Direct Generation of OAM Mode-Group and Its Application in LoS-MIMO System

Abstract

A partial slotted curved waveguide leaky-wave antenna which can directly generate orbital angular momentum (OAM) mode-groups (MG) with high equivalent OAM order l <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> = ±40 at 60 GHz is proposed in this letter. This partial arc slotted antenna is designed based on the circular traveling-wave antenna which can generate a single mode conventional OAM wave, so it can be termed as a partial arc transmitting (PAT) scheme compared with the full 2π aperture slotting of the circular traveling-wave antenna. The full-wave simulation results show that the generated OAM MGs present a high gain beam with a helical phase distribution. Thus it can be used in a MG based line-of-sight (LoS) multiple-in-multiple-out system (MG-MIMO), whose performance is numerically analyzed. These MGs can improve the signal-to-noise ratio (SNR) and decrease the spatial correlation of sub-channels, thereby the MG-MIMO has a better performance in terms of capacity or BER than conventional MIMO.