A wireless security device, such as a door or window motion sensor, that can be mounted almost entirely within a recess of a door, window or frame, with only the antenna mounted on the surface of the door or window jamb. The wireless security device has a housing suitable for being embedded within a structure such as a door, window or frame. In the housing are a security sensor circuit adapted to generate an alarm signal when activated, a radio frequency (RF) transmitter connected to the security sensor circuit for transmitting an RF signal when the alarm signal is generated, and a power source (such as a battery, piezoelectric element, solar cell or fuel cell) for supplying operating power to the security sensor circuit and the RF transmitter. A substantially flat surface mountable strip is located in proximity to the housing and is suitable for being mounted outside (i.e. along the surface of the structure). The surface mountable strip has an antenna that is coupled to the RF transmitter for emitting electromagnetic energy corresponding to the RF signal from the transmitter. In addition, the embedded antenna provides a predictable transmission pattern resulting in increased range and reliability.