Fourier Rotman Lens Enabled Directional Modulation Transmitter

Figure 19

The detected constellation patterns along (a) 85° and (b) 67° in the dual-beam DM systems when the (a) DQPSK and (b) DBPSK type receivers were equipped. The DQPSK signals and the DBPSK signals with the same power were applied at the 7th and the 9th beam ports of the Fourier Rotman lens, respectively. The same interference with −10 dB power excited the remaining 11 beam ports. SNR for each receiver case was set to 25.8 dB or 21.2 dB along their desired communication directions, that is, 90° or 72°.

(a)

(b)