Graphene-based Millimeter Wave Spatial Amplitude Modulator With Four Transmission Poles

We present an amplitude controllable spatial modulator, which consists of an artificially constructed metamaterial and a graphene layer, to realize four transmission channels in gigahertz (GHz). The four transmission poles TP
1
, TP
2
, TP
3
and TP
4
are located at 26.5GHz, 29.3GHz, 32.6GHz and 35.9GHz, respectively. By applying a bias voltage between the metamaterial and the ptype silicon layer, more than 60% modulation depth is achieved for TP
1
, TP
2
and TP
3
, the modulation depth for TP
4
is 54.5%. Therefore, the modulator indicates many potential applications for multichannel communication system.