Communications: radio wave antennas – Antennas – Spiral or helical type
Reexamination Certificate
2000-07-27
2002-07-16
Wong, Don (Department: 2821)
Communications: radio wave antennas
Antennas
Spiral or helical type
C343S7000MS, C343S853000, C343S702000
Reexamination Certificate
active
06421029
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a helical antenna in which radiation elements are provided in helical form on the surface of a cylindrical member composed of a dielectric, and to a method of manufacturing this helical antenna.
2. Description of the Related Art
Helical antennas are used as the antennas for portable terminals in portable telephone systems that employ-non-geostationary satellites.
FIG. 1
is a perspective view of an example of this type of helical antenna of the prior art.
Referring to
FIG. 1
, helical antenna
102
of the prior art is shown that includes element
100
, feeder circuit
200
, and connection pins
310
. Element
100
is formed by winding flexible print circuit board
120
in the form of parallel quadrilaterals around dielectric pipe
110
. Flexible print circuit board
120
is secured to dielectric pipe
110
by an adhesive or a double sided tape.
Feeder circuit
200
is formed from circuit board
104
(also referred to as a “dielectric board”) made up from a disk-shaped dielectric having a larger diameter than dielectric pipe
110
. Microstrip lines (not shown in the figure) are formed and a chip-type 4-distributor, resistor, and capacitor are mounted on one surface of dielectric board
104
, these components having the function of a 4-distributor/combiner circuit. A ground conductor is formed on the other surface of dielectric board
104
. Since this type of feeder circuit is well known in the art, and functionally, is not an element that is closely connected to the present invention, a detailed explanation of these components is omitted.
FIG. 2
is a sectional view showing the connection points between element
100
and feeder circuit
200
in helical antenna
102
shown in FIG.
1
. In the figure, components identical to those shown in
FIG. 1
bear the same reference numerals.
As shown in
FIG. 2
, a plurality of connection pins
310
are arranged at the edge of element
110
. Each of connection pins
310
passes through a through-hole formed in dielectric board
104
of feeder circuit
200
. One end of connection pins
310
is soldered to element
100
and the other is soldered to feeder circuit
200
.
In the configuration of helical antenna
102
of the prior art, element
100
and dielectric board
104
are connected by inserting connection pins
310
through dielectric board
104
, and the outside diameter of feeder circuit
200
is therefore greater than the outside diameter of dielectric pipe
110
. This factor is not advantageous for reducing the outside diameter of helical antenna
102
.
An antenna that is incorporated into a portable telephone is preferably as compact as possible, and, for example, a helical antenna of the following construction has been proposed to eliminate the above-described drawback.
FIG. 3
is a perspective view showing another example of a helical antenna of the prior art. In the figure, constituent elements identical to those of
FIG. 1
bear the same reference numerals.
Helical antenna
106
shown in
FIG. 3
includes element
100
A, feeder circuit
200
A, and connection pins
310
. Element
100
A is formed by winding flexible print circuit board
120
A, which is shaped as a parallel quadrilateral, around dielectric pipe
110
A. The outside diameter of feeder circuit
200
A is somewhat larger than the outside diameter of element
100
. The electrical configuration of feeder circuit
200
A is the same as that of feeder circuit
200
shown in FIG.
1
.
FIG. 4
is a sectional view showing in detail the connection points between element
100
A and feeder circuit
200
A in the helical antenna
106
shown in FIG.
3
. In the figure, constituent elements that are the same as those shown in
FIG. 3
bear the same reference numerals.
The walls of dielectric pipe
110
A are thicker on the side of feeder circuit
200
A than in other portions of dielectric pipe
110
A. and holes for inserting connection pins
310
are formed in this thicker portion of dielectric pipe
110
A. Flexible print circuit board
120
A is wound around dielectric pipe
110
A such that its lower end-bends inwards at the lower end of dielectric pipe
110
A. Flexible print circuit board
120
A is secured to dielectric pipe
110
A by means of an adhesive or a double sided tape.
The upper ends of connection pins
310
are inserted into the above-described holes in dielectric pipe
110
A, and the lower ends are inserted into through-holes formed in dielectric board
104
of feeder circuit
200
A. Connection pins
310
are then connected to feeder circuit
200
A by soldering at these through-holes. The upper ends of connection pins
310
, on the other hand, are soldered to the end of flexible print circuit board
120
A that is bent inside dielectric pipe
110
A.
This helical antenna
106
allows each of connection pins
310
to be provided at points closer to the center of dielectric board
104
than in helical antenna
102
shown in
FIG. 1
, and the outside diameter of feeder circuit
200
A can therefore be made smaller than that of feeder circuit
200
shown in FIG.
1
.
Nevertheless, this helical antenna
106
has the drawback that the process of winding flexible print circuit board
120
A around dielectric pipe
110
A is complicated by the necessity of bending the lower end of flexible print circuit board
120
A inside the lower end of dielectric pipe
110
A. A further drawback is the increased number of fabrication steps required for forming holes in dielectric pipe
110
A for inserting connection pins
310
.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a helical antenna that is compact and that can be assembled reliably in a short time, as well as a method of fabricating the helical antenna.
To achieve the above-described objects, the helical antenna according to the present invention comprises a plurality of radiation elements provided in helical form that are spaced at intervals from each other on the outer surface of a cylindrical member that is composed of a dielectric, a circuit board on which is mounted a feeder circuit for supplying high-frequency energy to the radiation elements, and a connector for electrically connecting the radiation elements and the circuit board. The circuit board is arranged below the cylindrical member, and the connector is arranged between the lower end of the cylindrical member and the circuit board. The connector is composed of an insulating material and is provided as a solid unit with a plurality of connection pins that electrically connect the end of each radiation element with the circuit board.
According to a preferable embodiment of the present invention, the connector includes a connector body, and the plurality of connection pins are provided on the connector body. The connector body includes a lower portion that is formed with an outside diameter that is substantially equal to the outside diameter of the cylindrical member and an upper portion that is formed with an outside diameter that allows insertion inside the cylindrical member with substantially no gap. The lower ends of the connection pins protrude downward from the lower surface of the lower portion of the connector body. The upper ends of the connection pins protrude upward from the lower portion of connector body with a gap between the connection pins and the outer surface of the upper portion of the connector body. The connector body is then joined to the cylindrical member by inserting the upper portion of the connector body into the lower end of the cylindrical member and interposing the lower end of the cylindrical member between the outer surface of the upper portion of the connector body and the upper ends of the connection pins. The upper ends of the connection pins are thus electrically connected to the ends of the radiation elements, and moreover, the lower ends of the connection pins are electrically connected to the circuit board.
In the fabrication method of the helical antenna according to the present invention, a cylindrical member, a circui
Chen Shih-Chao
NEC Corporation
Sughrue & Mion, PLLC
Wong Don
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