Gain-sensitivity analysis for cascaded two-ports and application to distributed-parameter amplifiers

Int J RF and Microwave Comp Aid Eng

Güroğlu

2006

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 F req ‫؍‬ 0.46 dB N 1,12 and V ireq ‫؍‬ 1, G Treq ‫؍‬ 12 dB N 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.

“…Comparing (2) and (3), we obtain the following equations for the generator reflection coefficient and independent complex wave impressed by the generator, respectively:…”

Section: A Scattering-matrix Modelling Via Network Elementsmentioning

confidence: 99%

Section: A Scattering-matrix Modelling Via Network Elementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Adjoint network method applied to the performance sensitivities of microwave amplifiers

Int J RF and Microwave Comp Aid Eng

Güroğlu

2006

Adjoint sensitivity analysis of the T, Π, and L types of microstripline low noise amplifiers

Demi̇rel

Int J Numerical Modelling

Mahoutı

2015

Self Cite

SUMMARYIn this work, the sensitivities of the Gain G T , noise figure F, magnitudes and phases of the input Γ in and output Γ out reflection coefficients of low noise amplifier are carried out analytically with respect to the matching mirostrips' widths and lengths depending upon the position and the configuration types, using adjoint network method via wave approach for different types of matching networks. Thus, not only these analytical gradient expressions can be implemented with either the gradient-based or non-gradient optimization algorithms even simple metaheuristic algorithm for a high-speed and improved design of the microstrip amplifiers but at the same time the tolerance limitations of the designs can be provided depending on type of the matching network. As a case study, performance sensitivities of the T, Π, L types of microstrip low noise amplifier with the design target parameters of G Tmax , F min and |Γ in | = 0.3 with the operation bandwidth of 10-18 GHz are worked out and compared with results of the numerical perturbation and chain sensitivity matrix methods. Furthermore, performance sensitivity characteristics of the microstrip lines for all types of amplifier circuits are given, and comparisons are made among microstrip lines at the same positions along the operation bandwidths.

Gain gradients applied to optimization of distributed-parameter matching circuits for a microwave transistor subject to its potential performance

Int J RF and Microwave Comp Aid Eng

Demi̇rel

2008

Self Cite

In this article, a rigorous design procedure is carried out for a microwave amplifier by employing the Feasible Design Space and simple analytical gain gradients of the matching circuits. Physical lengths and characteristic impedances of the transmission lines used in the matching circuits are chosen as the design variables and their lower and upper limits are bounded by the limits of the planar transmission line technology so that resulted microwave amplifier can be realized by this technology. Feasible Design Target Space is determined by the compatible performance [noise (F), input VSWR (V i ), gain (G T )] triplets and their source Z S (x i ) and load Z L (x i ) terminations resulted from the performance characterization of the active device. These triplets take into account the physical limitations of the device and realization conditions so that F req ! F min , V ireq ! 1, G T min G T req G T max ; and Z S (x i ) and Z L (x i ) terminations be taken place within the ''Unconditionally Stable Working Area''. Design of the amplifier for the compatible performance triplets is reduced to the design of the Z S (x i ) and Z L (x i ), i = 1. . . N terminations, which is achieved by the gain optimization of the two passive, reciprocal matching two-ports using the Darlington theorem. Analytical expressions of the gain gradients of the matching circuits are obtained by the two different methods: (i) chain sensitivity matrix approach; (ii) adjoint network approach. Gain gradients of the L-, T-, and P-types of distributed-parameter matching circuits are obtained as worked examples. Then typical design examples are given with together the synthesized, target, simulated characteristics. V V C 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE 18: 99-111, 2008.