Premium
Switched parasitic feeds for parabolic antenna angle diversity
Author(s) -
Durnan Gregory J.,
Thiel David V.,
O'Keefe Steven G.
Publication year - 1999
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/(sici)1098-2760(19991120)23:4<200::aid-mop2>3.0.co;2-5
Subject(s) - parasitic element , optics , reflector (photography) , physics , passive radiator , wavelength , offset (computer science) , parabolic antenna , parabolic reflector , radiation pattern , antenna (radio) , electrical engineering , optoelectronics , antenna aperture , engineering , computer science , light source , programming language
The radiation direction from a parabolic dish antenna can be electronically controlled through the use of a switched parasitic element closely coupled to a dipole feed. Through the application of a dc voltage, the half‐wavelength‐long parasitic element is switched between open and short circuit using a p‐i‐n diode at its center. With a parasitic element vertically offset from the horizontal dipole, the performance of the antenna in both switch positions has been optimized. At 1.5 GHz, using a 2.4 m diameter reflector, beam skewing on the order of 1.5° at the −6 dB point can be achieved for a feed element spacing of 0.6 wavelengths. At a parasitic element spacing of 0.5 wavelengths, the main lobe is better than 15 dB above the unshifted null. The analysis of such a structure requires the calculation of the current in both the driven element and the parasitic element and the summation of their fields on the surface of the reflector independently. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 23: 200–203, 1999.