A metamaterial device has a coaxial structure including rotational symmetry about a longitudinal axis of coaxial conductors. In a disclosed example, a series inductance portion has a relatively smaller circumferential dimension compared to another portion of a conductor. A series capacitance portion comprises an interruption in the conductor. A shunt capacitance portion has the largest circumferential dimension of the conductor. A shunt inductance portion comprises a relatively small electrical connection between first and second conductors. A disclosed example metamaterial structure is useful, for example, as a filter in a wireless communication device.