slotted waveguide antennas
S. S. Sekretarov, D. M. Vavriv
In the paper, design and manufacturing approaches to the development of slotted waveguide antenna arrays intended for the implementation in modern radar systems are described. Both, the recent advances in the theory of this type of antennas and modern computational capabilities enable for an essential advance of antenna characteristics.
In particular, this is applicable to the development of slotted waveguide antennas for the Ka-band frequency band and even for higher frequencies. The problem with the antennas development for these frequency bands has been due to finite tolerances of the mechanical fabrication of antenna elements what has not allowed to provide an acceptable reproducibility of antenna characteristics in the operational frequency band. The design approaches and corresponding fabrication processes that are described in the paper make possible to achieve a good reproducibility of the antenna characteristics and a reasonable compliance of the simulation and experimental data. The obtained results are illustrated by an example of Ka-band antenna system which is used in a radar intended for providing flight safety of helicopters and other aircrafts.
The paper describes also a monopulse slotted waveguide antenna with a circular aperture, which is forming the antenna main beam inclined from the antenna surface normal on the value significantly larger than the beamwidth. The development of such antenna has required the usage of a novel feeding system and a modification of the design approach. The practical realization of this antenna is used in a Ku-band search and tracking radar.
Recently, an appreciable progress is observed in the development of such antennas with extended operational frequency range. The existing performance capabilities are illustrated by the results of the development of a slotted waveguide antenna having the relative operational frequency bandwidth over 15%. The achieved antenna characteristics are able to extend possible areas of the application of considered antennas. For example, it is considered an application of the designed antenna in a X-band synthetic aperture radar with the slant-range resolution of about 20 cm.