www.gusucode.com > rf 工具箱matlab源码程序 > rf/stabilitymu.m
function [mu,muprime] = stabilitymu(s_params) %STABILITYMU Calculates the stability factor MU of a 2-port network % [MU,MUPRIME] = STABILITYMU(S_PARAMS) the stability factor MU and MU % prime, of a two port network by % % MU = (1 - |S11|^2) / (|S22 - CONJ(S11) * DELTA| + |S21*S12|) % MUPRIME = (1 - |S22|^2) / (|S11 - CONJ(S22) * DELTA| + |S21*S12|) % where DELTA = S11*S22 - S12*S21 % % S_PARAMS must be either a 2x2xK numeric array of K 2-port S-parameters, % or a 2-port sparameters objects. % % MU defines the minimum distance between the center of the unit Smith % chart and the unstable region in the load plane (the load is considered % port 2). % % MUPRIME defines the minimum distance between the center of the unit % Smith chart and the unstable region in the source plane (the source is % considered port 1). % % Having MU>1 (or MUPRIME>1) is necessary and sufficient for the 2-port % linear network, described by the S-parameters, to be unconditionally % stable. % % Reference: Marion Lee Edwards and Jeffrey H. Sinsky, A New Criterion % for Linear 2-Port Stability Using a Single Geometrically Derived % Parameter, IEEE Trans. Microwave Theory Tech., Vol. MTT-40, no. 12, pp. % 2303-2311, December 1992. % % See also STABILITYK, GAMMAMS, GAMMAML, sparameters % Copyright 2003-2015 The MathWorks, Inc. narginchk(1,1) % Check input s_params if ~isnumeric(s_params) validateattributes(s_params,{'numeric','sparameters'},{}, ... 'stabilitymu','S-Parameters',1) end CheckNetworkData(s_params,2,'S_PARAMS'); % Get the S-parameters [s11,s12,s21,s22] = deal(s_params(1,1,:),s_params(1,2,:), ... s_params(2,1,:),s_params(2,2,:)); % Calculate stability MU and MUPRIME abss11s11 = abs(s11 .* s11); abss21s12 = abs(s21 .* s12); abss22s22 = abs(s22 .* s22); delta = s11 .* s22 - s12 .* s21; mu = (1 - abss11s11) ./ (abs(s22 - conj(s11) .* delta) + abss21s12); muprime = (1 - abss22s22) ./ (abs(s11 - conj(s22) .* delta) + abss21s12); mu = mu(:); muprime = muprime(:);