Achieving Full-Duplex Communication: Magnetless Parametric Circulators for Full-Duplex Communication Systems

In a crowded electromagnetic spectrum with ever-increasing demand for higher data rates to enable multimedia-rich applications and services, the efficient use of wireless resources becomes crucial. For this reason, full-duplex communication [1]-[4], which increases the capacity of transmission channels by operating the uplink and downlink simultaneously on the same frequency channel (see Figure 1), is returning to the spotlight after decades of being presumed impractical. This long-held assumption resulted mainly from the need for large isolation (IX) between the transmit (Tx) and receive (Rx) nodes [also known as self-interference cancellation (SIC)], which typically needs to be greater than 100 dB, a challenging task that requires several innovations at the network and physical layer levels.