JP2023039343A - Printed dipole antenna and adjustment method of direction of directive main beam of printed dipole antenna - Google Patents

Abstract

To change the directivity of main beam direction of a printed dipole antenna in any direction.SOLUTION: A printed dipole antenna includes a first antenna layer 2 having a first conductor pattern 22, and a second antenna layer 3 on which the first antenna layer 2 is laminated and which has a second conductor pattern 32, and the effective relative permittivity for the first conductor pattern and the effective relative permittivity for the second conductor pattern are different from each other, and the longitudinal dimension L1 along the element axis of an antenna element portion 222 of the first conductor pattern 22 and the longitudinal dimension L2 along the element axis of the antenna element portion 322 of the second conductor pattern 32 are different from each other.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a printed dipole antenna, and more particularly to a technique for adjusting the directivity main beam direction of a printed dipole antenna.

A printed dipole antenna is an actual example of a printed antenna, which is a planar antenna comprising a dielectric substrate, a radiating element formed thereon, and a feeding line for exciting the radiating element and connecting a transmitter and receiver. known (Non-Patent Document 1). A dipole antenna is a resonant antenna that operates near a resonant frequency determined by the dimensions of the radiating elements and also requires a balanced feed.

Manabu Yamamoto, ``Invited Paper/Fundamentals and Practices of Printed Antennas'', Special Issue on Antennas and Propagation Technologies that Support the Fundamentals of Wireless Technology, Transactions of the Institute of Electronics, Information and Communication Engineers B Vol. J97-B No. 9 pp. 714-730, The Institute of Electronics, Information and Communication Engineers, 2014

By the way, a printed dipole antenna is constructed by forming a radiating element (also called a "dipole element") on a dielectric substrate (in other words, a printed substrate), and the longitudinal dimension of the dipole element along the element axis is It is usually set to 1/2 of the effective wavelength of the desired operating frequency. As the operating frequency, the center frequency of the used frequency band is generally used. At this time, the directivity main beam direction of the dipole antenna exists in a direction perpendicular to the element axis of the dipole element.

Here, when a double-sided dielectric substrate (printed substrate) is used, a structure in which a right element and a left element constituting a dipole antenna are divided into a surface layer and a back layer is generally arranged. When using a multi-layer substrate, a structure in which the right element and the left element that constitute the dipole antenna are arranged separately in the surface layer and the inner layer, in addition to being arranged separately in the surface layer and the back layer, is also possible.

When multiple materials are used to form a multilayer substrate, the effective wavelength of the operating frequency changes depending on the dielectric constant of each layer. The effective wavelength of the operating frequency of each of the arranged right and left elements is determined according to the dielectric constant of each layer. For this reason, when the effective wavelength of the operating frequency differs between the right element and the left element, the longitudinal dimension along the element axis of each element is aligned to 1/4 of the effective wavelength of the operating frequency of either element, and both have the same dimension. , there is a problem that the directivity main beam direction of the dipole antenna is tilted (that is, it deviates from the direction perpendicular to the element axis of the dipole element). It should be noted that this phenomenon is considered to be caused by the inclination of the equiphase plane of the radiated electromagnetic field due to the difference in the excitation phases of the left and right elements due to the shift in the resonance frequencies of the left and right elements.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a printed dipole antenna and a method for adjusting the directivity main beam direction of a printed dipole antenna, which can change the directivity main beam direction of the printed dipole antenna to any direction. do.

In order to solve the above problems, a printed dipole antenna according to the present invention has an effective relative permittivity for a first conductor pattern and an effective relative permittivity for a second conductor pattern that are different from each other, and the first conductor The longitudinal dimension along the element axis of the antenna element portion of the pattern and the longitudinal dimension along the element axis of the antenna element portion of the second conductor pattern are characterized by being different from each other.

The printed dipole antenna according to the present invention has the longitudinal dimension along the element axis of the antenna element portion of the first conductor pattern and the longitudinal dimension along the element axis of the antenna element portion of the second conductor pattern. are each set to 1/4 of the effective wavelength of the operating frequency.

The printed dipole antenna according to the present invention may further have a circuit layer on which arbitrary circuits are provided.

Further, in the method for adjusting the directivity main beam direction of the printed dipole antenna according to the present invention, the effective relative permittivity of the first conductor pattern and the effective relative permittivity of the second conductor pattern are different from each other, and the first The longitudinal dimension along the element axis of the antenna element portion of the second conductor pattern and the longitudinal dimension along the element axis of the antenna element portion of the second conductor pattern are set to mutually different values.

According to the printed dipole antenna and the method for adjusting the directivity main beam direction of the printed dipole antenna according to the present invention, the longitudinal dimension along the element axis of the antenna element portion of the first conductor pattern and the antenna element of the second conductor pattern Since the longitudinal dimension along the element axis of each part is different from each other, it is possible to change the directivity main beam direction of the printed dipole antenna in any direction.

In the printed dipole antenna according to the present invention, when the longitudinal dimensions of the antenna element portions of both the first conductor pattern and the second conductor pattern are set to 1/4 of the effective wavelength of the operating frequency, , it is possible to ensure good performance as a dipole antenna by ensuring resonance at the operating frequency.

When the printed dipole antenna according to the present invention further has a circuit layer, the antenna part and the circuit part can coexist on one multi-layer substrate, and the antenna part and the circuit part can be separated from each other. It is possible to reduce the required substrate area because there is no need to divide the substrate into two.

1 is a perspective view showing a schematic configuration of a printed dipole antenna according to Embodiment 1 of the present invention; FIG. FIG. 2 is a schematic perspective plan view in the Z-axis direction of the printed dipole antenna of FIG. 1; (A) is a perspective plan view of a printed dipole antenna. (B) is a perspective plan view of the first antenna layer. (C) is a perspective plan view of the second antenna layer. FIG. 2 shows a radiation pattern in the XY plane of the printed dipole antenna of FIG. 1; FIG. 4 is a perspective view showing a schematic configuration of a printed dipole antenna according to Embodiment 2 of the present invention; FIG. 4 is a perspective view showing a schematic configuration of a printed dipole antenna according to another embodiment of the invention;

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the illustrated embodiments. In the following description, as shown in each figure, the X-axis, Y-axis, and Z-axis directions of a three-dimensional orthogonal coordinate system are defined for the printed dipole antenna 1, and the arrows of the Z-axis are defined. Let the direction be upward, and let the direction opposite to the direction of the arrow of the Z-axis be downward. It should be noted that each figure is only a diagram for explaining the schematic configuration of the printed dipole antenna 1 according to the present invention, and does not strictly specify the detailed structure of each part and the mutual dimensional relationship.

(Embodiment 1)
FIG. 1 is a perspective view showing a schematic configuration of a printed dipole antenna 1 according to Embodiment 1 of the present invention. The printed dipole antenna 1 is a module for wireless communication using, for example, a microwave band or a millimeter wave band. , and formed as a whole as a multi-layer substrate.

The first antenna layer 2 is formed in a predetermined shape inside or on the surface of the first dielectric substrate 21 having a predetermined relative dielectric constant (inside in the example shown in the figure). and a first conductor pattern 22 that is connected.

The second antenna layer 3 is formed in a predetermined shape inside or on the surface of the second dielectric substrate 31 having a predetermined relative dielectric constant (inside in the example shown in the figure). and a second conductor pattern 32 that is connected to the substrate.

The first dielectric substrate 21 forming the first antenna layer 2 and the second dielectric substrate 31 forming the second antenna layer 3 are made of materials different from each other. are made of different materials.

Although the materials of the first and second dielectric substrates 21 and 31 are not limited to a specific type, they may be ceramic materials such as low temperature co-fired ceramics (LTCC: an abbreviation for Low Temperature Co-fired Ceramics) or various other materials. A resin material may be used.

In the illustrated example, the printed dipole antenna 1 is configured by laminating the second antenna layer 3 and the first antenna layer 2 in order in the Z-axis direction to form a multilayer substrate. The upper surface of the first antenna layer 2 is open.

As shown in FIGS. 1 and 2, the printed dipole antenna 1 according to the first embodiment includes the first antenna layer 2 having the first conductor pattern 22 and the first antenna layer 2 laminated together. and a second antenna layer 3 having a second conductor pattern 32, and the dielectric constant of the first dielectric substrate 21 forming the first antenna layer 2 and the second antenna layer 3 are formed. The relative permittivity of the second dielectric substrate 31 is different from each other, and the longitudinal dimension L1 of the antenna element portion 222 of the first conductor pattern 22 and the longitudinal dimension L2 of the antenna element portion 322 of the second conductor pattern 32 are different. and are different from each other.

The direction of the directivity main beam of the printed dipole antenna is adjusted by adjusting the longitudinal dimension L1 along the element axis of the antenna element portion 222 of the first conductor pattern 22 and the element axis of the antenna element portion 322 of the second conductor pattern 32. This is done by adjusting the lengthwise dimension L2 along the line with mutually different values.

The first conductor pattern 22 includes a strip-shaped feed line portion 221 along the Y-axis direction (the feed line portion is also referred to as a feed line), and the tip of the feed line portion 221 (specifically, the Y-axis end in the direction of the arrow) and a band-shaped antenna element portion 222 along the X-axis direction.

The antenna element part 222 functions as a radiation conductor and works as an antenna element. Regarding the antenna element part 222, the belt-shaped longitudinal axis along the X-axis direction is called an "element axis".

The second conductor pattern 32 is connected to a belt-shaped feed line portion 321 along the Y-axis direction and the tip of the feed line portion 321 (specifically, the end in the direction of the arrow on the Y-axis), and is connected to the X-axis direction. and a strip-shaped antenna element portion 322 along the .

The antenna element section 322 functions as a radiation conductor and works as an antenna element. Regarding the antenna element portion 322, the belt-shaped longitudinal axis along the X-axis direction is called an “element axis”.

The base end of the feed line portion 221 of the first conductor pattern 22 (specifically, the end in the direction opposite to the direction of the Y-axis arrow) and the base end of the feed line portion 321 of the second conductor pattern 32 (specifically, Specifically, the end of the Y-axis in the direction opposite to the direction of the arrow) is electrically connected to the feeding point 5 .

The feed line portion 221 of the first conductor pattern 22 formed on the first antenna layer 2 and the feed line portion 321 of the second conductor pattern 32 formed on the second antenna layer 3 are separated from each other in the Z-axis direction by In other words, they are formed at positions overlapping each other (in plan view).

In addition, the antenna element portion 222 of the first conductor pattern 22 extends from the tip of the feed line portion 221, and the antenna element portion 322 of the second conductor pattern 32 extends from the tip of the feed line portion 321 in the X-axis direction. are formed to extend in mutually opposite directions along. These two antenna element portions 222 and 322 form a printed dipole, which functions as a radiation element/driving element of a planar antenna to form a dipole antenna.

That is, the current from the feeding point 5 passes through the transmission path composed of the feed line portion 221 of the first conductor pattern 22 and the feed line portion 321 of the second conductor pattern 32, and passes through the antenna element portion 222 and the antenna element portion 322. propagates to and radiates into space.

Here, two dipole elements (specifically, a right element and a left element) that constitute the dipole antenna; and) the longitudinal dimension along each element axis is typically set to 1/4 of the effective wavelength of either antenna layer at the desired operating frequency, ie, both are set to the same length dimension. However, in order to satisfy the desired performance and specifications of the multilayer substrate as a whole, and to use materials suitable for each of the circuits arranged on each layer, a plurality of substrates (in the example shown in the figure, the first antenna The first dielectric substrate 21 of the layer 2 and the second dielectric substrate 31 of the second antenna layer 3 correspond to the first dielectric substrate 21 and the second dielectric substrate 31 of the second antenna layer 3) are formed of mutually different materials, and substrates of a plurality of materials are laminated to form a multilayer structure. It may form a substrate.

When multiple materials are used to form a multilayer substrate, the effective wavelength of the operating frequency changes depending on the dielectric constant of each layer. The effective wavelength of the operating frequency of each of the right and left elements arranged in parallel depends on the dielectric constant of each layer. Therefore, if the effective wavelength of the operating frequency differs between the right element and the left element, the longitudinal dimension along the element axis of both elements should be aligned to 1/4 of the effective wavelength of either operating frequency. When set to the dimensions, the dipole antenna directivity main beam direction is tilted (specifically, deviates from the direction perpendicular to the element axis of the dipole element) because the left and right elements have different resonance frequencies.

Therefore, in the present invention, the longitudinal dimension L1 along the element axis (that is, the X-axis direction) of the antenna element portion 222 of the first conductor pattern 22 and the element axis of the antenna element portion 322 of the second conductor pattern 32 are By setting and adjusting the longitudinal dimension L2 along different values (ie, L1≠L2; see FIG. 2), the directivity main beam direction of the dipole antenna is adjusted.

For example, the effective wavelength of the operating frequency determined based on the relative permittivity of the first dielectric substrate 21 of the first antenna layer 2 and the second dielectric substrate 31 of the second antenna layer 3 By adjusting the longitudinal dimension L1 of the antenna element portion 222 of the first conductor pattern 22 and the longitudinal dimension L2 of the antenna element portion 322 of the second conductor pattern 32 according to the ratio, the resonance frequencies of the left and right elements are adjusted. are the same, the directivity main beam direction of the dipole antenna is adjusted along the direction perpendicular to the element axis of the antenna element portions 222 and 322 .

In order to ensure good characteristics as a dipole antenna, it is necessary for the left and right elements to resonate at their respective operating frequencies. Both longitudinal dimensions L2 should be set to 1/4 of the effective wavelength based on the dielectric constant of each layer.

However, depending on the purpose, conditions, and conditions of use of the printed dipole antenna 1, by adjusting the longitudinal dimension L1 and the longitudinal dimension L2, the resonance frequencies of the left and right elements can be adjusted to different values, and the directivity of the dipole antenna can be changed. The main beam direction of the antenna element portion 222, 322 may be adjusted along any direction other than perpendicular to the element axis of the antenna element portion 222,322.

According to the printed dipole antenna 1 and the method for adjusting the directivity main beam direction of the printed dipole antenna according to the first embodiment, the dielectric constant of the first dielectric substrate 21 constituting the first antenna layer 2 and the second The relative permittivity of the second dielectric substrate 31 constituting the antenna layer 3 is different from each other, and the longitudinal dimension L1 along the element axis of the antenna element portion 222 of the first conductor pattern 22 and the second conductor pattern Since the longitudinal dimension L2 along the element axis of the antenna element portion 322 of 32 is different from each other, it is possible to change the directivity main beam direction of the printed dipole antenna in an arbitrary direction.

As a specific example, operating characteristics of the printed dipole antenna 1 according to Embodiment 1 will be described with reference to FIG. FIG. 3 is a diagram showing a radiation pattern (specifically, gain distribution in each direction) of the printed dipole antenna 1 on the XY plane.

First, the antenna element portion 222 of the first conductor pattern 22 and the antenna element portion 322 of the second conductor pattern 32 have the same longitudinal dimensions L1 and L2 along the element axis (that is, the X-axis direction). Since the resonance frequencies of the left and right elements are different, as shown in FIG. It exists in the 120 degree direction with a shift.

On the other hand, for the antenna element portion 222 of the first conductor pattern 22 and the antenna element portion 322 of the second conductor pattern 32, longitudinal dimensions L1 and L2 along the element axis (that is, the X-axis direction) are resonated. By adjusting the frequencies to be the same (where L1 ≠ L2, and in the example shown in the figure, L1 < L2), as shown in FIG. is in the direction perpendicular to the element axis (the 90 degree direction in the figure).

According to the printed dipole antenna 1 and the method for adjusting the directivity main beam direction of the printed dipole antenna according to the first embodiment, the length of the antenna element portions 222 and 322 of the first conductor pattern 22 and the second conductor pattern 32 When both the directional dimensions L1 and L2 are set to 1/4 of the effective wavelength of the operating frequency, it is possible to ensure good performance as a dipole antenna by ensuring resonance at the operating frequency. It becomes possible.

(Embodiment 2)
FIG. 4 is a perspective view showing a schematic configuration of a printed dipole antenna 1 according to Embodiment 2 of the present invention. Although this embodiment differs from the above-described first embodiment in that it further includes a circuit layer 6, the rest of the configuration is the same as that of the above-described first embodiment. are denoted by the same reference numerals, and descriptions thereof are omitted.

The circuit layer 6 is provided on the lower surface of the antenna layer 3, and includes a third dielectric substrate 61 having a predetermined dielectric constant, and a dielectric substrate 61 inside or on the surface of the third dielectric substrate 61. ) and a predetermined circuit disposed therein. Although the circuit arranged in the circuit layer 6 is not limited to a specific type or configuration, for example, a filter circuit including a bandpass filter that passes only an antenna signal in a specific band may be provided.

The third dielectric substrate 61 and the first dielectric substrate 21 and the second dielectric substrate 31 may be made of different materials, or may be made of the same material. may

According to the printed dipole antenna 1 according to the second embodiment, since it further has the circuit layer 6, in addition to the effects of the above-described first embodiment, one multi-layer substrate can be provided with an antenna part as well. The circuit portion can coexist, and the antenna portion and the circuit portion do not need to be separated on different substrates, and the necessary substrate area can be reduced.

Although the embodiments of the present invention have been described above, the specific configuration is not limited to the above-described embodiments. Included in the invention.

For example, in the above embodiment, the feed line portions 221 and 321 are formed in strips along the Y-axis direction. It may be formed in any shape.

Further, in the above embodiment, the first dielectric substrate 21 constituting the first antenna layer 2 and the second dielectric substrate 31 constituting the second antenna layer 3 are made of different materials. In particular, each dielectric constant is made of materials different from each other. is not an essential configuration in the present invention, and moreover, having a plurality of dielectric substrates is not an essential configuration in the present invention. For example, it has a single dielectric substrate, the antenna element portion of the first conductor pattern is formed/arranged on the surface of the dielectric substrate, and the antenna element portion of the second conductor pattern is formed on the dielectric substrate. When formed/arranged on the inner layer, the antenna element portion formed/arranged on the surface of the dielectric substrate is sandwiched between the air and the dielectric, so the effective relative permittivity is lower than the original relative permittivity. On the other hand, since the antenna element portion formed/arranged in the inner layer of the dielectric substrate is sandwiched between the same dielectric (in other words, a single dielectric), the effective relative permittivity is the original relative permittivity Therefore, the effective relative permittivity of the antenna element formed/arranged on the inner layer of the dielectric substrate is the effective relative permittivity of the antenna element formed/arranged on the surface of the dielectric substrate relatively high compared to Even in such a case, since the longitudinal dimension along the element axis of the antenna element portion of the first conductor pattern and the longitudinal dimension along the element axis of the antenna element portion of the second conductor pattern are different from each other, Effects similar to those of the above embodiment can be exhibited. That is, the gist of the present invention is that the effective relative permittivity of the first conductor pattern and the effective relative permittivity of the second conductor pattern are different from each other, and the longitudinal direction of the antenna element portion of the first conductor pattern along the element axis. The directional dimension and the longitudinal dimension along the element axis of the antenna element portion of the second conductor pattern are different from each other.

Further, as shown in FIG. 5, the base end of the feed line portion 321 of the second conductor pattern 32 (specifically, the end in the direction opposite to the direction of the Y-axis arrow) is provided in the second antenna layer 3. ), the ground pattern 4 may be formed so as to be connected to the . In this case, the base end of the ground pattern 4 (specifically, the end in the direction opposite to the direction of the Y-axis arrow) is electrically connected to the feeding point 5 .

REFERENCE SIGNS LIST 1 printed dipole antenna 2 first antenna layer 21 first dielectric substrate 22 first conductor pattern 221 feed line section 222 antenna element section L1 longitudinal dimension of the antenna element section along the element axis 3 second antenna layer 31 Second dielectric substrate 32 Second conductor pattern 321 Feed line portion 322 Antenna element portion L2 Longitudinal dimension along the element axis of the antenna element portion 4 Ground pattern 5 Feeding point 6 Circuit layer 61 Third dielectric substrate

Claims (4)

the effective relative permittivity for the first conductor pattern and the effective relative permittivity for the second conductor pattern are different from each other,
The longitudinal dimension along the element axis of the antenna element portion of the first conductor pattern and the longitudinal dimension along the element axis of the antenna element portion of the second conductor pattern are different from each other,
A printed dipole antenna characterized by: Both the longitudinal dimension along the element axis of the antenna element portion of the first conductor pattern and the longitudinal dimension along the element axis of the antenna element portion of the second conductor pattern are each at an operating frequency. set to 1/4 of the effective wavelength,
The printed dipole antenna according to claim 1, characterized in that: further comprising a circuit layer on which any circuit is provided;
3. The printed dipole antenna according to claim 1, wherein: the effective relative permittivity for the first conductor pattern and the effective relative permittivity for the second conductor pattern are different from each other,
setting the longitudinal dimension along the element axis of the antenna element portion of the first conductor pattern and the longitudinal dimension along the element axis of the antenna element portion of the second conductor pattern to mutually different values;
A method for adjusting a directional main beam direction of a printed dipole antenna, characterized by:

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