S22'de gözlenen kink-etkisi dikkate alınarak genişbantlı GaN LNA MMIC ve mikro/nano proses geliştirilmesi

Broadband low noise amplifiers (LNA) are one of the key components of the numerous applications such as communication, electronic warfare, and radar. The requirements for higher bandwidth, higher speed, higher survivability, higher reliability, etc. pushes the technological boundaries. The demand for high performance circuit components without a compromise stimulates the utilization of the high-end gallium nitride (GaN) technology to develop better monolithic microwave integrated circuits (MMIC) in a smaller footprint. To support the progress, the development of a proper GaN high electron mobility transistor (HEMT) technology and proper circuit models have become critical. To support the efforts and contribute to the progress, a 0.25 μm microstrip (MS) GaN HEMT technology is developed in Bilkent University Nanotechnology Research Center (NANOTAM). The technology development yield that the MS GaN HEMT technology is capable of supporting ≥4.4 W/mm output power (POUT), ≥50% power added efficiency (PAE), ≥15 dB gain, and ~1 dB noise figure (NF) at 10 GHz. Moreover, the gate structure of the technology is studied by evaluating the kink-effect (KE) in the output reflection coefficient (S22) of the HEMT to support the broadband operation. Besides the technology development, the small-signal (SS) and noise equivalent circuit models are studied, and the developed models present high convergence with the measurements. The accuracy of the models contributes to development of the cascode HEMT based LNAs even without fabricating the cascode HEMT. Furthermore, the developed models and the proper gate structure are used to develop the broadband QFN packaged GaN LNA MMIC for the mobile radio communications and the military & commercial radar applications. The results of the circuit models and the GaN LNA MMIC also yield that the developed MS GaN HEMT technology is capable for developing different solutions up to 18 GHz.