Transistor test fixture with convex surface of the support blocks
View Patent ↗Microwave micro-strip or coplanar waveguide (CPW) transistor test fixtures have the top surface of the input and output blocks forming a convex shape, to allow the soft dielectric substrate to be stretched over the surface and establish secure and continuous ground contact with the block surface and eliminate spurious cavities and discontinuities.
1. A radio frequency (RF) test fixture for RF transistors (device under test, DUT), comprising
a) an input and an output metallic support block, said blocks having convex top surface,
b) a DUT-carrying block (INSERT), said DUT having input and output terminals;
whereby
each support block has an input side and an output side;
and whereby
sheets of flexible, surface-metallized soft dielectric (plastic) substrate, having a top surface and a bottom surface, are deposited and secured on the convex top surface of the support blocks, said sheet having one or more microstrip transmission lines fabricated (etched) on their top surface;
and whereby
the INSERT is inserted and secured between the input and output support blocks;
and whereby
the input support block has one or more input RF connectors on its input side and is attached to the INSERT on its output side;
and whereby
the output support block has one or more output RF connectors on its output side and is attached to the INSERT on its input side;
and whereby
the axis of the convex top surface of the support blocks is parallel to the axis between the INSERT and the RF connectors;
and whereby
the transmission lines lead from the RF connectors to the DUT terminals.
2. The DUT as in claim 1 being a packaged RF transistor.
3. The fixture as in claim 2 ,
whereby the microstrip transmission line(s) on the input support block lead from the RF connector(s) to the DUT input terminal(s) and the microstrip transmission line(s) on the output support block lead from the DUT output terminal(s) to the RF connector(s).
4. The fixture as in claim 1 ,
whereby the dielectric substrates are conductively coated (metallized) on the bottom surface, which faces the convex top surface of the input and output support blocks,
and have one or more micro-strip line(s) fabricated (etched) on their conductively coated (metallized) top surface.
5. The fixture as in claim 1 ,
whereby the dielectric substrates have one or more coplanar waveguide (CPW) transmission line(s) fabricated on their conductively coated (metallized) top surface.
6. The fixture as in claim 5 ,
whereby the dielectric substrates are stretched perpendicularly to the axis of the transmission lines on each block, to establish continuous, secure and cavity-free ground contact between the metallized bottom of the dielectric substrates and the convex top of the support blocks.
7. The fixture as in claim 6 ,
whereby the curvature of the convex top surface of the support blocks is small enough to allow for the dielectric substrates, after said substrates have been deposited and secured, to remain within their elasticity range.