RF Spatial Modulation Using Antenna Arrays

A new method of spatial linear modulation is presented for the RF signal modulation. The constant envelope and phase modulated signals are transmitted to an antenna array and then combined in space; the linear modulation is realized at the same time. The concentric antenna pairs are applied to eliminate the mismatch of phase delay among the modulated signals from different antenna pairs. The measurement results of an RF signal around 2.45 GHz modulated by a 3.84 Mbps QPSK signal are presented. The proposed spatial modulator is able to simplify RF transmitter design and achieve highly efficient power transmission.