Multiband reception antenna for terrestrial digital audio broadcast bands
First Claim
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1. A multiband conformal antenna for receiving broadcast signals in Band-III and L-band, comprising:
- a support surface;
first and second antenna feedpoints disposed on said support surface;
a first dipole conductor disposed on said support surface directly connected with said first feedpoint;
a second dipole conductor disposed on said support surface directly connected with said second feedpoint;
a conductive loop affixed to said support surface, said conductive loop being generally rectangular extending a relatively greater distance horizontally than vertically;
a first impedance circuit coupling said conductive loop to said first feedpoint; and
a second impedance circuit coupling said conductive loop to said second feedpoint;
wherein said first and second dipole conductors have a combined length equal to about one-half wavelength of a wave within said L band and wherein said first and second impedance circuits provide a relatively greater impedance at L-band frequencies than at Band-III frequencies so that said antenna is equivalent to a loop antenna at Band-III frequencies and a half-wave dipole antenna at L band frequencies.
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Abstract
The invention combines a loop antenna and a dipole antenna in a conformal antenna on the rear window glass of an automotive vehicle above the defogging heater grid. The loop and dipole are adapted to receive Digital Audio Broadcasting (DAB) signals in both L band and Band-III frequency bands with maximum sensitivity to vertically polarized signals while requiring minimal space on the window glass. Inductive components separate portions of the antenna pattern for signals at predetermined frequencies in order to create the different effective antenna shapes at the different frequency bands.
84 Citations
9 Claims
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1. A multiband conformal antenna for receiving broadcast signals in Band-III and L-band, comprising:
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a support surface; first and second antenna feedpoints disposed on said support surface; a first dipole conductor disposed on said support surface directly connected with said first feedpoint; a second dipole conductor disposed on said support surface directly connected with said second feedpoint; a conductive loop affixed to said support surface, said conductive loop being generally rectangular extending a relatively greater distance horizontally than vertically; a first impedance circuit coupling said conductive loop to said first feedpoint; and a second impedance circuit coupling said conductive loop to said second feedpoint; wherein said first and second dipole conductors have a combined length equal to about one-half wavelength of a wave within said L band and wherein said first and second impedance circuits provide a relatively greater impedance at L-band frequencies than at Band-III frequencies so that said antenna is equivalent to a loop antenna at Band-III frequencies and a half-wave dipole antenna at L band frequencies. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification