Patent ID: 7194390

Claim:
A method for calculating an amplifier's greatest lower bound of noise figure pertaining uniformly over an operating band of said amplifier comprising the following steps: (a) inputting minimum noise figure values Fmin and inputting frequency values freq corresponding to said minimum noise figure values Fmin, inputting source reflectance values sOpts, which are source reflectance values for achieving said minimum noise figure at said corresponding frequency values freq, and inputting noise resistance values RNZO which are noise resistance values with zero reflectance for said frequency values freq; (b) initializing a proposed minimal attainable noise figure F; (c) computing a center function center from said Fmin, sOpt, and RNZ0 values; (d) computing a radius function r 2 from said Fmin, sOpt, and RNZ0 values; (e) selecting interpolation points InterpData from maximum Fmin values; (f) resampling center and r 2 over a defined frequency grid; (g) extrapolating said resampled center and said resampled r 2 to smooth end points; (h) extending said extrapolated and smoothed center and said extrapolated and smoothed r 2 to negative frequencies; (i) computing an ///Hk/// indicator corresponding to said proposed minimal attainable noise figure F; (j) determining whether said proposed minimal attainable noise figure F is attainable from said ///Hk/// indicator; (k) incrementing said proposed minimal attainable noise figure F and continuing from step (c) if proposed minimal attainable noise figure F is not attainable in step (j); and (l) outputting proposed minimal attainable noise figure F once attainable from said ///Hk/// indicator, wherein said outputted proposed minimal attainable noise figure F is equated with said greatest lower bound of noise figure.