Pegatron and Rohde & Schwarz test dual-stream FR3 arrays at 13 and 15 GHz

Pegatron and Rohde & Schwarz have reported testing a phased array with dual polarisation at 13 GHz and 15 GHz, using two transmission streams to explore the capacity available in FR3 wireless links. The setup combines Pegatron's antenna hardware with an FSWX signal and spectrum analyser and an SMW200A vector signal generator. ^[1]

The reported exhibition configuration used 100 MHz of bandwidth and 4096 QAM, from which the companies give a projected data rate of 1.7 Gbit/s. They also describe an office trial over 40 metres using 5G NR, 100 MHz of bandwidth and 1024 QAM, with a peak expected rate of 1.4 Gbit/s. Both figures describe the throughput expected from the configurations; the release does not present them as measured end to end application goodput. ^[1]

The array integrates beamforming ICs, RF front ends and antenna elements, with separate horizontal and vertical polarisation paths. Its steering and dual-stream operation place several RF relationships under examination at once, including the amplitude and phase behaviour of the paths used to form and receive the beams. ^[1][2]

The FSWX's multiple inputs allow coherent signals to be captured together, providing a view of those relationships that is lost when each path is examined independently. Its product documentation describes comparisons of amplitude, phase and group delay between array ports, as well as measurements against a modulated reference signal. The architecture also supports cross-correlation to reduce the contribution of the analyser's own noise in appropriate measurements. ^[2]

That capability changes the measurement workflow used in Pegatron's earlier work, where horizontal and vertical signal controls had to be adjusted separately on a conventional spectrum analyser. In the newer setup the channels can be analysed in parallel. ^[1]

FR3 spans the frequencies between the established lower cellular bands and millimetre-wave spectrum. Work in this range seeks additional bandwidth with less demanding propagation than the higher frequencies, while the eventual bands available for deployment depend on standardisation and regional regulation. The 13 GHz and 15 GHz measurements examine array performance within that research area. ^[3]

Pegatron says it is also developing array modules at 7 GHz and 8 GHz for Massive MIMO applications. ^[1]