This letter concerns a compact ultrawideband dual-port, dual-polarization antenna working from 6 to 9 GHz that can be integrated conveniently into a miniaturized transceiver, such as a car key, a dongle, or a small remote control, that uses a CR2032 battery. In fact, the proposed antenna is at one with the battery and the battery holder and assures a direct current connection between the battery and the transceiver electronics. It follows that the volume overall is almost the same as that occupied by the battery plus the battery holder. The low reflection coefficient at both input ports and the good isolation allow having an envelope correlation coefficient lower than −30 dB in the entire frequency band.