Trends in monolithic microwave integrated circuits

Current trends in the fabrication of monolithic microwave integrated circuits (MMICs) are reviewed. The technologies developed predominantly make use of semi-insulating GaAs substrates, GaAs FET active elements, and lumped element circuits. An increasing number of MMIC designs incorporate innovative designs, including actively matched amplifiers and mixers, analog and digital functions, SAW circuits, and increased Q with lower resistance. A new generation of hybrid integrated circuits is also being developed which is expected to compete with conventional MMICs due to the potential for significant cost reduction. MMICs are considered to have the greatest potentials in applications requiring large quantities of similar circuits, circuits using large numbers of transistors or small areas for passive elements, and novel circuits such as SAWs monolithically combined with FETs.