Details

Autor(en) / Beteiligte

• Krycia, Joseph R

Titel

Design of guided mode resonant filters at microwave and millimeter wave frequencies using genetic algorithms

Ort / Verlag

ProQuest Dissertations & Theses

Erscheinungsjahr

2005

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• For decades engineers have exploited the structural properties of composites to develop material systems with desirable mechanical properties. Only recently have investigators applied similar concepts towards the development of composite materials with “designer” electromagnetic properties. These designer materials are called metamaterials and are generally defined as a composite of two or more materials producing an “effective” electromagnetic material with desirable properties. Examples of metamaterials includes the very popular research topics of photonic crystals and left handed materials. One application of metamaterials that is of particular interest is the design of frequency selective materials or surfaces (FSS). An FSS is in general, a single material or material structure that transmits (or reflects) only specific frequencies. Most FSS are designed using a periodic array of metallic patterns (e.g. dipoles, crosses, patches…). Analytical as well as numerical algorithms have been developed for producing FSS structures based on the size and shape of the metallic arrays. For very narrow band applications, however, losses in the metal surfaces can be significant enough to necessitate the search for a different FSS design methodology. Moreover, for applications that have stringent out-of-band signature requirements it may be necessary to reduce the amount of metal in the FSS structure. As a result, an all dielectric FSS is of interest. Fortunately, a design approach has been developed using the concepts of metamaterials to produce all dielectric FSS structures. This approach, called the Guided Mode Resonant Filter (GMRF) method, constructs a periodic pattern of wavelength scale dielectrics of different permittivity. The overall goal of this project was to study the application of GMRF at lower frequencies (i.e. microwave and millimeter wave bands) and large scale applications (e.g. radomes) requiring in some cases 2D GMRF. To this end, the following specific goals were accomplished; (1) Rigorous 1D and 2D analysis codes were developed using the rigorous coupled wave (RCW) method. (2) Design algorithms based on genetic algorithms were developed for the synthesis of 1D and 2D GMRF transmission filters. (3) Specific designs requiring only a single low dielectric material and air were demonstrated. (4) Specific designs with relatively low dielectric constant materials were demonstrated. (5) Finite element analysis was used to validate 1D and 2D GMRF designs. (6) Experimental test samples were fabricated at both the microwave and millimeter wave frequency band.