Wideband Retroreflector

There are many known methods of retransmitting radio wave signals intra-building and inter-building, as well as ground-to-aircraft or ground-to-satellite. Some techniques modulate the reflection coefficient of an antenna. Prior art has used frequency multiplication or field effect transistor (FET) mixing to modulate the reflection coefficient of an antenna, and therefore the reflected amount of incident power to perform this function. This method is limited by its instantaneous bandwidth to about 50 MHz and its overall efficiency, in addition to the tendency to produce large amounts of harmonics. Other techniques include optical retroreflectors and RFID transponders. Optical retroreflectors reflect the illuminating energy; RFID transponders use a fixed RF frequency with resonant circuits.