Low‐noise one‐port microwave transistor amplifier

A new type of a microwave reflection amplifier with very low noise properties is presented. The proposed amplifier consists of a circulator and a one-port circuit with the use of a transistor operating under negative resistance conditions. An expression for estimating the noise figure for this type of amplifier is proposed. Experimental results show that such a class of amplifiers that use only one transistor provides a higher transmission gain and a smaller noise figure than a conventional single-stage amplifier, making it interesting to operate at millimeter-wave frequencies. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 100–104, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10236