The mainstream types of chipless tags are digitally encoded and work at more than one millimetre range, like silicon chips. Their potential markets go beyond the lowest cost-highest volume potential markets because they have other attributes beyond cost.
or red shift. noun, Astronomy. 1. a shift toward longer wavelengths of the spectral lines emitted by a celestial object that is caused by the object moving away from the earth. Compare cosmological redshift, Doppler effect, gravitational redshift. Origin of redshift.
Ian, that site does not support your statement. It only says that the Wolf Effect occurs at the source and so doesn't require a scattering medium for the redshift to occur in transit. The Wolf Effect does require scattering of light at the source whether you want to admit it or not. It is basic physics.