Publications

DAJANI, I, MORSE, EC & ZIOLKOWSKI, RW 1993, 'WEAKLY NONLINEAR GEOMETRICAL-OPTICS IN PLASMAS', PHYSICA D, vol. 64, no. 1-3, pp. 237-250.
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DONNELLY, R & ZIOLKOWSKI, RW 1993, 'DESIGNING LOCALIZED WAVES', PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, vol. 440, no. 1910, pp. 541-565.
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Guo, YJ & Barton, SK 1993, 'Fresnel Zone Plate Reflector Incorporating Rings', IEEE Microwave and Guided Wave Letters, vol. 3, no. 11, pp. 417-419.
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A novel high-efficiency Fresnel zone plate reflector antenna is presented. The reflector consists of an inhomogeneous array of circular conducting rings printed on a grounded substrate. By adjusting the geometrical parameters of the rings and the distances between them, the reflector provides a space-varying phase correction required for focusing an incoming plane wave. Compared with a phase reversal zone plate, an average of 3-dB gain improvement and significant sidelobe reduction have been obtained. © 1993 IEEE

Guo, YJ & Barton, SK 1993, 'Multilayer phase correcting fresnel zone plate reflector antennas', International Journal of Satellite Communications, vol. 11, no. 2, pp. 75-80.
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Owing to its flat nature and light weight etc., the Fresnel zone plate antenna is becoming very attractive for such applications as DBS reception and receive‐only VSAT. The disadvantages of low efficiency and high sidelobes of the simple and the phase reversing zone plates can be improved by using phase correcting techniques. In this paper, a systematic investigation on the efficiency and sidelobe performance of subzone phase correcting zone plate antennas is presented. The design of a form of multilayer phase correcting zone plate reflector is described. A quarter‐wave zone plate reflector constructed with three dielectric layers and metallized rings is reported, with measured peak efficiency of 55 per cent. Copyright © 1993 John Wiley & Sons, Ltd.

Guo, YJ & Barton, SK 1993, 'On the subzone phase correction of fresnel zone plate antennas', Microwave and Optical Technology Letters, vol. 6, no. 15, pp. 840-843.
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Subzone phase correction is a practical technique to produce high‐efficiency Fresnel zone plate antennas. In this article a strict theory underlying the technique is presented. A closed‐form expression of the focal field for the subzone phase correcting Fresnel zone plate (FZP) illuminated by a plane wave is given first. The subzone division and the corresponding phase correction are then optimized to produce the maximum focal field intensity. To overcome the difficulty of placing many subzone phase shifters in the narrow outer full‐wave zones, an aperiodic subzone phase correction technique is proposed. Copyright © 1993 Wiley Periodicals, Inc., A Wiley Company

LICHTENBERG, B, GALLAGHER, NC & ZIOLKOWSKI, RW 1993, 'CLOSED-FORM, LOCALIZED WAVE SOLUTIONS IN OPTICAL-FIBER WAVE-GUIDES - COMMENT', JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION, vol. 10, no. 9, pp. 2090-2091.
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Veitch, D 1993, 'The approach to constrained equations', Physics Letters A, vol. 183, pp. 319-326.

ZIOLKOWSKI, RW 1993, 'PROPERTIES OF ELECTROMAGNETIC BEAMS GENERATED BY ULTRA-WIDE BANDWIDTH PULSE-DRIVEN ARRAYS - REPLY', IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, vol. 41, no. 4, pp. 520-522.

ZIOLKOWSKI, RW & JUDKINS, JB 1993, 'APPLICATIONS OF THE NONLINEAR FINITE-DIFFERENCE TIME-DOMAIN (NL-FDTD) METHOD TO PULSE-PROPAGATION IN NONLINEAR MEDIA - SELF-FOCUSING AND LINEAR-NONLINEAR INTERFACES', RADIO SCIENCE, vol. 28, no. 5, pp. 901-911.
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ZIOLKOWSKI, RW & JUDKINS, JB 1993, 'FULL-WAVE VECTOR MAXWELL EQUATION MODELING OF THE SELF-FOCUSING OF ULTRASHORT OPTICAL PULSES IN A NONLINEAR KERR MEDIUM EXHIBITING A FINITE RESPONSE-TIME', JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, vol. 10, no. 2, pp. 186-198.
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ZIOLKOWSKI, RW, BESIERIS, IM & SHAARAWI, AM 1993, 'APERTURE REALIZATIONS OF EXACT-SOLUTIONS TO HOMOGENEOUS-WAVE EQUATIONS', JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION, vol. 10, no. 1, pp. 75-87.
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GUO, YJ & BARTON, SK 1992, 'HIGH-EFFICIENCY ZONE-PLATE REFLECTOR INCORPORATING PRINTED RESONATORS', EIGHTH INTERNATIONAL CONFERENCE ON ANTENNAS AND PROPAGATION, PTS 1 AND 2, 8TH INTERNATIONAL CONF ON ANTENNAS AND PROPAGATION, INST ELECTRICAL ENGINEERS, HERIOT WATT UNIV, EDINBURGH, SCOTLAND, pp. 620-622.

Piccardi, M, De Stefano, L, Cucchiara, R & Cinotti, TS 1993, 'Processing of variable size images on a cellular array: Performance analysis with the Abingdon Cross Benchmark', Proceedings of the International Conference on Application-Specific Systems, Architectures and Processors, pp. 172-175.
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© 1993 IEEE. Handling a continuous flow of variable size images is a requirement for real time computer vision machines. A modular system based on a small size SIMD cellular array of 1-bit processing elements has been developed with this goal in mind and it is now evaluated against the Abingdon Cross Benchmark specifications. The benchmark tests the combination of algorithms and architecture and generates a quality factor expressed as the ratio of the image lateral size and the processing time. The examined machine supports an efficient means to automatically partition, process and reconstruct images larger than the array size. The authors briefly describe the system, discuss the selected algorithms and present performance results and estimates for several system configurations.

Van De Groenendaal, JG & Braun, RM 1993, 'Rural communications in multi-path channels: Spread spectrum applications', Proceedings of the 1993 IEEE South African Symposium on Communications and Signal Processing, COMSIG 1993, pp. 167-172.
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© 1993 IEEE. All radio communications occur in channels that have definite multipath characteristics. Two effects that are predominant in such a model, depending on the delay relative to the bit period, are Inter Symbol Interference (ISI) and fading. In this paper ISI is investigated in greater detail and the theoretical error performance for BPSK in a multi-path channel is derived. It is also shown how spread spectrum improves the error performance of BPSK without a "rake" receiver in such an environment and the selection of parameters of spread spectrum to maximize error performance is briefly discussed.

Veitch, D 1993, 'Novel models of broadband traffic', Global Telecommunications Conference, 1993, including a Communications Theory Mini-Conference. Technical Program Conference Record, IEEE in Houston. GLOBECOM’93., IEEE, IEEE, pp. 1057-1061.

ZIOLKOWSKI, RW 1992, 'ULTRA-WIDE BANDWIDTH, MULTI-DERIVATIVE ELECTROMAGNETIC SYSTEMS', ULTRA-WIDEBAND, SHORT-PULSE ELECTROMAGNETICS, 2nd WRI International Conference on Ultra-Wideband Short-Pulse Electromagnetics, PLENUM PRESS DIV PLENUM PUBLISHING CORP, POLYTECH UNIV, BROOKLYN, NY, pp. 251-258.