Rod antenna, particularly for mobile FM signal transducing applications
First Claim
1. Rod antenna for transducing radio signals, particularly for mobile frequency modulation (FM) reception havinga support rod (10) of insulating material,and comprisinga first, spiral winding (11) wound and spirally progressing on a first longitudinal portion (b) of the rod;
- a second winding (12) wound and spirally progressing on an adjacent second portion (a) of the rod,the winding sense and spiral progression of said second winding being opposite to that of said first winding, and said windings being connected at the adjacent ends at an intermediate location along the length of the rod;
an electrical connection element (14, 22;
20,
26) electrically connected to the free end (16) of one (12) of said windings;
wherein the sum of the lengths of the rod of the first and second portions over which said windings extend (a+b) is about 1/8 of the median wave length of the radio signals to be transduced;
and wherein the extended wire length of the respective first and second windings (11,
12), each, is about 1/4 of the median wave length of the signals to be transduced.
1 Assignment
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Accused Products
Abstract
To provide a short FM antenna, of about for example 40 cm length for mobile radio, for example automobile radio application, without degradation of signal strength with respect to an about 1 m long FM antenna, a conically tapering insulating rod, for example of fiberglass, has two windings applied thereover, the two windings, each, having a straight wire length of about 1/4 the median wavelength of the FM band, and the overall length (l) of the rod having said two windings applied thereover being about 1/8 of the median wavelength. The oppositely wound windings (11, 12) are connected at their center, and may be formed as one bifilar winding, with the lower end of the lower winding being connected to an electrical terminal for standard connection to, for example, a coaxial antenna connector for an automobile radio. A spiral spring can be interposed if extreme deflectability of the antenna is desired, for example to prevent damage if the antenna, applied to an automotive vehicle, is passed through a power washing and scrubbing station.
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Citations
11 Claims
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1. Rod antenna for transducing radio signals, particularly for mobile frequency modulation (FM) reception having
a support rod (10) of insulating material, and comprising a first, spiral winding (11) wound and spirally progressing on a first longitudinal portion (b) of the rod; -
a second winding (12) wound and spirally progressing on an adjacent second portion (a) of the rod, the winding sense and spiral progression of said second winding being opposite to that of said first winding, and said windings being connected at the adjacent ends at an intermediate location along the length of the rod; an electrical connection element (14, 22;
20,
26) electrically connected to the free end (16) of one (12) of said windings;wherein the sum of the lengths of the rod of the first and second portions over which said windings extend (a+b) is about 1/8 of the median wave length of the radio signals to be transduced; and wherein the extended wire length of the respective first and second windings (11,
12), each, is about 1/4 of the median wave length of the signals to be transduced. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification