Impact of Lower Substrate on Phase Modulation Function at High Frequency

It is worth mentioning that the phase modulation function of the unit at high-frequency is still determined by the outer circular patch diameter 'r1' in Fig. 2. The two rings in the upper substrate serve as a reflective ground in relation to the upper circular patch. Therefore, the inclusion of the lower substrate with rings and circular patch has minimal effect on the reflective functionality generated by the upper substrate.