Abstract: A device for coupling a radio frequency transceiver of an MRI system utilizes a tunable hybrid network. The network is formed of fixed value capacitors connected to transmission lines that provide inductive reactance to the network. The connection of the components is such that an input signal applied to one node produces a pair of signals in quadrature at two other nodes. In order to insure that the pair of signals have the proper phase and amplitude relationship a fixed capacitor is connected across specific pairs of the transmission lines. The point of connection of that capacitor to the transmission lines is chosen to properly tune the network.