UC Davis

In this work, we develop and analyze a new software-defined pulsed ultra-wideband (UWB) transmitter for pulsed radar systems. As compared to conventional analog pulse generator-based transmitters, the implementation of a software-defined generator allows for flexibility in pulse shaping and bandwidth based on situation. The implementation of the software-defined transmitter is vital as it allows for (1) an advantage in imaging targets at different distances and (2) the potential to suppress ringing and clutter through implementation of digital pre-distortion (DPD). The system is tested in applications with ground penetrating radar (GPR). First, we discuss the architecture and design of the software-defined transmitter operating from DC-11.9 GHz that implements an arbitrary waveform generator (AWG), amplifier, and switching network. In addition to evaluating these components, we perform scans outside of Kemper Hall at UC Davis to show how flexibility from the software-defined radar allows for detection of different target types. Next, we describe the design and evaluation of a UWB 3:1 switching network on a 45 nm RFSOI process operating from DC-67 GHz potentially useful for radar. Aside from the hardware design, we also establish a DPD algorithm that uses Wiener filter compensation followed by an iterative feedback loop to decrease measured ringing and increase pulse fidelity. We show the effectiveness in applying this DPD algorithm for pulses with a 20-dB bandwidth up to 8.46 GHz. Additionally, we show an adjusted DPD algorithm useful for compensating pulses out of a non-linear transmission line using a look-up table-based approach. Lastly, we analyze the effect of realistic vibration on a UWB transmitter for B-scan image quality of GPR scans.