Picosecond Pulse Labs

Formfactor, Inc.

John Ebner

Steven H Pepper

Agoston Agoston

Robert Norton

Benjamin N Eldridge

David W Pratt

Eric Hill

Edin Sijercic

Jason William Cosman

Improved electrically conductive guide plates for vertical probe arrays are provided by patterning a thin metal layer disposed on an insulating substrate. Holes passing through the guide plate for guiding probes can be electrically connected or isolated from each other in any pattern according to the deposition of the metal. Such structures can include several distinct ground and/or voltage planes. Furthermore, passive electrical components can be included in the guide plate, by patterning of the deposited metal and/or by integration of passive electrical components with the deposited metal traces.

Direct metalized guide plate

Improved impedance matching is provided in vertical probe arrays having conductive guide plates by providing ground pins connecting the guide plates that do not mechanically touch the device under test or the input test apparatus. Such ground pins can be disposed in predetermined patterns around corresponding signal probes to improve an impedance match between the probes and the test apparatus and/or the device under test. Preferably all impedances are matched to 50&#x3a9; as is customary for high frequency work.

Probe head with inductance reducing structure

Frequency converters include waveguides configured for a local oscillator (LO) signal, an intermediate frequency (IF) signal, and an RF signal. A multimode IF waveguide can be used for selectively coupling of an IF signal and to reduce signal contributions produced by the LO signal. Typically, the multimode waveguide is situated to that the IF signal and the LO signal propagate in different waveguide modes, and a selected one of these signals can be selectively attenuated. In some examples, a periodically stepped waveguide is used to enhance propagation of a selected waveguide mode or a lossy conductor is used to attenuate a selected waveguide mode.

Waveguide samplers and frequency converters

An ultrafast sampler includes a series of Schottky diodes configured with a coplanar waveguide to form a nonlinear transmission line (NLTL) that compresses a local oscillator input to form a series of strobe pulses. Strobe pulses of opposite polarity are capacitively coupled to sampling diodes to obtain samples of a signal applied to a signal input. The samples are directed along an intermediate frequency waveguide to, for example, a signal processor such as an oscilloscope, for storage and analysis. The intermediate frequency waveguide is configured so that conductors of the intermediate frequency waveguide receive signal samples of a common polarity and strobe samples of opposite polarities so that portions of strobe pulses delivered to a signal processor are distinguished from signal samples. In an embodiment, the intermediate frequency waveguide and the strobe waveguide are symmetrically situated along a common axis, and conductors of the strobe waveguide are positioned between the axis and the conductors of the intermediate frequency waveguide. The sampling circuit is defined on a GaAs substrate and a coaxial-to-airline-to-substrate transition is configured to deliver signals from a coaxial cable to the sampling circuit. A signal output is configured to direct the signal back into a coaxial cable.

Ultrafast sampler with coaxial transition

An ultrafast sampling system includes an interposer and a sampler that include series of Schottky diodes configured with a non-parallel waveguide to form shocklines or nonlinear transmission line (NLTLs) that produce a differential strobe pulse. The shocklines are defined by non-parallel conductors that are configured as, for example, triangular, dentate, arcuate, or other shapes, or as conductors that have edges that are triangular, dentate, arcuate, or the like. The conductors are defined with respect to a substrate, and are airbridged so that at least some portions of the conductors are displaced from the substrate to reduce waveguide capacitance. Electrical connection to the sampler is made with airline having a inner conductor that is deformable to contact an input pad defined on the sampler.

Growing community of inventors

Portland, OR, United States of America

John Ebner