ESAKuKaLNA – Low-noise amplifiers in the Ku- and Ka-bands for satellite applications

Low noise microwave amplifiers (LNA) are a vital component for realising high performance radio frequency (RF) receiver front ends in Earth observation systems. However, in conventional Ku- or Ka-band radar or passive radiometer instruments, unwanted signals from transmit signal leakage and Radio-Frequency Interference (RFI) can degrade or destroy the LNA MMIC (Monolithic Microwave Integrated Circuit). RF protection circuits are used to protect the LNA. Limiters, circulators or parallelised amplifiers are typically integrated in the front-end to increase the system robustness against excessive power. These solutions introduce losses, degrade the noise figure performance and increase the overall dimensions of the front-end unit.

With the advent of low noise gallium nitride (GaN) technology, robust LNA MMICs can be designed which may not require a limiter at the input, or require a less demanding limiter, hence improving the noise figure of the receive front-end. Recent studies have demonstrated that GaN combines high input signal power handling capabilities, while achieving state-of-the-art low noise performance which makes this technology an excellent choice for robust LNA development.