Analytical model and parameter extraction to account for the pad parasitics in RF-CMOS

A model which considers the pad parasitic effects when performing on-wafer S-parameter measurements on microwave devices fabricated on silicon substrates is presented. The model parameters are directly determined using a simple and analytical measurement-based method, allowing the electrical representation of the complete test structure using an equivalent circuit. The validity of the model is verified by achieving excellent agreement between simulated and experimental data up to 55GHz. In addition, a recently reported simplified deembedding procedure is improved and compared to a conventional one to study its validity as frequency increases.     

Unified method for determining the complex propagation constant of reflecting and nonreflecting transmission lines

In this letter, a unified method for computing the complex propagation constant /spl gamma/ of reflecting and nonreflecting lines is presented. The method uses a new matrix representation of the wave cascade matrix of a line having any characteristic impedance. To overcome the sign ambiguity problem inherent to the classical method some parameters of the fictitious X/sub AM/ matrix are used and determined by the method itself. The success of the new procedure to resolve the sign ambiguity problem lies in the new matrix representation of the wave cascade matrix of a line having any characteristic impedance and in the reliable criterion to determine the a/sub m//c/sub m/ and b/sub m/ parameters of the fictitious X/sub AM/ matrix.     

Reliable method for computing the phase shift of multiline LRL calibration technique

In this paper, a new method for computing the phase shift of lines used in the multiline line-reflect-line (m) calibration technique is presented. The new method is based on a matrix approach to determine the traveling wave /spl lambda/ and uses a reliable criterion to compute the constants a/c and b. The new method overcomes the problem of sign ambiguity of the eigenvalues /spl lambda//sub 1/ and /spl lambda//sub 2/, inherent to the classical method. Another advantage of the new method of computing the phase shift is that the physical length of lines is not needed. The new method computes the line phase shift from the knowledge of the traveling wave /spl lambda/, that is, without previous knowledge of the wave propagation constant.     

Influence of the SRO as passivation layer on the microwave attenuation losses of the CPWs fabricated on HR-Si

In this letter, silicon rich oxide (SRO) is used as the passivation layer of coplanar wave guides (CPWs) fabricated on high resistivity silicon (HR-Si). The microwave performance of the CPWs is evaluated computing the attenuation loss (/spl alpha/) of the device in the 0.045-50 GHz frequency range. It is shown that for frequencies lower than 5 GHz the losses of CPWs using SRO as a passivation layer are lower than those of CPWs using SiO/sub 2/. It is also shown that using a combination of thermal and CVD SiO/sub 2/, a reduction of the losses of CPWs is obtained.     

Advances in Linear Modeling of Microwave Transistors

Heterojunction field effect transistors (HFET) based on gallium nitride (AlGaN/GaN) and metal semiconductor field effect transistors (MESFETs) based on silicon carbide (SiC) are the preferred transistors for high-power amplifier circuit designs rather than MESFETs, high electron mobility transistors (HEMTs) and pseudomorphic HEMTs based on gallium arsenide (GaAs) or indium phosphide (InP) semiconductor technology. While AlGaN/GaN and SiC are good candidates for high-power applications, GaAs and InP semiconductor technologies are the preferred transistors in low-power, low-voltage, and low-noise applications [1].