Design of an LNA and an Active Mixer for Frequency Decrease for Application in ISM Frequency Band Using the TSMC 90nm Technology
Nikolaos Houridis
Abstract
This thesis presents the theoretical background and design methodology of a Low Noise Amplifier (LNA) and a double balanced active Mixer (Down Conversion Gilbert Mixer) targeting the ISM frequency band. The combination of the two circuits composes the core of a receiver architecture which aims to receive the high frequency signal from the antenna and transfer it to the baseband frequency. An additional high linearity LNA topology targeting transceiver architectures is also presented.
The theoretical part of this thesis presents the mathematical expressions that govern the operation of the studied circuits as well as the characteristics that represent their performance. The practical part of this thesis analyzes the design process of the individual circuits (LNA and Down Conversion Gilbert Mixer) and highlights their performance. The combination of the two individual circuits follows and the performance aspects of the resulting chain is presented. It is noted that with the completion of the design at the schematic level, the physical design (layout) of the circuits is implemented, and the results are compared qualitatively with the ones from the schematic design. The high linearity LNA is designed and optimized with an in-house circuit optimization software tool.
The design was made in TSMC90nm technology using the Cadence suite. The total chain of the LNA and the mixer in extracted simulation has a conversion gain of 31dB, noise figure 1.71dB while in terms of chain linearity the 1dB compression point is at -17.7dBm while the 3rd order intercept point is -9.47 dBm. The high linearity LNA has 16dB gain, 1.11dB noise figure and the IIP3 is 23.67dBm.