DBF array antenna systems at 8.45 GHz

In adaptive array antenna techniques, the digital beamforming (DBF) array antenna is expected to play an important role in next generation mobile communication systems. The DBF array antenna is a kind of adaptive array antenna, which can realize the desired beamforming by adjusting the weight parameter of each antenna element. The received analog signals are first converted to digital ones, and then the antenna pattern is computed in a desired form by digital signal processing. We demonstrate a DBF array antenna systems at 8.45 GHz. This frequency band is a candidate for next generation wireless telecommunication in Japan. We describe two different concepts for a DBF array antenna. One is a compact receiver for a mobile terminal with direct conversion. Another is a triple conversion superheterodyne receiver to examine directions-of-arrival (DOA) and beamforming. We also demonstrate an A/D converter module for these receivers for online processing.