C. Migliaccio

Foreign Objects Debris Detection (FOD) on Airport Runways Using a Broadband 78 GHz Sensor

This paper describes a compact broadband (73-80 GHz) mm-Wave front-end used for FOD detection application. The design philosophy of our system is to have several low-profile, low-cost mm-Wave sensors placed along the runway. Tests were conducted on the small airport of Aix Les Milles (south of France). High sensitivity and simultaneous objects detection capabilities were shown. Even very small objects like nuts were seen. The extension of the actual detection range is needed in order to go from 110 m (in the most favourable case) to 500 m.

94 GHz Folded Fresnel Reflector Using C-Patch Elements

A 94 GHz folded Fresnel reflector (FFR) for helicopter collision avoidance Radar is presented. The antenna system consists of a primary source illuminating a semi-reflecting grid that reflects the primary source polarization toward the main reflector opposite the grid. The main reflector has two functions. It focuses the field in the desired direction and rotates the incident polarization by 90deg to enable it to pass through the grid and radiate. Specific patch elements having a C-shape have been designed for this purpose. In order to increase overall efficiency, the reflector combines 8 correcting zones in its center and 4 at the periphery. The reflector is manufactured using standard photolithographic techniques. The primary source consists of a metal waveguide covered with a small frequency selective surface (FSS) for matching purposes. The maximum measured gain is 36.5 dBi at 94 GHz. The maximum side lobe level is -18 dB. The return loss value does not exceed -25 dB. The frequency bandwidth -3 dB in gain and return loss is 10%. In-flight measurements were conducted demonstrating the ability to detect power lines at distances up to 680 m.

Folded Reflectarrays With Shaped Beam Pattern for Foreign Object Debris Detection on Runways

Design of a folded reflectarray antenna (FRA) by phase only control to provide a cosecan squared beam pattern in elevation and a pencil-beam pattern in azimuth to detect objects on the ground, e.g., on runways. A very compact folded reflectarray antenna was fabricated and its radiation pattern over frequency was simulated. During the design process a conical horn was developed, which illuminates the array, with symmetrical radiation pattern for all planes and for a frequency range of 76 to 81 GHz. As the FRA consists of a single layer substrate this kind of antenna could be a candidate for low-cost production in FOD detection on airports in the future.

Performance of obstacle detection and collision warning system for civil helicopters

Some helicopters strike the power lines under the good weather conditions. Helicopter pilots sometimes have some difficulties to find such long and thin obstacles. We are developing an obstacle detection and collision warning system for civil helicopters in order to solve such problems. A color camera, an Infrared (IR) camera and a Millimeter Wave (MMW) radar are employed as sensors. This paper describes the results of different flight tests that show good enhancement of radar detection over 800m range for power lines. Additionally, we exhibit the processed fusion images that can assist the pilots in order to recognize the danger of the power lines.

W-Band Fresnel Zone Plate Reflector for Helicopter Collision Avoidance Radar

A high gain Fresnel zone plate reflector is presented for helicopter collision avoidance radar at 94 GHz. The antenna system consists of a compact, airtightness and low return loss primary source illuminating a printed reflector with Fresnel plate zone phase correction. In order to increase the overall efficiency, the reflector combines 8 correcting zones in its center and 4 on the border. Reflected phase of over 360deg is achieved by means of circular ring or combined circular and ring patches. The reflector is fabricated using standard photolithographic techniques. The primary source consists of a small FSS made by a double slot array antenna pasted on the aperture of a standard WR-10 waveguide. Antenna measurements were conducted using a compact base arrangement. The antenna performs 37.8 dBi at the center frequency of 94 GHz with a maximum value of the return loss value not exceeding -25 dB. The frequency bandwidth at -3 dB in gain and return loss is of 9%

Millimeter wave radar for the obstacle detection and warning system for helicopters

An obstacle detection and warning system for civil helicopters is now being developed. An infrared camera and a 94 GHz millimeter wave (MMW) radar have been used as its sensor. Experimental MMW radars have been built to examine their propagation properties and obstacle detection performance. A 94 GHz Vivaldi antenna has been fabricated for a compact radar antenna. Measured results demonstrated that the experimental FMCW radar has a satisfactory range and accuracy. It was also shown that the Vivaldi antenna worked well at A 90 to 100 GHz frequency range.

Millimeter-Wave Radar for Rescue Helicopters

A collision avoidance and warning system for civil helicopters in Japan has been developed. A real-time warning method was applied using an image fused from a coloured video, an IR sensor data and mm-wave radar measurements. This paper focuses on the FM-CW mm-wave radar sensor and the associated antennas, working at 94 GHz. Flight tests were conducted in order to detect power lines. Thanks to two different antennas, power line response was measured in vertical and horizontal polarizations. Maximum detection ranges are of 800 and 600m respectively. This variation comes from the antenna gain difference. Radar resolution is limited by the allocated bandwidth at 94 GHz which is 200 MHz. Comparisons were conducted on the ground with an integrated FM-CW radar working at 77 GHz and achieving 500 MHz bandwidth

76.5 GHz millimeter-wave radar for foreign objects debris detection on airport runways

The paper is a joint work between the LEAT (France) and the ENRI (Japan) in the framework of a Sakura project supported by the JSPS and the French Ministry of Foreign Affairs. The purpose is the study of a FOD (Foreign Object Debris) detection system on airport runways. A FM-CW mm-Wave radar working between 76.25 and 76.75 GHz is used together with a high directivity printed reflectarray. Measurement results show detection capabilities of a -20 tlBsm cylinder up to 35 m which is 10 m less than the FAA recommendations. Antenna improvements are discussed for reaching the requirements and system performance as well as the use of calibration objects.

Reflectarray using an offset prolate feed at 94 GHz

The design of an offset reflectarray illuminated by an original primary source at 94 GHz was tested successfully. The antenna shows very low side lobe and cross-polarization levels. These results are of interest for multi-beam applications, when the system is fed by several sources. Simulations were made with a computer-model that gives, in less than 10 minutes on a standard PC, a good approximation of the radiation pattern in the H-plane. The problem of the specular reflection has still to be overcome as well in simulations as in the design. In order to solve it partially, the next step will be the realization of an offset feed with a main radiation in the specular direction.

Whole-microwave system modeling for brain imaging

In this paper, we present the results of a whole-system modeling of a microwave measurement prototype for brain imaging, consisting of 160 ceramic-loaded antennas working around 1 GHz. The modelization has been performed using open source FreeFem++ solver. Quantitative comparisons were performed using commercial software Ansys-HFSS and measurements. Coupling effects between antennas are studied with the empty system (without phantom) and simulations have been carried out with a fine numerical brain phantom model issued from scanner and MRI data for determining the sensitivity of the system in realistic configurations.