Patent ID: 7129783

Claim:
A coupler for communicating a signal between at least two ports, the coupler comprising, a first stage amplifier having an input coupled to a third port, a second stage amplifier having an output coupled to a second port, a first pair of delays comprising a first delay coupled between outputs of the first and second stage amplifiers, and comprising a second delay coupled between inputs of the first and second stage amplifiers, the first pair of delays providing accumulative signal strength at the second port when the signal is present at the third port, a first port at the output of the first stage amplifier, the first and second delays serving to provide cancellation of the signal strength so that signal at the third port is absent at the first port, the first delay providing a transmission path between the second port and the first port for coupling the signal between the second port and the first port, and the coupler further comprising, one or more stage amplifiers having respective pairs of delays disposed at outputs and inputs of the amplifiers having transconductances are related to each other by Pascal's triangle.