lab3_2011 - ECE145a 218A lab project#4 Reactively Tuned Amplifier Mark Rodwell 2009 Your assignment is to design and construct a reactively tuned

lab3_2011 - ECE145a 218A lab project#4 Reactively Tuned...

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1 ECE145a / 218A lab project #4 Reactively Tuned Amplifier . Mark Rodwell, 2009. Your assignment is to design and construct a reactively tuned amplifier as diagramed in Figure 1. The transistor is to be an Avago AT-42035; I suggest biasing the device at Vce=8 Volts and Ic=10 mA. Please note that Avago is a recent spin-off of Agilent, in turn a spin-off of Hewlett-Packard; the part appears in the parts library of the 2009 version of ADS as a pb_HP_AT42035_19920721. In Figure 1, resistors Rf, Rcc, and Rbx set the transistor DC bias current and DC collector-emitter voltage. Rbx and Rcc are isolated at RF using quarter-wave chokes. Rf is present for DC bias, but will degrade the transistor high-frequency gain, hence this resistor should be large (1 kOhm or more); more on this later. Reduction of the transistor gain by Rf can be avoided by isolating the resistor from the RF signal path (Figure 2). For this bias arrangement, the 2 supplies should be +15V and - 15 V. Clearly, if the matching networks use shunt lines to ground, the blocking capacitors must be placed between the transistor and the matching network. The design sequence is as follows. The transistor must be DC-biased. From the S-parameters, the device stability at the design frequency is determined. One then adds

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