MaxLinear showcased its Sierra SoC at MWC, hoping to catch the eye of radio makers with a proposition: Massive MIMO (mMIMO) using ceramic filters, thanks to the shiny new Passive Intermodulation (PIM) cancellation capabilities, enabling much lighter FDD radios. We learned much of the detail in a pre-MWC call, but at the show, Gerry Leavey, Senior Director of Network Infrastructure, allowed us to get hands on with the chip and the test station, squeezing us in just ahead of a meeting with a major European MNO that sounded quite enticing. Using conventional metal cavity filters in the antenna, an FDD mMIMO unit becomes impractically heavy – something that cannot be carried up by a technician. Ceramic cavity filters are much…