A quantum model for Josephson-based metamaterials working in the Three-Wave Mixing (3WM) and Four-Wave (4WM) regimes at single-photon level is presented. The transmission line taken into account, namely Traveling Wave Josephson Parametric Amplifier (TWJPA), a bipole composed by chain of rf-SQUIDs which can be biased DC current or magnetic field order to activate 3WM 4WM nonlinearities. exploits...

Using a traveling-wave optical parametric amplifier with two orthogonally oriented type-I BBO crystals pumped by picosecond pulses, we generate vertically and horizontally polarized squeezed vacuum states within a broad frequency-angular range. Depending on the phase between these states, fluctuations in one or another Stokes parameter are suppressed below the shot-noise limit. Because of the l...

We report traveling-wave amplifiers having 1–112 GHz bandwidth with 7 dB gain, and 1–157 GHz bandwidth with 5 dB gain. A third amplifier exhibited 5 dB gain and a 180GHz high-frequency cutoff. The amplifiers were fabricated in a 0.1m gate length InGaAs/InAlAs HEMT MIMIC technology. The use of gate-line capacitive-division, cascode gain cells and low-loss elevated coplanar waveguide lines have y...

Redundancy is a major concern to satellite communication amplifier systems. This paper examines the various types of redundant systems used in satellite communication systems from a system reliability viewpoint. To overcome the ambiguities involved with comparing MTBFs, the paper discusses amplifier reliability based on static reliability concepts. Both traditional switched redundant systems an...

The paper proposes a maximum likelihood sequence estimator (MLSE) receiver for satellite communications. The satellite channel model is composed of a nonlinear traveling wave tube (TWT) amplifier followed by a multipath propagation channel. The receiver is composed of a neural network channel estimator (NNCE) and a Viterbi detector. The natural gradient (NG) descent is used for training. Comput...

The structure of a steady state multifrequency model of a traveling wave tube amplifier is exploited to describe the generation of intermodulation frequencies and calculate their growth rates. The model describes the evolution of Fourier coefficients of circuit and electron beam quantities and has the form of differential equations with quadratic nonlinearities. Intermodulation frequencies are ...

In this paper, we present a novel predistortion method based on Fuzzy Wavelet Neural Networks (FWNN) to linearize the High Power Amplifier (HPA) for WiMAX (Worldwide interoperability for Microwave Access). To analyze and evaluate the proposal, we are considered the model of Traveling Wave Tube Amplifiers (TWTA), both memoryless and with memory. The simulation results show that the proposed sche...