Coaxial resonant slot antenna, a method of manufacturing thereof, and a radio terminal
First Claim
1. A coaxial resonant slot antenna comprising:
- a conductive cubic having a shape of a rectangular prism;
a strip conductor having a length extending along a resonant axis of an inner space of said conductive cubic; and
a slot for transmitting an electromagnetic wave, said slot being formed on one surface of said conductive cubic;
wherein said slot is composed of a first slot part having a length extending perpendicular to the resonant axis, two portions of a second slot part having a length extending parallel to the resonant axis and two portions of a third slot part having a length extending perpendicular to the resonant axis and which is shorter in length than the first slot part, each of ends of the first slot part, second slot part, an third slot part and the portions thereof being connected continuously in an order of third, second, first, second, third, the first slot part being arranged crossing said strip conductor; and
wherein said strip conductor is arranged, in its entirety, as insulated from said conductive cubic.
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Accused Products
Abstract
A coaxial resonant slot antenna having a novel structure is provided to further reduce the dimensions of radio terminals incorporating such an antenna. Also provided are a novel method of fabricating such a coaxial resonant slot antenna and a radio terminal having a novel structure using such a coaxial resonant slot antenna. An entire strip conductor is arranged inside a flat conductive cubic such that the strip conductor is insulated from the conductive cubic. A connection point between the strip conductor and a radio frequency transmission line is provided at a position about 1/4 of wavelength away from one end of the strip conductor. A slot is shaped into a narrow rectangle, a generally upside-down "U", or a generally upside-down "U" having another slot on each end. It is desired that the center slot crosses the strip conductor along the length thereof and in the height direction thereof, the distance between the ends being equivalent to about 1/2 of wavelength used. The radio terminal has a plurality of antennas associated with the present invention arranged on a plurality of surfaces and provides a connection mechanism for varying the number of antennas to be used in the talk mode and the standby mode.
129 Citations
20 Claims
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1. A coaxial resonant slot antenna comprising:
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a conductive cubic having a shape of a rectangular prism; a strip conductor having a length extending along a resonant axis of an inner space of said conductive cubic; and a slot for transmitting an electromagnetic wave, said slot being formed on one surface of said conductive cubic; wherein said slot is composed of a first slot part having a length extending perpendicular to the resonant axis, two portions of a second slot part having a length extending parallel to the resonant axis and two portions of a third slot part having a length extending perpendicular to the resonant axis and which is shorter in length than the first slot part, each of ends of the first slot part, second slot part, an third slot part and the portions thereof being connected continuously in an order of third, second, first, second, third, the first slot part being arranged crossing said strip conductor; and wherein said strip conductor is arranged, in its entirety, as insulated from said conductive cubic. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A radio terminal incorporating a multilayer circuit board having n stripline layers, comprising:
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a radio frequency component arranged on a first layer or a n-th layer or both of said multilayer circuit board; a first stripline pattern formed on a m-th layer of said multilayer circuit board, wherein 1≦
m≦
n-2;a second stripline pattern formed on a position opposed to said first stripline pattern of a p-th layer of said multilayer circuit board wherein 3≦
p≦
n and p≦
m+2, said second stripline pattern having generally the same shape as that of said first stripline pattern;a stripline conductor shaped in a strip formed at a position between said first stripline pattern and said second stripline pattern on o-th layer of said multilayer circuit board, wherein m<
o<
p;a plurality of first through-holes parallel to each other formed around said stripline conductor for electrically connecting an outer periphery of said first stripline pattern to an outer periphery of said second stripline pattern; and a slot formed on said first stripline pattern such that said slot crosses said stripline conductor; wherein said stripline conductor is not in electrical contact with one of said first stripline pattern, said second stripline pattern, and said plurality of first through-holes, said radio frequency component is electrically connected to said stripline conductor, and one of said first stripline pattern, said second stripline pattern, and said plurality of first through-holes is connected to a ground conductor provided on one of a second layer to n-1-th layer. - View Dependent Claims (10, 11, 12)
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13. A radio terminal incorporating a multilayer circuit board in a casing of said radio terminal, comprising:
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a coaxial resonant slot antenna arranged on a first main surface of said multilayer circuit board; a first radio frequency circuit located near a connecting point of said coaxial resonant slot antenna arranged on said first main surface; a second radio frequency circuit located far from a connecting point of said coaxial resonant slot antenna arranged on a second main surface of said multilayer circuit board opposite to said first main surface; and a frequency synthesizer arranged at a position opposite to said coaxial resonant slot antenna on said second main surface; said coaxial resonant slot antenna comprising; a conductive cubic which is a rectangular prism in overall shape; a strip conductor narrow in shape arranged along the resonance axis of the inner space of said conductive cubic; and an electromagnetic wave send/receive slot formed on a front surface of said conductive cubic such that said slot crosses said strip conductor; wherein said coaxial resonant slot antenna is arranged on said multilayer circuit board such that a rear surface of said conductive cubic comes in contact with said first main surface, said coaxial resonant slot antenna having uni-directivity in the direction opposite to said second main surface, said strip conductor in its entirety is insulated from said conductive cubic and a connection point of said strip conductor to said first radio frequency circuit is arranged at a position equivalent to about 1/4 of wavelength of said radio terminal away from one end of said strip conductor, and one of stripline layers in said multilayer circuit board is used as a ground layer, said conductive cubic is connected to said ground layer via a through-hole, a control signal line is formed on a stripline layer between said ground layer and the rear surface of said conductive cubic, and said frequency synthesizer is electrically connected to said control signal line via a through-hole. - View Dependent Claims (14)
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15. A radio terminal incorporating a coaxial resonant slot antenna, comprising:
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a speaker and a microphone arranged at positions in the proximity of a rear surface of a casing of said radio terminal facing an operator in a talking state; a first coaxial resonant slot antenna having a single-side pattern arranged at a position in the proximity of the rear surface of the casing of said radio terminal facing the direction opposite to the operator in the talking state, said first coaxial resonant slot antenna in the talking state, radiating an electromagnetic wave in a direction approximately opposite to the operator; monitoring means for monitoring whether said radio terminal is in the talking state or a standby state; and a second coaxial resonant slot antenna arranged at a position in the proximity of a front surface of the casing of said radio terminal facing the operator in the talking state; wherein, if said radio terminal is determined to be in the talking state by said monitoring means, only said first coaxial resonant slot antenna is driven and, if said radio terminal is determined to be in the standby state by said monitoring means, both said first coaxial resonant slot antenna and said second coaxial slot antenna are driven.
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16. A coaxial resonant slot antenna comprising:
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a conductive cubic having a shape of a rectangular prism in shape; a strip conductor having a length extending along a resonant axis of an inner space of said conductive cubic; and a slot for transmitting and receiving an electromagnetic wave, said slot being formed on one surface of said conductive cubic; wherein said slot is composed of a first slot part having a length extending perpendicular to the resonant axis, two portions of a second slot part having a length extending parallel to the resonant axis, two portions of a third slot part having a length extending perpendicular to the resonant axis and which is shorter in length than the first slot part, and two portions of a fourth slot part having a length extending parallel to the resonant axis and which is shorter in length than the second slot part, each of ends of the first slot part, second slot part, third slot part, and fourth slot part and the portions thereof being connected continuously in an order of fourth, third, second, first, second, third, fourth, the first slot part being arranged crossing said strip conductor; and wherein said strip conductor is arranged, in its entirety, as insulated from said conductive cubic. - View Dependent Claims (17, 18, 19, 20)
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Specification