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US 6,608,605 B2Granted
Multi-band uniform helical antenna and communication device having the same
AssigneeHewlett-Packard Development Company, L.P.
InventorsMan Wei Lee, Huan Fong Tan
Life of this patent
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Abstract
A helical antenna tuned to a first and a second resonant frequency is disclosed. The helical antenna includes an elongated conductor formed as a uniform spiral. The uniform spiral has a plurality of turns about a longitudinal axis. The plurality of turns has a predetermined pitch and the elongated conductor has a length which is approximately one-quarter of a wavelength of the first resonant frequency. The helical antenna further includes a first dielectric element and a second element. Both elements are coupled to the spiral to selectively tune the antenna to the second resonant frequency. A wireless communication device including the helical antenna is also disclosed.
Claims6
A multi-band helical antenna, comprising:
- a first section attached to a whip-antenna connection base;
- a second section adjacent to and distal from the first section;
- a helical coil electrically connected to said whip-antenna connection base and extending through both the first and second sections, and having a uniform winding pitch and diameter throughout;
- a first core of a first dielectric material at least disposed in the first section and that imposes a first distributed inductance and capacitance effect on a near-end part of the helical coil;
- a second core of a second dielectric material having a different dielectric constant than that of said first dielectric material, and disposed only in the second section, and abutting the first core, and further that imposes a second distributed inductance and capacitance effect on a distal-end part of the helical coil;
- wherein, the antenna has a first resonance at 0.25 wavelengths of a first frequency, and a second resonance at 0.75 wavelengths of a different and higher second frequency that is substantially lower than the third harmonic of the first frequency, and does not resonate at 0.75 wavelengths of said first frequency.
3 more elements
A multi-band helical antenna, comprising:
- a first section attached to a whip-antenna connection base;
- a second section adjacent to and distal from the first section;
- a helical coil electrically connected to said whip-antenna connection base and extending through both the first and second sections, and having a uniform winding pitch and diameter throughout;
- a first core of a dielectric material at least disposed in the first section and that imposes a first distributed inductance and capacitance effect on a near-end part of the helical coil;
- a second core of a conductive material electrically insulated to prevent shorting of the helical coil, and disposed only in the second section, and abutting the first core, and further that imposes a second distributed inductance and capacitance effect on a distal-end part of the helical coil;
- wherein, the antenna has a first resonance at 0.25 wavelengths of a first frequency, and a second resonance at 0.75 wavelengths of a different and higher second frequency that is substantially lower than the third harmonic of the first frequency, and does not resonate at 0.75 wavelengths of said first frequency.
3 more elements
A method for making a helical antenna resonate at two frequencies other than its quarter-wave fundamental and three-quarter-wave third harmonic frequencies, comprising:
- disposing a first core of a first dielectric material at least disposed in a first section of a helical coil and that imposes a first distributed inductance and capacitance effect on a near-end part of the helical coil;
- disposing a second core of a second dielectric material in a second section of said helical coil and that imposes a second distributed inductance and capacitance effect on a distal-end part of said helical coil;
- wherein, an antenna comprising said helical coil has a first resonance at 0.25 wavelengths of a first frequency, and a second resonance at 0.75 wavelengths of a different and higher second frequency that is substantially lower than the third harmonic of the first frequency, and does not resonate at 0.75 wavelengths of said first frequency.
A multi-band radio, comprising:
- a radio receiver for operating on a first and a second radio frequency band in which said second radio frequency band is substantially less than the third harmonic of said first radio frequency band;
- a first section attached to an antenna connection base attached to the radio receiver;
- a second section adjacent to and distal from the first section;
- a helical coil electrically connected to said antenna connection base and extending through both the first and second sections, and having a uniform winding pitch and diameter throughout;
- a first core of a first dielectric material at least disposed in the first section and that imposes a first distributed inductance and capacitance effect on a near-end part of the helical coil;
- a second core of a second dielectric material having a different dielectric constant than that of said first dielectric material, and disposed only in the second section, and abutting the first core, and further that imposes a second distributed inductance and capacitance effect on a distal-end part of the helical coil;
- wherein, the helical coil has a first resonance at 0.25 wavelengths of a first frequency in said first radio frequency band, and a second resonance at 0.75 wavelengths of a different and higher second frequency that is substantially lower than the third harmonic of the first frequency and in said second radio frequency band.
4 more elements
Dependencies are inferred from the claim text.