JPH08213831A - Microstrip antenna - Google Patents

Abstract

PURPOSE: To provide a high gain antenna in which frequency setting and adjustment and decision of a feeding point that is caused when the size of a quadrilateral microstrip antenna including a one-side short-circuit quadrilateral microstrip antenna is made small are facilitated. CONSTITUTION: The quadrilateral microstrip antenna is formed by a dielectric board 3, a copper foil ground board 1 formed to one side of the dielectric board 3 and a copper foil radiation element 2 formed to the other side of the dielectric board 3. Then the radiation element 2 is separated into plural parts in parallel by a separation strip 7, the separated radiation elements 2 are connected electrically by a connection conductor 6 to form a radiation section for the quadrilateral microstrip antenna whose length is an electric length of 1/2 wavelength or to form a radiation section for the quadrilateral microstrip antenna whose length is an electric length of/4 wavelength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip antenna for a compact and high-performance portable wireless device such as a mobile phone and a mobile communication device.

[0002]

2. Description of the Related Art In recent years, small radios such as portable telephones and mobile communication devices have rapidly spread, and along with this,
There is a strong demand for miniaturization and thinning of each component. The microstrip antenna is a typical antenna used as a component of the above-mentioned small radio, and is also called a patch antenna because of the shape of the radiating element. With the spread of smaller radios, the antenna becomes even smaller. There has been a demand for reduction in thickness, reduction in thickness, and improvement in accuracy.

FIG. 6 shows an example of a rectangular microstrip antenna that has been generally used in the past. In this drawing, 1 is a copper foil-shaped base plate, 2 is a radiating element, 3 is a dielectric, and 4 is a power feed. It is a point. This square microstrip antenna is an antenna that positively utilizes the radiation loss from a microstrip resonator consisting of a copper foil-shaped ground plane, a radiation element, and a dielectric. Select approximately 1/2 wavelength of the transmission / reception frequency.

On the other hand, FIG. 7 shows a conventional example of a single-sided short-circuited rectangular microstrip antenna in which power is fed from the back surface of the radiating element 2. In this drawing, 1 is a copper foil-shaped ground plane, 2 is a radiating element, and 3 is a dielectric. A body 4, a feeding point, and 5 are short-circuit conductors for short-circuiting the copper foil-shaped base plate and the copper foil-shaped radiating element.

Since the value of the antenna input impedance usually changes depending on the position of the feeding point, the feeding point of this single-sided short-circuit rectangular microstrip antenna is determined at a position corresponding to the desired antenna input impedance. Such a single-sided short-circuit type square microstrip antenna is
Generally used as an antenna for the purpose of miniaturization, a half-wavelength resonance type square microstrip antenna as shown in FIG. It is configured as a rectangular microstrip antenna, and the total length of the radiating element and the short-circuit conductor is electrically selected to be approximately 1/4 wavelength of the transmission / reception frequency.

In such a single-sided short-circuited rectangular microstrip antenna, since the short-circuit conductor 5 has a role as an inductance element loaded in the antenna, the resonance frequency of the antenna can be changed by changing the width (W) of the short-circuit conductor. Can be changed.

[0007]

As described above, the single-sided short-circuit type rectangular microstrip antenna is shorted to the ground plane by a short-circuit conductor at approximately 1/2 point of the 1 / 2-wavelength resonance type square microstrip antenna. A four-wavelength resonance type square microstrip antenna is constructed, and as a result,
The area of the radiating element is reduced to about half that of the resonance type square microstrip antenna, and the short-circuit conductor has a role as an inductance element loaded in the antenna, so that the width (W) of the short-circuit conductor is changed. The size can be further reduced by utilizing the fact that the resonance frequency of the antenna can be changed.

However, when the size is reduced by narrowing the width (W) of the short-circuit conductor, the resonance frequency of the antenna greatly fluctuates due to a slight change in the width (W) of the short-circuit conductor, and the frequency band of the rectangular microstrip antenna is held. Since the width is about 2 to 3% of the resonance frequency, it is very difficult to set and adjust the frequency, and high manufacturing accuracy is required.

Further, since the position of the feeding point is closely related to the width (W) of the short-circuit conductor as in the case of the frequency, a high manufacturing precision is required to determine the position of this feeding point. . Therefore, a single-sided short-circuit type rectangular microstrip antenna with a variable width of the short-circuit conductor can be miniaturized, but high manufacturing precision is required for setting and adjusting the frequency and determining the position of the feeding point, etc. Not at all.

Therefore, an object of the present invention is to facilitate the frequency setting and adjustment, the determination of the feeding point position, etc., which occur when miniaturizing a rectangular microstrip antenna including a single-sided short-circuiting type rectangular microstrip antenna, and to realize a high gain antenna. To provide.

[0011]

In order to solve the above-mentioned problems, in the single-sided short-circuit type rectangular microstrip antenna of the present invention, in addition to the short-circuit conductor whose width can be varied, the radiating element is divided into a plurality of parts. A separation band or a radiating element is divided into a plurality of notches at one or more locations of the radiating element, and the remaining part of the notch is used as an electrical connection portion of each radiating element to form a connection band, A part of the radiating element is electrically connected to the separation band through a connection conductor whose width can be varied, and the short-circuit conductor, the connection conductor, or the connection width of the connection band can be varied. The antenna resonance frequency and the antenna input impedance can be changed by the.

[0012]

In the rectangular microstrip antenna including the single-sided short-circuit type rectangular microstrip antenna constructed as described above, the width of the short-circuit conductor can be varied or the width and position of the narrow connection band formed in the radiating element can be varied. For controlling the resonance frequency of the antenna and the position of the feeding point by varying the width of the connection conductor formed by cutting out the radiating element or the connection band for The object of the present application is achieved by making it possible to manufacture a rectangular microstrip antenna more simply and practically.

[0013]

Embodiments of the present invention will be described more specifically below with reference to the drawings. FIG. 1 is a first embodiment of the present invention, in which 1 is a copper foil-shaped base plate, 2 is a copper foil-shaped radiating element separated into a plurality of layers by the formation of separation bands described later, and 3 is the base plate 1 on the back surface. A dielectric having the radiating element 2 formed on the surface thereof, 4 a feeding point connected to the radiating element, and 5 a short circuit for electrically short-circuiting the copper foil-shaped ground plane and the copper foil-shaped radiating element. A conductor, 6 is a connecting conductor for connecting each of the divided radiating elements 2, and 7 is a separation band for separating the radiating elements into a plurality.

FIG. 5 is an explanatory view for explaining the resonance frequency characteristic and antenna input impedance characteristic of the single-sided short-circuit type rectangular microstrip antenna when the widths of the short-circuit conductor 5 and the connection conductor 6 are changed. In the first embodiment shown in FIG. 1, the resonance frequency and the antenna input impedance (Z) when the width (W1) of the short-circuit conductor 5 and the width (W2) of the connecting conductor 6 are changed with the feeding point 4 fixed. ) Changes will be described below.

First, the width (W2) of the connecting conductor 6 is fixed,
Explaining the case where the width (W1) of the short-circuit conductor 5 is changed, the short-circuit conductor 5 is loaded as an inductance element with an inductance corresponding to the width (W1). Therefore, when the width (W1) of the short-circuit conductor 5 is gradually narrowed, as shown in FIG.
The resonance frequency of the antenna gradually decreases as shown by the curve A in FIG.

At this time, the antenna input impedance (Z) increases as the width (W1) of the short-circuit conductor 5 decreases. Next, the width (W1) of the short-circuit conductor 5 is fixed in a narrowed state to some extent, and the width (W2) of the connection conductor 6 provided for electrically coupling the separated radiating element to a part of the separation band portion. ) Will be described.

First, with the width (D) of the radiating element from the short-circuit conductor 5 to the separation band 7 fixed, the width (W
As 2) is narrowed, the connection conductor becomes an inductance element and an inductance corresponding to the width (W2) of the connection conductor is loaded as in the case of the short-circuit conductor 5 described above, so that the curve B shown in FIG. The resonance frequency of the antenna gradually decreases as shown in.

Next, the width (D) of the radiating element from the short-circuit conductor 5 to the separation band 7 is increased, and the separation band is formed at a position distant from the short-circuit conductor 5. As the width (W2) is narrowed, the resonance frequency of the antenna gradually decreases as shown by the curve C in FIG.

In this case, the curve C has a gentler slope than the curve B. That is, when the width (D) of the radiating element from the short-circuit conductor 5 to the separation band is increased, the slope at which the resonance frequency becomes lower becomes gradually gentle. In view of this result, the width (D) of the radiating element from the short-circuit conductor 5 to the separation band 7
When is extremely increased, the change of the resonance frequency is hardly seen.

Next, the antenna input impedance (Z) on the curves B and C will be described. In both the curves B and C, the antenna input impedance (Z) becomes higher as the width (W2) of the connecting conductor becomes narrower. Comparing the curve B and the curve C at a certain resonance frequency (Fd), the antenna input impedance (Z) is larger at the point Fd of the curve B. That is, it can be confirmed that the smaller the width (D) of the radiating element from the short-circuit conductor to the connecting conductor portion, the greater the change in the antenna input impedance (Z).

As described above, the desired resonance frequency (F
To adjust to d), for example, first, the width (W
1) is narrowed to some extent and set to a frequency higher than the desired resonance frequency (Fd), and then the width (W
2) may be sequentially narrowed to a desired resonance frequency (Fd). At this time, for example, when the antenna input impedance (Z) is higher than the desired antenna input impedance, the width (W1) of the short-circuit conductor may be widened to some extent, and then the width (W2) of the connection conductor may be narrowed. The antenna input impedance can be obtained.

In the above description, first, the width (W
Although the method for adjusting the width (W2) of the connecting conductor by adjusting 1) has been described, it goes without saying that the width (W1) of the shorting conductor is adjusted after adjusting the width (W2) of the connecting conductor. May be. Further, in addition to the above method, if the width (D) of the radiating element from the short-circuit conductor 5 to the separation band 7, that is, the distance from the short-circuit conductor to the connecting conductor is changed and adjusted, resonance is easier. It is possible to adjust the frequency and the antenna input impedance.

This embodiment can be easily manufactured by using, for example, a double-sided copper-clad dielectric substrate in which copper foil is attached to both surfaces of a printed circuit board or a dielectric such as Teflon or glass epoxy resin. For the short-circuit conductor, a thin copper plate, aluminum plate or other electrically conductive metal may be used. Also, the short-circuit conductor need not be particular about the material on the plate, and the front and back sides are electrically connected. There is no problem even with a short-circuit pin or the like that can be used. Further, as for the connecting conductor, electrically conductive and electrically conductive metal such as a thin copper plate or an aluminum plate may be used. The connection of the short-circuit conductor or the connection conductor to the radiating element is not particularly limited as long as good electrical conduction can be achieved by soldering, welding, or the like.

Next, regarding the second embodiment of the present invention,
This will be described with reference to FIG. In FIG. 2, 1 is a copper foil-shaped ground plane, 2 is a copper foil-shaped radiation element, 3 is a dielectric having the ground plane 1 formed on the back surface, and the radiation element 2 is formed on the front surface, and 4 is the radiation element. Connected feeding points, 5 is a short-circuit conductor for electrically short-circuiting the copper foil-shaped ground plane and the copper foil-shaped radiating element, 8
Is a connection band, and 9 is a notch formed at an appropriate portion of the dielectric band to form the connection band.

The connection band has the same function as the connection conductor constructed in the first embodiment. That is, the width of the dielectric is partially narrowed by cutting out a part of the radiating element on the dielectric substrate, and this part is used as a connection band to have the same function as the connection conductor.

Since the connection band is loaded with an inductance corresponding to the width of the connection band as an inductance element like the connection conductor, the method of changing and adjusting the resonance frequency and the antenna input impedance is the same as that of the first embodiment. Is. Next, a third embodiment of the present invention will be described with reference to FIG.

In FIG. 3, 1 is a copper foil-shaped base plate, 2 is a copper foil-shaped radiating element that is arranged in a plurality of separate pieces, 3 is the base plate 1 formed on the back surface, and the radiating element 2 is on the front surface. The formed dielectric 4 is a feeding point electrically connected to the radiating element,
Reference numeral 6 denotes a connection conductor that electrically connects the radiating elements 2 divided into a plurality of parts, and 7 denotes a separation band that separates the radiating elements into a plurality of parts.

The fact that the short-circuit conductor and the connecting conductor function as loading inductance elements described in the first embodiment can be applied to the 1 / 2-wave rectangular microstrip antenna of FIG. 7 described as a conventional example. From this fact, the third embodiment is an example in which the two separation bands 7 generated in the three radiating elements are connected by the connecting conductors 6, and each connecting conductor 6 has its width (W1, W2). ), And is loaded on the 1 / 2-wave rectangular microstrip antenna of this embodiment.

At this time, one of the separation bands is formed substantially in the center of the radiating element, and if one of the connecting conductors 6 is loaded in the separation band formed in the center, the change of the resonance frequency is large. As described above, the separation band is formed at the end deviated from the center of the radiating element, and if the connection conductor 6 is loaded on the separation band formed at this end, the change in the resonance frequency becomes small. is there.

For example, as in the third embodiment, one connecting conductor (width: W1) is connected to the separation band portion located in the center, and the other connection is made to the separation band portion located away from the center. When a conductor (width: W2) is connected, the value and amount of change are different, but the tendency of change in resonance frequency and antenna input impedance is the same as in the single-sided short-circuit rectangular microstrip antenna shown in the first embodiment. Becomes

That is, according to the present example, the tendency of changes in the resonance frequency and the antenna input impedance is that the short-circuit conductor shown in the first and second embodiments is comparable to one connecting conductor (width: W1) in this example. Moreover, the connection conductors shown in the first and second embodiments are comparable to the other connection conductors (width: W2) of this embodiment, and as a result, the change shown in FIG. 5 is observed.

Therefore, also in the structure shown in the third embodiment, the resonance frequency and the antenna input impedance can be easily adjusted as in the case of the first embodiment.
Finally, a fourth embodiment of the present invention will be described with reference to FIG. In this embodiment as well, as in the second embodiment, a part of the radiating element on the dielectric substrate is cut out to form a connection band in this cutout, and the connection band is formed in the first or third embodiment. It is characterized by performing the same operation as the connection conductor disclosed in.

Like the connection conductor of the third embodiment, the connection band in this example serves as an inductance element and is loaded with an inductance according to the width of the connection band. Therefore, the resonance frequency and the antenna input impedance can be changed and adjusted. The same operation as in the third embodiment is performed. Note that the number of radiating elements divided or divided into a plurality of numbers need not be limited to the number in each of the embodiments described above, and may be set according to the adjustment degree of the resonance frequency and the antenna input impedance.

Although the embodiment of the present invention has been described with reference to FIGS. 1 to 5, the development of other embodiments is not excluded as long as it is based on the technical gist of the present invention.

[0035]

As described above, according to the present invention, in a rectangular microstrip antenna including a single-sided short-circuit type rectangular microstrip antenna, a connection for electrically connecting the radiating elements separated into the width of the short-circuit conductor or a plurality of short-circuit conductors is provided. By changing the width and position of the narrow connection band formed by cutting out the conductor or radiating element, the resonance frequency of the antenna and the position of the feeding point are finely adjusted, and as a result, it is easy to maintain high gain. The resonance frequency and the antenna input impedance can be easily adjusted, and the miniaturization of the rectangular microstrip antenna can be achieved with high accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention in a single-sided short-circuit type rectangular microstrip antenna.

FIG. 2 is a perspective view showing a second embodiment of the present invention in a single-sided short-circuit type rectangular microstrip antenna.

FIG. 3 is a perspective view showing a third embodiment of the present invention in a rectangular microstrip antenna.

FIG. 4 is a perspective view showing a fourth embodiment of the present invention in a rectangular microstrip antenna.

FIG. 5 is an explanatory diagram illustrating a resonance frequency characteristic and an antenna input impedance characteristic of a single-sided short-circuit type rectangular microstrip antenna.

FIG. 6 is a perspective view of a conventional 1 / 2-wave rectangular microstrip antenna.

FIG. 7 is a perspective view of a conventional single-sided short-circuit type rectangular microstrip antenna.

[Explanation of symbols]

 1 Ground plane 2 Radiating element 3 Dielectric 4 Feed point 5 Short-circuit conductor 6 Connection conductor 7 Separation band 8 Connection band 9 Notch

Claims (6)

[Claims] 1. A dielectric substrate, a copper foil-shaped base plate formed on one surface of the dielectric substrate, and a copper foil-shaped radiating element formed on the other surface of the dielectric substrate. In the rectangular microstrip antenna described above, the radiating element is divided into a plurality of parallel pieces, and a connecting conductor is provided for electrically connecting the divided radiating elements, and the radiating elements are electrically connected via the connecting conductor. Connect, 1/2
A microstrip antenna comprising a radiating portion of a rectangular microstrip antenna which operates at an electric length of a wavelength. 2. The radiating element is divided into at least three or more parallel parts, and a plurality of connecting conductors for electrically connecting the divided radiating elements are provided, and the radiating elements are electrically connected through the connecting conductors. 2. The microstrip antenna according to claim 1, wherein the radiation section of the rectangular microstrip antenna is connected to each other and operates at an electric length of ½ wavelength. 3. A dielectric substrate, a copper foil-shaped base plate formed on one surface of the dielectric substrate, and a copper foil-shaped radiating element formed on the other surface of the dielectric substrate. In the rectangular microstrip antenna, the copper foil of the radiating element is cut out to divide the radiating element into a plurality of parallel pieces, and a narrow copper foil connecting portion is formed in the cutout portion to form the copper foil connecting portion. 2. The micro unit according to claim 1, wherein the plurality of divided radiating elements are electrically connected to each other to form a radiating section of a rectangular microstrip antenna which operates at an electric length of ½ wavelength. Strip antenna. 4. A copper foil of a radiating element is cut out to divide the radiating element into at least three or more parallel parts, and a narrow copper foil connecting portion is formed in each of the notch portions, and the copper foil connecting portion is formed. 4. The microstrip antenna according to claim 3, wherein each radiating element is electrically connected through the radiating element to form a radiating portion of a rectangular microstrip antenna which operates at an electric length of ½ wavelength. 5. A dielectric substrate, a copper foil-shaped base plate formed on one surface of the dielectric substrate, a copper foil-shaped radiating element formed on the other surface of the dielectric substrate, and the copper. In a single-sided short-circuit type rectangular microstrip antenna composed of a grounding board on a foil and a short-circuit conductor that electrically short-circuits a radiation element on a copper foil, the radiation element is divided into a plurality of parallel radiations, and each divided radiation is A connection conductor for electrically connecting the elements is provided, and the radiating elements are electrically connected through the connection conductor,
A microstrip antenna comprising a radiation portion of a single-sided short-circuit type rectangular microstrip antenna which operates at an electric length of a wavelength. 6. A dielectric substrate, a copper foil-shaped base plate formed on one surface of the dielectric substrate, a copper foil-shaped radiating element formed on the other surface of the dielectric substrate, and the copper. In a single-sided short-circuiting type rectangular microstrip antenna composed of a ground conductor on a foil and a short-circuit conductor for electrically short-circuiting the radiating element on the copper foil, a plurality of radiating elements are formed by cutting out the copper foil of the radiating element. Along with the parallel division, a narrow copper foil connection portion is formed in the cutout portion, and the plurality of divided radiating elements are electrically connected via the copper foil connection portion, and the electrical length of 1/4 wavelength The microstrip antenna according to claim 5, wherein a radiating portion of a single-sided short-circuit type rectangular microstrip antenna that operates in length is configured.