Capacitive-type, electrically short, broadband antenna and coupling systems

An antenna for transmitting or receiving radiation having a wavelength .lambda. comprising:

• a first electrode forming a first surface of a capacitor radiator,
• a second electrode, spaced from said first electrode by a gap, and forming a second surface of said capacitor radiator,
• the sum of the gap dimension and the dimensions of said first and second electrodes not exceeding .lambda./4,
• an inductor having one end thereof coupled to one of said first and second electrodes,
• wire means for connecting said one end of said inductor to said one of said first and second electrodes,
• additional wire means for connecting the other of said electrodes to ground, and
• means for at least partially shielding said wire means and said additional wire means so as to minimize transmission or reception of electromagnetic energy of wavelength .lambda. therefrom so that transmission or reception of electromagnetic energy primarily emanates from said electrode surfaces.

An antenna for transmitting or receiving radiation having a wavelength .lambda. comprising:

• a first electrode forming a first surface of a capacitor radiator,
• a second electrode, spaced from said first electrode by a gap, and forming a second surface of said capacitor radiator,
• an antenna length not exceeding .lambda./4, where a gap dimension is defined as the shortest straight line path between the first and second electrode surfaces, and the antenna length is defined as the sum of the gap dimension and the first and second electrode dimensions extending along said straight line path,
• an inductor having one end thereof coupled to one of said first and second electrodes,
• wire means for connecting said one end of said inductor to said one of said first and second electrodes,
• additional wire means for connecting the other of said electrodes to ground, and
• means for inhibiting transmission or reception of electromagnetic energy of wavelength .lambda. from said wire means and said additional wire means so that transmission or reception of electromagnetic energy primarily emanates from said electrode surfaces.

An antenna for transmitting or receiving radiation having a wavelength .lambda. comprising:

• a first electrode forming a first surface of a capacitor radiator,
• a second electrode, spaced from said first electrode by a gap, and forming a second surface of said capacitor radiator,
• the sum of the gap dimension and the dimensions of said first and second electrodes not exceeding .lambda./4,
• an inductor having one end thereof coupled to one of said first and second electrodes,
• wire means for connecting said one end of said inductor to said one of said first and second electrodes, additional wire means for connecting the other of said electrodes to ground, and
• said first and second electrodes forming cylindrical surfaces and having axes of revolution coincident with one another.

An antenna for transmitting or receiving radiation having a wavelength .lambda. comprising:

• a first electrode forming a first surface of a capacitor radiator,
• a second electrode, spaced from said first electrode by a gap, and forming a second surface of said capacitor radiator,
• the sum of the gap dimension and the dimensions of said first and second electrodes not exceeding .lambda./4,
• an inductor having one end thereof coupled to one of said first and second electrodes,
• wire means for connecting said one end of said inductor to said one of said first and second electrodes,
• said other end of said inductor connected to at least one of a transmitter and receiving for transmitting and receiving said radiation respectively,
• additional wire means for connecting the other of said electrodes to ground,
• whereby said first and second electrodes and said inductor form a series connected LC circuit;
• said first and second electrodes being substantially flat surfaces and arranged parallel to one another, and
• housing means for shielding said inductor.

An antenna for transmitting or receiving radiation having a wavelength .lambda. comprising:

• a first electrode forming a first surface of a capacitor radiator,
• a second electrode, spaced from said first electrode by a gap, and forming a second surface of said capacitor radiator,
• the sum of the gap dimension and the dimensions of said first and second electrodes not exceeding .lambda./4,
• an inductor having one end thereof coupled to one of said first and second electrodes,
• wire means for connecting said one end of said inductor to said one of said first and second electrodes, additional wire means for connecting the other of said electrodes to ground, and
• wherein said first and second electrodes form conducting surfaces of an insulating cylindrical support member and wherein each of said first and second electrodes have a closed cap region on one end thereof to enclose said insulating cylindrical support member.

An antenna for transmitting or receiving radiation having a wavelength .lambda. comprising:

• a first conductor having a side thereof non-concavely curved with respect to a plane;
• a second conductor, disposed directly on an opposite side of said plane and having a side non-concavely curved with respect to said plane, said second conductor having a length substantially equal to the length of said first conductor, said first and second conductors being separated by a gap coincident with said plane to thereby define a capacitance;
• an inductor coupled at one end thereof to at least one of said first and second conductors and coupled at the other end thereof to at least one of a transmitter and receiver, said inductor and first and second conductors forming a series connected LC resonance circuit;
• wherein said first and second conductors have a length of approximately .lambda./4 or less at a resonant frequency of said LC resonant circuit;
• and
• wherein said antenna includes a housing enclosing said inductor.