  A Josephson parametric amplifier (JPA) is executed in a three-dimensional
(3D) microwave cavity by coupling it to a superconducting quantum interference
device (SQUID) that is embedded in a two-dimensional resonator. The JPA is
activated in a three-wave mixing configuration by injecting ac magnetic flux,
at twice the 3D cavity frequency, into the SQUID. An 8.3 GHz cavity is measured
in a non-degenerate phase-insensitive configuration which yields gains in
excess of 40 dB, where a 20 dB gain results in an operational bandwidth of 0.4
MHz, a 1 dB compression point of -115 dBm with half a quantum of added noise.
