Page 90 - ITU Journal, Future and evolving technologies - Volume 1 (2020), Issue 1, Inaugural issue

ITU Journal on Future and Evolving Technologies, Volume 1 (2020), Issue 1

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Dual splitting Quad splitting Incident plane wave
20x20 pattern

2
E linear
normalized
Circular beam Dual-circular beam
Dual splitting - shifted Quad splitting - shifted 1 pattern (40x40) pattern

Ε 2

0
(a)
2
E linear
normalized

2
E logarithmic (dB) Phase φ Amplitude A
(b)
0 Ε 2 20 0 φ 2π 0 Α 1

(c)
Fig. 12 – (a) Element states and far-field scattering diagram of a 4-bit metamaterial array for 6 different cases. (b) Element states and
scattering diagrams for triple- and quintuple-beam scattering, assuming continuously adjustable states with absorption capabilities. (c)
Comparison between a tile with resistor elements (left) and a tile without (right) for an in-plane triple-beam splitting functionality. A
non-uniform amplitude pattern (A mn) can eliminate all side-lobes and provide increased security to the signal. The incident field in all cases
is a vertically impinging plane wave, chosen for simplicity; yet any plane wave or point source input can be considered by a corresponding
shift of the phase for each unit cell.

70 © International Telecommunication Union, 2020