Communications: radio wave antennas – Antennas – Microstrip
Reexamination Certificate
2003-04-01
2004-09-28
Chen, Shih-Chao (Department: 2821)
Communications: radio wave antennas
Antennas
Microstrip
C343S725000, C343S895000
Reexamination Certificate
active
06798383
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a small built-in radio communication antenna which is small and light and which has excellent gain and broadband tuning characteristics, and, more particularly, to a small low-posture antenna that is suitable for industrial production.
BACKGROUND ART
A whip antenna which resonates at &lgr;/2 is used as an antenna which sends and receives GHz (gigahertz) class radio waves.
However, when the mechanical length of a whip antenna is about 10 cm, it becomes difficult to handle. Therefore, it has often been used by making it stowable/extendable by forming it into an extendable type or a tilting-down type.
However, in a stowable/extendable type, not only is it troublesome to operate the antenna, but also the antenna may break due to collision with an external obstacle when the antenna is in an extended posture.
To overcome this problem, a built-in antenna which is made short to the order of &lgr;/4, and which does not need to be extended/stowed has been developed. This technology has been created by the present inventor, and an application thereof is separately being filed by the present applicant (Japanese Patent Application No. 2000-237629). (This application will hereunder be referred to as “earlier application which is not yet publicly known.”)
FIG. 9
is a schematic view which is drawn as
FIG. 1
in the earlier application which is not yet publicly known.
A plate-shaped antenna
1
having an overall length of &lgr;/4 is bent into an L shape, with an end
1
a
at a short side of the antenna
1
being mounted to and supported by a bottom plate
2
.
On the other hand, an input end
3
b
of a &lgr;/4 antenna exciter
3
is connected to an output end of a high-frequency circuit
4
, and an open end
3
a
thereof opposes and is spaced from an open end
1
c
of the plate-shaped antenna
1
in order to provide an electrostatic coupling capacity c.
The antenna of the earlier application that is not yet publicly known, shown in
FIG. 9
, has an overall electrical length of &lgr;/4, and its mechanical length can be decreased to less than &lgr;/4. When this antenna is used as a built-in antenna, extending and contracting operations do not need to be carried out, so that this antenna is very convenient to use, and will not break when it collides with an external obstacle. In addition, since the antenna has wideband tuning characteristics and high gain, the antenna provides excellent characteristics.
After filing the application of the above-described invention that is not yet publicly known, the present inventor has promoted experiments and research for practical application. It has been confirmed that, even under practical conditions, the antenna provides the desired advantages. On the other hand, it has been found and confirmed that there is still room for improvement.
This room for improvement will be described below. In order for the antenna device to operate with good characteristics, it is necessary for the electrostatic coupling capacity c to be an appropriate value that realizes a critical coupling state, and for the parallelism and the interval between a long side of the plate-shaped antenna
1
, formed into an L shape, and the bottom plate
2
to be proper values.
Under laboratory use conditions, the aforementioned requirements do not give rise to particular problems, but, when such antennas (
FIG. 8
) are industrially produced in large quantities, it is difficult to maintain uniformity in the qualities of many products (more specifically, the uniformity in the characteristics of the antennas).
This is because it is not easy to restrict with high precision the positions and the postures of such plate-shape antennas
1
. which are bent into an L shape by punching out a metal plate into strips, when their short-side ends are mounted to the bottom plate
2
.
Further, it is not easy to position with high precision the antenna exciter
3
with respect to the plate-shaped antenna
1
.
The present invention has been achieved in view of the above-described problems, and has as its object the provision of a technology which, by improving the antenna of the earlier application which is not yet publicly known, is made suitable for maintaining uniformity in qualities in industrial production and makes it possible to further reduce the height (interval between a plate-shaped antenna and a bottom plate), without impairing characteristic features, such as smallness, not requiring extending and contracting operations, and high performance (particularly, wideband tuning characteristics).
DISCLOSURE OF INVENTION
A structure of a method of an invention of claim
1
created to achieve the aforementioned end is that of a method for forming an antenna which is tuned near a wavelength &lgr;, wherein an antenna pattern which resonates at &lgr;/4 is formed on a surface of a substrate, wherein the substrate is made to oppose and is supported with respect to a planar portion of a metallic frame, wherein a helical coil which resonates at &lgr;/4 is supported by the metallic frame, wherein one end of the antenna pattern is connected to and is brought into electrical conduction with the metallic frame, and wherein one end of the helical coil and one end of the antenna pattern are made to oppose each other in order to provide capacitance and the other end of the helical coil is connected to an output end of a high-frequency circuit in order to make the helical coil act as an antenna exciter.
In addition to including the structural requirement of the invention of claim
1
. a structure of a method of an invention of claim
2
includes a structural requirement in which, in means for connecting and bringing into electrical conduction the helical coil and the output end of the high-frequency circuit, a core wire of a coaxial cable is connected to and brought into electrical conduction with one end of the helical coil, and an external conductor is connected to and brought into electrical conduction with the metallic frame, and wherein the other end of the core wire of the coaxial cable is connected to the output end of the high-frequency circuit, and the external conductor is connected to a bottom plate of the high-frequency circuit.
A structure of a method of an invention of claim
3
is that of a method for forming an antenna which is tuned near a wavelength &lgr;, wherein an antenna pattern which resonates at &lgr;/4 is formed at one end of a surface of a substrate, wherein an exciter pattern which resonates at &lgr;/4 is formed near the other end of the substrate, wherein the antenna pattern and the exciter pattern are made to oppose each other and to be spaced from each other in order to provide capacitance therebetween, wherein the substrate is supported by a metallic frame having a planar portion that opposes the substrate, and wherein one end of the exciter pattern is connected to an output end of a high-frequency circuit.
In addition to including the structural requirement of the invention of claim
3
, a structure of a method of an invention of claim
4
includes a structural requirement in which, in means for connecting and bringing into electrical conduction the exciter pattern and the high-frequency circuit, a core wire of a coaxial cable is connected to and brought into electrical conduction with one end of the &lgr;/4 exciter pattern and an external conductor is connected to and brought into electrical conduction with the metallic frame. and wherein the other end of the core wire of the coaxial cable is connected to the output end of the high-frequency circuit and the external conductor is connected to a bottom plate of the high-frequency circuit.
In addition to including the structural requirement of either claim
1
or claim
3
, a structure of a method of an invention of claim
5
includes a structural requirement in which the antenna pattern generally has a strip shape and has a rectangular or zigzag portion formed on the substrate, and in which the substrate is supported by the metallic frame, and a portion near the zigzag portion is connected to a
Ebine Nobuhito
Hirabayashi Katsuki
Hirahaya Kuniaki
Kojima Koutarou
Nakase Kazuhiko
Chen Shih-Chao
Frommer William S.
Frommer & Lawrence & Haug LLP
Sony Corporation
LandOfFree
Low profile small antenna and constructing method therefor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low profile small antenna and constructing method therefor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low profile small antenna and constructing method therefor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3257744