A lens antenna array with adaptive optical processing

• Published in: IEEE transactions on antennas and propagation Vol. 50; no. 5; pp. 607 - 617
• Main Authors: Fotheringham, E., Romisch, S., Smith, P.C., Popovic, D., Anderson, D.Z., Popovic, Z.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.2002; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptive arrays; Adaptive optics; Antenna arrays; Arrays; Carriers; Dynamical systems; Dynamics; Electric circuits; Electronics; Holographic optical components; Holography; Lens antennas; Lenses; Optical arrays; Optical data processing; Optical devices; Optical filters; Optical receivers; Wireless communications
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2002.1011226

This paper presents an X band smart antenna array in which adaptive processing of the received signals is performed by dynamic holographic optical circuitry. The optical circuitry adaptively extracts the principal component of the received signal space, that is the strongest first-order independent temporal component of the ensemble of received signals. The adaptive receiver system can be used, for example, to mitigate multipath interference effects and can separate one received signal from another even though their power spectra may entirely overlap. A prototype two-channel system is designed to fit in a standard-size briefcase and consume less than 50 W of power. The input to the system are modulated waves with a carrier in X band and the output is an electronic demodulated signal. Three major components of this system are described in detail: (1) the quasi-optical lens antenna array front end with angle-of-arrival preprocessing and downconversion, (2) the two-channel electrooptic modulation and optical carrier suppression stage, and (3) the smart optical processor (auto-tuning filter). Component and end-to-end system measurements give quantitative indicators for the usefulness of optical processing in wireless communications.