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

Abstract

This study addresses the intrinsic limitations of the miniaturisation of very‐high frequency‐band quadrifilar helical antennas. Several designs with a relative size (i.e. the ratio between antenna's heights after and before the miniaturisation) down to 27% are obtained using an optimisation process based on intensive full‐wave electromagnetic simulations. Reported simulation and experimental results underline the impact of height reduction on the antennas main descriptors: radiation pattern, directivity, polarisation purity, input matching, efficiency and maximum achievable gain. It was observed that the efficiency and the gain do not decrease linearly with the reduction of the antenna height and the input matching is slightly improved for the compact antennas. The shape of radiation pattern and the polarisation purity are not significantly degraded for relative size down to 27%.

Miniaturization of Compact Quadrifilar Helix Antennas for Telemetry, Tracking and Command Applications

“…As expected, the phase center of QHAs/CQHAs is always located on the symmetry axis of CQHAs and positioned below the phase center of the QHA. As a general rule, the phase center approaches the antenna ground plane as the height reduction increases [26]. The position of the phase center is in the range of CQHA height for moderate reduction size factor and can slightly exceed the antenna height for very compact CQHAs.…”

“…(6) can be very useful in practice: for a given antenna height (or R H ), the designer can predict the gain achievable by a CQHA, checking if the resulting compact antenna fulfills the launch system requirement and decide if the proposed CQHA is suitable for the TTC system. The impact of the miniaturization process on the wire supported CQHA was investigated by the authors in [26] with a focus on the phase center stability. Exact location of the phase center is crucial mainly for high resolution GPS (Global Positioning Systems) application.…”

“…For TTC application it is not convenient to use antennas with negative gain (in dBi) and consequently, G max > 0 dBi is required as an additional goal GF4. The optimization process uses the Grid Search Method implemented in FEKO and is based on the methodology described in [6] and [26]. Thousands of CQHAs based on sinusoidal, standard or modified prefractal and, SMMF [24,27] profiles were chosen for optimization purposes.…”

Twist and Glide Symmetries for Helix Antenna Design and Miniaturization

“…The miniaturization of helix antennas has been the focus of several research studies, mainly for quadrifilar helix antennas [21][22][23][24]. The techniques that have been generally employed for their miniaturization are core dielectric loadings [25,26], meander lines [27] and loading of the pointed ends of the helix arms [28].…”

Miniaturized wideband quadrifilar helix antenna for satellite navigation application

“…Some miniaturization and bandwidth broadening methods have been presented in the literature. For example, winding, [2][3][4][5][6][7][8][9] or folding [10][11][12][13][14][15] helical arms can be a good choice for the QHA miniaturization. Dielectric loading method, that is, using material with a high dielectric constant, also reduces the size of a QHA, 16,17 this method has the most compact size, but the bandwidth is very narrow.…”