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Switching coaxial PCB testpoint

IP.com Disclosure Number: IPCOM000017944D
Original Publication Date: 2001-Oct-01
Included in the Prior Art Database: 2003-Jul-23
Document File: 1 page(s) / 558K

Publishing Venue

Siemens

Related People

Claus Bjerre Pedersen: AUTHOR

Abstract

In radio-based electronic products without an external RF (radio frequency) connector (an external connec- tor is used for connecting accessories or an antenna and is typically used for production tests as well) the need for a RF connection in for instance production- testers often stipulates a 50 ohms coaxial PCB (printed circuit board) testpoint for a likewise coaxial 50 ohms testneedle in the test equipment. The method proposed here gives a new scope for development in the design of such a RF coaxial testpoint. A testpoint which is required to be 50 ohms can load the RF signal paths quite heavily, especially if they are far from 50 ohms. The problem is that the testpoint will keep loading the RF circuits also after production. The idea is that the outer RF signal ground ring is divided into two or three equal size arcs (circular elements) of which only one is the original RF signal ground (see fig. 1). The remaining one or two arcs will now be floating unless a coaxial testneedle is connected to the PCB, in which case they are grounded. The reason for two or three segments is that these geometric constructions ensures that the testneedle will connect to all pads.

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Information / Kommunikation

Switching coaxial PCB testpoint

Idee: Claus Bjerre Pedersen, DK-Aalborg

In radio-based electronic products without an externalRF (radio frequency) connector (an external connec-tor is used for connecting accessories or an antennaand is typically used for production tests as well) theneed for a RF connection in for instance production-testers� � � often� stipulates� a� 50 ohms coaxial PCB(printed circuit board) testpoint for a likewise coaxial50 ohms testneedle in the test equipment. The methodproposed here gives a new scope for development inthe design of such a RF coaxial testpoint. A testpointwhich is required to be 50 ohms can load the RFsignal paths quite heavily, especially if they are farfrom 50 ohms. The problem is that the testpoint willkeep loading the RF circuits also after production.

The idea is that the outer RF signal ground ring isdivided� into� two� or� three equal size arcs (circularelements) of which only one is the original RF signalground (see fig. 1). The remaining one or two arcswill� now� be� floating� unless� a� coaxial� testneedle isconnected to� the� PCB,� in� which� case� they� aregrounded. The reason for two or three segments isthat these geometric constructions� ensures� that� thetestneedle will connect to all pads.

The technical problem solved here is that the behav-ior of the coaxial testpoint can be differentiated be-tween production and real-life. One typical series ofproducts which could benefit from this method a...