?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fwww.eledia.org%2Fstudents-reports%2F514%2F&rft.title=Innovative+Approaches+for+Optimized+Performance+in+Time-Modulated+Linear+Arrays&rft.creator=Rocca%2C+Paolo&rft.creator=Massa%2C+Andrea&rft.subject=TU+Technical+Reports+and+Publications&rft.description=In+time-modulated+arrays%2C+time+is+exploited+as+an+additional+degree+of+freedom+for+the+array+synthesis+in+order+to+better+control+the+radiated+beam.+More+specifically%2C+by+properly+turning+on+and+off+the+array+elements+according+to+suitable+time+sequences%2C+the+synthesis+of+patterns+with+low+side+lobe+levels+(SLLs)+%5B1%5D%5B2%5D+is+obtained+and+the+opportunity+of+optimizing+the+array+performances+in+time-varying+wireless+scenarios+enabled.+Unfortunately%2C+time-modulated+arrays+generate+undesired+harmonics%2C+the+so-called+sideband+radiations+(SR)%2C+which+represent+a+non-negligible+loss+of+radiated+power+%5B3%5D.+In+order+to+overcome+such+a+drawback+and+to+improve+the+performances+of+the+array%2C+evolutionary+optimization+approaches+have+been+recently+and+successfully+applied.+In+%5B4%5D+and+%5B5%5D%2C+a+Differential+Evolution+(DE)+algorithm+has+been+used+to+optimize+the+static-mode+coefficients+as+well+as+the+durations+of+the+time+pulses+leading+to+a+significant+reduction+of+the+sideband+level+(SBL).+In+%5B6%5D%2C+the+minimization+of+the+SLL+at+the+carrier+frequency+and+of+the+SBL+in+uniformly+excited+time-modulated+arrays+has+been+performed+by+means+of+a+Simulated+Annealing+(SA)+technique.+In+such+a+framework%2C+a+Genetic+Algorithm+(GA)+based+strategy+has+been+considered+in+%5B7%5D+to+optimize+the+time+sequences+where+the+modulation+period+was+subdivided+in+shorter+time+steps.+This+paper+presents+an+innovative+approach+based+on+a+Particle+Swarm+Optimizer+(PSO)+aimed+at+further+enhancing+the+performances+of+time-modulated+linear+arrays+in+terms+of+SBL+reduction.+From+the+mathematical+formulation+of+the+problem+at+hand%2C+it+follows+that+two+parameters+controls+the+synthesis+process%3A+the+switch-on+intervals+(i.e.%2C+the+durations+of+the+rectangular+time+pulses+of+the+time+modulating+sequence)+and+the+switch-on+instants+(the+times+when+the+excitation+coefficients+switch+on).+More+in+detail%2C+since+the+principal+pattern+at+the+carrier+frequency+is+a+function+of+the+switch-on+intervals%2C+whereas+the+SBL+depends+by+both+the+parameters%2C+the+target+of+the+synthesis+procedure+is+the+optimization+of+the+switch-on+instants+to+reduce+the+SBL+for+a+given+principal+pattern+(i.e.%2C+fixed+switch+on+intervals).+In+the+following%2C+the+problem+is+briefly+formulated+and+some+selected+results+are+reported+to+assess+the+effectiveness+of+the+proposed+approach.&rft.date=2011-01&rft.type=Technical+Report&rft.type=NonPeerReviewed&rft.format=text&rft.language=en&rft.identifier=http%3A%2F%2Fwww.eledia.org%2Fstudents-reports%2F514%2F1%2FDISI-11-193.C174.pdf&rft.identifier=++Rocca%2C+Paolo+and+Massa%2C+Andrea++(2011)+Innovative+Approaches+for+Optimized+Performance+in+Time-Modulated+Linear+Arrays.++%5BTechnical+Report%5D+++++