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Time-Modulation in Array Antenna Synthesis for New Generation Communication Systems

 
 
A modern antenna system should be able to maintain high quality communication links through a suitable modification of its operating conditions (i.e., radiation pattern and frequency band) to avoid jammings and interference signals from external sources. In this framework, time-modulated arrays have proved to be very flexible systems since they allow to reconfigure the radiated pattern just acting on the state (on/off) of a set of RF switches inserted in the feed network: thanks to these features, they can be considered as very good candidates for the new generation transmission systems controlled via software, the Software Defined Radio (SDR), since they allow to completely reconfigure the beam in a reliable and simple way through digital signals in function of the working scenario.
   
Satellite systems for wireless communications, radar applications, antenna for cellular base stations, earth observation

 

 
Pulse Sequence
 
Unfortunatly, the use of time-modulation technique in antenna array synthesis produces undesired radiations that correspond to a power wasting that affect array performance: to overcome this drawback, members of the ELEDIA Research Center have developed innovative strategies in order to get the suitable pulse sequences exciting the elements of the array that allow to synthesize a desired pattern at the work frequency minimizing the amount of wasted power in the sideband radiation. Several approaches based on the particle swarm optimization have been proposed in order to achieve the best compromise between the simplicity of reconfiguration of the system and the power loss, considering both communication and radar applications. Moreover, the possibility to exploit the sideband radiations for useful purposes have been investigated with the aim of synthesizing multi-beam patterns at different harmonic frequencies radiated by a single antenna system.

 
Antenna Sketch

 
Synthesized Beam Pattern

Keywords: Time-Modulation, Time-Modulated Arrays, Harmonic Beamforming, Adaptive Antenna Systems, Particle Swarm Optimization


See Also
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    doi:10.1109/TAP.2010.2041165
  • P. Rocca, L. Manica, L. Poli, and A. Massa, "Synthesis of compromise sum-difference arrays through time-modulation," IET Radar Sonar Navigation, vol. 3, no. 6, pp. 630-637, Nov. 2009. 
    doi:10.1049/iet-rsn.2009.0058
  • L. Poli, P. Rocca, L. Manica, and A. Massa, "Time modulated planar arrays - analysis and optimisation of the sideband radiations," IET. Microw. Antennas & Propag., Vol. 4, Iss. 9, pp. 1165-1171, 2010. 
    doi:10.1049/iet-map.2009.0379
  • L. Poli, P. Rocca, L. Manica, and A. Massa, "Pattern synthesis in time-modulated linear arrays through pulse shifting," IET. Microw. Antennas & Propag., Vol. 4, Iss. 9, pp. 1157-1164, 2010. 
    doi:10.1049/iet-map.2009.0042
  • P. Rocca, L. Poli, G. Oliveri, and A. Massa, "Synthesis of time-modulated planar arrays with controlled harmonic radiations," J. Of Electromagn. Waves and Appl., vol. 24, no. 4, pp. 827-838, 2010. 
    doi:10.1163/156939310791036304
  • L. Poli, P. Rocca, G. Oliveri, and A. Massa, "Adaptive nulling in time-modulated linear arrays with minimum power losses," IET. Microw. Antennas Propag., vol. 5, no. 2, pp. 157-166, 2011. 
    doi:10.1049/iet-map.2010.0015
  • P. Rocca, L. Poli, G. Oliveri, and A. Massa, "Synthesis of Sub-Arrayed Time Modulated Linear Arrays Through a Multi-Stage Approach", IEEE Trans. Antennas Propag., vol. 59, no. 9, pp. 3246-3254, Sep. 2011. 
    doi:10.1109/TAP.2011.2161535
  • L. Poli, P. Rocca, G. Oliveri, and A. Massa, "Harmonic beamforming in time-modulated linear arrays through particle swarm optimization," IEEE Trans. Antennas Propag., vol. 59, no. 7, pp. 2538-2545, Jul. 2011. 
    doi:10.1109/TAP.2011.2152323
  • L. Poli, P. Rocca, G. Oliveri, and A. Massa, “Failure correction in time-modulated linear arrays,” IET Radar, Sonar & Navigation, vol. 8, no. 3, pp. 195-201, Mar. 2014.
    doi:10.1049/iet-rsn.2013.0027
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    doi:10.1109/TAP.2013.2288109
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    doi:10.1109/TAP.2013.2256096
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    doi:10.1109/LAWP.2012.2183849
  • P. Rocca, L. Poli, and A. Massa, "Instantaneous directivity optimization in time-modulated array receivers," IET Microwaves, Antennas & Propagation, vol. 6, no. 14, pp. 1590-1597, Nov. 2012.
    doi:10.1049/iet-map.2012.0400
  • P. Rocca, L. Poli, L. Manica, and A. Massa, "Synthesis of monopulse time-modulated planar arrays with controlled sideband radiation," IET Radar, Sonar & Navigation, vol. 6, no. 6, pp. 432-442, 2012.
    doi:10.1049/iet-rsn.2012.0005
  • L. Poli, P. Rocca, and A. Massa, "Sideband radiation reduction exploiting pattern multiplication in directive time-modulated linear arrays," IET Microwaves, Antennas & Propagation, vol. 6, no. 2, pp. 214-222, 2012.
    doi:10.1049/iet-map.2011.0159