These RF switches are called "solid state", they are operated by a semiconductor, usually GaAs, PIN diode or P-Hemt, for signal or low power, often used in instrumentation and wireless applications.
The most important difference from the mechanical types consists of the remarkable switching speed (at least 1000 times faster) and this makes them suitable for particular applications such as modulators, high-speed wireless TX - RX switches, etc...
The "absorptive" types, also called "non-reflective" or "terminated", are used in applications where is needed to terminate the unused port (that is not switched at the time) rather than leave it open or free.
