Three resonator parasitically coupled microstrip antenna array element
First Claim
1. A broadbanded microstrip antenna comprising:
- a conductive reference surface;
a driven conductive RF radiator element spaced less than one-tenth of a wavelength above said reference surface;
a conductive RF feedline connected to said driven element;
a first passive conductive RF radiator element spaced above and capacitively coupled to said driven element, said first passive element being electrically isolated from said driven element and said conductive reference surface; and
a second passive conductive RF radiator element spaced above said first passive element and capacitively coupled to said driven element, said second passive element being electrically isolated from said driven element and said conductive reference surface,wherein the sizes of said driven, first and second elements, the spacings between said driven, first and second elements, and the Quality factors of said driven, first and second elements are dimensioned to account for inter-element capacitance between said driven element, first passive element and second passive conductive elements and said antenna resonates over a wide, substantially continuous band of frequencies, said driven element being effectively coupled in series by inter-element capacitance with said first and second passive elements, said first and second passive elements being effectively coupled in parallel with one another by inter-element capacitance.
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Accused Products
Abstract
A three resonator capacitively coupled microstrip antenna structure includes an inverted stacked array of elements with a lowermost driven element directly connected to a transmission line connector, and passive elements stacked above the driven element and separated from the driven element and from one another by dielectric layers. The dimensions, spacings and quality factors of the elements are chosen so that at least one, and possibly two elements are resonant at any given frequency within a desired frequency operating range. The resulting antenna structure offers very broad bandwidth at relatively low VSWR in a compact, rugged package. The manner in which parameters of the stacked antenna structure are specified to achieve desired VSWR bandwidth and radiation efficiency is also described.
162 Citations
35 Claims
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1. A broadbanded microstrip antenna comprising:
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a conductive reference surface; a driven conductive RF radiator element spaced less than one-tenth of a wavelength above said reference surface; a conductive RF feedline connected to said driven element; a first passive conductive RF radiator element spaced above and capacitively coupled to said driven element, said first passive element being electrically isolated from said driven element and said conductive reference surface; and a second passive conductive RF radiator element spaced above said first passive element and capacitively coupled to said driven element, said second passive element being electrically isolated from said driven element and said conductive reference surface, wherein the sizes of said driven, first and second elements, the spacings between said driven, first and second elements, and the Quality factors of said driven, first and second elements are dimensioned to account for inter-element capacitance between said driven element, first passive element and second passive conductive elements and said antenna resonates over a wide, substantially continuous band of frequencies, said driven element being effectively coupled in series by inter-element capacitance with said first and second passive elements, said first and second passive elements being effectively coupled in parallel with one another by inter-element capacitance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A broadbanded microstrip antenna comprising:
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a conductive reference surface; a driven conductive RF radiating element spaced less than one-tenth of a wavelength above said reference surface, said driven element dimensioned to resonate in response to signals within a first band of radio frequencies; a conductive RF feedline connected to said driven element; a first passive conductive RF radiating element spaced above and only parasitically coupled to said driven element, said first passive element dimensioned to resonate in response to signals within a second band of radio frequencies, said first passive element effectively connected in series with said driven element through capacitive coupling with said driven element; and a second passive conductive RF radiating element spaced above said first passive element and only parasitically coupled to said driven element, said second passive element dimensioned to resonate in response to signals within a third band of radio frequencies, said second passive element effectively connected in series with said driven element through capacitive coupling and effectively connected in parallel with said first passive element through capacitive coupling with said first element, wherein said first, second and third bands are different from and overlap one another, said elements are arranged in a stack, and said driven, first and second elements are dimensioned such that inter-element capacitive coupling is accounted for by said driven, first and second element dimensions and said antenna is resonant over a substantially continuous band of frequencies wider than the sum of said first, second and third radio frequency bands. - View Dependent Claims (17, 18, 19, 20)
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21. A broadband microstrip antenna comprising:
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a conductive reference surface; a first dielectric layer disposed on said reference surface; a first discoid conductive element disposed on said first dielectric layer, said first element having a diameter of approximately 0.7 y; a second dielectric layer disposed on said first element, said second layer having a thickness x; a second discoid conductive element disposed on said second layer, said second element having a diameter of approximately 0.9 y; a further dielectric layer disposed on said second element; a third discoid conductive element disposed on said third layer, said third element having a diameter y; and RF transmission line means connected between said reference surface and said first element for coupling RF signals to and/or from said first element, wherein said second element resonates at a lower frequency than said third element. - View Dependent Claims (22)
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23. A broadband microstrip antenna comprising:
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a conductive reference surface; a first dielectric layer disposed on said reference surface and having a thickness D; a first discoid conductive element disposed on said first dielectric layer, said first element having a diameter within the range of 0.60 inches and 1.90 inches; a second dielectric layer disposed on said first element, said second layer having a thickness within the range of 0.005 inches and 0.015 inches; a second discoid conductive element disposed on said second layer, said second element having a diameter within the range of 0.75 inches and 2.4 inches; a third dielectric layer disposed on said second element, said third layer having a thickness within the range of 0.110 inches and 0.375 inches; a third discoid conductive element disposed on said third layer, said third element having a diameter within the range of 0.840 inches and 2.70 inches; and RF transmission line means connected between said reference surface and said first element for coupling RF signals to and/or from said first element. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A process for producing a broadband microstrip antenna comprising the steps of:
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(1) providing a first layer of dielectric laminate having first and second conductive layers adhered to opposing surfaces thereof, said first conductive layer being resonant at a frequency FHIGH ; (2) connecting said first and second conductive layers to center and ground connections, respectively, of an RF transmission line; (3) providing a second layer of dielectric laminate having a third conductive layer resonant at a frequency FLOW lower than said frequency FHIGH adhered to a first surface thereof, said second layer having an insulative surface opposing said first surface; (4) disposing said second layer insulative surface on said second conductive layer; (5) disposing a third layer of insulative material on said third conductive layer; providing a further layer of dielectric laminate having a fourth conductive layer resonated at a third frequency FMID between said frequencies FHIGH and FLOW adhered to a surface thereof; and bonding said further layer surface and/or said fourth conductive layer to said third insulative material layer.
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35. A broadbanded microstrip antenna comprising:
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a conductive reference surface; a driven conductive microstrip patch RF radiator element above said reference surface; a conductive RF feedline connected to said driven element;
a first planar passive conductive RF radiator element spaced above and capacitively coupled to said driven element and resonating about a first frequency; anda second planar passive conductive RF radiator element spaced above said first passive element and capacitively coupled to said driven element, said second element having a larger surface area than said first element surface area and resonating about a frequency higher than said first frequency, wherein said driven, first and second elements are dimensioned such that inter-element capacitance is optimized and said antenna is resonant over a wide, substantially continuous band of frequencies.
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Specification