Circuit boards including capacitive coupling for signal transmission and methods of use and manufacture
First Claim
1. A circuit board for mounting electrical components and having conductive layers spaced apart and electrically insulated from each other, and at least one circuit for transmitting AC signals from one layer to another, the AC signal transmitting circuit comprisinga conductive signal pad formed by a first conductive layer in the circuit board and adapted for coupling with means for generating an AC signal,a conductive receptor pad formed by a second conductive layer in the circuit board and adapted for coupling with means for responding to the AC signal, anda dielectric layer arranged between the signal and receptor pads, the thickness and dielectric constant of the dielectric layer and the respective areas of the signal and receptor pads being selected for developing effective capacitive coupling between the signal and receptor pads in order to electrostatically transmit the AC signal from the signal pad to the receptor pad,the signal and receptor pads and the dielectric layer having electrical characteristics approaching a resonant frequency condition in the AC signal transmitting circuit whereby capacitive reactance and inductive reactance approach equality in order to optimize capacitive coupling.
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Accused Products
Abstract
A circuit board and method of forming a circuit board with signal and receptor pads arranged on layers spaced apart in a Z direction with a dielectric layer therebetween, parameters of a resulting AC signal transmitting circuit resulting wherein:
capacitive reactance is defined by the equation (I) ##EQU1## where F is frequency and C is capacitance; inductive reactance is defined by the equation (II)
X.sub.L =2πFL
where F is frequency and L is inductance;
capacitance is defined by the equation (III) ##EQU2## where A is the effective mutual area of the signal and receptor pads, D is Faraday'"'"'s constant, E is the dielectric constant, and τ is the thickness of the dielectric layer; and
inductance is defined by the equation (IV)
L=0.005 ln (4h/d)μH/in.
where ln indicates the natural logarithm for the value 4h/d, where h is the distance above a ground plane, and d is the equivalent diameter of a conductor;
wherein capacitance and inductance are established in equations I and II with XC and XL being equal or approaching equality and the values of A, D, τ, IN, h (etc.) are preselected or calculated from equations III and IV.
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Citations
14 Claims
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1. A circuit board for mounting electrical components and having conductive layers spaced apart and electrically insulated from each other, and at least one circuit for transmitting AC signals from one layer to another, the AC signal transmitting circuit comprising
a conductive signal pad formed by a first conductive layer in the circuit board and adapted for coupling with means for generating an AC signal, a conductive receptor pad formed by a second conductive layer in the circuit board and adapted for coupling with means for responding to the AC signal, and a dielectric layer arranged between the signal and receptor pads, the thickness and dielectric constant of the dielectric layer and the respective areas of the signal and receptor pads being selected for developing effective capacitive coupling between the signal and receptor pads in order to electrostatically transmit the AC signal from the signal pad to the receptor pad, the signal and receptor pads and the dielectric layer having electrical characteristics approaching a resonant frequency condition in the AC signal transmitting circuit whereby capacitive reactance and inductive reactance approach equality in order to optimize capacitive coupling.
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7. A method of forming a circuit board for mounting electrical components and having conductive layers spaced apart and electrically insulated from each other, and at least one circuit for transmitting AC signals from one layer to another, comprising the steps of forming a conductive signal pad and conductive receptor pad on surfaces of the circuit board spaced apart in a Z direction with a dielectric layer therebetween,
the conductive signal pad being adapted for coupling with means for generating an AC signal, coupling the conductive signal pad with means for generating an AC signal, coupling the conductive receptor pad with means for responding to the AC signal, selecting the thickness and dielectric constant of the dielectric layer and the respective areas of the signal and receptor pads for developing effective capacitive coupling between the signal and receptor pads in order to electrostatically transmit the AC signal from the signal pad to the receptor pad, and selecting electrical characteristics of the signal and receptor pads and the dielectric layer to approach a resonant frequency condition in the AC signal transmitting circuit whereby capacitive reactance and inductive reactance approach equality in order to optimize capacitive coupling.
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13. A circuit board for mounting electrical components and having conductive layers spaced apart and electrically insulated from each other, and at least one circuit for transmitting AC signals from one layer to another, the AC signal transmitting circuit comprising
a conductive signal means formed by a first conductive layer in the circuit board and adapted for coupling with means for generating an AC signal, a conductive receptor means formed by a second conductive layer spaced apart in a Z direction from the first conductive layer in the circuit board and adapted for coupling with means for responding to the AC signal, a dielectric layer arranged between the signal and receptor means, characteristics for the conductive signal means, the conductive receptor means and the dielectric layer arranged therebetween being selected for developing effective signal transmission coupling between the signal and receptor means in order to electrostatically transmit the AC signal from the signal means to the receptor means, and the signal and receptor means and the dielectric layer having electrical characteristics approaching a resonant frequency condition in the AC signal transmitting circuit whereby capacitive reactance and inductive reactance approach equality in order to optimize capacitive coupling.
Specification