Contents I. Introduction
Advances in InP-based high electron mobility transistor (HEMT) epitaxial growth and the process technology have allowed the realization of millimeter-wave and submillimeter-wave frequency MMICs [1], , [3], expanding the state-of-the-art performance for high speed communications, spectroscopy, and remote sensing. For example, with atmospheric windows at 140, 220, and 340 GHz, there is high interest in passive and active imaging applications which include direct-detection radiometers, through-wall imaging, concealed or improvised weapons detection, and next generation synthetic aperture radar (SAR). These applications raise the demand for low-noise amplifiers (LNA) with high gain, large bandwidth, and low power consumption. Due to the higher carrier density, superior electron mobility, and higher low-field electron velocity, InP devices clearly outplay the established GaAs technologies in terms of the requisite figures-of-merit needed to demonstrate the aforemention systems.
