IEEE Transactions on Microwave Theory and Techniques

A scalable approach to the modeling of millimeter- wave field-effect transistors is presented in this paper. This is based on the definition of a lumped extrinsic parasitic network, easily scalable with both the number of fingers and the finger widths. The identification of the extrinsic network parameters is carried out by means of accurate full-wave electromagnetic simulations based on the layou... View full abstract»

The least squares solution for the entire small-signal equivalent circuit is itself a formidable task. In this paper, a systematic approach comprising the total and conventional least squares method in analytically obtaining the small-signal field-effect transistor (FET) parameters values is introduced. The proposed method eliminates the conventional ldquocold FETrdquo and ldquohot FETrdquo modeli... View full abstract»

In this paper, a Volterra analysis built on top of a normal harmonic balance simulation is used for a comprehensive analysis of the causes of AM-PM distortion in a LDMOS RF power amplifier (PA). The analysis shows that any nonlinear capacitors cause AM-PM. In addition, varying terminal impedances may pull the matching impedances and cause phase shift. The AM-PM is also affected by the distortion t... View full abstract»

An enhanced lossy substrate model is developed with important features of broadband accuracy and scalability. The broadband accuracy is justified by a good match with open pad S -parameters measured up to 110 GHz and MOSFETs' S- and Y-parameters over 40 GHz. The proven model can accurately simulate four noise parameters ( NFmin, Rn, Re( Yopt), and Im( Yopt View full abstract»

A new nonlinear charge-conservative scalable dynamic electro-thermal compact model for laterally defused MOS (LDMOS) RF power transistors is described in this paper. The transistor is characterized using pulsed I-V and S-parameter measurements, to ensure isothermal conditions. A new extrinsic network and extrinsic parameter-extraction methodology is developed for high-power RF LDMOS transis... View full abstract»

In this paper, we propose a circularly polarized balanced radar front-end topology with a Tx leakage canceller. This radar is composed of a dual-orthogonal fed microstrip patch antenna, a 90deg delay line, a differential cross-coupled oscillator, two Lange couplers, a Wilkinson combiner, and a mixer. We implemented circularly polarized balanced Doppler radars by using a printed circuit board and I... View full abstract»

An RF electrostatic discharge (ESD) protection for millimeter-wave (MMW) regime applied to a 60-GHz low-noise amplifier (LNA) in mixed-signal and RF purpose 0.13-mum CMOS technology is demonstrated in this paper. The measured results show that this chip achieves a small signal gain of 20.4 dB and a noise figure (NF) of 8.7 dB at 60 GHz with 65-mW dc power consumption. Without ESD protection, the L... View full abstract»

In this paper, a highly linear and low noise CMOS active tracking low-pass filter is presented to overcome a local oscillator harmonic mixing problem for Advanced Television Systems Committee terrestrial and cable digital TV tuner integrated circuits. A transconductor linearization technique based on a method of multiple gated transistors is adopted to improve the linearity performance. The cutoff... View full abstract»

This paper analyzes the power losses in distributed multiharmonic matching networks and proposes a methodology to minimize these losses, which are critical in designing harmonic controlled or switching mode power amplifiers (PAs). The effect of the harmonic output matching topology on PA performance is studied. An analytical evaluation is developed to show the effect of the harmonic network topolo... View full abstract»

A newly introduced inverse class-E power amplifier (PA) was designed, simulated, fabricated, and characterized. The PA operated at 2.26 GHz and delivered 20.4-dBm output power with peak drain efficiency (DE) of 65% and power gain of 12 dB. Broadband performance was achieved across a 300-MHz bandwidth with DE of better than 50% and 1-dB output-power flatness. The concept of enhanced injection predi... View full abstract»

The building blocks of a 0.5-V receiver, including a receiver front-end and a low-pass filter (LPF), are fabricated using 0.18-mum CMOS technology. At 5.6 GHz, the receiver front-end achieves a voltage gain of 17.1 dB and a noise figure of 8.7 dB, while dissipating at 19.4 mW. The fifth-order low-pass Chebyshev filter achieves a corner frequency of 2.6 MHz and an input-referred noise of 28.5 nV/sq... View full abstract»

In this paper, the effects of limited drain current and transistor's on resistance on the performance of an LDMOS inverse class-E power amplifier (PA) are analyzed using a simplified transistor model of piecewise linear dc I-V curves. The minimal magnitude of driving signal, the maximal voltage gain, and the maximal output power of an inverse class-E PA can be defined with the maximal drain... View full abstract»

A self-switched biasing quadrature voltage-controlled oscillator (VCO) is presented. It is implemented by directly injecting the oscillation signal of one VCO core into the other VCO core through the divided tail current sources without additional active devices for coupling. The proposed coupling structure automatically switches the NMOS field-effect transistors used in VCO cores and current sour... View full abstract»

A new grouping strategy for the analysis of two-port arbitrarily shaped H-plane devices in rectangular waveguides is presented. The new grouping strategy accelerates a previous method based on the method of moments and the Green's function of an infinite line source placed inside two parallel plates. The computational cost of analyzing several H-plane filters of different geometries is reduced by ... View full abstract»

Circuit modeling of high-frequency devices described by tabulated multiport parameters has generated immense interest during recent years. In most cases, equivalent circuit models (ECMs) are available to the designers, which correlate well with the measured parameters at lower frequencies, however, deviate at higher frequencies. Traditional efforts to improve ECMs are device specific, laborious, a... View full abstract»

A method intended to characterize enclosed computational electromagnetic domains in terms of interaction and response of a defined set of surface excitations is described. The finite-element method is used to compute a matrix relating surface current and tangential field in terms of an appropriate basis set such that a coupled solution with a boundary integral formulation is rendered seamless. The... View full abstract»

We introduce a tuning space-mapping technology for microwave design optimization. The general tuning space-mapping algorithm is formulated, which is based on a so-called tuning model, as well as on a calibration process that translates the adjustment of the tuning model parameters into relevant updates of the design variables. The tuning model is developed in a fast circuit-theory based simulator ... View full abstract»

An innovative method for fast analysis of geometrical variations in electromagnetic wave problems is proposed. The method is based on a perturbative approach applied to the solution of the linear integro-differential operator of the electromagnetic problem in presence of small domain modifications. This approach has been embedded in a classical finite-element framework to achieve a very fast techn... View full abstract»

A new microwave imaging technique is proposed for reconstruction of 2-D complex permittivity profiles in dielectric samples located in a waveguide system. The spatial distributions of the dielectric constant and the loss factor are approximated by continuous functions whose functional parameters are determined using a neural network technique backed by full-wave finite-difference time-domain analy... View full abstract»

This paper presents an efficient and robust algorithm for passivity enforcement of S -parameter-based macromodels. The method computes updated values of the model residues by least squares fitting of nonpassive residuals of the scattering matrix. Several examples show that the proposed method yields accurate passive macromodels at a limited computational cost. View full abstract»

This paper describes a computer-aided design tool especially conceived for the efficient time-domain simulation of strongly nonlinear mixed digital, baseband, and RF circuits operating in multiple time scales. The proposed numerical method is based on a 3-D envelope oriented technique over an innovative multiple-line double multirate shooting strategy, and is tested with an illustrative circuit ex... View full abstract»

This paper discusses the physics behind the operation of dual-mode bandpass filters from a field theoretical point of view. It is argued that the two degenerate modes of the empty dual-mode cavity, commonly taken as the vertical and horizontal polarizations, become nonphysical when coupling and tuning elements are inserted. Instead, the original degenerate modes are rotated, or modified in a compl... View full abstract»

This paper presents a new wire-bond free technique for suppressing slot-line mode excitation in coplanar waveguides (CPWs) bends. The suppression of slot-line mode is obtained by applying a slow wave structure to the shorter slot of the right-angle bend. The structure is modified into a circular-shaped bend where the slow wave compensation is then used to equalize the electrical length of the inne... View full abstract»