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

Millimetre‐wave polarization‐dependant monopulse printed Fresnel reflector

“…The reflector bandwidth is narrower than a conventional printed FZP [5]. When the frequency increases, the radiation pattern is more dissymmetric, and the gain decreases (Figs.…”

“…Therefore, a Fresnel reflector is preferred to a reflect array since the number of different patches is the number of correcting zones P. Furthermore, choosing a high value of P (typ. P ¼ 8) provides a phase compensation close to the reflect array [5]. The radius of each zone is calculated with the classical Fresnel formula as follows:…”

“…At high frequencies, quasi-optical antennas, like parabolic reflectors or lenses are more efficient than line-fed arrays but are less compact and more difficult to fabricate. A possible solution for having compact and quasi-optical antenna is to use printed reflectors like reflectarrays [4] or Fresnel reflector [5].…”

Bi‐band fresnel reflectarray for unmanned aerial system (UAS)‐satellite communication

“…In spite of active solutions were recently proposed , we propose a fully passive single layer solution for ease of fabrication and power consumption in order to obtain a low cost antenna. Multi‐resonant elementary cells associated to Fresnel reflectarray were studied. First, we describe how the elementary cell works, then we explain the principle of Fresnel reflectarray and finally simulations and measurement of a demonstrator are shown.…”

Reflectarray element based on variable line length for millimeter-wave radar applications

“…The development of millimeter-wave radars has become an important research domain over the past few years, such as automotive radars working at 77 GHz [1], [2] and obstacle de tection radar implanted on helicopters working at 94 GHz [3], [4]. The detection radars working at 76 GHz or 78GHz for foreign object debris (FOD) detection on airports are now developing [5], [6].…”