Around April next year companies in Japan hope that a small part of the UHF
spectrum will be allowed for RFID
systems. This will be at 950 to 956 MHz.
Although this is slightly different to the UHF band used in the US and proposed for Europe, it has been chosen because the cellular network in Japan works at frequencies lower than this.
Speaking to some companies at the Auto-ID Expo in Japan last week, several told IDTechEx
that April may be optimistic - it could be later in 2005 or even 2006 before it changes. This is because there are a few key issues to overcome. One example is the problem of being so close to the cellular frequency
range - below 950Hz or above 956MHz the RF signal must be -64db. This is not much more than background noise and is difficult to achieve. Cellphone provider NTT DoCoMo is keen that this remains the case because it is concerned at potential disruption to its services.
Two proposed methods to achieve this sharp cut off outside the RFID range are not ideal: either turn the power down, in which case the range of the tag
reduces, or use filters, but this adds expense.
However, these issues will eventually be resolved - there is a huge amount of interest in UHF systems in Japan - and many Japanese manufacturers are prototyping and testing UHF tags now, to use in the domestic market as the power regulations change and also to export before then.