Circularly polarised wideband quadrifilar helix antenna with ultra‐wide beamwidth isoflux pattern for a S‐band satellite ground station

Abstract

A quadrifilar helix antenna (QHA), with an improved isoflux radiation pattern for S‐band satellite ground stations, is designed and fabricated. The performance of the antenna with respect to its beam pattern, axial ratio and efficiency is investigated. To have optimum coverage of a low earth orbit satellite rotating the Earth's surface with one fixed pattern ground station antenna, an ultra‐wide beamwidth isoflux pattern covering the complete upper hemisphere is required. The presented QHA antenna not only satisfies the required beam shape but also its pattern stays unchanged within a wide bandwidth. Besides that, an efficient Wilkinson power divider as the antenna's feed is designed to match the input impedance of helices appropriately, resulting in efficiency enhancement to >85%. The measured results, which indicate the performances of the proposed antenna in terms of the reflection coefficient, radiation pattern and axial ratio, are in good agreement with the simulation results within 2 to 2.2 GHz frequency band.

X‐band dual‐band horn antenna with isoflux pattern for deep‐space applications

“…Helix antennas are often employed when a shaped radiation beam is needed, as they allow for the shaping of the radiation pattern for various types of coverage. 5,6 However, they also possess certain characteristics such as a requirement for substantial lengths to achieve necessary isoflux patterns, complicated feeding systems, and careful selection of dielectric materials due to thermal considerations. Passive array antennas are another viable option for space-based applications owing to their low profile, light weight, and flexible pattern performance, but require careful observation of certain aspects, including the difficulty of achieving a better isoflux pattern with a small number of radiating elements.…”

“…Isoflux radiation pattern antennas have long been utilized in Low Earth Orbit (LEO) and High Earth Orbit (HEO) spacecraft TT&C or telecommunications due to their ability to maintain a constant power density on Earth. Helix antennas are often employed when a shaped radiation beam is needed, as they allow for the shaping of the radiation pattern for various types of coverage 5,6 . However, they also possess certain characteristics such as a requirement for substantial lengths to achieve necessary isoflux patterns, complicated feeding systems, and careful selection of dielectric materials due to thermal considerations.…”

Advanced Optimization of an Isoflux Reflectarray

“…To maximize the link-time during the GS passage, isoflux-shaped beams are sought to compensate for the path loss in a specified wide angular range. LEO spacecraft antennas employed to produce gain isoflux patterns in circular polarization are mainly helix antennas [1], [2] and choke ring horns [3], [4], [5], in recent years lightweight planar antennas, such as meta-surfaces [6], [7], [8] and reflectarrays [9], [10], are topic of research, with particular emphasis on applications such as high-gain global coverage in satellites mega-constellations [11].…”

Design of miniaturised printed quadrifilar helix antenna with isoflux coverage and wide‐angle circular polarisation

“…Whereas, the bandwidth is narrow (<5%). To enhance the bandwidth, four-feed network is applied for exciting the PQHA [18], and wide-beamwidth isoflux pattern is realised by tuning the pitch and helix radius. Regrettably, the AR (around 5 dB) is deteriorated and the size is large.…”