Design and development of 1 KW solid state RF amplifier

• Published in: Journal of physics. Conference series 2010-02, Vol.208 (1), p.012013
• Main Authors: Ashok, Gayatri, Kadia, Bhavesh, Jain, Pragya, Kulkarni, S V, Group, Icrh-Rf
• Format: Article
• Language: English
• Subjects: Bipolar transistors; Circuit design; Design; Design criteria; Loading; Low noise; MOSFETs; Noise levels; Output; Physics; Power amplifiers; Semiconductor devices; Solid state
• ISSN: 1742-6596; 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/208/1/012013

Since low power tube based RF amplifiers are complicated, occupy a large space and are bulky, the efforts are on to develop indigenously 1 KW solid state technology based RF Power amplifier. A power level of 1KW is chosen for the initial design because RF power Mosfets upto 250 watt are easily available and by clubbing 3-4 stages the power level of 1 KW can be made. Presently design and testing of 100-watt stage is in progress. The first 2 stages are designed to give 5 Watt RF power using bipolar transistors and are operated in CE, Class A to provide low noise level at the output of the system. The 3rd stage will be MOSFET based MRF 174, which is ideally suited for class A operation and is designed for 100 Watt RF power. The last stage will be MOSFET based ARF446 power MOSFET in TO-247 plastic package. This amplifier will be used in the classical push- pull configuration. This paper describes the design aspects as well as the test results of 100 watt amplifier on 50 Ohm dummy load along with the specifications, design criteria, circuit used, operating parameters of 1 KW Solid State RF power amplifier to be used as driver for 91.2 MHz, 1.5 MW stage for ICRH experiments on SST-1 tokamak .