Among the noise parameters expressed in the reflection coefficient form (F/sub 0/, |/spl Gamma//sub 0/|, //spl Gamma//sub 0/ and r/sub n/), the noise resistance r/sub n/ is of critical importance to the design of low-noise receivers. Very low values of r/sub n/ allow for optimizing the performance of microwave broad-band amplifiers employed in receiver front-ends. We here present a sensitivity analysis performed on typical circuit models of FET's previously characterized in our lab. Such analysis has been aimed at determining the key elements that mostly affect the behavior of r/sub n/ at microwave frequencies. We have also observed how the noise performance may be improved by tuning the value of the input (gate, source) inductances which are responsible of the U-shaped curves typically observed for r/sub n/ in MESFET's and HEMT's.
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机译：在以反射系数形式（F / sub 0 /，| / spl Gamma // sub 0 / |，// spl Gamma // sub 0 /和r / sub n /）表示的噪声参数中，噪声电阻r / sub n /对低噪声接收器的设计至关重要。 r / sub n /的极低值可优化接收器前端中使用的微波宽带放大器的性能。在这里，我们介绍了在我们实验室中先前表征的FET的典型电路模型上进行的灵敏度分析。此类分析旨在确定主要影响微波频率下r / sub n /行为的关键元素。我们还观察到如何通过调整输入（栅极，源极）电感的值来改善噪声性能，该输入电感是在MESFET和HEMT中通常观察到的r / sub n /的U形曲线的原因。
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