Behavioral modeling of RF and microwave circuit blocks for hierarchical simulation of modern transceivers

Abstract

The development of simulation and macromodeling techniques for RF and microwave communication systems has been a high priority research subject for several years. If one observed this last years an impressive improvement of simulation tools performances, the full chip simulation of modern TX-RX chains remains a real stumbling block, as the transistor count has considerably increased. This paper discusses the hierarchical RF simulation issue using the same Harmonic Balance or Envelope Transient simulation engine for both transistor level description and circuit bloc macro-models. This method can reduce the size of the problem to enable accurate and fast simulation of large size circuits. The concept requires however to develop macro-modeling techniques taking into account impedance mismatch effects, which are discussed here.

New methodology for mixed simulation of active antenna

“…Several models have been proposed to encounter this problem in PA [9], [10] thanks to a formalism called nonlinear scattering functions, introduced in [11]. The nonlinear scattering functions consist in defining a nonlinear relation for the [S] parameters: However, these models are only a linear approximation in regards to the output incident wave "a 2 ".…”

Implementation of X-parameter models in harmonic-balance simulators

“…It has been shown through dynamic Volterra series concept that, sweeping the driving frequency over the bandwidth of interest of the circuit, the resulting characteristics (| | ), (| | ) and (| | ) in (1) may appropriately describe the relations between modulation signals in the vicinity of the various harmonic components of [3]- [4]. Hence, defining ̂ ( ) ∫ ( ) and ̂ ( ) ∫ ( ) , the modulation signals at the vicinity of harmonic component , on port number i, the circuit model expresses as below.…”

Time-domain envelope measurements for characterization and behavioral modeling of nonlinear devices with memory

“…Time-domain measurement principles and techniques are now well established for CW carriers and their harmonics [4]- [6]. However, accurate measurements of nonlinear devices driven by wideband modulated carriers are required to build behavioral models because modulated signals are necessary to probe memory effects in nonlinear solid-state RF devices [7]- [9]. Basically, using the current configuration of the LSNA [10], which can be considered as a reference instrument for calibrated measurements of time-domain waveforms, the modulation bandwidth of RF signals that can be measured is limited to 10 MHz [10].…”

“…Among the interesting studies, we can quote the introduction of the "scattering functions" [22]- [25]. Recently, the introduction of the notion of the large-signal -parameters (LSSPs) enabled understanding of these problems in rigorous and powerful circuit envelope formalism [7]. Basically, without entering in the details, we can say that this concept is derived from the Volterra theory and enables us to write, to first order, the input/output relationships as follows: (6) In the above, and represent, respectively, the incident and reflected wave amplitudes on port .…”