Abstract: A method and system configures a wireless communication device to support simultaneous signal propagation using a single narrow band antenna. An antenna tuner controller (ATC) configures a tunable low band matching circuit to provide a first antenna matching in order to support propagation of a low band signal with a first signal path. The ATC configures a tunable high band matching circuit to provide a second antenna matching which can support propagation of a high band signal within a second signal path. In addition, the ATC provides isolation between the tunable matching circuits, utilizing a diplexer circuit having a low band component coupled to the first signal path and a high band component coupled to the second signal path. The ATC simultaneously propagates the low and high band signals using a single, shared narrow band antenna coupled to the first and second signal paths.