Millimeter-wave self-heterodyne transmission technique and a simple millimeter-wave diversity-reception system

We introduce a millimeter-wave self-heterodyne transmission technique and a simple system that provides diversity in reception. Millimeter-wave oscillators with higher levels of phase-noise and frequency offset are relatively cheap; the technique allows the use of such oscillators in millimeter-wave communications systems regardless of the modulation format because the effects of the oscillator are canceled at the receiver. Applying this technique thus provides extremely stable and low-phase-noise transmission as well as a lower-cost millimeter-wave communications system. We also show that the use of millimeter-wave self-heterodyning is applicable to the cost-effective creation of easy-to-handle combining-diversity reception systems and that an extra-CNR margin of 3 dB can be obtained by the two-branch structure for diversity in reception.