Sparse cruciform reflector with phased array feed

Summary form only given. This paper presents the results of a study of a phased array feeding structure for an electrically large parabolic cruciform reflector antenna. Large reflector antennas are useful in remote sensing and communications due to their high gain. The cruciform shape is a trade-off in performance to deal with the difficulty in deploying a full parabolic reflector. The phased array feeding structure is an arrangement of two orthogonal linear phased arrays which resembles the cruciform shape of the sparse reflector. This feed directs more transmitted energy towards the sparse reflector arms, and less towards the unfilled areas between the arms, when compared with feeds for complete apertures. The current configuration yields a cruciform shaped far-field pattern with negligible backlobes throughout the L-band. To achieve this, there are three arrays behind the main excited array. These three arrays consist of passive reflecting elements. Each reflecting array has the same number of elements and element spacing as the excited array. The distance of the reflecting arrays behind the excited array is based on a Yagi-Uda design for operation at 1 GHz, 1.5 GHz, and 2 GHz. Initially an array of microstrip antennas was considered but did not meet the necessary bandwidth constraint of 1 GHz centered at 1.5 GHz.