Helical antenna for portable radio communication equipment
First Claim
1. A small size helical antenna for radio communication equipment including at least one of a portable transmitter/receiver, a pocket telephone, and a small power type mobile telephone, said helical antenna comprising:
- a first conductor being continuously wound helically from a top end to a bottom end, said first conductor connected to a casing of said equipment; and
a second conductor being helically wound together in parallel with said helically wound first conductor with a predetermined space between facing surfaces thereof;
wherein said second conductor having a same length as said first conductor, a predetermined length from a top end of said second conductor is folded in parallel to a remaining portion of said second conductor to form a folded part with said predetermined space between facing surfaces thereof, an unfolded part thereof is helically wound in parallel together with said first conductor with a bottom end of said second conductor aligned with said bottom end of said first conductor to form a parallel feeder, and said folded part of said second conductor and a predetermined length from said top end of said first conductor comprise a radiator.
1 Assignment
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Accused Products
Abstract
A small size helical antenna for radio communication equipment such as a portable transmitter/receiver, a pocket telephone, or a mobile telephone of small power type. The helical antenna is comprised of first and second parallel conductors wound in a coil shape. The second conductor is folded in parallel to the remaining part of the second conductor at some length in accordance with the transmitting/receiving frequency from the top end. The folded part and the upper part of the first conductor form a radiator of the dipole antenna structure and the parallel part of the first and the second conductors form a parallel feeder. The third conductor having the same length as the folded part may be provided on the lower part of the second conductor. According to the above-described structure, no return current flows from the helical antenna to the casing of the radio communication equipment on which the helical antenna is connected, thereby the directivity becomes maximum in a horizontal plane and an effect caused by holding the casing by a human hand is decreased.
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Citations
34 Claims
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1. A small size helical antenna for radio communication equipment including at least one of a portable transmitter/receiver, a pocket telephone, and a small power type mobile telephone, said helical antenna comprising:
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a first conductor being continuously wound helically from a top end to a bottom end, said first conductor connected to a casing of said equipment; and a second conductor being helically wound together in parallel with said helically wound first conductor with a predetermined space between facing surfaces thereof; wherein said second conductor having a same length as said first conductor, a predetermined length from a top end of said second conductor is folded in parallel to a remaining portion of said second conductor to form a folded part with said predetermined space between facing surfaces thereof, an unfolded part thereof is helically wound in parallel together with said first conductor with a bottom end of said second conductor aligned with said bottom end of said first conductor to form a parallel feeder, and said folded part of said second conductor and a predetermined length from said top end of said first conductor comprise a radiator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification