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We investigate radiation-induced effects on the DC, AC and thermal characteristics of high-performance SiGe HBTs fabricated on thin-film SOI. TCAD simulations indicate novel heavy-ion charge collection phenomena resulting from the unique [C.sub.B][E.sup.B]C device layout of this technology platform. Index Terms--C-SiGe, Heterojunction bipolar transistors, radiation effects, SiGe HBT, silicon-on-insulator (SOI), TCAD.

This paper presents a detailed investigation of the dual base method for intrinsic and extrinsic HBT's base resistance extraction that is of utmost importance for process monitoring and device modeling purpose. Ring emitter test structures layout, dc measurement conditions, and extraction methodology have been improved to get reliable results. A particular attention has been drawn to the external base resistance extraction and the effect of parasitic resistances is highlighted. The method has been generalized for an extraction of the base resistance specific parameters using any number of geometries (widths and lengths) and therefore demonstrates the base resistance scalability. This method is applied to a ST state-of-art fully self aligned double poly BiCMOS SiGeC technology, and results are discussed. Index Terms--Base resistance, bipolar modeling, dual base test structure, sheet resistance.

The technology optimization of a vertical SiGeC heterojunction bipolar transistor (HBT) on thin-film silicon-on-insulator (SOI) substrates is presented. Findings reveal fully functional devices and ideal operation for high and low collector doping.

The time invariant (TI) widely linear (WL) minimum variance distortionless response (MVDR) beamformer for the optimal reception of an unknown signal corrupted by potentially noncircular interferences is discussed. Findings reveal the suitability of the beamformer for spectrum monitoring or passive listening in noncircular context.

Three polarization diversity (PD)-2q-MUSIC algorithms depending on the a priori knowledge about the polarization of the sources are discussed. Results suggest the increase in performance of PD-2q algorithms with q when resolution in both direction of arrival and polarization is required.

An extension of the Music method to an arbitrary even order 2q (q greater than equal to 1) is proposed, giving rise to the 2q-Music methods. The performance analysis of these methods show off important results for direction-finding applications and in particular the best performance with respect to 2-Music and 4-Music, of 2q-Music method with q > 2, despite their variance, when some resolution is required.

New enlightening results about the behavior, properties, and performance of the optimal widely linear (WL) receiver for demodulation of a binary phase-shift keying (BPSK) signal corrupted by rectilinear interferences are presented. By simple algebraic operation of demodulation on the baseband signal, the minimum shift keying and Gaussian minimum shift keying (GMSK) modulations can be made to approximately correspond to a BPSK modulation allowing the application of the simple antenna interference cancellation (SAIC) concept to the GMS cellular network at the mobile level.

The Independent Component Analysis using Redundancies in the quadricovariance (ICAR) algorithm, exploiting the information contained in the data statistics at fourth order only is proposed. This algorithm allows the processing of overdetermined mixtures of sources, provided the latter have marginal fourth-order (FO) cumulants with the same sign, which is generally the case in radio communications contexts.

A new blind identification (BI) method that exploits the fourth-order data statistics only (FOBIUM) is presented to process both overdetermined and underdetermined instantaneous mixtures of statistically independent sources. The FOBIUM method is shown to require a relatively weak number of snapshots to generate good output performances for currently used radiocommunication sources, such as quadrature phase shift keying (QPSK) sources.

The mechanisms, resolution and maximal processing capacity of numerous 2qth order array processing methods are discussed. The geometry, number of Virtual Sensors (VSs) of the Virtual Array (VA) and the number of sources that could be processed by a 2qth order method by exploiting the algebraic structure of C (sub 2q,x) are controlled by the arrangement of the 2qth order data statistics.

An analysis conducted to check the behavior, and to propose adaptations of the current second-order (SO) blind source separation (BSS) methods is presented. The extension for deterministic sources like frequency shift keying (FSK) and continuous phase frequency shift keying (CPFSK) sources is proposed.

An analysis conducted to check the behavior, and to propose adaptations of the current second-order (SO) blind source separation (BSS) methods is presented. The extension for deterministic sources like frequency shift keying (FSK) and continuous phase frequency shift keying (CPFSK) sources is proposed.

The problem is addressed of estimating second-order statistics of a frequency-selective Rayleigh channel in the context of the wideband code division multiple access (CDMA) mode of the Universal Mobile Telephone Service (UMTS). Performances are evaluated, and it is shown that significant improvement of the performance of a RAKE receiver is achieved.

Fourth-order (FO) direction finding (DF) methods have been usually employed for non-Gaussian signals. It has been shown through the use of the virtual cross-correlation (VCC) concept that the application of FO cumulants for the DF problem increases the effective aperture of an arbitrary antenna array. This led to the virtual array (VA) concept. The VA concept is presented through an alternative manner that is easier and more direct to handle than the VCC tool.

Linear-quadratic (LQ) filters for signal detection and direction-of-arrival estimation in the real case were extended to the complex plane. Specifically, an optimal second-order complex LQ array receiver for random and non-random signals was designed for the non-Gaussian case using a criterion based on the deflection or output signal-to-noise ratio. Its performance in an environment corrupted by spatially fourth-order white noise was also evaluated.

The use of widely linear mean square estimation (WLMSE) in statistical signal processing of complex data is better than using linear systems. In normal complex data regression is widely linear, as it is linear to both x and x* axes, where x* is a complex conjugate of x. However WLMSE should not be used where circularity is assumed. The use of WLMSE and a comparison of the MSE using widely linear and linear systems is used.

Research into blind identification of single-input multiple-output systems using second-order statistics only is presented. It is concluded that the parametric subspace method gives consistent channel estimates when only an upper bound of the channel order is identified.

Research into the behaviour of the current second-order and fourth-order cumulant-based blind source separation methods for zero mean, (quasi)-cyclostationary and cyclo-ergodic sources is presented.