Alejandro Badolato

3-D High-Resolution Imaging Radar at 300 GHz With Enhanced FoV

We have developed a 3-D high-resolution radar at 300 GHz with a cell resolution of 1×1.6×1.6 cm3 at a standoff distance of 8 m for security applications. The selection of an operating frequency of 300 GHz, a bandwidth of 27 GHz, and a field of view of 50×90 cm2 improves the through-clothes imaging of person-borne concealed objects. The radars antenna design allows single-pixel imaging at a frame rate of two frames per second. A reduction in cost and power consumption and improvements in image quality are additional requirements taken into account in the design of this radar system.

Low-Cost CW-LFM Radar Sensor at 100 GHz

This paper presents a W -band high-resolution radar sensor for short-range applications. Low-cost technologies have been properly selected in order to implement a versatile and easily scalable radar system. A large operational bandwidth of 9 GHz, required for obtaining high-range resolution, is attained by means of a frequency multiplication-based architecture. The system characterization to identify the performance-limiting stages and the subsequent design optimization are presented. The assessment of system performance for several representative applications has been carried out.

Bifocal Reflector Antenna for a Standoff Radar Imaging System With Enhanced Field of View

A unique multireflector bifocal antenna design for real-time standoff imaging applications is presented in this work. The antenna is used in combination with a 300 GHz radar sensor to acquire images at 8 m over a large (80 × 50 cm) field of view (FoV). The increased FoV is obtained by the use of an antenna system composed by a bifocal elliptical Gregorian with an extended subreflector to allow for fast scanning of a beam spot. The scanning is achieved by the combination of the rotation and vertical tilting of a flat small secondary mirror. The design, simulations, prototype description and experimental results of a manufactured working prototype are presented.

DDS-Based Signal-Generation Architecture Comparison for an Imaging Radar at 300 GHz

Submillimeter-wave imaging radars for standoff detection require broadband and fast-switch signal-generation architectures in order to achieve a high-range-resolution and near-video-rate imaging system. The signal generation has a strong influence on the radar image quality, primarily due to the transmitted phase noise. Two direct digital synthesis-based architectures for continuous-wave linear-frequency-modulated signal generation have been fabricated and tested for a high-range-resolution imaging radar at 300 GHz for standoff sensing of person-borne concealed threats. In order to select the signal-generation architecture that ensures the proper operation of the imaging radar with a cost-saving objective, three figures of merit have been used: 1) radar image quality; 2) power consumption; and 3) cost. The impact of the signal-generation architectures on the imaging radar indicates that both architectures present a similar radar performance in terms of radar image quality, although the narrowband direct-digital-synthesis/phase-locked loop scheme is a cost-effective solution compared with the broadband direct-digital-synthesis scheme in order to develop an affordable and energy-efficient high-performance preindustrial radar prototype.

Experimental radar imager with sub-cm range resolution at 300 GHz

This paper presents a high range resolution radar sensor working in the submillimeter-wave band for standoff detection and security applications. Low-cost technologies have been properly selected in order to implement a versatile and easily scalable radar system. A large operational bandwidth, required for high range resolution, is attained by means of a frequency multiplication-based architecture. This radar system sweeps a bandwidth of 27 GHz. The final application allows the generation of 3D images by means of the radar front-end integrated with a bifocal ellipsoidal Gregorian reflector system. The scene of interest is elliptically scanned at a standoff range of 8 m.

100-GHz FMCW radar front-end for ISAR and 3D imaging

This paper presents the design of a 100-GHz imaging radar system with operating bandwidth of 9 GHz and, thus, a theoretical range resolution below 2 cm. The high-resolution FMCW radar consists of a front-end of commercial components (COTS) operating at frequencies up to 100 GHz. Different technologies are involved in this development such as digital signal generation, microstrip designed circuits or waveguide components. An experimental trial has been performed. Results show that the effective range resolution is better than 3.1 cm, without resorting to any technique for compensation of amplitude non-linearities of the transmitted waveform.

Optimization of a compact THz imaging radar for real-time operation

A summary of obstacles and solutions in the Universidad Politécnica de Madrids CW-LFM (continuous-wave linear frequency modulation) imaging radar towards enabling real-time through-clothes threat detection with a compact system is presented. Image acquisition has been designed to permit a 2 fps (frames per second) video feed, and a newly developed signal-processing and image representation software, run on a mixed CPU-GPGPU (central processing unit general-purpose graphics processing unit) architecture, allows speeds up to 5 fps. Additional hardware modifications have yielded reductions in cost, power consumption, and volume.

Characterization of a 300 GHz imaging radar for standoff detection

A complete characterization of a 300 GHz high-resolution imaging radar with large Field of View is carried out in order to optimize its operational parameters. This imaging radar has been designed for standoff detection in security applications. The characterization is focused primarily on the spatial and range resolution. The results show that the imaging radar presents a resolution better than 2 cm. 3D images revealing a threat hidden under clothing validate the imaging radar performance.