JPH05299929A - Antenna - Google Patents

Abstract

PURPOSE:To attain miniaturization, to extend the directivity and to attain the broad band application by providing a folded part folded along a face in crossing with a radiation electric field face of the antenna to the antenna. CONSTITUTION:The antenna comprising a dielectric body plate 2 whose thickness is thin in comparison with the operating wavelength inserted between a radiation conductor 1 and a ground conductor 3 and a feeder 9 for power supply fitted to a feeding point on the radiation conductor 1 is provided with a folded part 5 folded along a face in crossing with a radiation electric field face of the antenna. Then the size AB=CD+DE is selected to obtain a length of L=L1+L2 for the folded part 5 (folded part 5a of the radiation conductor 4) and the folded part 5a is folded along a face almost vertical in crossing with a radiation electric field face of the antenna (E plane). Thus, the reception of radio waves from plural directions is attained because of the folded structure to extend the directivity, the size is made smaller than that of a conventional microstrip antenna and the radio equipment is made also small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip type antenna suitable for use in a small radio.

[0002]

2. Description of the Related Art Conventionally, as a mobile wireless device such as a small portable wireless device or a car phone, particularly as a small antenna in the UHF band, a radiation conductor is arranged on a dielectric substrate and a dielectric facing the radiation conductor is used. A microstrip antenna in which a ground conductor is provided on the reflection surface of a body substrate is used.

FIG. 10A shows such a one-side short-circuit type microstrip antenna, and FIG. 10B shows a structure called an inverted F-type antenna.

In FIGS. 10A and 10B, 1 is a radiation conductor and 3
Is a ground conductor, and these conductors 1 and 3 are arranged so as to be sandwiched between the upper and lower surfaces of a substrate of a dielectric 2 having a large dielectric constant ε such as Teflon, and wide or wide from the end of the radiation conductor 1. A configuration in which the ground conductor 3 is short-circuited via a narrow ground conductor plate 4 so that power is supplied to the radiation conductor 1 via a power supply line, or a power supply line is connected to the ground conductor 4 to connect the radiation conductor 1 to the ground conductor 4. It is known to use a non-powered board.

Further, these inverted F-type antennas or one-side short-circuit type microstrip antennas are widely used in wireless communication systems for communication between mobile bodies. For example, among these handy type portable telephones, a detachable inverted F-shaped antenna or the like is attached to the portable telephone for the purpose of using the portable telephone even if it is separated from the car telephone. There is.

FIG. 11 shows the outline of the configuration described in the above publication.
In the following description, reference numeral 10 denotes a casing formed of synthetic resin or the like in a substantially vertically long rectangular shape. The handset 12 is attached to the upper side of the front panel 11 of the casing 10 and the transmitter 13 is attached to the lower side. ..

The inverted F-shaped antenna 6 is attached to the upper part of the back plate 15 of the casing 10 so that it can be built in the casing 10 of the portable telephone. The inverted F-shaped antenna 6 is similar to that shown in FIG. 10B. The radiation conductor 1 has a plate shape, 4 is a ground conductor plate, and 9 is a feeder line.

[0008]

At first glance, the antenna described in the above-mentioned conventional structure is configured such that the ground conductor 4 is bent from the radiation conductor 1, but this is the ground conductor 4 and is radiated. not formed by bending a conductor 1, for example, the length L should be selected to substantially lambda _0/4 of the frequency wavelength lambda ₀ of the received radio wave the radiation conductor is in the UHF band, or the like 1 radiation conductor 1 shown in FIG. 10B There is a problem that the length L becomes long and miniaturization becomes extremely difficult.

Further, as shown in FIG. 11, in a portable telephone device or the like, since the inverted F-type antenna 6 is attached to the back plate 15 of the housing 10, the back plate 15 side is placed on the desk. When placed, there is a problem that the radiation conductor 1 is completely shielded and radio waves cannot be received.

The present invention is intended to provide a microstrip type antenna which solves the above problems and which can be downsized as compared with an ordinary microstrip type antenna, has broader directional characteristics, and can have a wider band. To do.

[0011]

As shown in FIG. 1, a first antenna of the present invention has a plate-shaped dielectric 2 which is thinner than a wavelength and is sandwiched between a radiating conductor 1 and a grounding conductor 3 to form a radiating conductor. An antenna having a feeder line 9 for supplying electric power to the feeding point on 1 has a bent portion 5 which is bent along a plane intersecting with a radiation electric field plane of the antenna.

As shown in FIG. 4, the second antenna of the present invention is different from the first invention in that the thickness of the dielectric 2 between the radiation conductor 1 and the ground conductor 3 is different at the bent portion 5. Is.

The third antenna of the present invention is, as shown in FIG. 1 or 2, a ground conductor plate 4 or a plurality of ground conductor plates 4 for connecting a part of the radiation conductor 1 and the ground conductor 3 in the first or second invention. The conductor wire is provided.

As shown in FIG. 3, the fourth antenna of the present invention is the same as the first to third inventions, but is folded at a plurality of positions along a plurality of planes intersecting the radiation electric field plane. It has bent portions 5 and 14.

As shown in FIG. 1, the fifth antenna of the present invention is the same as the first to fourth inventions, except that the dielectric material sandwiched between the radiation conductor 1 and the ground conductor 3 is made of air. It will be.

A sixth antenna according to the present invention is the wireless device housing 1 according to any one of the first to fifth inventions, as shown in FIGS.
An antenna having a bent portion 5 in 0 is housed.

[0017]

According to the first to sixth antennas of the present invention, because of the bent structure, it is possible to receive radio waves from a plurality of directions, the directional characteristics are expanded, and the antenna is downsized as compared with a normal microstrip antenna. The wireless device can also be downsized. Also, when the wireless device is built in the housing, the shape of the antenna can be changed according to the shape of the housing, and the antenna whose shape can be changed according to the installation conditions can be obtained. Further, it is possible to obtain a band that can have a wider band than that of a normal microstrip and is less susceptible to the end effect.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the antenna of the present invention will be described in detail below with reference to FIGS. 10 and 11 in the figure.
Corresponding parts are designated by the same reference numerals, and redundant description will be omitted.

1A and 1B are schematic diagrams showing a one-side short-circuited microstrip antenna of the present invention for comparison with a conventional one-side short-circuited microstrip antenna. That is, FIG. 1A is a conventional side short-circuited micro-strip antenna, Figure 1B shows a side short-circuited micro-strip antenna of the present embodiment, 1 each is formed in a square shape, selecting length L to lambda _0/4 In the example shown in FIG. 1B, the length L is L ₁ +
Selected equal to L ₂ .

The resonance frequency of the length L of the radiation conductor 1 shown in FIG. 1A is determined by the length from point A to point B. That is, since the point A is short-circuited by the ground conductor plate 4, which will be described later, it has a zero potential, and the point B is an open end and resonates at the frequency of the maximum potential.

In this example, AB = CD + DE is selected so that the length is L = L ₁ + L ₂ and the bent portion 5 (radiation conductor 5
The bent portion 5a) of the
Is bent along a surface substantially perpendicular to the radiation field surface (E surface) of the antenna.

For example, when the resonance frequency is 818 MHz and the relative permittivity ε = 1 (air), the length AB = L is 92 mm.
(1/4 wavelength), and the length of L ₂ = DE is appropriately selected according to the device housing.

The ground conductor 3 and the radiation conductor 1 are short-circuited at the end A by the ground conductor plate 4 or by a plurality of conductor wires such as through holes.

Accordingly, the ground conductor 3 and the dielectric 2 are also composed of the ground conductor bent portion 5c forming the bent portion 5 and the dielectric bent portion 5b. The position of the power supply line 9 for supplying electric power to the ground conductor 3 is selected at a point where the impedance is approximately 50Ω and soldered. The impedance of 50Ω is matched with the impedance of the coaxial cable of the feeder 9.

In the configuration of FIGS. 1A and 1B, the bent portion 5
The dielectric between the radiating conductor 1 and the grounding conductor 3 of the microstrip antenna having the above structure is an air layer with ε = 1 and its thickness is h, and the radiating conductor 1 is cantilevered with respect to the grounding conductor 3 by the grounding conductor plate 4. However, it is also possible to use a dielectric material such as Teflon between the radiation conductor 1 and the ground conductor 3 so that the thickness h can be reduced.

When the dielectric 2 shown in FIG. 1B is air, the thickness h and the length L ₂ = D of the bent portion 5a of the radiation conductor 1 are set.
The resonance frequencies measured with E as a parameter are shown in Table 1 below.
Shown in.

[0027]

[Table 1]

In Table 1, L ₂ = 0 shows the result for the conventional one-side short-circuited microstrip antenna shown in FIG. 1A. In the microstrip antenna of this normal configuration, if the thickness h of the dielectric 2 is increased, the size of the apparent radiation conductor 1 at a high frequency appears longer than the actual size due to the so-called end effect, so the resonance frequency is 780 MHz.
From 774 MHz to 774 MHz, to 734 MHz and 734 MHz, the edge effect can be confirmed.

On the other hand, as in this example, the bent portion 5 is formed on the surface intersecting the E surface, and L ₂ = DE is 10 mm to
When changed to 50 mm, there are variations at L ₂ = 10 mm, but L ₂ = 3 from 768 MHz to 791 MHz.
At 0 mm, from 774 MHz to 784 MHz, the same L
_{At 2} = 50 mm, the resonance frequency tends to increase from 759 MHz to 785 MHz. Furthermore, when L ₂ = 20 mm, it is 78
In the range of 9 MHz to 782 MHz, L ₂ = 40 mm
However, the resonance frequency is 80 in the range of 80MHz to 783MHz.
The change range is 8MHz and 19 compared to 0-700MHz
It can be seen that within 2% of the resonance frequency at MHz and within the measurement error range, the end effect does not appear like L ₂ = 0.

FIGS. 2A and 2B are a perspective view and a side sectional view of a one-side short-circuit type microstrip antenna showing another embodiment of the present invention. A dielectric 2 such as Teflon or Mycarex having a large relative dielectric constant is shown. was formed in a substantially L shape in a dielectric bent portion 5b consisting of a vertical portion perpendicular to the flat portion, the width 10m in this top to the length of the dielectric 2 L ₁ + L ₂ is lambda _0/4
The L-shaped radiation conductor 1 of about m to 50 mm is fixed.

The radiation conductor bent portion 5a of the radiation conductor 1 is E
A ground conductor 3 is also provided on the lower surface of the dielectric 2 formed in an L-shape and facing the radiation conductor 1 so as to be orthogonal to the surface.
To form. This portion is composed of a flat portion and a bent portion 5c.

The end face opposite to the bent portion 5a of the radiation conductor 1 is also bent so as to be orthogonal to the E-plane and penetrates the dielectric 2 to form a ground conductor plate 4, which is short-circuited to the upper end of the ground conductor 3. There is. The grounded braided shield wire of the power supply line 9 is soldered to the ground conductor 3, the core wire is soldered to the radiation conductor 1, and the soldering position L ₃ of the core wire is adjusted to the impedance of the power supply line 9 from the position of the ground conductor plate 4. , For example, the point of 50Ω is selected. With such a configuration, the thickness of the dielectric 2 can be reduced, the band can be easily widened, and the size can be reduced.

FIGS. 3A and 3B show still another embodiment of this embodiment, in which a second bent portion 14 is formed on the opposite side to the bent portion 5 in the structure of FIG. ,
The radiation conductor 1 and the dielectric 2 as well as the ground conductor 3 are bent into a substantially U-shaped cross section, and the total length L of the radiation conductor 1 is L = L ₄ + L ₅ + L _{6 in} the side sectional view shown in FIG. 3B. the length is selected to lambda _0/4 of the wavelength lambda ₀ of the resonance frequency, the second bending portion 14 is bent portion 14a of the radiation conductor 1, a dielectric 2 of the bent portion 14b, constituted by bent portions 14c of the grounding conductor 3 The ground conductor plate 4 is bent at the bent portion 14a of the radiation conductor 1.
The connection position of the core wire of the power feed line 9 is short-circuited to the ground conductor 3 from the end of the power feed line 9 and the impedance of the power feed line 9 is matched with the impedance of the microstrip antenna. Of course, the first and second bent portions 5 and 14 are bent so as to intersect the E surface as shown in FIG. 3A.

In the above-described embodiment, the case where the side cross section is formed into a U-shaped bent portion has been described. For example, the side cross section is E.
It can be bent into an appropriate shape such as being bent in a Z shape or a step shape so as to be orthogonal to the plane. According to the above-described embodiment, a microstrip antenna having a wider directional characteristic can be obtained.

FIG. 4 shows still another embodiment of this example, and relates to improvement of the example shown in FIG. 1B. That is, the thickness h 2 of the bent portion 5b of the dielectric ₂ and the thickness h _{1 of the} flat portion are different, and for example, h ₁ <h ₂ is configured. The dielectric constant of the dielectric 2 may be different at this portion. For example, the h ₁ portion may be Teflon and the h ₂ portion may be air or the like. According to this structure, by making the dielectric h ₁ thin and making h ₂ thick, a wider band microstrip antenna can be obtained.

In the above-described microstrip antennas of the respective embodiments, the case where the grounding conductor plate 4 or the conductor wire composed of a plurality of through holes is arranged at the end of the radiation conductor 1 has been described. Of course, the grounding conductor plate 4 and the like are provided. It can also be configured with no configuration.

The construction and the method of handling the microstrip antenna constructed as described above will be explained with reference to FIGS.

5 and 6, parts corresponding to those in FIG. 11 are designated by the same reference numerals and duplicate explanations are omitted. For example, as shown in FIG. 5, the microstrip 6A described in FIGS. 2A and 2B is used.
The bent portion 5 is placed inside the top plate 17 and the back plate 15 of the housing 10, and the radiation conductor 1 is placed outside (the top plate 17 and the back plate 1).
5)).

With this structure, the radio wave received from the direction of the top plate 17 (B direction) of the housing 10 of the wireless device and the back plate 1 are received.
It also becomes possible to receive radio waves from 5 directions (C direction).

That is, even if the back plate 15 side is covered with a desk and the radio waves from the C direction are cut off, the radio waves from the A direction of the top plate 17 can be received, and the microstrip antenna 6A having the two-direction directivity can be received. You can do it. Of course, when used as a portable wireless device as shown in FIG. 6, even if a person 16 holds the housing 10 of the wireless device by hand, the receiving directions are B and C.
Since it can be matched with either direction, the directional characteristics can be expanded compared to the unidirectional directivity, and a microstrip antenna that is easy to receive can be obtained.

The microstrip antenna 6B indicated by the alternate long and short dash line in FIG. 5 is shown in FIG. 2 shows a usage state of a plurality of bent portions 5 and 14 formed, in which an antenna 6B is arranged on the inner surface of the housing 10 along the left and right side plates 18, 19 of the housing 10 and the back plate 17. It In this case, it can be seen that an antenna having three-direction directivity sensitive to radio waves from the D and E directions can be constructed in the same manner as the rear plate 15 of the housing 10 and the left and right side plates 18 and 19 in the C direction.

8 and 9 show the directional characteristics of the microstrip antenna having the structure shown in FIGS. 2A, 2B and 10A and the dielectric 2 being air. In this example, the frequency in FIG. 8 is 0.792 GHz, and the conventional frequency in FIG. 9 is 0.
It is 78 GHz, and it can be seen that the directional characteristics are obviously improved.

7A and 7B show the frequency characteristics and Smith diagram of the microstrip antenna of L ₂ = 0 mm and h = 8 mm shown in FIG. 1A.
Similarly, C and D show the frequency characteristic and Smith diagram of L ₂ = 30 mm and h = 8 mm in Table 1 of the microstrip antenna shown in FIG. 1B.

In FIGS. 7A and 7B, the matching frequency 734.
At 340003 MHz, the bandwidth is 1.8%, while in the present example shown in FIGS.
The bandwidth is 2.8% at 20002 MHz, and it can be seen that the bandwidth can be increased according to this example.

The antenna of the present invention is constructed as described above,
First, the bent portions 5 and 14 are arranged so as to be orthogonal to the E plane.
Since the directional characteristic is provided, the unidirectional characteristic can be changed to the multidirectional characteristic, and the directional characteristic can be expanded.

Further, it is possible to reduce the size of the microstrip antenna, and it is possible to obtain a microstrip antenna in which the shape of the microstrip antenna can be freely adjusted according to the bending direction.

Further, it is possible to obtain a band that can be made wider than the ordinary microstrip antenna and is less susceptible to the end effect.

[0048]

According to the present invention, a microstrip antenna having the following features can be obtained. (1) The directional characteristics are expanded due to the bent structure. (2) The size can be made smaller than that of a normal microstrip antenna. (3) It can be designed according to the actual grounding conditions. (4) It is possible to make the band wider than that of a normal microstrip antenna. (5) Less susceptible to edge effects than a normal microstrip antenna.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an antenna of the present invention.

FIG. 2 is a configuration diagram of an antenna of the present invention.

FIG. 3 is a plan view and a side sectional view showing another embodiment of the antenna of the present invention.

FIG. 4 is a side sectional view showing still another embodiment of the antenna of the present invention.

FIG. 5 is a perspective view showing a state in which the antenna of the present invention is mounted on the housing of a wireless device.

FIG. 6 is a diagram illustrating a usage state of the antenna of the present invention.

FIG. 7 is a characteristic explanatory view showing a Smith chart as well as a frequency characteristic chart of the present invention and a conventional one.

FIG. 8 is a diagram showing directional characteristics of the antenna of the present invention.

FIG. 9 is a diagram showing directional characteristics of a conventional antenna.

FIG. 10 is a perspective view of a conventional antenna.

FIG. 11 is a perspective view of a conventional portable telephone device.

[Explanation of symbols]

 1 Radiation Conductor 2 Dielectric 3 Grounding Conductor 4 Grounding Conductor 5 Back Plate 6, 6A, 6B Antenna 10 Case

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 14, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art Conventionally, as a mobile wireless device such as a small portable wireless device or a car phone, particularly as a small antenna in a frequency band of UHF or higher, a radiation conductor is arranged on a dielectric substrate and A microstrip antenna in which a ground conductor is provided on the reflecting surface of a facing dielectric substrate is used.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

In FIGS. 10A and 10B, 1 is a radiation conductor and 3
Is a ground conductor, the both conductors 1 and 3, disposed so as to sandwiched the upper and lower surfaces of the substrate dielectrics 2-out如Teflon, ground wide or narrow from the ends of the radiating conductor 1 Conductor plate 4
Made a structure in which short-circuited to the ground conductor 3 through a generally release <br/> morphism conductor 1 through the feed line was also a way to supply power to is known.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

At first glance, the antenna described in the above-mentioned conventional structure is configured such that the ground conductor 4 is bent from the radiation conductor 1, but this is the ground conductor 4 and is radiated. not formed by bending a conductor 1, for example, FIG. 10 of the radiation conductor 1 shown in a length L should be selected to substantially lambda _0/4 of the frequency wavelength lambda ₀ of the received radio wave the radiation conductor is in the UHF band, etc. There is a problem that the length L of 1 becomes long and miniaturization becomes extremely difficult.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0030

[Correction method] Change

[Correction content]

FIG. 2A, B are those showing a perspective view and a side sectional view of one side shorted microstrip antenna showing another embodiment of the present embodiment, perpendicular dielectric 2 such as Te CFC planar portion Approximately L with the dielectric bending part 5b composed of the vertical part
Formed in the shape of a letter, and the length L ₁ + L ₂ is
It is represented by the following formula, and the L-shaped radiation conductor 1 having a width of about 10 mm to 50 mm is fixed.

[Equation 1]

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

The end face of the radiation conductor 1 opposite to the bent portion 5a is also bent so as to be orthogonal to the E-plane, penetrates the conductor 2 to form the ground conductor plate 4, and is short-circuited to the upper end of the ground conductor 3. .. The grounded braided shield wire of the power supply line 9 is soldered to the ground conductor 3, the core wire is soldered to the radiation conductor 1, and the soldering position L ₃ of the core wire is adjusted to the impedance of the power supply line 9 from the position of the ground conductor plate 4. , For example, the point of 50Ω is selected. According to this structure, the dielectric
It is possible to obtain a device that is miniaturized by the ratio (approximately 1 / √ε _r times) .

[Procedure Amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

FIGS. 3A and 3B show still another embodiment of this embodiment, in which a second bent portion 14 is formed on the opposite side to the bent portion 5 in the structure of FIG. ,
The radiation conductor 1 and the dielectric 2 as well as the ground conductor 3 are bent into a substantially U-shaped cross section, and the total length L of the radiation conductor 1 is L = L ₄ + L ₅ + L _{6 in} the side sectional view shown in FIG. 3B. the length is the effective wavelength of the resonance frequency and lambda _g, selected λ _g / 4,
The second bent portion 14 is the bent portion 14 of the radiation conductor 1.
a, the bent portion 14b of the dielectric 2 and the bent portion 14c of the ground conductor 3, the ground conductor plate 4 is short-circuited from the end of the bent portion 14a of the radiating conductor 1 to the ground conductor 3 and the core wire of the feeder line 9 is connected. The connection position is selected at a position where the impedance of the feeder 9 matches the impedance of the microstrip antenna. Of course, the first and second
The bent portions 5 and 14 are bent so as to intersect the E surface as shown in FIG. 3A.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction content]

[0048]

According to the present invention, a microstrip antenna having the following features can be obtained. (1) The directional characteristics are expanded due to the bent structure. (2) The size can be made smaller than that of a normal microstrip antenna. (3) It can be designed according to the actual installation conditions. (4) It is possible to make the band wider than that of a normal microstrip antenna. (5) Less susceptible to edge effects than a normal microstrip antenna.

[Procedure Amendment 8]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 10

[Correction method] Change

[Correction content]

[Figure 10]

Claims (6)

[Claims] 1. An antenna comprising a radiation conductor and a ground conductor sandwiching a dielectric thinner than the wavelength, and a feeding line for supplying electric power to a feeding point on the radiation conductor is attached to the radiation field surface of the antenna. An antenna having a bent portion that is bent along the intersecting surface. 2. The thickness of the dielectric between the radiation conductor and the ground conductor is different at the bent portion.
The antenna described. 3. The antenna according to claim 1, further comprising a ground conductor plate or a plurality of conductor wires that connect a part of the radiation conductor and the ground conductor. 4. The antenna according to claim 1, further comprising a bent portion that is bent at a plurality of positions along a plurality of surfaces that intersect the radiation electric field surface. 5. The antenna according to claim 1, wherein a dielectric material sandwiched between the radiation conductor and the ground conductor is made of air. 6. The antenna according to claim 1, wherein an antenna having the bent portion is housed in a radio device housing.