Fig. 2: Phasor diagrams for the frequency components f₁ (black arrow line) and f₂ (red arrow line) with normalized complex amplitudes.

a \({A}_{{f}_{1}}\) = \({e}^{i{{{{{\rm{\pi }}}}}}/4}\), \({A}_{{f}_{2}}\) = \({e}^{-i{{{{{\rm{\pi }}}}}}/4}\); b \({A}_{{f}_{1}}\) = \({\frac{1}{2}e}^{i{{{{{\rm{\pi }}}}}}/4}\), \({A}_{{f}_{2}}\) = \({e}^{i{{{{{\rm{\pi }}}}}}/2}\); c \({A}_{{f}_{1}}\) = \(\frac{1}{2}{e}^{-i{{{{{\rm{\pi }}}}}}/4}\), \({A}_{{f}_{2}}\) = \({\frac{1}{2}e}^{i{{{{{\rm{\pi }}}}}}/2}\). d–f The corresponding time-varying reflection coefficients of Partitions 1# and 2# for the manipulations of \({f}_{1}\) and \({f}_{2}\), respectively. The frequency of incident waves is 4.25 GHz, and the modulation frequencies of the two regions are \({\triangle f}_{1}\) = 100 kHz and \({\triangle f}_{2}\) = 200 kHz, respectively. The generated harmonic orders are −1^st and +1^st in Partitions 1# and 2#, so that the corresponding frequencies are \({f}_{1}\) = 4.2499 GHz and \({f}_{2}\) = 4.2502 GHz.