1,721,057 research outputs found
Photonic generation of microwave phase coded radar signal
No full textIn modern radar systems, the requirements of resolution, sensitivity, and flexibility are pushing the development of reconfigurable and software-defined radio-frequency (RF) signal generators, capable of producing radar pulses with arbitrary amplitude and phase, over high-frequency carriers with the phase stability required by coherent radar applications. In this work we propose a photonic based approach for generating very-high-frequency radar signals with advanced phase coding. The scheme exploits a Mode Locked Laser and an IQ electro-optical Mach Zehnder Modulator. Experimental results obtained around 25GHz relative to Barker and Frank codes are presented and compared with numerical simulations in order to demonstrate the effectiveness of the proposed technique. The proposed scheme shows potentials for wideband modulation and could represent a promising solution for the implementation of fully digital radar systems
SDR multiband radars based on photonics for aerial and naval scenarios:from the concept to the field trials
No full textPhotonic generation of phase-modulated RF signals for pulse compression techniques in coherent radars
Full text linkA novel and flexible photonics-based scheme is proposed for generating phase-coded RF pulses suitable for coherent radar systems with pulse compression techniques. After selecting two modes from a mode-locked laser (MLL), the technique exploits an optical in-phase/quadrature modulator driven by a low-sample rate and low-noise direct digital synthesizer to modulate the phase of only one mode. The two laser modes are then heterodyned in a photodiode, and the RF pulse is properly filtered out. The scheme is experimentally validated implementing a 4-bit Barker code and a linear chirp on radar pulses with a carrier frequency of about 25 GHz, starting from an MLL at about 10 GHz. The measures of phase noise, amplitude- and phase-transients, and autocorrelation functions confirm the effectiveness of the scheme in producing compressed radar pulses without affecting the phase stability of the optically generated high-frequency carriers. An increase in the radar resolution from 150 to 37.5 m is calculated. The proposed scheme is capable of flexibly generating software-defined phase-modulated RF pulses with high stability, even at very high carrier frequency, using only a single commercial device with potentials for wideband modulation. It can therefore allow a new generation of high-resolution coherent radars with reduced complexity and cost. © 1983-2012 IEEE
Photonics for Ultrawideband RF Spectral Analysis in Electronic Warfare Applications
No full textElectronic warfare receivers must satisfy particularly demanding requirements, and current electronic solutions must find a tradeoff between the request for high performance (in particular, very wide bandwidth, very high sensitivity, and very linear response) and the need for light and small systems. Photonics has been often proposed as a potential enabler of performance improvements, thanks to its wide tunability and precision, and recently the advancements of the photonic integration technologies are also promising strong reductions of size and weight. In this paper, we present an overview of the photonics-based solutions proposed so far in the field of electronic warfare. In particular, we focus on the specific implementation of a spectrum scanner we have recently proposed. Besides the performance in terms of bandwidth, linearity, and sensitivity, which are on par with the state-of-the-art electronic commercial systems, here, we report on our last advancements in terms of tuning speed. Further improvements are also discussed, in terms of both tuning speed and integrability
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