The consumer-level unmanned aerial vehicles (UAV) are small and an increasing treat to personal privacy and public security. Due to the small radar cross section (RCS) property and slow speed, it is difficult to detect UAVs by radar systems. This paper presents the design and analysis of the PLL-based synthesizer for passive or active UAV detection radar applications. The adaptive bandwidth of PLL ensures the loop stability to track exact frequency. In this design, the loop bandwidth is set around 400KHz with 8MHz reference clock. The integer N is programmed from 1 to 128, thereafter the inverse linear current in the charge pump is 64:1. Since the frequency operation ranges from 40MHz to 1.024GHz, the 8-bit end-of-counter (EOC) detector is a better solution for high-speed consideration. Based on a countdown counter configuration, the EOC detector detects the count state to reinitiate the counter to N and the cycle repeats. The PLL-based synthesizer is fabricated in a 90nm digital CMOS process with the core area of 0.24 x 0.47mm2. The core power consumption is 3.6mW from a 1V supply. The PLL-based synthesizer performs that the phase noise at 6MHz (or 8MHz) is below -100dBc/Hz, and below -110dBc/Hz at 12MHz (or 16MHz). The peak-to-peak tracking jitter at 240MHz is 7.2ns, and the RMS tracking jitter is 921ps. The overall settling time of the synthesizer is below 20μs, and the results guarantee the overall performance of the UAV detection radar.

Date Published: 3 May 2019
PDF: 7 pages
Proc. SPIE 11003, Radar Sensor Technology XXIII, 110031H (3 May 2019); doi: 10.1117/12.2518620

Published in SPIE Proceedings Vol. 11003:
Radar Sensor Technology XXIII
Kenneth I. Ranney; Armin Doerry, Editor(s)