A graphic design method for matched low-noise amplifiers

Performance characterization of a microwave transistor subject to the noise and matching requirements

“…where either the gain value with 1 or 2 can be used, which are given by (17) respectively, because for both, the same result is obtained. Gain and Z in at the tangent mismatch circles are calculated by the formulae given in (17.1)- (18).…”

“…A different design approach that consists of evaluating the noise/gain trade-off at the transistor level is introduced by Haus and Adler [13], with a new term 'noise measure (M)' tying the two key performance components of the amplifier, then this methodology is subsequently investigated in [14] and [15] and is very useful for multi-stage designs to control the overall LNA's noise figure. Different approaches implying the use of graphical techniques have been also proposed, as in [16,17].…”

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In this paper, the gain G T of a microwave transistor is expressed analytically in terms of the mismatchings (V in ≥ 1, V out ≥ 1) at the ports, noise figure F ≥ F min and the [z]-parameter and noise parameters. Different approaches implying the use of graphical techniques have been also proposed, as in [16,17].In fact, none of the proposed methodologies in earlier analyses resulted in the analytical formulations of the device performance capacity, first in the literature, in [18,19] the analytical formulation of the transducer gain G Tmin ( f ) ≤ G T ( f ) ≤ G Tmax ( f ) has been given in terms of the F( f ) and V in ( f ) in the [z]-parameter and [S]-parameter domains together with the {Z S ( f ), Z L ( f )} terminations, respectively, that result in the compatible {F req ≥ F min , V in ≥ 1, G Tmin ≤ G T ≤ G Tmax } triplets and their {Z S , Z L } terminations depending on the bias condition V DS , I DS , and frequency f to be used as performance characterization of the transistor. Then, a design configuration is constructed in the input impedance Z in -plane covering the gain and the required input and output mismatch circles within the Unconditionally Stable Working Area for the predetermined input termination Z S .

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Full flexible performance characterization of a feedback applied transistor with LNA applications

“…Here, simultaneous input power match and noise optimization have been adopted as the design strategy, mainly through using either series inductive or parallel capacitive circuits or a combination of both . In addition, a graphical design method for the single‐stage and two‐stage cascade low‐noise amplifiers with given feedback is presented in the load plane in Albinsson . Furthermore, in Victor and Nath , the optimum series feedback is determined for the noise and gain trade‐off using the noise measure, (M), introduced by Haus and Adler .…”

On the theoretical limits of noise-gain-mismatch tradeoff in the design of multi-stage cascaded transistor amplifiers

“…[1][2][3][4]) and is nowadays a text-book topic. This fact can generate the feeling that also the optimal multi-stage design problem has been thoroughly investigated and solved ( [5][6][7]). This feeling is also strengthened by the fact that, even at the higher microwave frequencies, the powerful computer-assisted optimization-based design software tools currently available in the market usually permit to achieve, without too much hassle, good performances in most practical cases.…”