The development of the Front-End Module (FEM) was carried out in collaboration with Filtronic Broadband.
“The band 24.25 to 27.5GHz was designated at the end of last year by the EU Radio Spectrum Policy Group (RSPG) as the preferred band, or ‘Pioneer Band’, for mmWave 5G,” explains Liam Devlin, CEO of Plextek RFI. “We welcome the opening up of this spectrum band for 5G, but we identified early on that there was a lack of components available at this frequency, and that led us to define this joint FEM development project.”
The FEM comprises a GaAs low-noise amplifier (LNA), power amplifier (PA) and transmit/receive switch housed in a custom laminate surface-mount (SMT) package measuring 10mm x 10mm. The receive path gain is 20dB across the full band, with a noise figure of 3.5dB. Transmit path gain is 19dB, and the output referred third order intermodulation (IP3) is +36dBm. Low-loss RF filtering has been integrated into the package structure, with a band-pass filter after the LNA and a harmonic rejection filter after the PA. Insertion loss figures are 0.7dB for the band-pass filter and 0.2dB for the harmonic rejection filter.
“This development has demonstrated that we can overcome the manufacturing challenges of integrating filters along with multiple die into an SMT package,” said Mike Weaver, managing director of Filtronic Broadband. “This is not easy at mmWave frequencies, and will give us a crucial head start towards eventual production when the market demand for 5G components at 26GHz begins to ramp up.”
