Improvements relating to apparatus for the directional propagation or reception of electromagnetic waves

摘要

654,224. Aerials. STEVENS, A. H. (Leland Stanford Junior University, Board of Trustees of). Sept. 10, 1941, No. 15332/43. Divided out of 654,221. [Class 40 (vii)] A fan - shaped - beam projector or receiver for use in the system described in Specification 654,221 comprises a resonant chamber 41 of cylindrical form excited by one or more loops 43 or dipoles 44 and having a slot 42 (or series of apertures) which is long compared with a wavelength. The device is rotatable about trunnions 45. A pencil-shaped-beam projector for use in the same system comprises a similarly-excited chamber of rectangular-box form, Fig. 2 (not shown), having in one face holes, a fraction of a wavelength in diameter and arranged in a circle of diameter large compared with a wavelength.