3-D Reflectarray Unit Cell with Wideband Performance and Integrated Sensing Capability

A reflectarray unit cell design with sensing capability at millimeter-wave frequencies is presented in this paper. The proposed unit cell is based on slotlines spatially arranged in 3-D. There are different parts that conform the reflectarray unit cell, these are: an impedance transformer, a main slotline, an EBG filter and a sensing zone. By modifying the length of the main slotline, phase tuning of the reflected wave is achieved while preserving good level of reflection. Moreover, the phase response is linear in the frequency range that goes from 30 GHz to 50 GHz. To implement the sensing function, the EBG filter is placed after the main slotline to allow some level of leakage through the unit cell. The simulated results show that depending on the angular direction of an incident wave, there is a certain phase difference value among the sensors located in the sensing zone of the unit cell.