Optoelectronic system for phase array antenna beam steering

Abstract

This paper presents a system for optoelectronic beam steering of a phase antenna array. The microwave signal from an RF generator controlled by a pulse generator is transmitted to the electrical input of an optical elevation control unit, which generates N microwave signals with independent amplitude and phase. The control unit utilizes an optical wave from a laser. All outputs of those control units are connected to inputs of N optical azimuth control units, which provide M linear element antennas control. Those units utilize an optical wave from a second laser. This way an M x N element of a planar antenna control is provided. The presented method is compared with the classical and electronic method, which consists of multi-bits microwave phase shifters for producing an electronic scanning effect. On the basis of this concept we realized 16-element linear antenna array printed on a dielectric substrate fully controlled by an optoelectronic system. A tuned wavelength laser in the range 1520-1600 nm and 10 mW optical output power has been used as an optical signal source. The optical signal is modulated by a microwave signal. The applied modulator operates in the third optical window, allowing optical signal modulation to 10GHz. Very high resolution and an excellent accuracy of the antenna beam positioning can be achieved. The optimal technique depends on the number of antenna elements, which implicates beam width. The presented method is preferred for very narrow antenna beams.

Multispectral detection circuits in special applications

“…It is supported by a large number of infrared guided missiles; limitation of possibilities of the airport protection, access to the airplane schedules and airplanes are an easy target (especially passenger planes). To prevent such occurrences the following security mechanisms are used: decreasing target's signature, using camouflage smoke, using pyrotechnics sources, radiation generators, multi-spectral detection systems as well as blinding systems [13,14]. Some of these security mechanisms have limited range of use e.g.…”