Covert communication using a directly modulated array transmitter

A Direct Antenna Modulation (DAM) scheme is configured on a 2-element array with 2-bit phase control. Such a transmitter is shown to generate constellations with two different orders simultaneously towards different transmitting angles. A possible covert communication scenario is presented in which a constellation with 16 desired signals can be generated at the intended direction, while at a second direction one with reduced number of distinct signal points is purposely generated to prevent accurate demodulation by eavesdropper. In addition, system can be configured to actively lead low-level constellation towards up to two independent pre-known eavesdropping angles.