Wide-band matched LNA design using transistor's intrinsic gate-drain capacitor

Abstract

This paper presents the development of a wide-band amplifier with matched input impedance and low noise temperature over 10-20 GHz. Here, the novel wide-band feedback mechanism provided by the transistor's intrinsic gate-drain capacitor will be analyzed in detail with both the derived input reflection coefficient and noise temperature of the resulting circuit confirmed by their simulated counterparts. It is thus clear why by fine tuning its output RC loading impedance and source inductance, a transistor's input reflection coefficient and noise temperature can be greatly improved over broad bandwidth. To demonstrate the feasibility of this novel approach, a wide-band low-noise amplifier (LNA) is designed and characterized. A bandwidth broadening mechanism using double feedback is also proposed for the future design of matched ultra-wide-band LNA.