Antenna equipment
First Claim
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1. An antenna equipment comprising:
- a rod antenna element;
a metal cylinder provided at one end of said rod antenna element and axially aligned therewith, said metal cylinder having a first predetermined length in its axial direction, said first predetermined length being an integral multiple of a quarter-wavelength;
an inner conductor connected to one end of said rod antenna element and extended substantially along the center axis of said metal cylinder to form a coaxial line in combination therewith; and
a feeder having a core conductor connected to said inner conductor and an outer conductor connected to said metal cylinder at one end thereof opposite from said rod antenna element;
said coaxial line forming a coaxial impedance converter and said metal cylinder having a notch formed by cutting out a part of its periphery a second predetermined length in its axial direction from its marginal edge at the side of said rod antenna element, whereby impedance of said coaxial impedance converter is matched with said rod antenna element at first and second different frequencies, respectively.
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Abstract
A rod antenna element is connected at its lower end to one end of a coaxial impedance converter, the other end of which is connected to a feeder. A coil antenna element is capacitively coupled to the rod antenna element to provide a double resonance characteristic. When held at its retracted position, the rod antenna element, inserted in an outer conductor of the coaxial impedance converter, may preferably form an inner conductor larger in diameter than that when the rod antenna element is at its extended-out position, and the rod antenna element is connected to a coil antenna element with a low impedance.
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Citations
31 Claims
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1. An antenna equipment comprising:
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a rod antenna element; a metal cylinder provided at one end of said rod antenna element and axially aligned therewith, said metal cylinder having a first predetermined length in its axial direction, said first predetermined length being an integral multiple of a quarter-wavelength; an inner conductor connected to one end of said rod antenna element and extended substantially along the center axis of said metal cylinder to form a coaxial line in combination therewith; and a feeder having a core conductor connected to said inner conductor and an outer conductor connected to said metal cylinder at one end thereof opposite from said rod antenna element; said coaxial line forming a coaxial impedance converter and said metal cylinder having a notch formed by cutting out a part of its periphery a second predetermined length in its axial direction from its marginal edge at the side of said rod antenna element, whereby impedance of said coaxial impedance converter is matched with said rod antenna element at first and second different frequencies, respectively. - View Dependent Claims (2, 3)
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4. An antenna equipment comprising:
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a first rod antenna element having a length that is an integral multiple of one-half wavelength to provide a first resonant frequency; a metal cylinder provided at one end of said first rod antenna element and axially aligned therewith, said metal cylinder having a length of a quarter-wavelength; an inner conductor connected to one end of said first rod antenna element and extended substantially along the center axis of said metal cylinder to form a coaxial line in combination therewith; a feeder having a core conductor connected to said inner conductor and an outer conductor connected to said metal cylinder at one side thereof opposite from said first rod antenna element; and a second coil antenna element disposed around a part of said first antenna element coaxially therewith and capacitively coupled to said first antenna element via a capacitor achieving, in cooperation with said second coil antenna element, a second resonant frequency; said coaxial line forming a coaxial impedance converter.
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5. An antenna equipment comprising:
- a metal cylinder;
an inner conductor extended in said metal cylinder along its center axis to form a coaxial line in combination with said metal cylinder; a first rod antenna element having a thickness larger than that of said inner conductor, said first rod antenna element projecting out from said metal cylinder and being retractable into said metal cylinder along its center axis; sliding contact means for causing one end of said inner conductor and said first rod antenna element to make sliding contact with each other; a feeder having a core conductor connected to said inner conductor and an outer conductor connected to said metal cylinder at one end thereof opposite from said first rod antenna element; and a second antenna element which is connected to said first rod antenna element when said first rod antenna element is retracted in said metal cylinder; wherein when said first rod antenna element is retracted in said metal cylinder, an inner end of said first rod antenna element makes contact with said core conductor of said feeder and said first rod antenna element together with said metal cylinder constitutes a coaxial impedance converter which matches the impedance of said second antenna element and said feeder and interconnects them, and when said first antenna element is extended out from said metal cylinder, said second antenna element is disconnected from said first antenna element, said inner end of said first rod antenna is separated from said core conductor of said feeder, and said metal cylinder together with said inner conductor constitute a coaxial impedance converter which matches the impedances of said first antenna element and said feeder and interconnects them. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
- a metal cylinder;
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13. An antenna equipment comprising:
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a metal cylinder; an inner conductor extended in said metal cylinder along its center axis and forming a coaxial line in combination with said metal cylinder; a first rod antenna element having a thickness larger than that of said inner conductor, said first rod antenna element projecting out from said metal cylinder and being retractable into said metal cylinder along its center axis; sliding contact means for bringing one end of said inner conductor and said first antenna element into sliding contact with each other; a feeder having a core conductor connected to said inner conductor and having an outer conductor connected to said metal cylinder at one end thereof opposite from said first rod antenna element; and a second coil antenna element connected at one end to a tip of said first rod antenna element, said second coil antenna element projecting out from a top end of said metal cylinder when said first antenna element is retracted in said metal cylinder; wherein when said first rod antenna element is retracted in said metal cylinder, an inner end of said first rod antenna element makes contact with said core conductor of said feeder and said first rod antenna element together with said metal cylinder constitute a coaxial impedance converter which matches the impedances of said second coil antenna element and said feeder and interconnects them, and when said first rod antenna element is extended out from said metal cylinder said inner end of said first antenna element is separated from said core conductor of said feeder, and said metal cylinder together with said inner conductor constitute a coaxial impedance converter which matches the impedances of said first rod antenna element and said feeder and interconnects them. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. An antenna equipment comprising:
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a rod antenna element; a metal cylinder provided at one end of said rod antenna element, with their center axes aligned with each other; an inner conductor connected to one end of said rod antenna element and extended substantially along the center axis of said metal cylinder to form a coaxial line in combination therewith; a first feeder having a core conductor connected to said inner conductor and an outer conductor connected to said metal cylinder at one end thereof opposite from said rod antenna element; a slot antenna formed by a slit formed in said metal cylinder in its axial direction; and a second feeder connected at one end to said slot antenna; wherein said coaxial line forms a coaxial impedance converter which matches the impedances of said antenna element and said first feeder and interconnects them. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification