Analysis and Optimization of Quadrifilar Antennas for Brazilian Satellites

Paper number

IAC-06-C2.P.1.06

Author

Mss. Luzia Lux Lock, Laboratório de Ciências Espaciais de Santa Maria, LACESM/CT - UFSM and Centro Regional Sul de Pesquisas Espaciais, CRSPE/INPE - MCT, Brazil

Coauthor

Dr. Carlos Alberto Iennaco Miranda, Brazil

Coauthor

Mr. Thiago Brum Pretto, Laboratório de Ciências Espaciais de Santa Maria, LACESM/CT - UFSM and Centro Regional Sul de Pesquisas Espaciais, CRSPE/INPE - MCT, Brazil

Coauthor

Mr. Diego dos Santos, Laboratório de Ciências Espaciais de Santa Maria, LACESM/CT - UFSM and Centro Regional Sul de Pesquisas Espaciais, CRSPE/INPE - MCT, Brazil

Coauthor

Mr. Nelson Jorge Schuch, Brazil

Year

2006

Abstract

Data Collecting (DCS) and Service Telecommunication (TMTC) systems require antennas that provide omni-directional coverage, in reception and transmission. Such coverage is obtained mounting for each system, a pair of quadrifilar helices on opposite sides of the satellite with right and left hand circularly polarization respectively. The Satellites SCD-1, SCD-2, as well their antennas, designed and developed by National Institute for Space Research – INPE/MCT, and CBERS-2, designed and developed trough a partnership between Brazil and China, use this type of antenna to accomplish the telemetry transmission and command (TTC) and data transmission. This paper presents analysis and optimization of quadrifilar antennas, and the results compared with the models used on the satellites constructed by INPE. The quadrifilar antenna is composed by two orthogonal bifilares fed in phase quadrature. The bifilar used is a two elements helical antenna. Each element is a half-turn, half-wavelength helix. As with all coaxially fed balanced antennas the bifilar requires a balun. The method used was the “infinite balun” which employs a semi-rigid coaxial cable as one of the elements of the bifilar. At the feed point the center conductor of the coax is soldered to the opposite wire, whose material is copper clad steel. The balun’s function is to distribute equal currents of opposite phase to flow on the outer surfaces of the coaxial cable and adjoining wire.
The 90 degree phase relationship between bifilars needed to produce the quadrifilar can be achieved by the self-phased method. The desired 90° degree phase difference is obtained by designing the orthogonal bifilars such that one bifilar is larger relative to the desired resonant frequency length and, therefore, inductive while the other bifilar is smaller and, therefore, capacitive. The antennas project developed by INPE, haven’t considered the effects of the materials used on their structure. With the modeling of this antenna, using the Solid Works Software®, and doing the simulation with the High Frequency Structure Simulator® (HFSS) software, the parameters are adjusted for the antenna optimization, thus becoming, more practical and advantageous the construction of the antenna.

Abstract document

IAC-06-C2.P.1.06.pdf

Manuscript document

IAC-06-C2.P.1.06.pdf (🔒 authorized access only).

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