Research and Test Apparatus

The Boeing Aero‐Space Research Division, Seattle, 24, Washington, U.S.A., has recently developed an extremely accurate resonant cavity X‐band dielectrometer for measuring the electrical behaviour of radomes and antennae covering materials at temperatures up to 2,700 deg. F. This new device, a third‐generation version of two earlier similar instruments, measures dielectric constant to within 1 per cent, and can also measure loss tangent. Temperature limits for continuous exposure of most current refractory dielectrics without serious electrical degradation are generally in the neighbourhood of 1,500 deg. F.