Reconfigurable holographic antenna for wide angle scanning with complementary resonance units based on liquid crystals

In this study, a novel holographic reconfigurable antenna featuring a compact-cell design for wide-angle scanning in liquid crystal technologies is proposed. The antenna’s radiating structure is ingeniously crafted to activate the complementary resonance mechanism, which is realised by an inductance equivalently formed by the slot in the ground layer and a tunable capacitor made by the combination of the metal strip, ground, and liquid crystals. This mechanism effectively mitigates challenges related to the limitations of resonant length in antenna unit design, thus facilitating a compact unit with a length less than 0.121 lambda. Additionally, the influence of the feed line width on the radiation characteristics of the antenna element was investigated, discovering that widths below 0.03 mm exert minimal influence, a dimension readily achievable with current manufacturing technologies. The designed antenna element achieves a return loss of less than −10 dB and an axial ratio exceeding 30 dB. The response time of the designed liquid crystal antenna is investigated. An array comprising 61 compact units was designed, incorporating a feeding structure compatible with LCD manufacturing standards. The measurement result confirmed that the array could effectively scan beams between −76° and +78°, consistently maintaining excellent matching properties.