Fet crossbar switch device particularly useful for microwave applications

Abstract

An FET crossbar switch device is implemented by using a split gate electrode and a shared source and drain pad to implement source and drain electrodes on an integrated circuit substrate. First and second inputs to the device are associated with first and second transmission lines, each of which is directly connected to a first and second source electrode areas. Disposed between the source electrode areas are respective drain electrode sections, each of which is coupled to an associated output transmission line. The input and output transmission lines are fabricated directly on the integrated circuit substrate. Gate fingers or electrodes are directed between respective drain electrodes and adjacent source electrodes. By properly biasing the gate electrodes, one can direct the first input to the first output with the second input directed to the second output. In a second state the first input can be connected to the second output with the second input disconnected or connected to the first output. In this manner, the device operates as a crossbar switch while providing extremely efficient operation at high microwave frequencies due to the symmetry of the device as employing transmission line geometry. The construction of the device reduces the need for matching networks. The entire device is implemented by microwave monolithic integrated circuit techniques and is extremely reliable and efficient.