Low‐noise one‐port microwave transistor amplifier

Abstract

that the mixer delivers the required performance for each communication band. Although the noise figure is around 14.7 and 12.7 dB for 940 MHz (GSM) and 1.8 GHz (DCS), respectively; it rises to 18.8 dB for 2.44 GHz (Bluetooth). The noise performance is adequate for GSM and DCS standards. One can consider the noise figure for the Bluetooth frequency to be high; but the overall receiver noise figures can be as high as 40 dB for Bluetooth applications [10], and hence the simulated mixer noise figure will not affect the system noise budget very much if it is used in such a Bluetooth receiver.The IIP3 simulations prove that the L match gives better results compared to the inductive match. The minimum simulated IIP3 is Ϫ4.3 dBm at 1.54 GHz, and the maximum IIP3 achieved is 2.8 dBm at 2.44 GHz. Within these extremes, the mixer linearity performance remains satisfactory for the standards with very stringent IIP3 requirements such as GSM (900 MHz) and DCS (1800 MHz). CONCLUSIONThe wideband operation capability of the conventional mixers is discussed in this Letter. The wideband characteristics of the mixers are investigated with the use of two different types of input matching circuits. The effects of the input matching and the major performance parameters of the mixers are simulated, and the results are plotted for the overall frequency range, 940 MHz-2.5 GHz. It is worth noting that the performance drops in both of the mixers as the frequency increases, but this drop does not affect the receiver system, because the mixer exhibits good characteristics for each communication standard, and remains in line with the requirements. As a result the multiband operation of a CMOS mixer for several communication standards is expected in the near future, because the circuit performance is enhanced by the developments in the device technologies and the circuit design techniques. Once there are wideband LNAs and VCOs operating the mixers in multiband applications will be the next step.

Comments on “low‐noise one‐port microwave transistor amplifier”

“…The authors of [1] failed to acknowledge the earlier work in [2][3][4][5][6][7], and the referees failed to notice this omission. [1] argue that the authors of [2] have failed to acknowledge significant earlier work in the same field. Regarding this, we appreciate the authors of [1] for providing a list of references related to this field.…”

“…[1] argue that the authors of [2] have failed to acknowledge significant earlier work in the same field. Regarding this, we appreciate the authors of [1] for providing a list of references related to this field. We admit that some of the references were unknown to us before sending the manuscript, but it is worthwhile to mention that others [3] have been cited by us in a recent work [4].…”

“…In [1], the authors reported an opportunity to achieve lower noise figure in negative resistance mode than in conventional transmission mode. In [7], it was shown that the optimum noise measure is the same for a reflection amplifier as for a transmission amplifier using the same transistor.…”

“…Thus the key points in [1], apart from the approximate noise analysis and the specific design example at a low microwave frequency, had been reported previously. The authors of [1] failed to acknowledge the earlier work in [2][3][4][5][6][7], and the referees failed to notice this omission.…”

“…Venguer et al [1] reported a low noise transistor based reflection amplifier, and described it as "a new type of a microwave reflection amplifier with very low noise properties . .…”