학술논문
Non-planar log-periodic antenna feed for integration with a cryogenic microwave amplifier
Document Type
Conference
Author
Source
IEEE Antennas and Propagation Society International Symposium (IEEE Cat. No.02CH37313) Antennas and propagation Antennas and Propagation Society International Symposium, 2002. IEEE. 4:140-143 vol.4 2002
Subject
Language
Abstract
The bandwidth of a microwave reflector telescope is limited by the size and figure accuracy of the mirror elements and by the feed which couples focused radiation to the receiver. A single or hybrid-mode feedhorn can efficiently illuminate a telescope aperture with low ohmic loss. Its gain varies quadratically with frequency, however, limiting its effective bandwidth to less than an octave. A log-periodic antenna (LP) can illuminate a telescope aperture over multi-octave bandwidths, but it has greater spillover and ohmic loss than a well-designed feedhorn. This paper describes a non-planar log-periodic antenna feed to which cryogenic electronics can be attached without the need for a long, lossy section of transmission line. With appropriate reflector optics to minimize defocusing with phase travel and baffles to redirect sidelobes onto the sky, this antenna offers a low noise, wideband alternative microwave feed for astronomical and SETI applications. It is currently being adapted for use on the Allen telescope array.