Wide-band compact microwave transistor amplifier methodology and the analysis of its input-matching mechanism using negative impedance converter

The design of broadband active-compensated amplifier system is an important problem in microwave systems. In this letter, a wide-band high-gain microwave transistor amplifier (MTA) design is presented with −10 dB input reflection coefficient. To achieve its characteristics, a novel input-matching mechanism is proposed. The recognition and comprehensive interpretation of this new input-matching mechanism is important for future development of wide-band MTA. In this article, broad-band impedance matching is proposed as a method for improving the matching level of amplifier. A new compensation network consisting of negative impedance converter (NIC) circuit is employed at the input of the amplifier operating at 4.2 GHz. The results show that the compensation network can improve the return loss level from −5.9 dB to −13.01 dB, and the resonant frequency can be controlled in a wide RF band. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 192–197, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23046