Patent Number: 6,297,711

Title: Radio frequency multiplexer for coupling antennas to AM/FM/WB, CB/WB, andcellular telephone apparatus

Abstract: An AM/FM/WB/CB/cellular telephone antenna includes a first frequencyself-resonant circuit at a position above the lower end of the antennasuch that the electrical length of the lower section of the antenna isequivalent to one-quarter wavelength for a frequency in the FM frequencyrange and a second frequency self-resonant circuit disposed below thefirst frequency self-resonant circuit. The first self-resonant circuitpresents a high impedance in the FM frequency band and the secondself-resonant circuit presents a high impedance in the cellular frequencyrange. The entire length of the antenna is equivalent to one-quarterwavelength in a frequency in the CB frequency band. The antenna wire iswound around a fiberglass core, and the FM self-resonant circuit is formedby a tightly wound, coiled section of the wire together with a thin-walledbrass tube extending over the core in the area of the tightly woundsection. A thin dielectric film is applied between the tube and thetightly wound section of antenna wire thereby forming a capacitor. Twoantennas, each comprising two frequency self-resonant circuits, areconnected by means of a multiplexing circuit to AM/FM/WB, CB/WB andcellular telephone apparatus.

Inventors: Seward; Glen J. (Cincinnati, OH), Bogdans; Paul A. (Grand Haven, MI)


International Classification:

Expiration Date: 10/02/2013