A passive system for increasing indoor coverage for mobile communications from TETRA to UMTS

In this paper a completely passive system is presented that allows increasing the signal levels inside (high) buildings. It consists of (a) high gain broadband rooftop antenna(s), and one (or more) small multiband antennas for the desired communication frequencies, connected to each other with low loss cables. It has been shown experimentally that terrain and building penetration attenuation can be compensated very effectively for only fractions of the cost of a base station in the building, and with an installation that requires no maintenance.