LC structure useful in radio frequency security systems
First Claim
1. An LC structure for use in radio frequency security systems and resonant at at least one radio frequency, said LC structure comprising:
- flexible insulative layer comprised at least of a dielectric layer (88) folded back on itself about a predetermined fold line (92;
111) with its inner surface either face to face or indirectly joined via at least one additional layer (62;
93) therebetween, said insulative layer having on one surface an electrically conductive layer (87) configured to form(a) first and second alike planar multi-turn spirals (89, 90;
109,
110), which, in cooperation, form an inductive element,(b) at least two substantially two-dimensionally shaped portions (107, 108;
114,
115), each electrically connected to a respective spiral (89, 90;
109,
110), symmetrically positioned on opposite sides of said fold line (92;
111), thereby being juxtaposed and having sandwiched therebetween at least said dielectric layer (88) to form a capacitive element, each of said portions (107, 108;
114,
115) having a substantially straight boarder parallel to and spaced a short distance from the respective substantially straight boarder of the other portion (107, 108;
114,
115), respectively, thus leaving therebetween an elongated region in which said conductive layer is at least predominantly absent, the two-dimensional shape of each of said two portions (107, 108;
114,
115) serving to thereby stiffen said insulative layer and to thereby cooperatively oppose any tendency of said (combined) insulative and conductive layers to fold along any line other than said predetermined fold line (92;
111) and thus precisely localize the fold such thatsaid two symmetrically positioned portions (107 and 108;
114,
115) and spirals (89, 90;
109,
110) are precisely juxtaposed opposite each other so that each turn of said first spiral (89;
109) is aligned with a respective turn of said second sprial (90;
110) in a counter-turn relationship with respect to each other when both are viewed from the same side, to thereby form a series of stripline loops each having distributed inductive and distributed capacitive components, so that--by virtue of said precisely localized fold--a predictable capacitance for said capacitive element results which, in combination with said inductive element, causes said LC structure to resonate at said radio frequency.
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Abstract
The proposed LC structure is comprised of a flexible insulative layer folded back on itself about a predetermined foldline, said insulative layer having on one surface an electrically conductive layer configured to form first and second alike planar multi-turn spirals which, in a like folded superposition, counter turn against each other (if viewed from the same side) alinged face-to-face, and turn by turn, spaced by said folded flexible insulative layer. At least first and second substantially two-dimensionally shaped conductive layer portions connect to said first and second multi-turn spirals on opposite sides of said foldline, thereby juxtaposing each other and having sandwiched therebetween at least said dielectric layer, and leaving between each other an elongated region in which said conductive layer is predominantly absent, for thus opposing any tendency of said layers to fold along any line other than said predetermined foldline.
50 Citations
29 Claims
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1. An LC structure for use in radio frequency security systems and resonant at at least one radio frequency, said LC structure comprising:
flexible insulative layer comprised at least of a dielectric layer (88) folded back on itself about a predetermined fold line (92;
111) with its inner surface either face to face or indirectly joined via at least one additional layer (62;
93) therebetween, said insulative layer having on one surface an electrically conductive layer (87) configured to form(a) first and second alike planar multi-turn spirals (89, 90;
109,
110), which, in cooperation, form an inductive element,(b) at least two substantially two-dimensionally shaped portions (107, 108;
114,
115), each electrically connected to a respective spiral (89, 90;
109,
110), symmetrically positioned on opposite sides of said fold line (92;
111), thereby being juxtaposed and having sandwiched therebetween at least said dielectric layer (88) to form a capacitive element, each of said portions (107, 108;
114,
115) having a substantially straight boarder parallel to and spaced a short distance from the respective substantially straight boarder of the other portion (107, 108;
114,
115), respectively, thus leaving therebetween an elongated region in which said conductive layer is at least predominantly absent, the two-dimensional shape of each of said two portions (107, 108;
114,
115) serving to thereby stiffen said insulative layer and to thereby cooperatively oppose any tendency of said (combined) insulative and conductive layers to fold along any line other than said predetermined fold line (92;
111) and thus precisely localize the fold such thatsaid two symmetrically positioned portions (107 and 108;
114,
115) and spirals (89, 90;
109,
110) are precisely juxtaposed opposite each other so that each turn of said first spiral (89;
109) is aligned with a respective turn of said second sprial (90;
110) in a counter-turn relationship with respect to each other when both are viewed from the same side, to thereby form a series of stripline loops each having distributed inductive and distributed capacitive components, so that--by virtue of said precisely localized fold--a predictable capacitance for said capacitive element results which, in combination with said inductive element, causes said LC structure to resonate at said radio frequency.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 28)
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19. An LC structure for use in radio frequency security systems, said structure having at least one radio frequency tuned circuit with integrally formed inductive and capacitive elements, comprising at least
a flexible insulative layer having, for attaining a predetermined resonance response of the LC structure, a predetermined thickness and having first and second faces and an electrically conductive circuit pattern (91; - 109 and 110;
87) affixed to one of said faces and defining at least first and second multi-turn inductive portions (89, 90;
109,
110), both portions being substantially alike and symmetrically positioned with respect to a reference line (92;
111) extending therebetween, and spiraling inwardly from their outer edges in opposite directions, an outermost leg (107, 108;
114,
115) of each of said inductive portions further having a substantially two-dimensional shape which includes a straight side which is parallel to the straight side of the matching leg of the respective other portion and is substantially spaced a short distance (marginal distance between 107 and 108;
114 and
115) therefrom, leaving therebetween an elongated region in which said conductive circuit pattern (91;
109 and 110;
87) is at least substantially absent, to thereby precisely define said reference line (92,
111) therebetween, wherein said flexible insulative layer is folded about said reference line (92;
111) with its facing surfaces being either directly or indirectly (62;
93) fixed together such that at least a double thickness of said flexible insulative layer lies between the folded portions (89, 90;
109,
110) of said circuit pattern (91;
109 and
110) and the respective turns of the respective inductive portions are precisely aligned with each other, the aligned portions and said insulative layer therebetween thus forming a distributed capacitive element, while the opposing conductive areas (107, 108;
114,
115) adjacent said reference line form respective plates of at least one more or less discrete capacitive element, the individual capacitive element and the distributed capacitive element adding to form the total capacitance of the tuned circuit. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 29)
- 109 and 110;
Specification