Communications: radio wave antennas – Antennas – Spiral or helical type
Reexamination Certificate
2000-06-14
2001-08-28
Phan, Tho (Department: 2821)
Communications: radio wave antennas
Antennas
Spiral or helical type
C343S860000
Reexamination Certificate
active
06281859
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to wireless radio equipment. More particularly, though not exclusively, the present invention relates to a method and apparatus for providing improved quadrifilar helix antennas.
2. Problems in the Art
Some antennas, such as satellite antennas, require circular polarization because the orientation of the user with respect to the satellite is not usually predetermined. Circular polarization is typically independent of orientation. Few antennas are suitable for circular polarization, especially for use with handheld wireless equipment. Three types of prior art circularly polarized antennas include turnstile antennas, patch antennas, and axial mode helical antennas. The turnstile and patch antennas are riot suitable for use with handheld equipment because the antennas are larger than desired. Axial mode helical antennas are not suitable for use with handheld equipment because of the excessive diameter of the antenna.
The most desirable type of circularly polarized antenna is a quadrifilar helix antenna. To meet beam width and size requirements for personal satellite communications, quadrifilars are made with ½ turn, ¼ wave elements. Hybrid power dividers are required to establish the phase between elements of the quadrifilar helix antenna. However, hybrid power dividers require more space than is desirable. Therefore, there is need for a quadrifilar helix antenna which does not require hybrid power dividers.
FEATURES OF THE INVENTION
A general feature of the present invention is the provision of a method and apparatus for providing an improved quadrifilar helix antenna which overcomes problems found in the prior art.
A further feature of the present invention is the provision of a method and apparatus for providing an improved quadrifilar helix antenna requiring no hybrid power dividers.
Further features, objects, and advantages of the present invention include:
A method and apparatus for providing an improved quadrifilar helix antenna which includes a planar transmission line ¼ wave impedance transformer as a matching circuit.
A method and apparatus for providing an improved quadrifilar helix antenna which includes a pi-network impedance transformer as a matching circuit.
A method and apparatus for providing an improved antenna having dual quadrifilar helix antennas and a bandpass filter for isolation.
A method and apparatus for providing an improved antenna having dual quadrifilar helix antennas and pi-network impedance transformers for isolation.
A method and apparatus for providing an improved quadrifilar helix antenna including parallel resonant circuits in series with each helical element.
These as well as other features, objects and advantages of the present invention will become apparent from the following specification and claims.
SUMMARY OF THE INVENTION
A quadrifilar helix antenna for a wireless device is used with a wireless device to transmit or receive signals. The invention is comprised of a plurality of helical antenna elements and an impedance transformer electrically connected to the antenna elements and connectable to the wireless device. The impedance transformer may optionally be comprising of a planar transmission line ¼ wave impedance transformer or a pi-network impedance transformer. The antenna may also be comprised of dual band quadrifilar helix antenna for transmitting or receiving two different frequency bands.
REFERENCES:
patent: 4799066 (1989-01-01), Deacon
patent: 5255005 (1993-10-01), Terret et al.
patent: 5346300 (1994-09-01), Yamamoto et al.
patent: 5349365 (1994-09-01), Ow et al.
patent: 5541617 (1996-07-01), Connolly et al.
patent: 5635945 (1997-06-01), McConnell et al.
patent: 6150994 (2000-11-01), Winter et al.
Sullivan Jon L.
Winter James Blake
Centurion Wireless Technologies, Inc.
Phan Tho
Thomte Dennis L.
Zarley McKee Thomte Voorhees & Sease
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