Temporal Focusing Effects of Time-Reversal Frequency Diverse Array Antenna

Omnidirectional or the phased-array antenna is usually adopted in the time-reversal literature, but it cannot focus the power of the transmitted signals in both time- and space-domains. In this letter, we propose the hybridization of time reversal and frequency diverse array (FDA), which transmits the signal with a small frequency offset across the array to generate both angle- and range-dependent beampattern, for temporal focusing. The time-reversal FDA channel is modeled in multipath scenarios. For the given parameters with 12 transmit elements spaced by half-wavelength, carrier frequency 1 GHz, and frequency offset 1 kHz, the peak of time-reversal FDA focusing is 18.7% higher than that of a standard FDA. Both theoretic analysis and simulation results verify that, while maintaining FDA angular-time periodicity, the FDA range periodicity is eliminated and the energy is focused at the target position by the use of time-reversal processing.