Alıcı-verici uygulamaları için GaN yükselteclerinin tasarımı ve geliştirilmesi

A transceiver, commonly known as a T/R module, is widely used in phased array radar systems for military, space, and commercial applications. Hybrid microwave integrated circuits and low-temperature co-fired ceramic technologies offer bulky solutions. However, advancements in GaN HEMT-based monolithic microwave integrated circuit (MMIC) technology have led to low-cost, compact, and efficient alternatives over the years. A microwave transceiver consists of a low noise amplifier (LNA), a high power amplifier (HPA), and a single-pole double-throw switch. The current thesis aims on indigenous design and development of LNA and HPA for an MMIC transceiver at X-band using NANOTAM's in-house 0.15/0.25 µm AlGaN/GaN fabrication process. Robustness, including survivability and reverse recovery time (RRT), and limiting output power are the primary focus of LNAs besides gain and noise figure (NF). The single-stage design based on cascode HEMT and three-stage designs based on source degenerated HEMTs are discussed in the frequency range of 8 to 12 GHz. It is shown that cascode HEMTs-based LNA have high survivability but at the cost of increased NF. In a three-stage design, RRT is studied as a function of the pulse width of the incoming signal. This LNA has the best combination of NF and survivability, surviving 42 dBm input power with sub-1.5 dB NF and having 23.2 dB gain with ±1 dB gain ripple. The output saturated power of the LNA is limited to 20 dBm using a novel un-gated HEMTs approach for easy integration with subsequent circuitry. Moreover, the design of a three-stage high power amplifier operating in the 8.5 to 11 GHz is discussed in detail. Two design approaches are described, and it is shown that reducing the power dissipation by reducing HEMT peripheries in the first and intermediate stages improves power added efficiency (PAE). The achieved PAE is higher than 43 % with more than 43 dBm output power in a compact size of 2.4 × 3.75 mm².