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Microwave Amplifiers (microwave + amplifier)

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Selected Abstracts

Adjoint network method applied to the performance sensitivities of microwave amplifiers

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2006
F. Güne
Abstract This work focuses on the performance sensitivities of microwave amplifiers using the "adjoint network and adjoint variable" method, via "wave" approaches, which includes sensitivities of the transducer power gain, noise figure, and magnitudes and phases of the input and output reflection coefficients. The method can be extended to sensitivities of the other performance measure functions. The adjoint-variable methods for design-sensitivity analysis offer computational speed and accuracy. They can be used for efficiency-based gradient optimization, in tolerance and yield analyses. In this work, an arbitrarily configured microwave amplifier is considered: firstly, each element in the network is modeled by the scattering matrix formulation, then the topology of the network is taken into account using the connection scattering-matrix formulation. The wave approach is utilized in the evaluation of all the performance-measurement functions, then sensitivity invariants are formulated using Tellegen's theorem. Performance sensitivities of the T- and ,-types of distributed-parameter amplifiers are considered as a worked example. The numerical results of T- and ,-type amplifiers for the design targets of noise figure Freq = 0.46 dB , 1,12 and Vireq = 1, GTreq = 12 dB , 15.86 in the frequency range 2,11 GHz are given in comparison to each other. Furthermore, analytical methods of the "gain factorisation" and "chain sensitivity parameter" are applied to the gain and noise sensitivities as well. In addition, "numerical perturbation" is applied to calculation of all the sensitivities. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006. [source]

Gain,bandwidth limitations of microwave transistor

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 6 2002
Filiz Güne
Abstract This work enables one to obtain the potential gain (GT) characteristics with the associated source (ZS) and load (ZL) termination functions, depending upon the input mismatching (Vi), noise (F), and the device operation parameters, which are the configuration type (CT), bias conditions (VDS, IDS), and operation frequency (f). All these functions can straightforwardly provide the following main properties of the device for use in the design of microwave amplifiers with optimum performance: the extremum gain functions (GT max, GT min) and their associated ZS, ZL terminations for the Vi and F couple and the CT, VDS, IDS, and f operation parameters of the device point by point; all the compatible performance (F, voltage,standing wave ratio Vi, GT) triplets within the physical limits of the device, which are F , Fmin, Vi , 1, GT min , GT , GT max, together with their ZS, ZL termination functions; and the potential operation frequency bandwidth for a selected performance (F, Vi, GT) triplet. The selected performance triplet and termination functions can be realized together with their potential operation bandwidth using the novel amplifier design techniques. Many examples are presented for the potential gain characteristics of the chosen low-noise or ordinary types of transistor. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12, 483,495, 2002. Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mmce.10049 [source]

Gain-assisted metamaterial embedded with gain elements

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2010
Tao Jiang
Abstract In this letter, an active metamaterial sample embedded with miniature monolithic microwave amplifiers is designed, experimentally realized, and measured. Experiments show that by proper design and direct current (DC) bias, the metamaterial sample provides almost linear amplification to an electromagnetic incidence, which can be used to compensate the loss inherent in traditional passive metamaterial and magnify the signal entered the metamaterial. This property would have important potentials in promoting the further researches of metamaterial-based applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 92,95, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24871 [source]