Synthetization Of Signals By The Transmission And Superposition Of Bipolar Impulses In Free Space

A low power prototype antenna array with multi-channel transmission capabilities is incorporated to synthesize sinusoidal signals in free space from non-periodic source signals. Synthesis of a specified continuous signal is suitable in applications for spatially targeted plasma generation at high power. The system operates with an external 2.4 GHz clock source which allows for a 0.417 ns step resolution. Each antenna transmits an amplitude scaled set of non-periodic bipolar impulses $( \sim 2$ ns wide) which enables synthesizing an arbitrary signal at a specific point in free space only limited by the available number of antennas. A specific bipolar impulse set is found through the particle swarm optimization, PSO, technique with appropriate goal function selection. While the optimization is simply carried out in the time domain, the respective delay between antennas is matched in the experiment through electronic delays and/or physical antenna positioning.