I know only panasonic call it inverter technology but I thought others
could
be using the same technology without calling it inverter which is only a
name that panasonic have come up with to give this technology a brand and
of
course this will be copyrighted so nobody else can use the term inverter
in
their microwave ovens, i.e a marketing strategy.



I don't think "inverter" can be copyrighted, it's a name that's been in use
for many years to describe certain types of switchmode power supplies. You
can bet that if any other oven manufacture was using similar technology,
they'd point it out in some obvious way even if they couldn't call it
Inverter.