Microstrip antenna system having nonconductively coupled feedline
First Claim
1. A microstrip antenna system comprising:
- an electrically conductive reference surface;
a layer of electrically conductive microstrip radiator structure disposed above said reference surface by a first predetermined distance less than one-tenth wavelength at the intended antenna operating frequency, said radiator structure including at least one conductively isolated two dimensional conductive area having a resonant dimension of substantially one-half wavelength at said operating frequency; and
a layer of electrically conductive microstrip feedline structure disposed intermediate said reference surface and said layer of radiator structure, said feedline structure including at least one predetermined coupling location positioned an odd integer number of one-fourth wavelength(s) from an effective r.f. short circuit to the underlying reference surface thus causing a concentration of electromagnetic fields to occur at the coupling location which is also disposed proximate to a predetermined corresponding feedpoint region of said radiator structure such that the concentrated electromagnetic fields operate to nonconductively couple r.f. energy to/from said radiator structure from/to said feedline structure.
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Accused Products
Abstract
A microstrip antenna system having one or more conductively isolated resonantly dimensioned radiator structures disposed less than about one-tenth wavelength above a ground plane is nonconductively coupled to an intermediate layer of microstrip feedline structure. The microstrip feedline structure includes various microstrip transmission line segments fed with reference to the ground plane and including predetermined coupling locations positioned an odd integer number of one-fourth wavelength(s) from an effective r.f. short circuit to the underlying ground plane. Such coupling locations are also disposed proximate a predetermined corresponding feedpoint region of the radiating structure such that electromagnetic fields concentrated at the coupling location operate to nonconductively couple r.f. energy to/from the radiator structure from/to the feedline structure. The coupling location is preferably disposed at a widened and relatively lowered r.f. impedance coupling tab segment of the transmission line having a width dimension which is sufficient to provide matched impedance coupling to the corresponding feedpoint region but which is also substantially less than the dimension of the radiator structure transverse to its resonant dimension. The effective r.f. short circuit may be provided by an actual conductive connection to the underlying reference surface or by an r.f. open circuit termination located an additional one-fourth wavelength therefrom along the feedline structure.
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Citations
23 Claims
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1. A microstrip antenna system comprising:
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an electrically conductive reference surface; a layer of electrically conductive microstrip radiator structure disposed above said reference surface by a first predetermined distance less than one-tenth wavelength at the intended antenna operating frequency, said radiator structure including at least one conductively isolated two dimensional conductive area having a resonant dimension of substantially one-half wavelength at said operating frequency; and a layer of electrically conductive microstrip feedline structure disposed intermediate said reference surface and said layer of radiator structure, said feedline structure including at least one predetermined coupling location positioned an odd integer number of one-fourth wavelength(s) from an effective r.f. short circuit to the underlying reference surface thus causing a concentration of electromagnetic fields to occur at the coupling location which is also disposed proximate to a predetermined corresponding feedpoint region of said radiator structure such that the concentrated electromagnetic fields operate to nonconductively couple r.f. energy to/from said radiator structure from/to said feedline structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A microstrip antenna system comprising:
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an electrically conductive reference surface; a layer of electrically conductive microstrip radiator structure disposed less than one-tenth wavelength above said reference surface at the intended antenna operating frequency, said radiator structure including a plurality of conductively isolated and unconnected two dimensional shaped conductive areas each of which has a resonant dimension of substantially one-half wavelength at said operating frequency; a layer of electrically conductive microstrip feedline structure disposed between said reference surface and said layer of radiator structure, said feedline structure including a plurality of widened coupling tab segments having lowered r.f. impedances, as compared to other segments of the feedline structure, said coupling tab segments each defining at least one predetermined coupling location positioned one-fourth wavelength from an effective r.f. short circuit to the underlying reference surface and wherein each of said coupling locations is positioned proximate a corresponding predetermined feedpoint region of said radiator structure, there being at least one such feedpoint region on each of said shaped conductive areas; and r.f. input/output means connected to couple r.f. signals to/from said feedline structure with respect to said reference surface which signals are, in turn nonconductively coupled to/from said radiator structure via said matched coupling locations and feedpoint regions. - View Dependent Claims (11, 12, 13, 14)
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15. A microstrip antenna system comprising:
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an electrically conductive reference surface; a thin layer of electrically conductive microstrip feedline structure disposed above said reference surface by a first predetermined distance and dimensioned with respect to an intended antenna operating frequency to produce regions of relatively intense electromagnetic fields at predetermined coupling location(s); r.f. feed means connected to said feedline structure and to said reference surface for feeding r.f. signals to/from the feedline structure with respect to said reference surface at said intended antenna operating frequency; and a thin layer of electrically conductive microstrip radiator structure disposed above said reference surface by a second predetermined distance which is greater than said first predetermined distance and which is also less than approximately one-tenth wavelength at the intended antenna operating frequency, said radiator structure having a resonant dimension of substantially one-half wavelength at the antenna operating frequency and a transverse dimension of at least one-half wavelength at the antenna operating frequency so as to define radiating slots along transversely directed edges of the radiator structure; said radiator structure having predetermined feedpoint regions located above and proximate said coupling locations of the underlying feedline structure and substantially matched in r.f. impedance therewith such that r.f. signals are efficiently coupled electromagnetically thereat to/from said radiator structure from/to said feedline structure. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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Specification