Some theoretical results for surface wave launchers

The design of surface wave launchers is examined and it is shown that the efficiency of a launcher of finite size can approach arbitrarily near to 100 per cent. For a given size of launcher, there is however a limit to the efficiency above which an increase is obtained only at the expense of frequency bandwidth. Launchers with efficiencies above this limit are classed as "super-efficient" by analogy with "super-gain" aerials. A general solution for an end-fire launcher is also given.