MMIC medium-power amplifier in K band with matching and power-divider/combiner networks implemented with the use of lumped elements

摘要

Modern microwave systems require low size, weight, and cost, leading to an increased use of monolithic integrated technologies. Radio-frequency integrated circuits (RFICs) and microwave monolithic integrated circuits (MMICs) are already extensively employed in consumer wireless applications, for instance. With such monolithic technologies, an exhaustive design is required because circuit adjustment after fabrication is not possible, and the success of the design process depends on the accuracy of the active and passive device models. Chip-size minimization is a key point in achieving lower production costs and higher integration level on monolithic circuits. At low microwave bands, the matching circuits in monolithic amplifiers employ lumped elements. Nevertheless, the increasing losses and parasitic effects of the lumped elements with frequency result in a practical limitation of the useful frequency range of such elements. Moreover, the usual electrical models of lumped elements could be not accurate enough to predict self-resonance or other high-frequency anomalous behavior. In general, at frequencies above the Ku hand, the distributed elements are preferred for implementing the passive circuitry. Nevertheless, significant size reduction can be obtained in K-band monolithic designs using lumped elements, as was already demonstrated with the use of coplanar technology in [1].