A Two-Channel Monopulse Telemetry and Tracking Antenna Feed

• Main Author: Yaminy, R. R.
• Other Authors: Radiation Systems, Inc.
• Language: en_US
• Published: International Foundation for Telemetering 1968
• Online Access: http://hdl.handle.net/10150/606519; http://arizona.openrepository.com/arizona/handle/10150/606519

International Telemetering Conference Proceedings / October 08-11, 1968 / Ambassador Hotel, Los Angeles, California === The two-channel monopulse telemetry and tracking antenna feed operates over the frequency range from 1435 to 2300 MHz. The feed was designed and developed for a 7-foot parabolic reflector located in the nose cone of an EC-135N aircraft. This airborne system maintains in-flight voice and telemetry communications with Apollo spacecraft during the injection and reentry phases of the Apollo missions. The feed consists of a planar multimode dual-polarized cavity-backed spiral radiator and two printed circuit comparators. The spiral radiator is excited in the sum and difference modes at both its inner and outer filament terminals. This allows the simultaneous reception of right-hand and lefthand circularly polarized signals. The sum and difference modes of excitation are precisely controlled to provide the proper reflector illumination functions for improved sidelobes and efficiency. Sidelobe levels in excess of 22 db, null depths greater than 40 db, boresight shifts of less than 0.25 degree, and system efficiencies of greater than 40 percent have been achieved.