Patent ID: 8072289

Claim:
A coupler apparatus for generating separate signal channels from a radio-frequency input, comprising: an input line configured for receiving a high-frequency input signal; a transmission line connecting said input line to an output line and to at least one separate signal channel; and means for creating a left-handed anti-parallel relationship between phase and group velocities below a transition frequency, Ï‰ 0 , and a right-handed parallel relationship between phase and group velocities above transition frequency Ï‰ 0 , within at least a portion of said transmission line, to generate backward wave coupling; wherein said means comprises an artificial composite right/left-handed (CRLH) transmission line (TL); wherein said CRLH TL comprises a unit cell; wherein said unit cell comprises a series combination of a right-handed inductor and a left-handed capacitor; and wherein said series combination of said right-handed inductor and said left-handed capacitor is coupled to a paralleled combination of a right-handed shunt capacitor and a left-handed shunt inductor.