elements are arranged point-symmetrically with respect to the feeding element.   The antenna device according to claim 1, wherein the plurality of parasitic elements are arranged in a row with the feeding element as a base point.   3. The device according to claim 1, further comprising a plurality of units of parasitic elements when a group of parasitic elements located at an equal distance from the feeding element as a base is defined as one unit. 4. Antenna device.   5. The antenna device according to claim 4, further comprising at least 5 units of parasitic elements.   4. The antenna device according to claim 3, wherein a plurality of parasitic elements are provided when the plurality of parasitic elements arranged in a line form one set. The antenna device according to claim 1, wherein the two adjacent parasitic elements form an overlapping region through an insulating layer forming the multilayer substrate.

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