Loss adjuster

Keeping track of a very fast-moving object can be a matter of life and death, particularly if it's a missile travelling at up to five times the speed of sound. It may be possible with the human eye from a safe distance but it's not an easy task for an automated system.

It can be done with an array of electronically-steered antennas, which effectively improve the focus of the signal on the object. It is swept back and forth very rapidly, rather like a searchlight. It sounds straightforward and is already used in military systems. But it has a major drawback that prevents it finding use in more widespread applications — it's very expensive.

This is because the focusing is done by phase shifters, devices that alter the output signal phase when a voltage is applied. A single ferrite or semiconductor shifter can cost more than £100 and, depending upon the application, some antennas may need up to 1,000. The devices may take up no more room than a unit on a standard computer rack but they are worth far, far more.