Gain enhancement methods for printed circuit antennas

Combinations of low/high permittivity and/or permeability substrates for highly directive planar metamaterial antennas

“…1, with constitutive parameters m r , 1 r , and thickness h, excited by a y-directed horizontal electric or magnetic dipole source placed at z ¼ h s or on the ground plane, respectively. The electric far field radiated by the electric dipole source at broadside can be found by means of a simple application of the reciprocity theorem [5]. This is done by letting a y-polarised incident plane wave, having an amplitude of the electric field equal to 2jk 0 h 0 exp(2jk 0 r)/(4pr) at the origin, impinge on the structure from broadside, and then calculating the reaction between the dipole source and the electric field inside the structure due to the incident plane wave.…”

“…The structures considered here consist of a grounded metamaterial layer that may have either high or low values of permittivity and/or permeability, excited by either an electric or a magnetic dipole source. Such structures are different from those where a cavity is created under a partially reflective surface that is formed by highpermittivity dielectrics [5][6][7], metallic FSS layers [8,9] or other periodic dielectric structures [10,11]. Although different in structure, the metamaterial antennas considered in this work are similar in terms of the mechanism of radiation: in fact, all the antennas in [1 -11] radiate a narrow beam because the feed excites slowly attenuating leaky waves, as demonstrated in the work of Lovat et al [4] and Jackson and Oliner [6].…”

Investigation of an optically induced superstrate plasma for tuning microstrip antennas

“…The high permittivity silicon layer which forms the superstrate could be used to increase the gain by increasing directivity. Since the illumination is from underneath and is unaffected by the superstrate thickness, this can be further optimized to increase directivity for the desired angle of radiation [17]. Multi-layered superstrates can also be used as long as the first layer is kept as the optically illuminated semiconductor layer.…”

3D Directive Radiation from a Horizontal Dipole Embedded in a Homogenized Grounded Wire-Medium Slab

“…The problem of calculating the far field radiated in an arbitrary direction ( ) , θ φ by a horizontal dipole embedded inside a wire-medium slab can be reduced, by means of the reciprocity theorem, to that of calculating the electric field produced at the source location by a plane wave impinging on the grounded slab from the same direction [7]. In order to solve the latter problem, the grounded wiremedium slab is modeled here as a homogeneous non-magnetic slab of thickness h (see Fig.…”