Communications: radio wave antennas – Antennas – Slot type
Reexamination Certificate
2001-05-02
2002-08-06
Wimer, Michael C. (Department: 2821)
Communications: radio wave antennas
Antennas
Slot type
C343S770000
Reexamination Certificate
active
06429824
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to notch antennas and, more specifically, to a notch antenna suitable for circularly polarized signals.
BACKGROUND OF THE INVENTION
Antennas for line-of-sight (LOS) communications applications, typically in the UHF or L-band frequency bands, often have differing gain, polarization and field of view (FOV) requirements. Applications such as satellite communications (SATCOM) also impose stringent limitations on antenna size, volume and weight. Ideally, antennas for these types of applications should have reasonable gain at the horizon while still providing good coverage throughout the remainder of the hemisphere.
Typical antennas of the prior art suitable for use in these applications generally require large cavities having absorbers behind the radiating elements and suffer from low gain because of a 3 dB signal loss to the cavity. Applications benefiting from better antennas (i.e., higher gain, smaller, lighter, etc.) include SATCOM, GPS, Joint Tactical Information Distribution System (JTIDS), cellular phone, Tactical Air Navigation (TACAN), IFF transponder and digital Personal Communications Systems (PCS). Further complicating matters is the fact that several of these systems are frequently co-located on vehicles and particularly airplanes, which further drives the need for aperture and volumetric efficiency. Also, circular polarization is generally required for SATCOM and GPS applications, and polarization purity is critical for communication applications utilizing frequency reuse by means of polarization diversity.
It is, therefore, an object of the invention to provide an antenna which is capable of both linear and circular polarization.
It is an additional object of the invention to provide such an antenna having high polarization purity for circularly polarized signals.
It is another object of the invention to provide a modified notch antenna capable of performing these objectives.
It is still another object of the invention to provide a modified notch antenna which is nestable within itself at a smaller size for simultaneously accessing a higher frequency band using the same aperture and volume.
SUMMARY OF THE INVENTION
The present invention features both a low profile, broadband antenna as well as a notch antenna with a unique signal feed. The broadband antenna includes an active conductive edge having a shape which approximates a quadratic curve. Two identical elements may be used in an opposed manner to form signals across their respective active edges, and two pairs of opposed identical elements may be used in quadrature for handling circularly polarized signals with a high degree of polarization purity. The quadratic curvature of the elements can provide sufficient space to co-locate a second, smaller antenna within the same volume and aperture as the larger antenna.
In another form, a notch antenna includes a slot formed between the active conductive element and ground, which slot is used for coupling signals through the antenna. This arrangement can be used in quadrature to provide circularly polarized signals with high polarization purity.
REFERENCES:
patent: 4723305 (1988-02-01), Phillips et al.
patent: 4804965 (1989-02-01), Roederer
patent: 4809009 (1989-02-01), Grimes et al.
patent: 5185611 (1993-02-01), Bitter, Jr.
patent: 5325105 (1994-06-01), Cermignani et al.
patent: 5786792 (1998-07-01), Bellus et al.
patent: 5898409 (1999-04-01), Holzman
patent: 5952982 (1999-09-01), Jorgenson et al.
patent: 5959591 (1999-09-01), Aurand
patent: 6025812 (2000-02-01), Gabriel et al.
patent: H1877 (2000-10-01), Van Etten et al.
patent: H1913 (2000-11-01), Vanetten et al.
LaRochelle Donald G.
O'Brien Michael J.
Asmus Scott J.
BAE Systems Information and Electronic Systems Integration Inc.
Maine Vernon C.
Maine & Asmus
Wimer Michael C.
LandOfFree
Low profile, broadband, dual mode, modified notch antenna 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, broadband, dual mode, modified notch antenna, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low profile, broadband, dual mode, modified notch antenna will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2905974