Broadband networks using wireless transmission techniques are a quick and flexible means of implementing subscriber access. Unoccupied frequency bands with sufficient bandwidth to allow the transmission of digital signals at very high bit rates are found only in the microwave bands. Because the path loss is fairly high at these frequencies, the diameter of radio cells is limited to a maximum of a few kilometres. This results in a microcellular system, which is best implemented in the form of a point‐to‐multipoint system, where one radio‐base station serves all subscribers registered in that radio cell. An interactive, broadband, ATM‐based radio local loop has undergone successful trials in Munich. Copyright © 2001 John Wiley & Sons, Ltd.

Low-loss H-plane waveguide filters for planar integrated assemblies are described showing high attenuation near the pass-band due to a special modification of the outer inverter circuits. The outer irises are replaced by short-circuited T-junctions resulting in at least one pole above or below the pass-band. Such filters favorably can be combined to low-loss diplexer circuits for mm-wave applications. Examples of a single filter as well as of diplexers in the 28 GHz and 38 GHz frequency range are given.