one puzzling aspect of recent Japanese ship design is the choice of C-band for the long range search component of the commonly deployed FCS-3 system. No other navy I'm aware of use a C-band radar for long range search purpose. C-band is very vulnerable to poor weather condition. For that reason, C-band is the most popular weather radar frequency.
according to the Japanese wiki page.
the decision to adopted C-band instead of S-band like the Aegis system was a controversial one.
pluses for the short wavelength C-band
1)better low attitude target detection
2)smaller lighter antenna
3)better ECCM due to wider bandwidth.
inferior compare to S-band
1)resistance to poor weather condition
2)long range performance.
while C-band may be the correct decision for smaller escort ship such as the Akizuki, IMO it is a poor choice for aviation ships such as the Hyuga and Izumo.