Single-Sideband Time-Modulated Phased Array With S-Step Waveform

Single-sideband time-modulated phased array (STMPA) provides beam-scanning capability and eliminates some undesired sidebands. To further improve the frequency spectrum, the time modulator of the STMPA with S-step waveform for better eliminating the undesired sidebands and widening the allowable signal bandwidth without aliasing is proposed in this letter. The S-step waveform is realized by digital attenuators in time modulators. Most of sidebands are eliminated and the allowable signal bandwidth becomes 4S times as wide as that of conventional time-modulated array (TMA). The general expressions of the sideband level (SBL) and the theoretical loss of the time modulator related to the number S of the steps are given. To experimentally verify the feasibility of the proposed design, the time modulator with four-step waveform and the corresponding four-element STMPA are fabricated and measured.