GaN-based single stage low noise amplifier for X-band applications

The emergence of Gallium Nitride (GaN)-based High Electron Mobility Transistors (HEMTs) devices has attracted attention, especially due to their high breakdown voltages and superior power handling capabilities. These features give a chance to design very high-efficiency high power amplifiers (HPA) on GaN-based Monolithic Microwave Circuit (MMIC) technology. The need for GaN HEMTs has made it increasingly attractive for this and switches and low-noise amplifiers (LNAs). With the advent of GaN HEMT monolithic technology, low noise amplifier preferences have also changed. GaN-based low-noise amplifiers (LNAs) can deliver noise to the system, amplifying a very low-power signal without significantly reducing the signal-to-noise ratio, reducing the overall system noise coefficient, without the need for protection and damage to limit circuits, to extremely high input power levels. It is one of the best candidates to perform the receiving stages that can withstand. Low noise amplifiers in receiver circuits are important for communication systems as they reduce the signal received from the antenna by giving low noise. Due to the inherent robustness of GaN HEMTs, LNAs designed using these devices can operate continuously without protection circuitry. In this thesis, an X-band MMIC LNA is designed using GaN HEMT with source degeneration. Passive circuit elements, transistors, and Silicon Carbide (SiC) based 0,15 μm/0,2 μm AlGaN/GaN HEMT microfabrication process developed in MMIC NANOTAM. Production consists of two stages. It includes the front and back steps, respectively. The produced transistors made the linear current (DC), small signal, and large-signal and noise coefficient measurements. The appropriate HEMT was selected for the LNA design and the design process was carried out in a single-stage structure using the source degenerate HEMT. The source degenerate HEMT topology provided both easy input mapping and stability. GaN-based LNA MMIC was designed, and after the production, measurements were taken on the wafer at room temperature and the best results were reported. LNA design provides a small signal gain of over 7 dB between 8-11 GHz, input and output losses better than 8,5 dB, noise coefficient better than 1,1 dB, the output power of 17,19 dBm and drain efficiency of 12,64%.