Gain–bandwidth limitations of microwave transistor

This work enables one to obtain the potential gain (G_T) characteristics with the associated source (Z_S) and load (Z_L) termination functions, depending upon the input mismatching (V_i), noise (F), and the device operation parameters, which are the configuration type (CT), bias conditions (V_DS, I_DS), and operation frequency (f). All these functions can straightforwardly provide the following main properties of the device for use in the design of microwave amplifiers with optimum performance: the extremum gain functions (G_{T max}, G_{T min}) and their associated Z_S, Z_L terminations for the V_i and F couple and the CT, V_DS, I_DS, and f operation parameters of the device point by point; all the compatible performance (F, voltage–standing wave ratio V_i, G_T) triplets within the physical limits of the device, which are F ≥ F_min, V_i ≥ 1, G_{T min} ≤ G_T ≤ G_{T max}, together with their Z_S, Z_L termination functions; and the potential operation frequency bandwidth for a selected performance (F, V_i, G_T) triplet. The selected performance triplet and termination functions can be realized together with their potential operation bandwidth using the novel amplifier design techniques. Many examples are presented for the potential gain characteristics of the chosen low‐noise or ordinary types of transistor. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12, 483–495, 2002. Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mmce.10049