Microwave Photonic Radars

Abstract

As the only method for all-weather, all-time and longdistance target detection and recognition, radar has been intensively studied since it was invented, and is considered as an essential sensor for future intelligent society. In the past few decades, great efforts were devoted to improving radar's functionality, precision, and response time, of which the key is to generate, control and process a wideband signal with high speed. Thanks to the broad bandwidth, flat response, low loss transmission, multidimensional multiplexing, ultrafast analog signal processing and electromagnetic interference immunity provided by modern photonics, implementation of the radar in the optical domain can achieve better performance in terms of resolution, coverage, and speed which would be difficult (if not impossible) to implement using traditional, even state-of-the-art electronics. In this tutorial, we overview the distinct features of microwave photonics and some key microwave photonic technologies that are currently known to be attractive for radars. System architectures and their performance that may interest the radar society are emphasized. Emerging technologies in this area and possible future research directions are discussed.

Microwave Photonic Array Radars

“…By tuning the pump power to adjust the phase variation slope, the time delay, as well as the phase of the microwave signal, can be changed. Based on this principle, an SBS-based microwave phase shifter was built with a phase tuning range of 168 degree and an operating frequency range over [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”

“…Nevertheless, constructing a true time delay beamforming network using microwave delay lines is very difficult, mainly because of the considerable transmission loss and uneven frequency response. Microwave photonic technology, which uses photonic devices to generate, transmit, and process microwave signals [5], [10], provides a promising solution to the above problems. Fig.…”

Field Experiment of Photonic Radar for Low-RCS Target Detection and High-Resolution Image Acquisition

“…The microwave photonics technology, which combines photonics and microwave engineering [9]- [11], has recently attracted attention as a promising solution for a low-RCS target detection and identification [12]. This technology is capable of generating coherent high-frequency and broadband radar signals with the aid of photonics [12]- [17]. There have been substantial efforts to implement radars by using microwave photonics technology for target image acquisition [15]- [21].…”

Photonic Generation and Application of a Bandwidth Multiplied Linearly Chirped Signal With Phase Modulation Capability

“…Due to the bottlenecks of state-of-the-art electronics technique, the generated signal has a limited bandwidth, low frequency, poor tunability, and the generator has a complicated configuration. To overcome these problems, photonic technique is proposed to generate a linearly chirped signal with improved frequency, expanded bandwidth, enhanced flexibility, and optimized electromagnetic interference immunity [4], [5], [6].…”