Browse Prior Art Database

A UNIVERSAL COPLANAR CROSS THROUGH

IP.com Disclosure Number: IPCOM000006827D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2002-Feb-06
Document File: 3 page(s) / 123K

Publishing Venue

Motorola

Related People

Kenneth V. Bauer: AUTHOR [+2]

Abstract

A universal coplanar cross through (UCCT) having advantages of DC isolation, light weight, single-sided circuit card compatibility, ease of circuit analysis and design and broad band operation is descrii The UCCf allows two signals having distinct frequencies on differ- ent signal paths to cross one another on a planar surface with reduced cross-coupling, distortion and/or loss.

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MOTOROLA INC. Technical Developments Volume 19 June 1993

A UNIVERSAL COPLANAR CROSS THROUGH

by Kenneth V. Bauer and David W. Corman

  A universal coplanar cross through (UCCT) having advantages of DC isolation, light weight, single-sided circuit card compatibility, ease of circuit analysis and design and broad band operation is descrii The UCCf allows two signals having distinct frequencies on differ- ent signal paths to cross one another on a planar surface with reduced cross-coupling, distortion and/or loss.

  A traditional technique for crossing two radio fre- quency signal paths requires multiple traces, each placed on different layers of multilayer circuit boards. Multi- layer circuit boards are expensive to manufacture and have greater weight per unit area than single layer cir- cuit boards using similar substrate materials. Addition- ally, transitions of conductors from one layer to another layer introduce parasitic impedances and/or admittances which complicate circuit design and/or result in reduced circuit performance. These disadvantages are amelio- rated by employing single-layer circuits having UCCTs for signal lime crossings.

  Figure 1 is a schematic diagram of a UCCT The UCCT comprises two signal paths, a low-pass signal path extending between nodes RF,, and a high-pass signal path extending between nodes RFHI.,,. The low pass signal path allows a first signal having a first fre- quency to be coupled between nodes RF,,, and not coupled to nodes RF,,i.WsS, while the high pass signal path allows a second signal having a second frequency to be coupled between nodes RF,,,, and not coupled to nodes RF,,,. The UCCT comprises capacitors C and inductors 2L having a common node.

  The high-pass signal path comprises admittances LT coupled in shunt with nodes RF,,,,. Admittances LT have low impedance to the tirst frequency and have high impedance at the second frequency. The high-pass sig- nal path further comprises capacitors C having capaci- tance C coupled in series between nodes RF,,,,,. An equivalent circuit for the high-pass signal path is pro- vided in Figure 2.

  Fire 2 iuustrates nodes RFaI.& having two capac- itors C coupled in series therebetween. A common node coupling capacitors C together also has inductance L coupled in shunt to ground, forming a high pass filter between nodes RF,,.Pass.

  The low-pass signal path (Figure 1) comprises admit- tances HT coupled in shunt with nodes RF,,,. Admit- tances HT have low impedance at the second frequency an...