Measuring Polymer Radome Transmission Loss at Millimeter Wave Frequencies
Polymer radome transmission loss at mmWave frequencies depends on dielectric loss tangent and wall thickness precision to maintain regulatory EIRP compliance.
FCC Part 15.255
Meaning
Federal regulations define the technical requirements for operation within the 57 to 71 gigahertz spectrum for unlicensed wireless devices. This specific rule set known as fcc part 15.255 governs power levels and occupied bandwidth for short range radar and high speed data links. Compliance ensures that devices do not cause harmful interference to authorized services while remaining durable against noise.
Emission Limit
Signal strength measurements for v band transmitters focus on equivalent isotropically radiated power. This differs from the conducted power at the antenna port. Under fcc part 15.255, the average power density must stay below nine microwatts per square centimeter at a distance of three meters.
Peak power spikes are also restricted to prevent momentary disruption of adjacent sensors. Limits vary depending on whether the device operates outdoors on fixed point to point links or as a mobile handset accessory. The measurement procedure accounts for the atmospheric absorption of oxygen which naturally attenuates signals in this frequency range.
Bandwidth Requirement
Modern silicon architectures for sixty gigahertz communication utilize wide channels to achieve multi gigabit throughput. The fcc part 15.255 standard allows for massive contiguous blocks of spectrum which supports low latency video streaming and industrial sensing. Frequency stability is mandatory to keep the signal within the designated edges across temperature extremes.
Compliance Validation
Laboratories use specialized millimeter wave mixers and horn antennas to verify the output characteristics of the integrated module. The test report for fcc part 15.255 details the spurious emissions and the spectral mask under various modulation schemes. Successful filing allows a manufacturer to market the product in the United States.