The wider the frequency range, the bigger the market for a printed transistor circuit. If we want a slowly adjusting use by date, where the label senses the time and temperature and changes the figure accordingly, then transistors working at kilohertz or below may suffice. Indeed, it may be adequate for the device to take several seconds to switch and that may be true of shelf edge labels as well.
If we want to replace ten trillion barcodes with radio frequency identification labels that are more reliable and versatile then we may need the most popular RFID frequency of 13.56 MHz. However, the second most popular RFID frequency of 850-950 MHz may be preferred and certainly the dream of a disposable mobile phone will call for transistors working near that range.
Then there is RFID at 2.45GHz, RFID and radar at 5.8GHZ and even the more speculative applications up to terahertz. To meet this spectrum of needs, some of the current options for printed transistors by frequency are shown below.
Unfortunately, the higher the frequency, the more experimental the product. Indeed, the higher frequency products often have serious limitations caused by poor on-off ratio, inherently expensive processes or use of high temperature substrates such as stainless steel foil.
However, all these options can be improved. There are no theoretical limits to the performance of any of them that are anywhere near to the current achievements.
For more on printed electronics attend Printed Electronics Asia or Printed Electronics USA. Also read Printed and Thin Film Transistors and Memory 2007-2027