Compact printed quadrifilar helix antennas for stratospheric balloons telemetry

L-band compact printed quadrifilar helix antenna with ‘Iso-Flux’ radiating pattern for stratospheric balloons telemetry

“…Such a configuration results in good circular polarization. The previously developed software [4,5] has been adapted to include basic curves defined by the superposition of N sinusoidal functions according to the following formula:…”

“…Various size-reduced helix antennas are presented in the literature, but they present mainly hemispherical patterns and the cross-polarization degradation induced by the sizereduction technique is usually not addressed [2,3]. The authors previously proposed to use pre-fractal and quasi-sinusoidal curves which led to sizereductions between 33% and 38 % [4,5], but the achieved co-polarization patterns have some non-conformities that needed to be improved.…”

Low profile meander line Printed Quadrifilar Helix Antenna

“…Although the electrical size of the conventional PQHA has been designed already tiny, the ultimate need is coming from the mobile headset and the satellite communication, especially in the military applications. It is well known that the equipments' stealth capability is one of the most important performances, while the antennas are always the complicated part in the Radar Cross Section (RCS) reduction, so the PQHA with low profile still to be one of the hot 1 [5] , meandering the printed linear elements [6] , insertion of gaps in the helix arms [7][8][9] , changing the turn angle of helix [10] , using pre-fractal method [11] and using different diameters of the two helices [12] . However, in the former method, using of the dielectric absorption reduces the radiation efficiency of the antenna, while the insertions of gaps make the fabrication complicated, and the pre-fractal method reduces the axial length only by 30%.…”

Miniaturisation of quadrifilar helical antenna: impact on efficiency and phase centre position

“…The wire-supported QHA is more suitable for low-frequency applications (VHF band), whereas the printed techniques are widely used for high-frequency applications (ultra-high frequency band or upper bands). Many QHAs have been reported in the literature including wire-supported QHA [1][2][3][4][6][7][8][9] and printed QHA [5,[10][11][12][13][14][15]. The most widely used QHAs are implemented on cylindrical surface (helix wires or printed lines are rolled up on cylindrical surfaces) but the helix can be formed to have also conical [16], spherical [17] or square surfaces [18].…”