Design study of digital beam forming antenna applicable to mobile satellite communications

Digital beamforming (DBF) techniques applicable to mobile satellite communications are discussed. Two types of configuration are shown for the receive mode: a method with a carrier recovery circuit after summing signals and a method using quasi-coherent demodulation. DBF using quasi-coherent demodulation seems to be preferable because of less dependency on the number of antenna elements and/or the amount of frequency offset. In the case of the transmit mode, a method of performing beamforming together with modulation using digital signal processing techniques at the baseband signals is found to be effective.<>