4 ms·

Looks like they're running on 900MHz. To be effective, 900MHz antennas usually must be rather large. May limit the useful applications. Edit: I stand correct

• tanvach 12y ago
  Yes that is correct, with traditional antenna design. I believe the collar itself has a hidden antenna to allow good impedance matching. Coming from communications engineering I find ultra band modulation scheme intriguing. I haven't seen any papers that on what this is exactly and am waiting for more information to come out! Ps: there is work on metamaterial based antenna design to shrink antenna dimensions http://en.m.wikipedia.org/wiki/Metamaterial_antenna http://en.m.wikipedia.org/wiki/Metamaterial_antenna