A Low-Cost and Compact Software-Defined UWB Transmitter for Radar Utilizing a Nonlinear Transmission Line

In this article, we present a compact software-defined ultrawideband (UWB) 0.4–8.3-GHz transmitter that utilizes a nonlinear transmission line (NLTL) to expand the frequency of a transmitted pulse from a low-cost 2.5-GHz bandwidth arbitrary waveform generator (AWG). The developed transmitter consists of an AWG, amplification boards, and an NLTL. By leveraging the software-defined capabilities of the AWG and applying a digital predistortion (DPD) algorithm, we can iteratively adjust the input pulse to fine-tune and optimize the output pulse bandwidth. Ultimately, the UWB transmitter can generate software-defined pulses up to 8.3 GHz and detect 0.25-mm surface objects with a 3-dB area of 1.4 cm.