Channel Multiplexing Network for a Millimeter Waveguide Transmission System

The Nippon Telegraph and Telephone Public Corporation (NTT) plans to make a field test for the practical application of the W-40G millimeter waveguide transmission system, using a frequency range of 43 GHz to 87 GHz and a clock frequency of 403 MBd. This paper describes channel multiplexing-demultiplexing networks fabricated for use in the test. First, frequency allocation and construction of the 43 ∼ 87 GHz multiplexing-demultiplexing networks are discussed. Second, newly developed hardware consisting of band-splitting filters and channel-dropping filters is described. Finally, overall loss, frequency response in amplitude and delay and pulse waveform transmission characteristics are shown. The overall losses of the networks constructed by three stages, namely, band-splitting filters (I), (II), and a channel-dropping filter, are 8 ∼ 12 dB over the frequency range from 43 GHz to 87 GHz, with the channel-dropping filters only partly installed. The experimental results suggest that these multiplexing-demultiplexing networks are suitable for the millimeter wave guided wave communication system.