During the past few years we have performed an effective wideband analysis for characterizing the electrodynamic behavior of phased array antennas, infinite periodic structures, frequency selective surfaces and related applications, with emphasis on gaining physical insight into the phenomenology of short-pulse radiation. The present contribution shows the current status of our network-oriented dyadic time domain Green's function (TD-GF) for a planar array of sequentially excited dipoles that constitutes a prototype study of sequentially short-pulsed radiation by infinite periodic arrays. The dispersive effects of the TD-Floquet waves (FW) and the consequences of a TE and TM field decomposition are discussed in details. In this network formulation, the equivalent TD transmission line (TL) voltages and currents excited by equivalent TD current generators are determined. An expression for the TM voltage TL-GF is provided for the first time in terms of incomplete Lipschitz-Hankel integrals and Bessel functions together with some remarks for its evaluation. As shown in previous publications for the scalar potentials, real-TD physical observables are determined by pairing TD Floquet waves with positive and negative indices. It is shown that the vectorial TD radiated field is reconstructed at any time with the superposition of a few TD-FWs. © 2007 IEEE.

This paper deals with a study of textured (mushroom-type) high-impedance substrates based on aperiodic-tiling geometries. In this connection, preliminary results from full-wave simulations are presented in order to explore possible applications as artificial-magnetic-conductor ground-planes for low-profile directive antennas. © 2007 IEEE.

We investigate the properties of the resonant modes that occur in the transparency bands of two-dimensional finite-size Penrose-type photonic quasicrystals made of dielectric cylindrical rods. These modes stem from the natural local arrangements of the quasicrystal structure rather than, as originally thought, from fabrication-related imperfections. Examples of local density of states and field maps are shown for different wavelengths. Calculations of local density of states show that these modes mainly originate from the interactions between a limited numbers of rods.

In this paper, we study the radiation from embedded sources in two-dimensional finite-size "photonic-quasicrystal" (PQC) slabs made of dielectric rods arranged according to a 12-fold symmetric aperiodic tiling. The results from our investigation, based on rigorous full-wave simulations, show the possibility of achieving broadside radiation at multiple frequencies, with high directivity (e.g., 15 dB) and low sidelobes (e.g., -12 dB). We also show that leaky waves are supported by a PQC slab and that the beamwidth is directly proportional to the leaky wave attenuation constant, which provides a physically incisive interpretation of the observed radiation characteristics. © 2009 The American Physical Society.

This letter deals with a study of aperiodically ordered textured (mushroom-type) high-impedance surfaces (HISs), and their possible application as artificial-magnetic-conductor groundplanes for low-profile directive antennas. In this framework, results from full-wave simulations are presented in order to characterize the electromagnetic response (in terms of impedance matching, directivity, and surface-wave suppression) of selected configurations based on representative categories of aperiodic tilings, and compare them with those of standard periodic HISs. © 2008 IEEE.

In this paper, we present a comparative study of the emission properties of line sources embedded in two-dimensional finite-size aperiodically-ordered "photonic-quasicrystal" slabs made of dielectric cylinders arranged according to representative categories of aperiodic tilings. Our study, based on a rigorous full-wave numerical method, indicates the possibility of achieving directive low-sidelobe emission at several frequencies. In this connection, parametric studies are presented, and similarities and differences with the periodic case are highlighted.