4 Port Devices
Four port devices can be realized by joining two 3 port devices via the appropriate ports. As system performance requirements become more demanding, new design approaches must be adopted. These include Faraday rotation devices and phase shift circulators. The bandwidth and isolation limitations of 3 port devices are overcome through a distributed architecture that enables more ferrite material to be incorporated into the transmission path, thereby achieving an increase in the biasing magnetic field. Phase shift circulators can be designed to handle higher RF power than 3-port devices.
