Browse Prior Art Database

STACKED CAPACITORS IN STRIPLINE CIRCUITS

IP.com Disclosure Number: IPCOM000007602D
Original Publication Date: 1996-May-01
Included in the Prior Art Database: 2002-Apr-09
Document File: 2 page(s) / 65K

Publishing Venue

Motorola

Related People

Richard Kommrusch: AUTHOR [+2]

Abstract

The novel idea of "Stacked Capacitors in Stripline Circuits" turns a problem stray capacitance into a useful component by getting control over its value. In some circuits it can be used to the designer's advan- tage and this results in a volume savings in the final multilayer ceramic package, (MLC).

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MOTOROLA Technical Developments

STACKED CAPACITORS IN STRIPLINE CIRCUITS

by Richard Kommrusch and Rong-Fong Huang

  The novel idea of "Stacked Capacitors in Stripline Circuits" turns a problem stray capacitance into a useful component by getting control over its value. In some circuits it can be used to the designer's advan- tage and this results in a volume savings in the final multilayer ceramic package, (MLC).

  The history of the idea is explained with the aid of Figure 1. The Starting point was a T/R switch design. It consisted of 2 diodes, 2 transmission lines and 4 DC blocking capacitors, (a). The switch can be used in TDMA radios. When transmitting, the signal goes to the antenna without loss to the receiver and when receiving the signal goes from the antenna to the receiver. The multilayer design caused 3 stray capacitors to occur. Note that the outer plates ofthe

capacitor form the stray to ground, (b). Although the stray C can not be eliminated it can be con- trolled and made larger by adding some plates near ground, (c). It would be even better if a use for the stray C could be found. Now, most of our radios need a harmonic filter, (d), at the antenna and it has 3 capacitors to ground. When this is combined with the T/R switch we get the circuit shown in (e). It makes use ofthe stray C's and requires the addition of only one new capacitor and a modification of the transmission lines. Figure l(t), shows the artwork of the center layer in the 20 layer p...