Communications: radio wave antennas – Antennas – Spiral or helical type
Reexamination Certificate
2001-05-09
2002-05-28
Wong, Don (Department: 2821)
Communications: radio wave antennas
Antennas
Spiral or helical type
C343S760000
Reexamination Certificate
active
06396460
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to chip antennas, and more particularly, to a broadband chip antenna for use in wireless communication networks and equipment, including short-distance wireless communication and personal mobile communication networks and equipment.
2. Description of the Related Art
When developing and designing wireless mobile communication devices, due to the constraint on size, monopole antennas
10
with a quarter wavelength, as shown in
FIG. 1
, are generally incorporated in device as basic units. However, the developing direction is moving slowly toward devices that are lighter, thinner, shorter, and smaller.
The concept of using a special winding shape to shorten the length of a wire antenna is first developed in 1984. For instance, a winding antenna of a zigzagging or meandering shape is disclosed by H. Nakano, H. Tagami, A. Yoshizawa, and J. Yamauchi in an article entitled “Shortening Ratios of Modified Dipole Antenna”, which is published in
IEEE Trans. Antennas Propagat
., AP-32, pp. 385-386. In 1996, a winding antenna of a bow-tie shape, which further shortens the antenna length, is disclosed in “IEEE AP-S International Symposium”, pp. 1566-1569 by M. Ali and S. S. Stuchly.
FIG. 2
shows a conventional chip antenna
20
of a meandering type (European patent 0 764 999 A1). The chip antenna
20
has a substrate
22
of a dielectric and/or magnetic material. A metal conductor
24
is disposed in or on the outer surface of the substrate as a meandering line, or a zigzagging line (not shown). One end of the metal conductor
24
is used as a feeding point
26
, which is connected to the feeding pad
28
. By utilizing the intrinsic characteristic, length, and number of turns or curves of the metal conductor, the general design principle regarding self-matching functions can be achieved so that the antenna can have proper resonance and radiation. However, one drawback of this type of chip antenna is that it has limited range on reduction of size.
As shown in
FIG. 3
, another type of conventional chip antenna
30
(U.S. Pat. No. 5,764,198) uses a spirally wounding conductor
32
and a capacitor
34
connected in parallel to achieve the matching function for the antenna. Although the chip antenna of this type is of a reduced size, its bandwidth is limited.
SUMMARY OF THE INVENTION
Due to the difficulty in bandwidth expansion for the above-discussed chip antenna, it is a primary object of the present invention to provide a chip antenna having a substrate, feeding pad, feeding conductor, matching unit, and meandering conductor to effectively expand bandwidth and reduce size.
The above and other objects, which will become apparent in reading the specification below, are realized by a chip antenna that has a substrate of a dielectric material and one or more layers, and a feeding pad formed on an outer surface of the substrate for signal injection. In particular, a meandering conductor is disposed on at least one layer of the substrate for use as a radiator unit. A conductor is disposed on a substrate layer for use as a feeding conductor for the antenna, and for propagating signals when connected to a signal source. A matching unit disposed on the layers of substrate includes a matching conductor and a ground in which the matching conductor is shielded by at least one plate of the ground. In particular, portions of the matching conductor are respectively connected to the meandering conductor, ground, and feeding conductor.
Other objects and the features will be apparent from the following detailed description of the invention with reference to the appended drawings.
REFERENCES:
patent: 5870065 (1999-02-01), Kanba et al.
patent: 6028554 (2000-02-01), Mandai et al.
patent: 6281848 (2001-08-01), Nagumo et al.
Chen Jian-Hong
Sheen Jyh-Wen
Tseng Wen-Jen
Clinger James
Intellectual Property Solutions, P.L.L.C.
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