G. Arjavalingam

Characterization of resistive transmission lines by short-pulse propagation

A method for completely characterizing resistive transmission lines by short-pulse propagation is described. Using the loss and dispersion of pulses propagated on two different lengths of line, together with the measured low-frequency capacitance, the frequency-dependent propagation constant, attenuation, and the complex impedance are determined. The basic method is demonstrated with results from low-loss cables and a well-controlled coplanar waveguide sample.<<ETX>>

A novel 24-GHz bandwidth coaxial probe

An electrical probe based on specially designed coaxial tips is shown to have 24-GHz bandwidth. It can be used to test high-speed signal propagation on planar or nonplanar chip or package interconnection structures with signal/ground pads as small as 50 mu m. The detailed fabrication procedure, characterization, and use of the probe are presented. A variation of the design has 500- Omega input impedance and a bandwidth of 19 GHz. >

Short-pulse propagation technique for characterizing resistive package interconnections

A novel technique for completely characterizing the frequency-dependent electrical properties of resistive transmission lines by short-pulse propagation is described. Time-domain measurements of the loss and dispersion of pulses propagated on two different lengths of the line under investigation, together with the measured low-frequency capacitance, are used to determine its broadband complex propagation constant and complex impedance. The technique is illustrated with measurements on a thin-film package interconnection structure. The measured line characteristics are then used in a transient circuit analysis program to predict output waveforms generated by logiclike signals. In the absence of modeling capabilities, the measured results can be used directly as input to circuit simulation programs. The authors illustrate this with the response of a 9.65-cm-long thin-film line to logiclike signals. >

Investigation of absolute photonic band gaps in two-dimensional dielectric structures

Abstract We examine the photonic band structure of two-dimensional (2D) arrays of dielectric holes using the coherent microwave transient spectroscopy (COMITS) technique. Such 2D hole arrays are constructed by embedding low-index rods (air) in a dielectric background of higher-index Stycast material (n = 3·60). The dispersion relation for electromagnetic wave propagation in these photonic crystals is directly determined using the phase sensitivity of COMITS. We find that both the square and triangular lattice structures exhibit photonic band gaps that are common to both polarizations for all wave-vectors along major symmetry axes. In addition, the connectivity of the high-index dielectric and the opening of a large gap for propagation with E field perpendicular to the hole cylinders are found to be important criteria for generating a large absolute photonic band gap.

Characterization of resistive transmission lines to 70 GHz with ultrafast optoelectronics

The complete characterization of resistive transmission lines with the short-pulse propagation technique is extended to 70 GHz. The wide-frequency coverage is made possible by the use of ultrafast photoconductive switches for pulse generation and sampling. The picosecond optoelectronic sampling oscilloscope is described and results of measurements on thin-film strip transmission lines are presented.<<ETX>>

Picosecond time-domain electromagnetic scattering from conducting cylinders

The microwave scattering properties of conducting cylinders are characterized by measuring their response to picosecond-duration electromagnetic pulses. The ultrafast electromagnetic transients are generated and detected with optoelectronically pulsed antennas. The time-domain response gives physical insight into the scattering process. In addition, Fourier analysis is used to obtain the frequency dependence of the scattered amplitude and phase from 15 to 140 GHz.<<ETX>>

Microwave diffraction and interference in reflection using transient radiation from optoelectronically pulsed antennas

Broadband (15–130 GHz) microwave interference and diffraction are demonstrated in a reflection configuration using transient radiation from optoelectronically pulsed antennas. The measured complex reflection function of Fabry–Perot interferometers and diffraction from amplitude gratings are presented. The effectiveness of the technique for quantifying the scattering from general three‐dimensional objects is discussed.

Electrical characterization and performance limits of a flexible cable

The electrical performance of a flexible-cable test structure is characterized from low frequencies up to 25 GHz. The experimental results are used to develop and refine models which describe the performance of such cables, with particular emphasis on the contribution of dielectric and resistive losses, including skin effect. The capability of triplate flexible cables to provide high-bandwidth connections over long lengths is investigated with the models developed. A triplate design is chosen because it offers high density, limited crosstalk, no loss through radiation, and relatively inexpensive fabrication. Bit rates of 100 Mb/s-1 Gb/s are considered for propagation over lengths up to 250 cm. The paper highlights the performance-limiting factors through realistic examples, including the contribution of interfaces to other interconnection structures.

Microwave reflection measurements on doped semiconductors with picosecond transient radiation

Broadband microwave reflection spectroscopy using the COMITS (coherent microwave transient spectroscopy) method is described. COMITS is particularly suited to reflection studies because the picosecond transient radiation emitted from planar antennas is strongly linearly polarized. The validity of the technique is verified by reflection measurements on isotropic and anisotropic dielectrics. Reflection studies on a series of doped silicon samples demonstrate that the carrier dynamics in the 15-140-GHz frequency range are well described by a simple Drude model.<<ETX>>

Characterization Of An Experimental Thin-Film Interconnection Structure.

Measurements and simulation of high-speed pulse propagation and cross-talk on an experimental thin-film transmission line structure are presented. The measurements are carried out using both an optoelectronic pulse generation and detection technique, and a recently developed non-contact high-speed sampling method based on a picosecond electron beam. We find through simulation that a quasi-static coupled transmission line model with frequency dependent skin-effect loss accurately predicts the pulse delay and distortion characteristics of our sample.