Increasing the Efficiency-Bandwidth Product and Impedance Bandwidth of Electrically-Small Antennas Through Parametric Space-Time Variation

A method for improving the efficiency-bandwidth product of electrically-small antennas (ESAs) through space-time variation is reported. By coupling radiative and non-radiative modes of the ESA using spatially-discrete traveling wave modulation (SDTWM), the time-varying antenna is made to radiate efficiently over an operating band that is 4.5 times larger than its LTI counterpart. Judicious choice of the modulation parameters allows this bandwidth enhancement to be obtained while keeping the reflected power more than 10 dB below the incident power.