Radio Frequency Systems, Inc.

Charles M Powell

George D Yarsunas

Ronald Andrew Marino

Warren Frederick Hunt

Dirk Hartung

This invention relates to a tapered slot antenna with broadband characteristics whose beamwidth is stable over both the PCS (1850-1990 MHz) and the cellular bands (824-894 MHz). In a first preferred embodiment, a dual band antenna is disclosed which uses a single column elliptically shaped Vivaldi notches as the radiating elements. In a second preferred embodiment, a dual band antenna comprising elliptically shaped Vivaldi notches and sub-reflector positioned between a main reflector and the dipoles is disclosed. This resultant antenna produces a stable, ninety-degree beamwidth with a bandwidth broad enough to cover the PCS and the cellular bands.

Dual band antenna using a single column of elliptical vivaldi notches

A space-tapered antenna has a collinear array of radiating elements coupled via a cable feeding system to a Butler matrix feed system. Either the collinear array has compressed rows spaced in a range of &frac38; to &frac14; &lgr;, where &lgr; is the operating wavelength of the antenna, the cable feeding system is a phase progression cable feeding system, or both. One 120&deg; space-tapered antenna has eight compressed rows spaced at &frac38; &lgr; for providing six 20&deg; degree beams with &minus;10 dB side lobe suppression. Another 120&deg; space-tapered antenna has eight compressed rows spaced at &frac14; wavelength for providing four 30&deg; beams with &minus;15 dB side lobe suppression. A 60&deg; space-tapered antenna has eight compressed rows spaced at &frac38; &lgr; in combination with a 22 &frac12;&deg; phase progression cable feeding system for providing three 20&deg; beams with &minus;14 dB side lobe suppression. One 90&deg; space-tapered antenna has eight compressed rows spaced at &frac14; &lgr; in combination with a 22 &frac12;&deg; phase progression cable feeding system for providing three 30&deg; beams with &minus;17 dB side lobe suppression. Another 90&deg; space-tapered antenna has four rows spaced at &frac12; &lgr; and a 45&deg; phase progression cabling feeding system for providing three 30&deg; beams with &minus;12 dB side lobe suppression.

Space tapered antenna having compressed spacing or feed network phase progression, or both

An improved log periodic dipole antenna, adapted for use in a cellular telephone system, has a plurality of radiating elements with differing lengths. The sequence of lengths selected results in a horizontal beam width of about 65 degrees and a front-to-back signal strength ratio exceeding 45 dB. This combination of characteristics reduces interference among adjacent cellular telephone transmitter sites, and reduces waste of transmission energy from the back of the antenna. A preferred sequence of radiating element lengths is long-short-long-short-long, which may be described as a &ldquo;double stacked hourglass&rdquo; configuration.

Double-stacked hourglass log periodic dipole antenna

The invention provides a log periodic dipole antenna having a microstrip center feedline and a log periodic hourglass dipole assembly. The microstrip center feedline means responds to an input radio signal for providing a microstrip center feed radio signal. The log periodic hourglass dipole assembly responds to the microstrip feed radio signal, for providing a log periodic hourglass dipole antenna radio signal.

Log periodic dipole antenna having an interior centerfeed microstrip

An antenna system producing a multi-beam antenna pattern having reduced sidelobe levels with a uniform beam pattern includes an antenna having a plurality of co-linear arrays of radiating elements including central co-linear arrays each of which has an identical number of radiating elements and a pair of outermost co-linear arrays each having a single radiating element. Each of the central co-linear arrays receives the full power output from a corresponding output of a Butler-matrix feed network except for two of the central radiating elements adjacent to the two outermost co-linear arrays, which each share the output power from a corresponding one of the outputs from the Butler-matrix feed network with one of the outermost co-linear arrays. In particular the power is shared between one of the outermost co-linear arrays and a corresponding one of the central co-linear arrays adjacent to the other outermost co-linear array utilizing a power splitter which splits the power between the corresponding central co-linear array and the outermost co-linear array. Each co-linear array includes a feed strap interconnected to each element in the co-linear array. The feed straps for the central co-linear arrays implement an identical trim configuration, and the feed straps for the outermost co-linear arrays introducing a phase shift of .lambda./2, where .lambda. is the wavelength of the electromagnetic energy to be received or transmitted.

Hybrid power tapered/space tapered multi-beam antenna

A circularly polarized antenna has an open reflector box, an array of crossed dipoles, and a single binary feed network. The open reflector box is formed of conductive material, has a ground plate and four side walls defining an opening, and has an input port for receiving an input signal. The single binary feed network is disposed within the open reflector box, is connected to the input port, and has a microstrip transmission line spaced from the ground plate. The microstrip transmission line has conductive bars mounted parallel to the ground plate and spaced therefrom forming an air dielectric low loss microstrip. Each pair of crossed dipoles has a first dipole comprising two downwardly bent radiating elements arranged at an angle with respect to the ground plate, and has a second dipole comprising two straight radiating elements arranged parallel to the ground plate. Each pair of crossed dipoles also has a pair of phase loop connectors and standoffs for respectively connecting an associated downwardly bent radiating element of the first dipole to a corresponding straight radiating element of the second dipole for providing circular polarization in an axial direction. One downwardly bent radiating element is connected to the ground plate, and another downwardly bent radiating element is connected to a respective conductive bar of the single binary feed network, for providing a circularly polarized horizontal beamwidth pattern having a horizontal width determined by the angle of the downwardly bent radiating elements with respect to the ground plate.

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Holland, PA, United States of America

Charles M Powell