JPH0897626A - Planar antenna - Google Patents

Abstract

PURPOSE: To provide an antenna with a thin profile suitable for a radio LAN or the like by connecting a feeding conductor to an impedance matching point of a 2nd radiation electrode interconnecting an earth electrode and a center of a 1st radiation electrode of a dielectric board. CONSTITUTION: A 1st radiation electrode 11 and an earth electrode 12 are short- circuited by a conductor 14 formed on a wall face having a throughhole 13 made to a dielectric board 10. The conductor 14 is formed not the entire wall face but a slit is formed in a direction in which the throughhole 13 is extended to allow a dielectric body 10 to be exposed partially. Then a metallic piece 15 having a guard 16 at its tip is inserted into the throughhole 13 and the) piece 15 receives feeding. An impedance matching point with 50ohms is in press contact with the guard 16, fixed by a solder or an adhesives or the like and connected to an inner conductor of a coaxial cable while being insulated from the earth electrode 12. Then the earth conductor 12 is connected to an outer conductor of the coaxial cable to form a feeding coaxial line. The antenna with thin profile has an omnidirectivity with respect to a vertically polarized wave and is suitable for a radio LAN or the like in which the degree of freedom in the mount method and the position is high.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a wireless LAN, VICS
The present invention relates to a thin planar antenna that can be used in the 2.5 GHz band, which is suitable for such purposes.

[0002]

2. Description of the Related Art As a kind of communication means, a wireless LAN or V
Commercialization of ICS is underway. These are wireless communications using frequencies in the 2.5 GHz band and use an antenna to transmit information. A whip antenna, which is a monopole antenna, is generally used as an antenna in this frequency band. This is because omnidirectionality can be obtained in the horizontal plane for vertically polarized waves.

This whip antenna is composed of a conductor rod extending vertically and a ground plane, and has a large size, and there are restrictions on a mounting method, a position and the like.

If a conductor plane is formed horizontally from the tip of the conductor rod of this whip antenna, the overall size can be shortened. And again, the horizontal plane and ground (earth)
Even if the plane is short-circuited, it similarly functions as an antenna.
However, in this case, since there is a matching point of 50 ohms in the middle of the short-circuited conductor, it is necessary to feed this point.

[0005]

If a dielectric is interposed between the upper and lower conductor planes of the antenna having the above structure, the vertical dimension can be further reduced. However, in this case, conductor films are formed on the upper and lower surfaces of the dielectric substrate and short-circuited by the conductor filling or inserting into the through holes formed in the dielectric substrate, and the impedance matching point is used as a power supply conductor. Need to be connected.

The present invention provides a thin planar antenna having omnidirectionality in the horizontal plane with respect to vertical polarization, and is easy to assemble and can be manufactured with a small number of parts. A planar antenna is provided.

[0007]

According to the present invention, the conductor in the through hole of the planar antenna thinned by filling the dielectric between the two conductor planes is used to branch from the impedance matching point. To solve the problem of.

That is, the first radiating electrode made of a metal film is formed on the front surface of the dielectric substrate, the ground electrode is made of a metal film on the rear surface of the dielectric substrate, and the wall surface of the through hole formed in the dielectric substrate is penetrated. A second radiating electrode made of a conductive material that connects the central portion of the first radiating electrode and the ground electrode, having a slit in which the dielectric is exposed in the direction in which the hole extends, is provided at the impedance matching point of the second radiating electrode. It is characterized in that a power feeding conductor is connected.

Further, the first radiation electrode made of a metal film is formed on the front surface of the dielectric substrate, the ground electrode made of a metal film is formed on the back surface of the dielectric substrate, and the through electrode is inserted into a through hole formed in the dielectric substrate. The second radiation electrode is provided with a second radiation electrode made of a conductive material that connects the central portion of the first radiation electrode and the ground electrode with a metal plate having a slit formed in the extending direction and in contact with the wall surface of the through hole. It is characterized in that a power feeding conductor is connected to the impedance matching point of the electrode.

[0010]

The conductor branched from the impedance matching point is insulated from the ground electrode and connected to the inner conductor of the coaxial cable, and the ground conductor is connected to the outer conductor of the coaxial cable to supply power. Alternatively, it is connected to the stripline conductor of the wiring board. The resonance frequency (wavelength) is determined by the length of the first power supply electrode extending in the horizontal direction, the length of the conductor that short-circuits the two planes, and the dielectric constant of the dielectric substrate.

Further, since the slit is formed on the wall surface of the through hole, the dielectric is exposed at that portion, and the change of the voltage generated in the dielectric can be taken out by the power feeding conductor.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front sectional view and FIG. 1B is a plan view showing an embodiment of the present invention. A first radiation electrode 11 extending horizontally is formed on the surface of a dielectric substrate 10 made of ceramic or the like, and a ground electrode 12 is formed on the back surface of the dielectric substrate 10 by a method such as printing. The ground electrode 12 is formed on almost the entire back surface of the dielectric substrate 10, but the first radiation electrode 11 on the front surface is formed.
The size of is determined by the frequency used, the dielectric constant and the thickness of the dielectric substrate 10.

The planar shape of the dielectric substrate may be circular or rectangular, and the first radiation electrode may be circular or rectangular. Also, a combination of these may be used.

In the planar antenna according to the present invention, the first radiation electrode 11 and the ground electrode 12 are short-circuited by the conductor 14 formed on the wall surface of the through hole 13 formed in the dielectric substrate 10. The conductor 14 is not formed on the entire wall surface of the through hole 13, but a slit is formed in the extending direction of the through hole so that the dielectric is partially exposed. And this through hole 13
A metal piece (15) having a flange (16) at the tip is inserted into and power is supplied. The flange portion 16 is brought into contact at an impedance matching point of 50 ohms, and usually fixed by solder, adhesive or the like. Then, it is insulated from the ground electrode 12 and is connected to the inner conductor of the coaxial cable (not shown). The ground electrode is connected to the outer conductor of the coaxial cable to form a coaxial line for power supply.

FIG. 2 is a perspective view showing another embodiment of the present invention. The dielectric substrate 20, the first radiation electrode 21, and the ground electrode (not shown) 22 are constructed in the same manner as in the embodiment of FIG. 1, but the conductor film is not formed on the wall surface of the through hole 23. A conductor plate 24 having slits is inserted into the through hole 23 in the vertical direction, that is, in the direction in which the through hole 23 extends. The conductor plate 24 is dimensioned to abut the wall surface of the through hole 23, and the upper end is connected to the first radiation electrode 21 and the lower end is connected to the ground electrode by soldering or the like. It is the same that a conductor piece similar to the above is inserted into the through hole and brought into contact with the metal plate at the impedance matching point. Similar to the above example, they are connected and fixed by soldering or the like, and are connected to the coaxial cable.

Incidentally, the conductor piece which is brought into contact with the conductor on the wall surface of the through hole may be movable. Positioning is performed at the same time as fixing to the substrate while adjusting it when mounting on the substrate.
Further, instead of the coaxial cable, it is also possible to connect to the receiving circuit / transmitting circuit using a strip line which is a wiring pattern of a substrate on which a dielectric substrate which is an antenna element is mounted.

FIG. 3 is a front sectional view showing an example in which an antenna element is mounted on a wiring board. The first radiation electrode 31 and the ground electrode 32 are short-circuited via the conductor 34, and the ground electrode 32 is conductively connected to the conductor pattern 38 of the wiring board 37. Also, 50
A conductor that contacts conductor 34 at the ohmic impedance matching point
35 is drawn out to the back surface of the wiring board 27 through the through hole of the dielectric substrate 30 and the through hole of the wiring board 37, and is connected to the conductor pattern 39. The conductor pattern 39 is connected to the inner conductor of the coaxial cable, and the conductor pattern 38 is connected to the outer conductor of the coaxial cable.

[0019]

According to the present invention, a thin planar antenna having omnidirectionality with respect to vertically polarized waves can be obtained, and an antenna having a high degree of freedom in mounting method, position, etc. can be used as a wireless LAN or V.
It can be used in ICS and the like.

Further, the electrodes of the dielectric substrate can be formed by the printing technique and the assembly can be performed by inserting only one pin.
A planar antenna that is easy to manufacture and inexpensive can be obtained.

Furthermore, by adjusting the position of the inserted pin that contacts the conductor, it becomes easy to manufacture a planar antenna used at different frequencies, and it becomes easy to deal with variations in the characteristics of the elements.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing another embodiment of the present invention.

FIG. 3 is a front sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 10, 20, 30: Dielectric substrate 11, 21, 31: First radiation electrode 12, 32: Earth electrode 14, 24, 34: (short circuit) conductor 15, 35: (feed) conductor

[Procedure amendment]

[Submission date] November 10, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

FIG. 3 is a front sectional view showing an example in which an antenna element is mounted on a wiring board. The first radiation electrode 31 and the ground electrode 32 are short-circuited via the conductor 34, and the ground electrode 32 is conductively connected to the conductor pattern 38 of the wiring board 37. Also, 50
A conductor that contacts conductor 34 at the ohmic impedance matching point
35 is drawn out to the back surface of the wiring board 37 through the through hole of the dielectric substrate 30 and the through hole of the wiring board 37, and is connected to the conductor pattern 39. The conductor pattern 39 is connected to the inner conductor of the coaxial cable, and the conductor pattern 38 is connected to the outer conductor of the coaxial cable.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1A is a front sectional view showing an embodiment of the present invention ,
(B) is a plan view

FIG. 2 is a perspective view showing another embodiment of the present invention.

FIG. 3 is a front sectional view showing another embodiment of the present invention.

[Description of Reference Numerals] 10, 20, 30: dielectric substrate 11, 21, 31: first radiation electrode 12 and 32: Ground electrode 14, 24, 34 :( short) conductors 15 and 35 :( feed) conductor

Claims (5)

[Claims] 1. A first radiation electrode made of a metal film on the front surface of a dielectric substrate, a ground electrode made of a metal film on the back surface of the dielectric substrate, and a through hole formed on the wall surface of a through hole formed in the dielectric substrate. A second radiating electrode made of a conductive material that connects the central portion of the first radiating electrode and the ground electrode, having a slit in which the dielectric is exposed in the direction in which the hole extends, is provided at the impedance matching point of the second radiating electrode. A planar antenna with a power supply conductor connected. 2. A first radiation electrode made of a metal film on the front surface of the dielectric substrate, a ground electrode made of a metal film on the back surface of the dielectric substrate, and inserted into a through hole formed in the dielectric substrate,
A second radiation electrode made of a conductive material for connecting the central portion of the first radiation electrode and the ground electrode with a metal plate having a slit formed in the direction of extension of the through hole and contacting the wall surface of the through hole; A planar antenna in which a feeding conductor is connected to the impedance matching point of the radiation electrode of 2. 3. The planar antenna according to claim 1 or 2, wherein the feeding conductor has a brim portion that abuts against the conductor on the wall surface of the through hole at the tip of the conductor piece. 4. The plane antenna according to claim 1, wherein the feeding conductor is movable while being in contact with the wall surface of the through hole. 5. A dielectric substrate is mounted on a wiring substrate so as to be in contact with the ground electrode side, the ground conductor is connected to a conductor pattern on the surface in contact therewith, and the power supply conductor is another conductor pattern on the same substrate. The planar antenna according to claim 1 or 2, which is connected to the flat antenna.