Analytical method for EBG resonator antennas design, FDTD validation

Global Synthesis Method for the Optimization of Multifeed EBG Antennas

“…This second step consists to find the complex coefficients (or weight) for the linear combination. The objective radiation pattern (Φ obj ) can efficiently be formed by combining an array factor with the transfer function of the EBG material [15][16][17]. This linear combination is given by (1).…”

“…It lies 15.0 mm above the ground plane. The EBG structure is designed to enhance the directivity in the direction θ = 30 • at the frequency f 0 = 11.35 GHz [4,[15][16][17]. The global EBG antenna dimensions are Lx = 330 mm and Ly = 280 mm.…”

“…An evaluation of the ability for the EBG antenna to radiate with a single lobe in the direction θ = 30 • was first made with the analytical method described in [4,8,[15][16][17]. This analysis provides a theoretical radiation pattern that can constitute the objective one (Φ obj ).…”

“…The first electromagnetic waveguide mode can radiate through the PRW, while its phase velocity is greater than the light's one, in other words, when the operating frequency is close to the cutoff of the waveguide mode. This leaky mode is excited with a radiating feed (like a patch antenna) or a set of several feeds (like an array of small antennas [12][13][14][15][16][17]). The resulting radiation pattern of the whole EBG structure depends on the radiation of the feeds.…”

“…(i) several feeds can be distributed under the PRW to enhance the directivity without reducing the bandwidth [12]; the distance between the feeds can be enlarged beyond one half wavelength because the EBG material is efficient to degrade the grating lobes [13]; thus, it is relatively easy to reach high directivities with few probes; this can simplify the design of the feed network; (ii) an array antenna with few feeds can be used to select a steered angle; the radiations of the different feeds under the EBG PRW are reinforced in a desired direction and suppressed in undesired directions, while the EBG structure purpose is to enhance the gain in this desired direction [14][15][16][17]. The functioning of an array feed for an EBG resonator seems different from the functioning of an usual phased array antenna [18][19][20][21].…”