Advanced synthesis of meta-antenna radiation pattern enabled by transformation optics

Abstract

Multi emission meta-radiating structures have been an important area of focus due to their potential applications in multi-user scenarios. Thereby, based on the concept of multi-folded transformation optics, a general approach for enabling the customizable multiple beam radiation of a planar antenna is propounded. The presented method is competent not only in creating any desired number of beams but also in adjusting their directivities. Antithetical to phased array antennas, with their complex feeding, heavyweight and costly elements, this goal was achieved via utilizing simple homogeneous materials elaborately designed by multiple folding of the virtual spaces to physical ones with an affine transformation. Several illustrative numerical simulations were performed in order to highlight the capability of the presented method in manipulating the planar source radiation. A meta-antenna structure consisting of a multi-folded layer and the patch antenna underneath, was designed, fabricated, and measured to authenticate the concept. The structure divides the radiated wave into two beams with arbitrary directions and different directivities. The experimental results of the realized meta-antenna structure exhibited good agreement with numerical simulations and theoretical predictions. The proposed approach could find applications in several fields of engineering where multiple emission is of utmost importance such as multiinput-multi-output systems, or could be used in waveguide applications like power dividers.

Bi-Functional Antenna Coating for Cloaking and Directivity Enhancement Made of Isotropic Materials

“…In order to realize such a bi-functional coating layer, a composite of SRR-meander line array is utilized as a building block, which is demonstrated in Fig. 8 [8,9]. To reduce the EM couplings between the building blocks, the SRR and meander line are both printed on two separated dielectric substrates of RO4003C.…”

“…Moreover, TO has been combined with microwave devices such as waveguide bend, which connects two waveguides even with different size at different angles without any EM field perturbations [6]. Besides, the theory of TO opens up new horizons for the antenna designs like antenna lens [7], antenna beam steering [8] and antenna pattern synthesis [9]. In [9] the authors propound a general approach for enabling the customizable multiple beam radiation of planar antennas.…”

“…Besides, the theory of TO opens up new horizons for the antenna designs like antenna lens [7], antenna beam steering [8] and antenna pattern synthesis [9]. In [9] the authors propound a general approach for enabling the customizable multiple beam radiation of planar antennas. Among all these applications, the invisibility cloak is one of the most interesting TO-based devices, which conceals interior objects [10,11].…”

Design of open devices based on multi-folded transformation optics

“…AS an ingenious mathematical approach, transformation optics (TO) [1][2][3][4][5][6] provides a powerful and convenient way to control the electromagnetic (EM) fields arbitrarily, arousing much attentions in the past two decades. Based on this methodology, novel devices with varied functions and applications have been proposed, designed and experimented with an unprecedented prosperity, including invisible cloaks [7][8][9][10][11][12][13], concentrators [14][15][16][17][18], illusory devices [19][20][21][22][23][24][25][26][27][28] and antennas [29][30][31][32][33][34][35] etc. The most striking device among them is invisible cloak, where some properly designed materials are utilized to direct the EM waves propagates smoothly around an arbitrarily shaped object, making the entire device (including the coated object) become invisible for the outside viewers.…”

Parallel integro-differential equation solving via multi-channel reciprocal bianisotropic metasurface augmented by normal susceptibilities

“…In another context, metasurfaces are known as two-dimensional versions of the metamaterial family [23] at subwavelength scales which cover a broad scope of applications due to their strong interactions with light and ease of fabrication [24]. They provide prominent abilities for polarizing [25][26][27][28], absorbing [29][30][31][32], channeling [33][34][35][36][37][38][39][40], and processing [41][42][43][44] waves, especially within optical frequencies.…”