Control of surface reflection phase by multiple embedded width-modulated microstrip resonators

The scattering characteristic of normally incident electromagnetic waves from a multiple stacked width modulated microstrip High Impedance Surface (HIS) is investigated. The unit cell is formed by stacking together three, width-modulated microstrip line based unit cells. Parameter values in terms of modulation width in individual cells are changed to characterize the phase reflective device exhibiting advanced controlling features of the observable in a specific wide frequency band. The reflections from stacked structures formed using different modulated but similar unit cells are compared with the reflection from a truly periodic structure consisting of identical unit cells. The effect of the modulation on different layers is discussed. The proposed solution enables efficient control of the reflection phase and hence suggests the configuration for reflectarrays and/or holographic surfaces.