Abstract
A nearfield characterisation of two dimensional metallodielectric frequency selective surfaces either in a single or double layer configuration is presented in this thesis.
Motivated by the current attention of the electromagnetic properties of nearfields, an inhouse periodic MoMbased computational tool is developed for the efficient and rigorous estimation of the nearfields in frequency selective surfaces (FSS) illuminated by a plane wave. For this purpose a thorough convergence study related to the calculation of the near fields is initially presented. The nearfield estimation allows us to calculate the power stored in an FSS at resonance which, in turn, can be used in the calculation of the loaded quality factor of the FSS. Based on the characterisation of various topologies, new techniques for the analysis of highlydirective and broadband
leaky wave antennas are proposed. An initial design based on a perturbed FSS results in a structure with multiband response and nearfields enhanced by more than 70 fold, which can be relevant to sensor applications. Subsequently, the nearfield technique is used in combination with reciprocity for the extraction of the radiation patterns in FabryPerot cavity antennas formed between a FSS and a metamaterial ground plane. Incombination with traditional array theory the complex dispersion characteristics of highgain subwavelength 2D FabryPerot leakywave antennas (LWA) consisting of two periodic metallodielectric arrays over a ground plane are extracted. This yields a
fast and rigorous tool for the characterisation of this type of antennas. Design guidelines are given throughout to synthesize a highlydirective antenna and a broadband leakywave antenna.
This thesis was fully funded by the Joint Research Institute for Integrated Systems in Edinburgh, Scotland.
Motivated by the current attention of the electromagnetic properties of nearfields, an inhouse periodic MoMbased computational tool is developed for the efficient and rigorous estimation of the nearfields in frequency selective surfaces (FSS) illuminated by a plane wave. For this purpose a thorough convergence study related to the calculation of the near fields is initially presented. The nearfield estimation allows us to calculate the power stored in an FSS at resonance which, in turn, can be used in the calculation of the loaded quality factor of the FSS. Based on the characterisation of various topologies, new techniques for the analysis of highlydirective and broadband
leaky wave antennas are proposed. An initial design based on a perturbed FSS results in a structure with multiband response and nearfields enhanced by more than 70 fold, which can be relevant to sensor applications. Subsequently, the nearfield technique is used in combination with reciprocity for the extraction of the radiation patterns in FabryPerot cavity antennas formed between a FSS and a metamaterial ground plane. Incombination with traditional array theory the complex dispersion characteristics of highgain subwavelength 2D FabryPerot leakywave antennas (LWA) consisting of two periodic metallodielectric arrays over a ground plane are extracted. This yields a
fast and rigorous tool for the characterisation of this type of antennas. Design guidelines are given throughout to synthesize a highlydirective antenna and a broadband leakywave antenna.
This thesis was fully funded by the Joint Research Institute for Integrated Systems in Edinburgh, Scotland.
Original language  English 

Qualification  Ph.D. 
Awarding Institution 

Supervisors/Advisors 

Award date  15 Oct 2010 
Publication status  Published  2010 