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Compact VHF quadrifilar helix antenna

This papers addresses the miniaturization of quadrifilar helix antennas (QHAs) for space application. An innovative miniaturization technique combining modified fractal curves and sinusoidal profiles is proposed in order to fit the dimension of QHA with the launching constraints. Reduction size ratio up to 70% is obtained without a significant degradation of the radiation pattern, directivity, polarization purity and input matching. The impact of the miniaturization technique as function of the relative height is analyzed and several conclusions are conducted.