Recent developments in RF interference

Present trends in the design of transmitters, receivers, and antennas for use in communications and radar are reviewed to assess their impact on interference, interference measurement techniques, shielding and prediction methods. It is shown that transmitter power output and antenna size have increased by a factor of 10 in the last decade and that similar increases are anticipated in the next five to ten years. Transmitter spurious outputs are now frequently greater than the desired outputs of transmitters a few years ago. It is also shown that receiver sensitivity improvement, as a result of new techniques (masers, parametric, amplifiers, etc.), may not be realizable unless antenna side- and backlobes are drastically reduced. It is further shown that the sensitivity and frequency range of field intensity meters must be increased to permit meaningful measurements in the light of these developments. It is suggested that the performance of filters for transmitters must be developed for receivers to reduce interference.