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Assumptions and Total Dissipated Power for SiGe versus GaN FWA Front End
A GaN FWA front end provides other benefits:
• Lower total power dissipation. To ensure an accurate comparison, the GaN power dissipation includes an extra
19.2 watts, to account for the 128 beamformer branches needed to feed the front ends. As shown in the following
figure, at the target EIRP of 65dBm, GaN provides a lower total power dissipation (127Pdiss) than SiGe. This is
better for tower-mounted system designs.
Comparing an All-SiGe FWA System to a Combination of SiGe Beamforming with GaN Front Ends
• Better reliability. GaN is more reliable than SiGe, with >107 hours MTTF at 200°C junction temperature. SiGe's
junction temperature limit is around 130°C.
• Reduced size and complexity. GaN's high power capabilities reduces array elements and size, which simplifies
assembly and reduces overall system size.
The takeaway: In wireless infrastructure applications, reliability is imperative because equipment must last for at least
10 years. For FWA, GaN is a better choice than SiGe for reliability, cost, lower power dissipation, and array size.
