However, due to millimeter-wave frequencies being higher than frequencies for conventional wireless transmissions, it has been difficult to develop amplifiers for practical use that are both compact and economical, and thus the millimeter band
is not yet widely used.
Because the millimeter band
is highly susceptible to losses caused by the skin effect, the researchers created a multi-stage coupled-line filter using a substrate of alumina, which is readily obtainable and offers excellent high-frequency performance.
This work combines a theoretical treatise of radio theory and standards with practical recommendations and case studies in planning and deploying modern digital microwave radio systems from UHF up to the millimeter bands
. Chapters cover link planning, reliability standards, transport technologies, radio equipment characteristics, microwave propagation, antenna considerations, frequency planning, and link design.
The series is also designed to operate in the millimeter bands
with an ultra low equivalent series resistance specifically for the RF/microwave, optical and cellular market.
The opening up of the three millimeter bands
will prove a boon for many commercial users.