Direct Antenna FSK Modulation with Time Modulated Arrays

An innovative time-modulated array (TMA) approach capable of simultaneously performing direct antenna frequency-shift keying (FSK) modulation and beam steering (BS) is proposed. Conventional binary FSK (BFSK) modulators are based on the commutation of two carriers and, to perform BS, a standard phased array with variable phase shifters (VPSs) is needed. Alternatively, the proposed TMA approach jointly performs BFSK modulation by transmitting each symbol over a different harmonic frequency, and BS by adjusting the on-off instants of the periodic binary sequences which control low-complexity 2-bit VPSs.