The Design of Wideband Nonreciprocal Transmission by Active Metasurface

The design of wideband nonreciprocal transmission is proposed by applying active metasurface, in which the meta-atom is composed of receiving antenna, guide-wave processing part, and transmitting antenna. Favorable spatial electromagnetic performance throughout a wideband is necessary for both the receiving and transmitting antennas. The guide-wave processing part enables one-way wave guiding by including the power amplifier with its bias circuits. By appropriately combining the three parts into one single meta-atom, good non-reciprocal transmission characteristics across a wideband were demonstrated in our field-circuit cosimulation. Furthermore, a prototype of metasurface consisting of 392 elements were fabricated and measured, yielding favorable wideband performance from 7.5 to 12.5 GHz, and wide-angle performance from −70° to +70° with more than 30 dB isolation between dual-direction transmission in the near-field measurement.