Reflector (antenna)

About: Reflector (antenna) is a research topic. Over the lifetime, 28730 publications have been published within this topic receiving 212618 citations.

Optical radar using a corner reflector on the moon.

Abstract: Lunar corner reflector landing proposal for laser beam precision measurements including Moon orbit, size, ephemeris time and libration

Inverse design of lightweight broadband reflector for relativistic lightsail propulsion

Abstract: Light can exert forces on objects, promising to propel a meter-scale lightsail to near the speed of light. The key to address many challenges in such an ambition hinges on the nanostructuring of li...

Front surface emitting diode laser

Abstract: A front-surface emitting, vertical-cavity laser and its method of making in which a vertical laser cavity with Bragg reflectors and an active layer, preferably formed by a quantum well, is formed on a substrate. Lateral current confinement is achieved by implanting a conductivity-reducing ion into the region surrounding the quantum well. Electrical contact to the upper side of the active layer is achieved by implanting a conductivity-increasing ion into the region surrounding the cavity between the active layer and the upper reflector. By such an electrical contact, the upper reflector can advantageously be composed of dielectric layers. Light is then emitted through the upper reflector.

Piezoceramic actuated aperture antennae

Abstract: Recently, it has been demonstrated that aperture antennae can have their performance improved by employing shape control on the antenna surface. The antennae previously studied were actuated utilizing polyvinylidene fluoride (PVDF). Since PVDF is a polymer with limited control authority, these antennae can only be employed in space based applications. This study examines more robust antenna structures devised of a thick metalized substrate with surface bonded piezoceramic (PZT) actuators. In this work, piezoceramic-actuated adaptive antennae of cylindrical-cut shape are studied. When a PZT actuator is attached to the reflector surface, the converse effect develops a bending moment in the structure making the reflectors bend inward or outward. This bending can be employed in antenna beam steering and shaping. In order to effectively construct the antenna, the piezoceramic-actuated antenna surface was modeled using classical curved beam theory and Newton's method. The deflection versus voltage relationship was then experimentally verified, and the resulting far-field radiation pattern was simulated on computer. The results emphasize two major points: firstly, the far-field radiation pattern can be altered in a positive fashion, and secondly the first two radiation modes of the antenna correspond to the first vibration mode shapes of the structure.

A Compact Dual-Band Pattern Diversity Antenna by Dual-Band Reconfigurable Frequency-Selective Reflectors With a Minimum Number of Switches

Abstract: A novel compact dual-band pattern diversity antenna is proposed. Dual-band reconfigurable frequency-selective reflectors are designed and applied to form a right-angle corner reflector antenna with reconfigurable patterns. With only one switch, the reconfigurable frequency-selective reflector can be controlled to be transmissive or reflective to vertically polarized waves at 2.45 and 5.25 GHz. By changing the combinations of the switch states, multiple patterns can be obtained. A dual-band feeding antenna designed via using the coupling effects is made to achieve well-matching conditions in all circumstances corresponding to various switch states at both frequencies. The measured results show good agreement with the calculated ones and demonstrate good pattern diversity virtues.