# Alternative Categorization of Radio Frequency Power Amplifier for Generalized Design Insights
###### Abstract  
In recent years, advancements in semiconductor technologies have significantly transformed Radio Frequency Power Amplifiers (RFPAs), enhancing their efficiency, size, and performance. Despite these advancements, the design of RFPs remains intrinsically linked to the specific applications for which they are intended. What proves effective in one context, such as communication technologies, may not be equally suitable in others, such as scientific instruments. This discrepancy highlights the lack of a systematic approach to RFPA design that can be applied across different applications. This paper delves into the fundamental concepts of RFPA design, adopting a comprehensive perspective. It further introduces an alternative categorization of RFPs, thereby providing a generalized design approach.  
efficiency; power amplifiers; categorization; systems engineering +
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valuable perspectives on the design requirements and optimization strategies for RF power amplifiers specifically developed for satellite communication systems [9].  
However, despite these valuable contributions, it is evident that a generalized theory for analyzing and designing RFPAs that need to incorporate a series of system requirements is yet to be developed. Moreover, most existing work centers its focus on the trade-off between efficiency and linearity, as reported by [PERSON] et al. [10]. While a thorough review of various techniques used to improve linearity and efficiency is presented by [PERSON] et al. [11], it also falls short of offering a comprehensive framework for selecting the optimal combination of design factors and making well-informed decisions.  
To address these problems adequately, the classification of RFPAs in a systematic manner is of utmost importance. While the practice of categorizing RFPAs using Classes is a well-established tradition in the field, it has also caused some uncertainty and discussions among engineers and researchers [12]. RFPAs are commonly classified based on their operational characteristics and functionality. However, this traditional classification can be ambiguous and misleading as the term \"operating class\" encompasses various features. These include bias point selection (Class A, AB, B, or C), matching network topologies (Tuned Load, Class F, etc.), or the operating conditions of the active device (Class E, Class S, etc.). Nonetheless, simply relying on the Class taxonomy may not be sufficient when designing an RFPA for a specific application. On the other hand, systems engineering has evolved as a transdisciplinary field to provide elegant solutions to complex problems [13]. Systems engineers must be able to define the objectives initially and, through consideration of all factors and possibilities, ultimately achieve these objectives while understanding the relationships between them [14]. This work addresses the missing link by simplifying and enabling the creation of elegant solutions for RFPA design using simplified concepts, thereby exploring the relationships.  
This work first introduces the basic terminology of RFPAs, and then an alternative categorization of RFPAs that organizes various design techniques by time, frequency, and space in an abstract and unified manner. It then presents a design methodology that can be incorporated into flow chart, referred to as vertical and horizontal flow. This flow diagram facilitates analysis, verification, and validation throughout the development of RFPAs.