100M-500M低噪放设计方案
This network represents a compromise between noise figure, input return loss, and gain. Capacitors C2 and C5 provide in-band stability, while resistors R5 and R7 provide low-frequency stability by providing a resistive termina-tion. The high-pass network on the output consists of a series capacitor C4 and shunt inductors L2, with L2 also providing a means of inserting drain voltage for biasing up the PHEMT. Very short transmission lines between each source lead and ground have been used. The RC feedback has a dramatic effect on in-band and out-of-band gain, stability, and input and output return loss.
Simulated vs. Actual Performance of the E-pHEMT Broadband LNAResults from the simulation of gain, NF, and for input and output return loss are shown in Figures 6 and 7, respectively. Measured gain and noise figure and input and output return loss appear in Figures 8 and 9, respectively. A summary of the measured results is shown in Table 2.
Figure 6. Simulation Results for Gain and Noise Figure.
Figure 7. Simulation Results for Input and Output Return Loss.
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