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In this thesis the major objective is the implementation of the inverse neural network concept in the design of printed lens (transmitarray) antenna. As it is computationally extensive to perform full-wave simulations for entire transmitarray structure and thereafter perform optimization, the idea is to generate a design database assuming that a unit cell of the transmitarray is situated inside a 2D infinite periodic structure. This way we generate a design database of transmission coefficient by varying the unit cell parameters. Since, for the actual design, we need dimensions for each cell on the transmitarray aperture and to do this we need to invert the design database. The major contribution of this thesis is the proposal and the implementation of database inversion methodology namely inverse neural network modelling. We provide the algorithms for carrying out the inversion process as well as provide check results to demonstrate the reliability of the proposed methodology. Finally, we apply this approach to design a transmitarray antenna, and measure its performance.

The field of autonomous driving is as active as it has ever been, but the reality where an autonomous vehicle can drive on all roads is currently decades away. Instead, using an on-the-fly learning method, such as qHebb learning, a system can,after some demonstration, learn the appearance of any road and take over the steering wheel. By training in a simulator, the amount and variation of training can increase substantially, however, an on-rails auto-pilot does not sufficiently populate the learning space of such a model. This study aims to explore concepts that can increase the variance in the training data whilst the vehicle trains online. Three computationally light concepts are proposed that each manages to result in a model that can navigate through a simple environment, thus performing better than a model trained solely on the auto-pilot. The most noteworthy approach uses multiple thresholds to detect when the vehicle deviates too much and replicates the action of a human correcting its trajectory. After training on less than 300 frames, a vehicle successfully completed the full test environment using this method. / Autonom körning är ett aktivt område inom både industrin och forskarvärlden, men ännu är en verklighet där förarlösa fordon kan ta sig fram oavsett väg, decennier bort. Istället kan man genom att använda en adaptiv inlärningsmodell som qHebb learning uppnå ett system som kan ta sig fram självmant på alla vägar, efter en initial inlärningsperiod. Genom att använda en simulator skulle möjligheten att träna en sådan modell öka avsevärt, likaså variationen av vägtyper och det omgivande landskapet. Dock klarar inte en enformig autopilot att fylla modellens lärningsrymd. Detta arbete stävar efter att utforska koncept som kan öka variationen på träningsdatan, medan fordonet kör. Tre prestandalätta metoder presenteras som alla överträffar autopiloten och resulterar i en modell som lärt sig att följa en väg längs kurvor och raksträckor. Det främsta konceptet använder sig av två tröskelvärden för att korrigera fordonets styrning då den avviker för mycket från den korrekta rutten. Efter träning på färre än 300 bilder lyckas denna metod slutföra alla testsegment utan kollision.