In this paper, the far-field pattern of a Cassegrain reflector is formulated. A novel illumination function is used to approximate the field distribution at the aperture of the reflector. The defined illumination function takes into account the central aperture blockage created by the subreflector. Using the illumination function, a closed-form expression describing the far-field radiation pattern

Since Hodgkin and Huxley described the nerve axon as a cable (H?H model), many efforts have been made to find more approximated transmission line models representing the nerve axon. This paper describes a simple model that represents the nerve axon in two parts: the internodal space as a lossy thin-film microstrip line and the node of Ranvier as an active complex load. The complex load terminating

In this study, we present the implementation of invasive weed optimization (IWO) in the maximization of main-lobe to side-lobe level for the non-uniform planar antenna array. The antenna arrays investigated in this study are generated using the chaos game algorithm (CGA) and shaped into selected fractal geometries chosen on the basis of their interesting performance. This CGA is picked out in orde

The impedance dependence of resonant tunneling diodes (RTDs) based on the GaAs/AlAs heterosystem is investigated in the range of 0.1?40 GHz. The analysis shows that the impedance of about 90% of unbiased RTDs is well described by an equivalent circuit (EC) consisting of parallel-connected resistance and capacitance and an additional resistance connected in series with this parallel combination. Wh

This paper demonstrates a highly efficient 3-stage Doherty power amplifier (PA) employing an envelope tracking (ET) technique. The ?3-stage? Doherty PA is the most efficient architecture for a high peak-to-average power ratio (PAPR) signal among the various Doherty PAs. However, because of the lower peaking biases than those of the ?N-way? Doherty PA, the proper load modulation is hard to be achie

In this paper, we address the architecture of a multi-antenna receiver and we aim at reducing the complexity of the analog front-end. To this end, an innovative architecture is introduced based on code multiplexing. This architecture uses the direct sequence spread spectrum technique in order to multiplex the different antennas contributions through a single In-phase/Quadrature (IQ) demodulator. S

In this paper, we address the architecture of multistandard simultaneous reception receivers and we aim to reduce the complexity and the power consumption of the analog front-end. To this end, we propose an architecture using the double orthogonal translation technique in order to multiplex two signals received on different frequency bands. A study case concerning the simultaneous reception of 802

In order to perform an accurate design, in particular in non-linear circuit, the equivalent circuit of inductors must be precisely described in a wide frequency band. Many models have been proposed to describe the behavior of inductors on lossy substrate. They consist of a great number of elements, often suggested by physical phenomena. Most of them cannot be extracted from measurements. In this p

Novel designs of circular waveguide components for lowpass, highpass, bandpass, and bandstop applications are presented. The filters are formed by cascaded TM-mode resonator sections which share a common axis, thus preserving the polarizations of input signals due to rotational symmetry. Moreover, the filters are smaller than standard TE-mode bandpass filters. Basic design considerations are discu

A four-stage distributed amplifier utilizing low-loss slow-wave shielded (SWS) transmission lines is implemented in a standard 0.13 ?m Complementary Metal-Oxide-Semiconductor (CMOS) technology. The amplifier when biased in its high current operating mode of I = 46 mA (at V = 2.2 V, P = 101 mW) provides a forward transmission gain of 11.3 ± 1.5 dB with a 3-dB bandwidth of 17 GHz and a gain-bandwidt

An in vitro system for 2.45 GHz microwave (MW) exposure with real-time fluorescence measurements is proposed. This system is specifically designed for the measurement of those biophysical parameters of living cells or membrane models which can be quantified by spectrofluorometric methods (e.g. membrane generalized polarization (GP), membrane fluidity, membrane potential, etc.). The novelty of the

This paper introduces a new approach to the modeling of capacitance in field-effect transistor (FET) devices, which we call . It is compared with existing formulations, which we call and . In doing so, it is necessary to normalize the theory of nonlinear capacitances and to clarify a number of matters. These include charge conservation and determination of charge functions from capacitance measur

In this work a de-embedding technique oriented to the evaluation of the load line at the intrinsic resistive core of microwave FET devices is presented. The approach combines vector high-frequency nonlinear load-pull measurements with an accurate description of the reactive nonlinearities, thus allowing one to determine the actual load line of the drain?source current generator under realistic con

We discuss the impact of orbital fluctuations on the noise spectrum of a free-running oscillator, exploiting a rigorous nonlinear perturbative analysis based on the Floquet theory, and providing evidence of its relevance for high- oscillators.

This paper describes existing and new criteria for comparison and optimization of non-linear power amplifiers such as RF or microwave transmitters. In addition to intermodulation, receiver noise, and losses in the transmission system, the proposed new criteria take into account efficiency or consumed power. This results in the global optimization of a combined signal-to-noise-plus-intermodulation

This paper analyzes the noise properties of balanced amplifier configurations in terms of noise waves and discusses the effect of various amplifier configurations on the noise and signal parameters. It shows how the noise generated in the load on the input coupler of a balanced amplifier deteriorates the amplifiers noise resistance parameter with respect to that of its component amplifiers. The pr

This paper reports on a novel voltage-mode class-S power amplifier for the 450 MHz band, based on GaN?HEMT monolithic microwave integrated circuits (MMICs). It achieves a peak output power of 3.4 W for a single tone at 400 MHz, encoded in standard band-pass delta-sigma modulation with 1.6 Gbps sampling frequency. The corresponding efficiency is 38%, peaking at 52% for 0.5 W output power. In order