X-band active balun MMIC in SiGe technology

Baluns are used to transform an unbalanced input signal into a balanced output signal. Baluns are essential components in many microwave circuits, e.g., balanced mixers, or other differential architectures. When the signal is received by the antenna, it is single ended, and thus need to be converted to a balanced signal to benefit from a differential system architecture. Being first in the receiver chain, having a passive balun, will degrade the noise figure significant, thus it is beneficial to have low noise amplifier, which behaves as a balun. For the receiver to have a large dynamic range this balun must also have good linearity, and a high compression point (D. Manstretta, IEEE JOURNAL OF SOLID-STATE CIRCUITS, 47, 2012, pp. 407–420).