The substrate integrated waveguide (SIW) technique makes it possible that a complete circuit including planar circuitry, transitions, and rectangular waveguides are fabricated in planar form using a standard printed circuit board or other planar processing techniques. In this paper, guided wave and modes characteristics of such an SIW periodic structure are studied in detail for the first time. A numerical multimode calibration procedure is proposed and developed with a commercial software package on the basis of a full-wave finite-element method for the accurate extraction of complex propagation constants of the SIW structure. Two different lengths of the SIW are numerically simulated under multimode excitation. By means of our proposed technique, the complex propagation constant of each SIW mode can accurately be extracted and the electromagnetic bandstop phenomena of periodic structures are also investigated. Experiments are made to validate our proposed technique. Simple design rules are provided and discussed.

Guided-wave and leakage characteristics of substrate integrated waveguide

A membrane probing assembly includes a probe card with conductors supported thereon, wherein the conductors include at least a signal conductor located between a pair of spaced apart guard conductors. A membrane assembly includes a membrane with contacts thereon, and supporting at least a signal conductor located between a pair of spaced apart guard conductors. The guard conductors of the probe card are electrically interconnected proximate the interconnection between the probe card and the membrane assembly. The guard conductors of the membrane assembly are electrically interconnected proximate the interconnection between the probe card and the membrane assembly.

Membrane probing system

A membrane probing assembly includes a support element having an incompressible forward support tiltably coupled to a rearward base and a membrane assembly, formed of polyimide layers, with its central region interconnected to the support by an elastomeric layer. Flexible traces form data/signal lines to contacts on the central region. Each contact comprises a rigid beam and a bump located in off-centered location on the beam, which bump includes a contacting portion. After initial touchdown of these contacting portions, further over-travel of the pads causes each beam to independently tilt locally so that different portions of each beam move different distances relative to the support thus driving each contact into lateral scrubbing movement across the pad thereby clearing away oxide buildup. The elastomeric member backed by the incompressible support ensures sufficient scrub pressure and reliable tilt recovery of each contact without mechanical straining of the beam. In an alternative embodiment, the contacts comprise conductive beams each supported on a loose U-shaped flap formed in the membrane assembly where each flap and beam is tiltably supported in inclined position by an elastomeric hub interposed between the flap and support.

Membrane probing system with local contact scrub

A wafer probe station is equipped with an integrated environment control enclosure substantially surrounding a supporting surface for holding a test device, such enclosure limiting fluid communication between the interior and exterior of the enclosure and preferably also providing EMI shielding and a dark environment. The limited communication between the interior and exterior of the enclosure is kept substantially constant despite positioning movement of either the supporting surface or probes. The positioning mechanisms for the supporting surface and probes each are located at least partially outside of the enclosure.

Wafer probe station having environment control enclosure

A direct current and a modulation signal are simultaneously applied to contact pads on a device under test, such as a laser diode, with a probe that reduces signal distortion and power dissipation by transmitting a modulated signal through an impedance matching resistor and transmitting of a direct current over a second signal path that avoids the impedance matching resistor.

Probe for combined signals

An original multimode thru-reflection line (TRL) algorithm is used to derive the generalized scattering parameters of multimode two-port networks. Theoretical developments are detailed for calibration procedures based on two ports as well as multiple-port vector network analyzer (VNA) measurements. First-run experimental results demonstrate the validity of this technique. This method allows the experimental characterization of multiconductor transmission-line devices. It could also be used to characterize power coupling to undesired modes in monolithic microwave integrated circuit (MMIC) structures using conductor-backed coplanar waveguides.

Multimode TRL. A new concept in microwave measurements: theory and experimental verification

The derivation of multimode S parameters of a multiconductor waveguide discontinuity is investigated using an analytical quasi TEM model. Analytical and full wave results are compared. On the basis of the proposed methodology, precise and simple equivalent circuits can be derived. Such analytical models can be implemented in CAD libraries.

Analytical and Full-Wave Characterization of Multimode Waveguide Discontinuities

This paper presents an original approach to analyze multimode waveguide discontinuities. The generalized scattering parameters are determined by a matrix pencil moment method associated with efficient numerically multimode matched loads placed at each physical port of the discontinuities. The analysis of both microstrip-coupled lines and coplanar lines asymmetric discontinuities is presented and successfully compared to experiments and available published results.

P. Kennis

Papers

Multimode TRL. A new concept in microwave measurements: theory and experimental verification

Analytical and Full-Wave Characterization of Multimode Waveguide Discontinuities

Accurate and efficient numerical method for the analysis of multimode waveguide discontinuities