An Optimal Low Noise Power Amplifier of Ultra-High Gain Extensively Applicable from 2.1 to 5.1 GHz

Devices fabricated through TSMC 0.18 micron CMOS process are modeled and implemented in Agilent ADS for the circuit designs. Two low-noise, well impedance-matched radio frequency amplifiers working at various nearby center working frequencies, 2.6 GHz and 2.8 GHz, are proposed using Class-E power amplifier mechanism. Both are deliberately put in series such that both can couple with each other, The resulting gain (S21) is as high as 75dB at 2.1GHz and increased approximately by summing over the two individual gains (S21(2.6GHz), and S21(2.8GHz)) just as expected. It is speculated that the enhanced features of S21 do not make the entering signals available for applications unless the signals are not rejected completely. Thus, even the slight chances of passing signals (S11 below 0 dB) are worth doing so because the gigantic gains can cover the lost reflected signals. It is even more encouraging to find S11 and S22 below 0 dB to be widened on the frequency responses, especially including S11 and S22 at 2.1 GHz, for example, which is originally exclusive prior to the combination of the two individual amplifiers. S12 addressing the isolation of the output from the input is always kept low enough and the minimum noise figures (NFmin) are mostly below 1.0. Therefore, the promoted applicable range of radio frequency on the amplifiers assures the promising futures on the low noise power amplifiers.