Georg Boeck

A new method for pHEMT noise-parameter determination based on 50-/spl Omega/ noise measurement system

A new method for determining the four noise parameters of pseudomorphic high electron-mobility transistors (pHEMTs) based on a 50-/spl Omega/ noise measurement system without a microwave tuner is presented. The noise parameters are determined based on the noise correlation matrix technique by fitting the measured noise figure of the active device. On-wafer experimental verification up to 26 GHz is presented and a comparison with a tuner-based method is given. The scaling rules for noise parameters have also been determined. Good agreement is obtained between simulated and measured results for 2/spl times/20 /spl mu/m, 2/spl times/40 /spl mu/m, and 2/spl times/60 /spl mu/m gatewidth (number of gate fingers /spl times/ unit gatewidth) 0.25-/spl mu/m double-heterojunction /spl delta/-doped pHEMTs.

Direct parameter-extraction method for laser diode rate-equation model

A new direct extraction method to determine the small-signal and rate-equation model parameters for laser diode is presented in this paper. This method differs from previous ones by extracting the whole model parameters without global numerical optimization techniques. The main advantage of this method is that a unique and physically meaningful set of extrinsic and intrinsic parameters are extracted by using a set of closed-form expressions based on the input reflection coefficients and modulation responses taken from on-wafer measurement. Simulated and measured results for the input reflection coefficients and modulation responses exhibit good agreement over a wide range of bias points.

Microwave noise modeling for InP-InGaAs HBTs

Analytical expressions for the noise parameters of microwave InP double heterojunction bipolar transistors (DHBTs) are presented in this paper. These expressions are derived from an accurate small-signal and noise equivalent-circuit model, which takes into account the influences of the base-collector capacitance and the base resistance distributed nature. Pad capacitances and series inductances are also included. Further simplified expressions for noise parameters in the low-frequency range are given. Good agreement is obtained between measured and calculated results up to 20 GHz for InP-InGaAs DHBTs with a 5/spl times/5 /spl mu/m/sup 2/ emitter area over a wide range of bias points.

A new method for determination of parasitic capacitances for PHEMTs

A new direct extraction method for the determination of the parasitic capacitances of PHEMTs is presented in this paper. This method is based on a general scalable small signal equivalent circuit model under pinch-off bias condition. The main advantage of this approach is that all parasitic capacitances including Cpg, Cpd and Cpgd can be extracted simultaneously by using PHEMTs of different sizes but with the same pad structure. Good agreement is obtained between modelled and measured results for 2 × 20 µm, 2 × 40 µm, 2 × 60 µm and 2 × 100 µm gate width (number of gate fingers × unit gate width) double heterojunction δ-doped PHEMTs.

An approach to determine small-signal model parameters for InP-based heterojunction bipolar transistors

A new method for the extraction of the small-signal model parameters of InP-based heterojunction bipolar transistors (HBT) is proposed. The approach is based on the combination of the analytical and optimization technology. The initial values of the parasitic pad capacitances are extracted by using a set of closed-form expressions derived from cutoff mode S-parameters without any test structure, and the intrinsic elements determined by using the analytical method are described as functions of the parasitic elements. An advanced design system is then used to optimize only the parasitic parameters with very small dispersion of initial values. Good agreement is obtained between simulated and measured results for an InP HBT with 5/spl times/5 /spl mu/m/sup 2/ emitter area over a wide range of bias points up to 40 GHz.

Relationships between common source, common gate, and common drain FETs

This paper comprehensively analyzes the relationship between common source (CS), common gate (CG), and common drain (CD) field-effect transistors (FETs). The signal and noise parameters of the CG and CD configuration can be obtained directly by using a simple set of formulas from CS signal and noise parameters. All the relationships provide a bi-directional bridge for the transformation between CS, CG, and CD FETs. This technique is based on the combination of an equivalent-circuit model and conventional two-port network signal/noise correlation matrix technique. The derived relationships have universal validity, but they have been verified at 2/spl times/40 /spl mu/m gatewidth (number of gate fingers /spl times/ unit gatewidth) double-heterojunction /spl delta/-doped AlGaAs/InGaAs/GaAs pseudomorphic high electron-mobility transistor with 0.25-/spl mu/m gate length. Good agreement has been obtained between calculated and measured results.

Empirical all region current based PHEMT DC model

This paper proposes an improved PHEMT DC model which covers high and low current applications, as well good agreement is obtained between simulated and measured results for a 0.25(1 /spl times/ 40) /spl mu/m double heterostructure PHEMT.

Authors' reply [to Comments on "Microwave noise modeling for InP-InGaAs HBTs"]

For original article by J. Gao, X. Li, H. Wang, and G. Boeck see ibid., vol.52, no.4, p.1624-72, April 2004. For comments by L. Escotte and J. Graffeuil see ibid., vol.53, no.1, p.415-16, January 2005.

An Improved On-Wafer Measurement Method for PHEMT Modeling for Millimeter Wave Application

An improved on-wafer measurement method by using coaxial calibration instead of on-wafer calibration for PHEMT modeling is proposed in this paper. The advantage is that S-parameters of PHEMT device can be measured on wafer without impedance standard substrate (ISS) after the S-parameters of the microprobes have been determined. Excellent agreement is obtained between on-wafer calibration measurement and coaxial calibration measurements, respectively.