New behavioral-level simulation technique for RF/microwave applications. Part III: Advanced concepts

✍ Scribed by S. L. Loyka; J. R. Mosig

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 184 KB
• Volume: 12
• Category: Article
• ISSN: 1096-4290
• DOI: 10.1002/mmce.10010

✦ Synopsis

The quadrature modeling structure is widely accepted as an efficient tool for the nonlinear simulation of RF/microwave bandpass stages (power amplifiers, etc.) for wireless applications. The common belief is that this structure can be applied to model only bandpass memoryless nonlinearities (which, however, may exhibit amplitude-to-phase conversion). In two recent articles [1, 2] the authors have extended the application of the quadrature modeling structure to modeling broadband nonlinearities, which makes possible to predict harmonics and even-order nonlinearities, to take into account the frequency response, etc. This article completes the overview of the instantaneous quadrature technique. The authors discuss its application to modeling AM, FM and PM detectors, which are strongly nonlinear elements with large memory (both the strong nonlinearity and large memory effects are essential for the detector proper operation), thus removing the limitation of nonlinearity to be memoryless or quasimemoryless. The identification of nonlinear interference/distortion sources is of great relevance for a practical EMC/EMI design. In the second part of this article, we discuss the dichotomous identification method, which is much more computationally efficient than a simple single-signal method, especially for a large number of input signals. Individual spectral components of a complex-spectrum signal can also be considered as input signals and, hence, it is possible to identify the spectral components responsible for a particular nonlinear interference/distortion (say, for a particular intermodulation product).