A dual beam planar antenna for Janus type Doppler navigation systems

Doppler Navigational Systems are relatively new and have been only recently declassified. For this reason very little has been published on the new problems in design which a Doppler system imposes on the antenna. It is the purpose of this paper to enumerate these problems and describe an antenna which has been used to solve them most successfully. This is a two-dimensional or planar dual beam antenna consisting of slotted waveguide linear arrays. The dual beams are formed by a proper choice of spacing and ohasing of the slot radiators in each linear array. By a unique combination of the linear arrays, lobe switching can be accomplished very simply with an R. F. switch and hybrid. One of the advantages in system application of this antenna is the inherent frequency compensation it possesses which renders the measured velocity independent of transmitter frequency drifts.