US3765022A — Extended aperture log-periodic and quasi-log-peri…

Claim 1

Independent Claim 258 words

In a log-periodic type antenna responsive to signals of frequencies in a selected frequency range in the 1/2 wavelength mode, the antenna including feed means extending along a feed axis and a plurality of radiating elements, each having first and second ends, coupled to said feed means at the first ends thereof at log-periodically related points along said axis to form a logperiodic like array, each element having an electrical length between its opposite ends which is substantially equal to 1/4 free space wavelength of the element''s resonant frequency, the improvement comprising: capacitive means comprising an overlapping line section serially connected to at least one of said elements intermediate its first and second ends to provide distributed capacitive loading for the element to tune out at least a part of its inductive reactance, so that the current distribution over the entire length of the capacitively loaded element whose physical length is greater than one-fourth wavelength of its resonant frequency is substantially similar to the current distribution on an element whose physical length is equal to the one-fourth wavelength of the resonant frequency, the physical length of said capacitively loaded element being less than 5/8 free space wavelength of its resonant frequency, the length of the element from said first end including said line section being definable as LI, and the length of the element from said second end and including said line section being definable as Lo, LI and Lo being not more than one-fourth and one-half of a free space wavelength respectively, of the element''s resonant frequency.

Claim 2

Dependent Claim 258 words

In a log-periodic type antenna responsive to signals of frequencies in a selected frequency range in the 1/2 wavelength mode, the antenna including feed means extending along a feed axis and a plurality of radiating elements, each having first and second ends, coupled to said feed means at the first ends thereof at log-periodically related points along said axis to form a logperiodic like array, each element having an electrical length between its opposite ends which is substantially equal to 1/4 free space wavelength of the element''s resonant frequency, the improvement comprising: capacitive means comprising an overlapping line section serially connected to at least one of said elements intermediate its first and second ends to provide distributed capacitive loading for the element to tune out at least a part of its inductive reactance, so that the current distribution over the entire length of the capacitively loaded element whose physical length is greater than one-fourth wavelength of its resonant frequency is substantially similar to the current distribution on an element whose physical length is equal to the one-fourth wavelength of the resonant frequency, the physical length of said capacitively loaded element being less than 5/8 free space wavelength of its resonant frequency, the length of the element from said first end including said line section being definable as LI, and the length of the element from said second end and including said line section being definable as Lo, LI and Lo being not more than one-fourth and one-half of a free space wavelength respectively, of the element''s resonant frequency.

Claim 3

Dependent Claim 31 words

The arrangement as recited in claim 1 wherein each of said elements is capacitively loaded by at least one line section at a point intermediate said first and second ends thereof.

Claim 4

Dependent Claim 13 words

The arrangement as recited in claim 1 wherein Lo/LI > or = 1.5.

Claim 5

Dependent Claim 31 words

The arrangement as recited in claim 3 wherein each of said elements is capacitively loaded by at least one line section at a point intermediate said first and second ends thereof.

Claim 6

Dependent Claim 241 words

In a log-periodic type antenna responsive to signals of frequencies in a selected frequency range in the 1/2 wavelength mode, the antenna including feed means extending along a feed axis and a plurality of radiating elements, each having first and second ends, coupled to said feed means at the first ends thereof at log-periodically related points along said axis to form a log-periodic like array, each element having an electrical length between its opposite ends which is substantially equal to 1/4 free space wavelength of the element''s resonant frequency, the improvement comprising: at least first and second capacitive means coupled to at least one element for providing capacitive loading therefor so as to tune out part of the inductive reactance thereof, so that the phase velocity of the current thereon at the resonant frequency is substantially constant along its entire length comparable to the constant phase velocity on an unloaded one-fourth wavelength long element at the same resonant frequency, said at least one element defining an inner portion, a center portion and an outer portion, said first capacitive means being connected to said inner and center portions, and said second capacitive means being connected to said center aNd outer portions, the total length of said at least one element between its first and second ends, being less than 1 wavelength of its resonant frequency, the center portion being not longer than the outer portion and not less than the inner portion.

Claim 7

Dependent Claim 241 words

In a log-periodic type antenna responsive to signals of frequencies in a selected frequency range in the 1/2 wavelength mode, the antenna including feed means extending along a feed axis and a plurality of radiating elements, each having first and second ends, coupled to said feed means at the first ends thereof at log-periodically related points along said axis to form a log-periodic like array, each element having an electrical length between its opposite ends which is substantially equal to 1/4 free space wavelength of the element''s resonant frequency, the improvement comprising: at least first and second capacitive means coupled to at least one element for providing capacitive loading therefor so as to tune out part of the inductive reactance thereof, so that the phase velocity of the current thereon at the resonant frequency is substantially constant along its entire length comparable to the constant phase velocity on an unloaded one-fourth wavelength long element at the same resonant frequency, said at least one element defining an inner portion, a center portion and an outer portion, said first capacitive means being connected to said inner and center portions, and said second capacitive means being connected to said center aNd outer portions, the total length of said at least one element between its first and second ends, being less than 1 wavelength of its resonant frequency, the center portion being not longer than the outer portion and not less than the inner portion.

Claim 8

Dependent Claim 24 words

The arrangement as recited in claim 5 wherein the length of said one element is not less than one-half wavelength of its resonant frequency.

Claim 9

Dependent Claim 58 words

The arrangement as recited in claim 5 wherein said first and second capacitive means are first and second line sections, the total length of said inner portion with said first line section, and the total length of said outer portion with said second line section being less than one-fourth and one-half wavelength respectively of the element''s resonant frequency.

Claim 10

Dependent Claim 28 words

The arrangement as recited in claim 7 wherein said center portion with said first and second line sections is less than one-half wavelength of the element''s resonant frequency.

Claim 11

Dependent Claim 24 words

The arrangement as recited in claim 8 wherein the length of said one element is not less than one-half wavelength of its resonant frequency.

Claim 12

Dependent Claim 194 words

An antenna comprising: feed means extending in a feed axis from a first end to a second end; and a plurality of radiating elements each having first and second ends, said first ends being coupled to said feed means between the first and second ends thereof at substantially log-periodically related points to form an antenna array, at least one of said elements comprising inner and outer element portions, said inner portion having one end corresponding to the element first end directly coupled to said feed means and an opposite end overlapping one end of said outer portion, which extends to the second element end, to form a line section which provides distributed capactive loading for said element to tune out at least part of its inductive reactance, the respective length of said inner and outer element portions being less than one-fourth and one-half of a wavelength at the element''s resonant frequency, with its total length being less than five-eighths wavelength of its resonant frequency, with the current distribution over the entire length of the capacitively loaded element being substantially similar to a 1/4 wavelength element at said resonant frequency which is not capacitively loaded.

Claim 13

Dependent Claim 194 words

An antenna comprising: feed means extending in a feed axis from a first end to a second end; and a plurality of radiating elements each having first and second ends, said first ends being coupled to said feed means between the first and second ends thereof at substantially log-periodically related points to form an antenna array, at least one of said elements comprising inner and outer element portions, said inner portion having one end corresponding to the element first end directly coupled to said feed means and an opposite end overlapping one end of said outer portion, which extends to the second element end, to form a line section which provides distributed capactive loading for said element to tune out at least part of its inductive reactance, the respective length of said inner and outer element portions being less than one-fourth and one-half of a wavelength at the element''s resonant frequency, with its total length being less than five-eighths wavelength of its resonant frequency, with the current distribution over the entire length of the capacitively loaded element being substantially similar to a 1/4 wavelength element at said resonant frequency which is not capacitively loaded.

Claim 14

Dependent Claim 148 words

A broadband antenna array comprising: a plurality of feed means; a plurality of capacitively loaded radiating elements, each element having first and second opposite ends connected to adjacent feed means, the elements being connected at points on said feed means spaced substantially log periodically from an array front end to an array back end, whereby when said feed means are energized in phase at a frequency within the design band the array includes an element for supporting wave propagation at infinite phase velocity, the elements about the array front end including an element, whose total length between said first and second ends is less than 1 wavelength of the highest frequency in said band, and the elements about the array back end include an element whose total length between its first and second ends is less than 1/2 free space wavelength of the lowest frequency in said band.

Claim 15

Dependent Claim 148 words

A broadband antenna array comprising: a plurality of feed means; a plurality of capacitively loaded radiating elements, each element having first and second opposite ends connected to adjacent feed means, the elements being connected at points on said feed means spaced substantially log periodically from an array front end to an array back end, whereby when said feed means are energized in phase at a frequency within the design band the array includes an element for supporting wave propagation at infinite phase velocity, the elements about the array front end including an element, whose total length between said first and second ends is less than 1 wavelength of the highest frequency in said band, and the elements about the array back end include an element whose total length between its first and second ends is less than 1/2 free space wavelength of the lowest frequency in said band.

Claim 16

Dependent Claim 42 words

The arrangement as recited in claim 11 wherein each capacitively loaded element is loaded by at least one capacitive means, the spacings between capacitive means on the same element and between capacitive means on corresponding elements within said array being substantially equal.

Claim 17

Dependent Claim 34 words

The arrangement as recited in claim 12 wherein the spacings between capacitive means on the same element and between capacitive means on corresponding elements being less than one-half wavelength of the element''s resonant frequency.

Claim 18

Dependent Claim 119 words

The arrangement as recited in claim 11 wherein said plurality of feed means comprising at least first and second substantially parallel feed means, with each of the elements between said first and second feed means being connected at said first end to said first feed means and at said second end to said second feed means, with all elements being substantially of equal length, and further including outboard elements coupled to said first feed means in a direction away from said second feed means and to said second feed means in a direction away from said first feed means, the lengths of said outboard elements decreasing substantially log periodically from the array back end to the array front end.

Claim 19

Dependent Claim 74 words

The arrangement as recited in claim 11 wherein the element at the back end of said array is capacitively coupled by at least one line section at the center thereof and the element at the front end of said array is capacitively coupled by at least two line sections, the spacing between line sections in the same element and in corresponding elements being less than 1/2 free space wavelength of the element''s resonant frequency.

Claim 20

Dependent Claim 160 words

A broadband antenna array comprising: a plurality of feed lines; a plurality of radiator means connected to extending between adjacent feed lines in said array, from an array front end to the array back end, with all radiator means substantially parallel and spaced substantially log-periodically from said array front end to the array back end; and capacitive means coupled to each of said radiator means to control the reactances of said radiator means whereby when said feed lines are excited in phase at the highest or lowest frequencies in said band, the radiator means at the front end and back end respectively of said array include radiator means which support a current at infinite phase velocity, the length of the radiator means at the back end of said array being less than one-half wavelength of the lowest frequency in said band, and the spacing between feed lines being less than 1 full wavelength of the highest frequency in said band.

Claim 21

Dependent Claim 160 words

A broadband antenna array comprising: a plurality of feed lines; a plurality of radiator means connected to extending between adjacent feed lines in said array, from an array front end to the array back end, with all radiator means substantially parallel and spaced substantially log-periodically from said array front end to the array back end; and capacitive means coupled to each of said radiator means to control the reactances of said radiator means whereby when said feed lines are excited in phase at the highest or lowest frequencies in said band, the radiator means at the front end and back end respectively of said array include radiator means which support a current at infinite phase velocity, the length of the radiator means at the back end of said array being less than one-half wavelength of the lowest frequency in said band, and the spacing between feed lines being less than 1 full wavelength of the highest frequency in said band.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1976-10-08	1977-04-09	1977-10-09	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1980-10-08	1981-04-09	1981-10-09	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1984-10-08	1985-04-09	1985-10-09	$7700.00	Window Closed / Lapsed

Extended aperture log-periodic and quasi-log-periodic antennas and arrays

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