Professor and Student Design UHF Antenna Amplifier
Saratov Chernyshevsky State University (Saratov) is a higher education and research institution in Russia. The university was founded in 1909 and is located on the Volga River in the city of Saratov. The university has 28 departments, more than 90 programs of study, and enrollment of about 28,000 students.
Most published papers describing the design flow for RF power amplifiers (PAs) lack information regarding exact solutions. Alexander Khvalin, a professor at Saratov, co-authored with student and now RF engineer Alexey Vorobiev a paper describing the development of a design method based on structural and parametrical optimization that would enable designers to achieve enhanced characteristics. The active device of choice was the Vishay Semiconductor’s bipolar junction transistor (BJT) BFR90, which was modeled according to the Gummel-Poon model-based method. Parametrical synthesis was confined to the solution of optimization problems, which meant achieving maximum gain and minimal voltage standing-wave ratio (VSWR) at both input and output in the operating bandwidth.
The authors used the NI AWR Design Environment platform to model the amplifier in the 0.3-0.8 GHz frequency range because of its ease of use and the ability to use electromagnetic (EM) documents and schematics in one project. The design of the amplifier was based on the two-stage antenna amplifier for decimeter-wave TV signals, which allowed for the maximum gain of 20 dB in the 0.3-0.8 GHz band.
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