Introduction

UWB technology is quickly gaining acceptance as a wireless technology with outstanding characteristics. To understand UWB, we begin with a look at its origins and its growth to date.

History

Early radios like Guglielmo Marconi’s spark gap design (1896) marked the beginning of Impulse Radio (IR) communications. Inspired by Heinrich Hertz’s (1888) experimental apparatus that proved James Clerk Maxwell’s theoretical electromagnetic waves (1865), the first wireless telegraph signals used short impulses to transmit information. These impulse signals were the forerunners of modern UWB communications. The spark gap designs were simple and easy to build with primitive components. However, early impulse radios were subject to interference from atmospheric sources and other transmitters.

In 1918 Edwin Armstrong’s super-heterodyne radio design enabled outstanding interference rejection of narrowband Amplitude Modulated (AM) signals. Continuous wave, narrowband wireless radio also excelled at long transmission distances and quickly replaced early impulse radios.

Impulse radio development languished for decades until modern test equipment technology ultimately rekindled interest. In 1962 the invention of the sampling oscilloscope made it possible for Gerald Ross to use transient impulses to characterize wideband radar components (1963). Sub-nanosecond pulse generation capability enabled previously difficult characterization of microwave component mismatches inside phased array coupler networks.