Design and development of MMIC amplifier becomes streamlined and cheaper by means of computer aided automation. However such design automation pre-requires adequate nonlinear models of transistors entering into the composition of MMIC amplifier. An objective of this work is automated MMIC amplifier design based on behavioral modeling. Design automation procedure using mathematical apparatus of X-parameters has been proposed.
X-parameters approach is based on Poly-Harmonic Distortion method and allows taking into account nonlinearity of single transistors as well as entire MMIC. Design procedure employs the library of transistor models corresponding to given technology used for transistor fabrication. Test matrix of different transistors has to be formed on the single wafer. X-parameters for each and every transistor of test matrix have to be measured at several operating conditions over working frequencies. Thereby the library of transistor models can be collected and then used for choice of transistors and selection of their operating conditions most matched for given MMIC specifications. Mathematical apparatus of X-parameters is also implemented for entire MMIC amplifier simulation based on single transistor models taken from library.
Experimental verification of proposed approach in case of gallium arsenide two-stage broadband driver amplifier has been demonstrated. The accuracy of nonlinear modeling has been proved sufficient for achieving the goal MMIC specifications. The first-pass design success is confirmed by measurements of the fabricated MMIC driver amplifier. X parameters guarantee the practical matching of measured data to the theoretical expectations not only in the linear mode of amplifier operation but also at significant input power at least up to +20dBm, when nonlinear behavior takes place above 1-dB compression point.
Impact of excitation of the harmonics and corresponding power transfer by those harmonics between stages of the amplifier converges monotonically with increase of number of harmonics. For practical MMIC driver amplifier simulation it is sufficient to take into account up to four excited harmonics.
Rorsman N., Stenarson J., Garcia M., Zirath N. An empirical
table-based FET model // IEEE Transactions on Microwave Theory and Techniques.
1999. V. 47. № 12. R. 2350 – 2357.
Curtice W. R.,
Ettenberg M. A nonlinear GaAs FET model for use in the design of output
circuitsfor power amplifier // IEEE Transactions on Microwave Theory and
Techniques. 1985. V. 33. № 12. P. 1383 –
Kacprzak T. Computer calculations of large-signal GaAs FETamplifier
characteristic // IEEE Transactions on Microwave Theory and Techniques. 1985.
V. 33. № 2. P. 129 – 135.
Barataud D., Mons S., Nebus J.-M., Villotte J. P.,
Obregon J. J., Quere R. Hot small-signal S-parameter
measurements of power transistors operating under large-signal conditions in a
load-pull environment for the study of nonlinear parametric interactions //
IEEE Transactions on Microwave Theory and Techniques. 2004. V. 52. № 3. P. 805
Verbeyst F., Bossche M. V., Schreurs D. S-functions
behavioral model order reduction based on narrowband modulated large-signal
network analyzer measurements // 75th IEEE Microwave Measurements Conference
(ARFTG). 2010. P. 1 – 6.
Betts L. Nonlinear vector
network analyzer applications // Microwave Journal. 2009. V. 52. № 3. P 78 –
Root D. E.,
Verspecht J., Sharrit D., Wood J., Cognata A. Broad-band
poly-harmonic distortion (PHD) behavioral models from fast automated
simulations and large-signal vectorial network measurements // IEEE
Transactions on Microwave Theory and Techniques. 2005. V. 53. № 11. 2005. P.
3656 – 3664.
Root D. E. Polyharmonic distortion modeling // IEEE Microwave
Magazine. 2006. V. 7. № 3. June. P. 44 – 57.
Bossche M. V., Verbeyst F. Characterizing componentsunderlarge
signal excitation: Defining sensible «large signal S-parameters» // 49th IEEE
Microwave Measurements Conference (ARFTG). 1997. P. 109 – 117.
Advanced Design System (ADS) software, Agilent
Technologies. http: // www. agilent. com /.