FMCW AND CHAOTIC MICROWAVE GENERATION USING NONLINEAR PHOTONIC SYSTEMS FOR V- AND W-BAND RADAR APPLICATION
Abstract
Radars have found their importance in numerous different application areas, such as sensing, ranging, imaging, and velocimetry, and thus have continuously attracted much research interest in the novel development of their schemes, architectures, and systems for the best possible performance and also for emerging yet promising functionalities. Radar schemes using frequency-modulated continuous-wave (FMCW) microwaves and chaotic microwaves, respectively, are highly attractive as they provide high range resolution, strong anti-jamming capability, high noise immunity, simple system structure, high signal-to-noise ratio, large dynamic range, and high measurement accuracy, stability, and sensitivity. These advantageous performance characteristics are attributed to their unique temporal and spectral microwave features. That is, FMCW radars adopt a type of sinusoidal microwave oscillation with its frequency varying linearly, triangularly, or step-wisely with time over a repeated period, and chaotic radars use another type of microwave oscillation with its amplitude varying irregularly with time, indicating a noise-like waveform and a broadband spectrum. For the generation of these two different microwaves, photonic approaches provide various promising advantages over their electronic counterparts, such as broad modulation bandwidth, wide and continuous carrier frequency tunability, high capability in achieving modulation over the millimeter-wave band, and long-distance microwave distribution through optical fibers. In this project, two novel photonic approaches based on nonlinear dynamics of semiconductor lasers are proposed and investigated to generate FMCW microwaves and chaotic microwaves, respectively, for better radar performance characteristics, such as broader modulation bandwidth for better resolution in longitudinal direction (i.e., range resolution), higher carrier frequency for better resolution in transverse direction (i.e., cross resolution), stronger anti-jamming capability, and higher noise immunity. Based on our preliminary study, while FMCW microwaves at a central frequency of up to 40 GHz can be generated with its frequency varying linearly or triangularly over a range of up to 4 GHz, chaotic microwaves at a carrier/central frequency of 30 GHz with an ultra-wide spectral distribution of up to 50 GHz can be generated. In this project, a further and comprehensive investigation on both FMCW microwave generation and chaotic microwave generation using nonlinear dynamics of semiconductor lasers will be conducted. The investigation includes (1) the feasibility of such microwave generation over V- and W-bands, (2) the possibility of such microwave generation with a broad spectral bandwidth, (3) the feasibility of such microwave generation with a widely tunable central frequency, (4) the possibility of long-distance fiber distribution of such generated microwaves, and (5) the feasibility of such microwave generation with different modulation formats or structure-less spectral profiles. Effects of various operational and intrinsic parameters will also be studied to fully understand the appropriate system design and operating conditions for the best performance. The approach in this research will be a combination of theoretical calculation, numerical simulation, and experimental investigation.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 10, 2022
- Source ID
- FA23862114032XX49
Entities
People
- Sheng-kwang Hwang
Organizations
- Air Force Office of Scientific Research
- National Cheng Kung University
- United States Air Force