Date Published: November 14, 2018
Publisher: Public Library of Science
Author(s): Touhidul Alam, Mohammad Tariqul Islam, Md. Amanath Ullah, Rahmi Rahmatillah, Kateryna Aheieva, Chow Chee Lap, Mengu Cho, Mohammad Maktoomi.
A compact UHF antenna has been presented in this paper for nanosatellite space mission. A square ground plane with slotted rectangular radiating element have been used. Coaxial probe feeding is used to excite. The rectangular slot of the radiating patch is responsible for resonating at lower UHF bands. One of the square faces of the nanosatellite structure works as the ground plane for the slotted radiating element. The fabricated prototype of the proposed antenna has achieved an impedance bandwidth (S11< -10dB) of 7.0 MHz (398 MHz– 405 MHz) with small size of 97 mm× 90 mm radiating element. The overall ground plane size is 100 mm × 100 mm × 0.5 mm. The proposed antenna has achieved a gain of 1.18 dB with total efficiency of 62.5%. The proposed antenna addresses two design challenges of nanosatellite antenna, (a) assurance of the placement of solar panel beneath the radiating element; (b) providing about 50% open space for solar irradiance to pass onto the solar panel, enabling the solar panel to achieve up to 93.95% of power under of normal conditions.
With the advent of modern technology nanosatellites are flourishing a new dimension in space communication. The launch of first CubeSat in 2003 introduced a new era for scientific, private, and government missions, research interest of universities  and enabled researchers to visualize and plan bigger mission with less expense . CubeSats missions are rapidly evolving as viable platform for Earth and space science. Simplicity, light weight, cost effectiveness and short development period make them ideal candidates for low earth orbit constellations. Nanosatellite Space missions are being fruitful in coastal and inland observation of flood, volcanic eruption, landslides, draught, forest fires, critical forecast of natural disaster, space atmosphere observation, monitoring agriculture and agri-environmental conditions. Nanosatellites are being designed in big scale for commercial, government and educational research because of continuous reduction of development cost, increased demand due to wide application range Moreover NASA space exploration missions have planned a telecom system for asteroid, lunar and planetary destinations by launching several CubeSats beyond earth orbit recently [3, 4].
The design layout of the proposed antenna is illustrated in Fig 1. The proposed antenna is designed considering the following issues-
The proposed antenna has been fabricated according to the listed parameters in Table 1. The antenna attached to the nanosatellite structure, shown in Fig 2. It is shown from Fig 2 that the proposed antenna is compatible with both 1U and 2U nanosatellite structure. The reflection coefficient of the proposed antenna has been measured using performance network analyzer (PNA) Agilent N5227A. The has been calibrated before calibration to minimize the I/O port mismatch, connecting cable loss, etc. To do that, N4694A MW electronic calibration (ECal) module was used. The reflection coefficient has been analyzed with and without integrating solar panel, shown in Fig 3. Fig 3 shows that a good input match with magnitude of reflection coefficient ≤-15dB. The reflection coefficient bandwidth increases after solar cell placement due to the lossy properties of the solar cell. Moreover, it is noted that the solar cell affected the input impedance and the resonance shifts by 10 MHz to lower frequency . This shifting effect in both simulation and measured results show good agreement.
This paper proposes a nanosatellite body-mounted 3D antenna for UHF communication. The design exclusively features 50% of open space for solar irradiance penetration onto nanosatellite single face where solar panels can be placed. The antenna prototype was fabricated and tested with 1U and 2U nanosatellite structure for performance investigation. The proposed antenna achieved realized gain of 1.18dB and total efficiency of 62.5% with nanosatellite body, which is unique outcomes of the proposed solar integrated UHF antenna.