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The linearization approach that exploits the modified baseband signal is applied in this paper to linearize a two-way broadband Doherty power amplifier. The required linearization signal formed as a product of the second-order nonlinearity of a nonlinear system is adequately processed in amplitude and phase in the digital domain. Then, the fundamental carrier second harmonic is modulated by the tuned...
In this paper a new approach for safety monitoring of dangerous gases in the industrial plants is proposed. A single artificial neural network is used for determination of the gas concentrations based on sensor array measurements, performing at the same time compensation of the temperature and humidity influence on the sensor outputs. The obtained results show good accuracy in gas concentration estimation,...
In this paper a broadband RF power amplifier operating at frequency range 0.75 GHz to 1.25 GHz is linearized by the even-order nonlinear signals at frequencies around the second harmonics that are inserted at the amplifier transistor gate and drain throughout the broadband matching circuits that provide high amplifier efficiency as well as adequate power level of the injected signal for the linearization...
This paper presents the linearization technique for RF power amplifiers that uses the modified baseband signals. The signal for linearization is formed in baseband, digitally processed by adjusting the amplitude and polarity and injected at the input and output of the amplifier transistor across the DC bias circuits. The modified baseband signal is one of the products of the second order nonlinearity...
3-D TLM approach based on the cylindrical grid and enhanced with the compact wire model has been used for modelling of an inverted circular microstrip patch (IMCP) antenna with the coaxial feed. The simulated results have been compared with the measured results and rectangular grid based TLM results. Additional, the influence of the air gap height on the resonant frequency of the IMCP antenna has...
A novel linearization technique for RF power amplifiers is presented in this paper. The proposed technique uses the modified baseband signal that modulates the fundamental carrier second harmonic. This additional signal processed for linearization is then injected, together with the fundamental useful signal, at the input of the amplifier transistor. Also, a prepared signal for linearization is inserted...
The linearization of broadband two-way Doherty amplifier for application in the frequency range 0.85–1.15GHz is considered in this paper. The carrier and peaking amplifiers in Doherty configuration comprise Freescale's transistor MRF281S LDMOSFET characterized by the maximum output power 4W and the broadband lumped element matching circuits. The linearization of the amplifier is carried out by the...
This article describes the synthesis of compact lumped element equivalent circuits for linear reciprocal multiports using a multiport generalized Foster representation. The multiport microwave device under investigation is a four-port coupled line coupler. The S-parameters are obtained from measurement. By means of system identification the poles and residues of the transfer function are extracted...
In this paper two-way Doherty amplifier with the additional circuit for linearization has been realized and measurements of the linearization influence to the third - and fifth-order intermodulation products have been carried out. The linearization approach uses the fundamental signals' second harmonics and fourth-order nonlinear signals that are extracted at the output of the peaking cell, adjusted...
In this paper two-way Doherty amplifier with the additional circuit for linearization has been realized and measurements of the linearization influence to the third-and fifth-order intermodulation products have been carried out. The linearization approach uses the fundamental signals' second harmonics and fourth-order nonlinear signals that are extracted at the output of peaking cell, adjusted in...
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