Application Note: Design of Low-Noise MMIC Amplifier

This application note demonstrates the use of APLAC Simulator in simulating the S parameters, noise, and stability of a low-noise MMIC amplifier. The amplifier IC is defined by its S parameters. This device could be used e.g. as a GPS preamplifier with center frequency of 1575,42 MHz. The application note is based on a technical article in UKW-Berichte 4/2002 and 1/2003 by Gunthard Kraus. The LNA is shown in Fig. 1 and the equivalent circuit at APLAC Editor is shown in Fig. 2.

Figure 1: A Low-Noise Amplifier

Figure 2: APLAC Editor equivalent circuit of the Low-Noise Amplifier

Simulating S Parameters
First simulation consists of AC frequency Sweep from 0.1GHz to 10GHz. S11 and S22 are presented in Fig. 3. We observe that especially S22 is quite pleasing. S21 is presented in Fig. 4. We can see from the picture, that the gain in middle frequency is about 22.5 dB. The APLAC
Simulation description is following:

Figure 3: S11 and S22

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Source: APLAC