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A new distributed amplifier (DA) topology is proposed, which is a combination of the conventional DA and the cascaded single-stage DA. This DA topology can provide wide bandwidth with considerations of the gain, noise figure (NF), and output power simultaneously, and requires reasonable dc power consumption. In this paper, two termination methods of this combination are investigated. From the measurements, the first DA proposed by Chen in 2011 has a small-signal gain of 20.5 dB, a 3-dB bandwidth of 35 GHz, and a gain-bandwidth (GBW) product of 371 GHz. The maximum output power at 1-dB output compression point (OP1~{dB}) is 8.6 dBm and the NF is between 6.8–8 dB at frequencies lower than 18 GHz. The chip size, including testing pads, is only \ 0.78 mm^2, and the ratio of the GBW to chip size is \476 GHz/mm^2. The second DA has a small-signal gain of 24 dB, a 3-dB bandwidth of 33 GHz, and a GBW product of 523 GHz. The maximum OP1~{dB} is 9 dBm and the NF is between 6.5–7.5 dB at frequencies lower than 18 GHz. The chip size including testing pads is only \ 0.83 mm^2, and the ratio of the GBW to chip size is \630 GHz/\ mm^2. To the authors' knowledge, the second circuit has the highest ratio of GBW to chip area and the highest figure-of-merit in \0.18- \mu\ m CMOS, and it has a comparable performance with other DAs in advanced process. [ABSTRACT FROM AUTHOR]

In this paper, an X-band pseudomorphic HEMT power amplifier (PA) is reported with two kinds of hysteresis phenomena; the first occurs in the dc–IV measurement, and the second is observed in the power measurement. The unusual phenomena can be attributed to the gate current resulting from the impact ionization coupling with the gate bias resistor, which is usually observed in the design of RF circuits to provide the gate bias. After the gate current is considered, two methods are proposed to analyze the hysteresis with the same conclusion. The cause of the encountered hysteresis is for the first time identified, and criteria for the selection of the gate bias resistor in order to avoid the hysteresis are proposed. Finally, a PA complying with these criteria is presented with good performances and without hysteresis. [ABSTRACT FROM AUTHOR]

There is an error in the order of the references [18] and [19] in the above-named article [ibid., vol. 61, no. 4, pp. 1533?1542, Apr. 2013]. The order of these references should be exchanged. The corrected order (and numbering) of these two references are shown as follows: [18] J. Kim and J. F. Buckwalter, "A 92 GHz bandwidth distributed amplifier in a 45 nm SOI CMOS technology," IEEE Microw. Wireless Compon. Lett., vol. 21, no. 6, pp. 329?331, Jun. 2011. [19] A. Jahanian and P. Heydari, "A CMOS distributed amplifier with distributed active input balun using GBW and linearity enhancing techniques," IEEE Trans. Microw. Theory Techn., vol. 60, no. 5, pp. 1331?1341, May 2012. [ABSTRACT FROM PUBLISHER]