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Efficiency enhancement of feedforward amplifiers by employing a negative group-delay circuit

Choi, Heungjae ORCID:, Jeong, Yongchae, Kim, Chul Dong and Kenney, J. Stevenson 2010. Efficiency enhancement of feedforward amplifiers by employing a negative group-delay circuit. IEEE Transactions on Microwave Theory and Techniques 58 (5) , pp. 1116-1125. 10.1109/TMTT.2010.2045576

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We will demonstrate an alternative topology for the feedforward amplifier. This amplifier does not use a delay element, thus providing an efficiency enhancement and a size reduction by employing a distributed-element negative group-delay circuit. The insertion loss of the delay element in the conventional feedforward amplifier seriously degrades the efficiency. Usually, a high-power coaxial cable or a delay-line filter is utilized for a low loss, but the insertion loss, cost, and size of the delay element still act as a bottleneck. The proposed negative group-delay circuit removes the necessity of the delay element required for a broadband signal suppression loop. With the fabricated two-stage distributed-element negative group-delay circuit with 30 MHz of bandwidth and -9 ns of group delay for a wideband code-division multiple-access downlink band, the feedforward amplifier with the proposed topology experimentally achieved 19.4% power-added efficiency and -53.2-dBc adjacent channel leakage ratio with 44-dBm average output power.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Engineering
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
Publisher: IEEE
ISSN: 0018-9480
Last Modified: 27 Oct 2022 10:08

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