A HIGH FREQUENCY MULTI-PORT SWITCHING CIRCUIT

摘要

This invention concerns a multi-port switching circuit which may operate at frequencies up to an even beyond 100 GHz. The invention may be implemented as a GaAs based monolithic microwave integrated circuit. The circuit comprises at least three ports arranged in a star configuration around a central ring. A single switching device is associated with each port. Each switching device is connected to two transmission lines to provide impedance matching and an interconnecting path around the ring. The transmission lines are initially chosen to have a length of a quarter wavelength at the centre of the band of operation of the switch. The matching lines and the lines which form the interconnecting ring are then subject to an optimisation procedure in which each pair of the switching devices is in turn modelled in their ON state while the remainder of the switching devices is modelled in their OFF state. The optimisation procedure aims to achieve low transmission and insertion loss, while providing good isolation.