The physical principle of an IRS is that the surface is composed of atoms, each of which acts as an “intelligent” scatterer: a small antenna that receives and re-radiates without amplification, but with a controllable phase-shift. Typically, an atom is implemented as a small patch antenna terminated with an adjustable impedance.
Intelligent Reflecting Surfaces: On Use Cases and Path ...
When is a transformation called an isometric transformation?
If there is no change in size or shape, then the transformation is called an isometric transformation. If the size of the object changes then the transformation is called a size transformation. Each transformation has a unique set of characteristics or rules that define the movement.
“Mirrors” exist only in textbooks, when a plane wave is impinging onto an infinitely large conducting plate (none of which exist in practice). Irrespective of how the IRS is constructed, if it is viewed from far enough away, its radiated field will have a beam width that is inversely proportional to its size measured in wavelengths.
Intelligent Reflecting Surfaces: On Use Cases and Path ...