The HA.31.A is an ISM 915MHz quarter wave-length monopole antenna. This helical coil antenna is perfect for your smart meter, smart security system, remote asset monitoring, and other wireless communication devices. The helical coil antenna has a 2dBi Peak gain and a 68% efficiency at 915MHz on a 126.8 x 80.1mm ground plane with matching components (orthogonally mounted to ground plane, see HAD.B.31 performance). Made of copper alloy, the helical coil is mechanically sturdy, with a wide-bandwidth. It can be easily mounted on the surface of your device main board by soldering. The antenna must be connected to a ground-plane to radiate efficiently.