A wideband F-shaped patch antenna for S-band CubeSats communications

A wideband S-band F-shaped patch antenna is proposed for CubeSats communications. To broaden bandwidth, it uses two arms with different lengths to generate a second resonant frequency. The effect of the arm length and width on the return loss, resonant frequency and impedance bandwidth on a 3U CubeSat is studied. The simulation results show that the antenna achieves a wideband of 1121 MHz (1.606-2.727 GHz) with a return loss below −10 dB over the entire frequency band from 1.606 to 2.727 GHz. The antenna has a high gain of 8.51 dB and a small return loss of −32.85 dB at 2.45 GHz

Implementation of message authentication code using DNA-LCG key and a novel hash algorithm

With the introduction of electronic form of data, the need for an automatic system of security to protect the integrity of data while being transferred from one place to another is required. This is especially the case for a network in which the systems are accessed over a public network or internet. Security mechanisms involve the use of more than one algorithm. They further require that the participants should possess a secret key, which raises issues about creation, distribution and proper usage of these keys. The most effective technique used in provisioning security is Message Authentication Code (MAC) which helps in preserving integrity. MAC involves the use of secret key along with a hash algorithm. In this paper, we present an implementation of MAC using a secret key created by Deoxyribonucleic Acid (DNA) and random output sequence of Linear Congruential Generator (LCG). The hash algorithm used is made more robust by adding complexity to the traditional SHA-160. The presented scheme RMAC (Robust Message Authentication Code) is tested on National Institute of Science and Technology (NIST) test suite for random numbers, avalanche criteria and resistance towards network attacks. The results reveal that the scheme is efficient and is applicable for a variety of security demanding environments

S-band Planar Antenna Designs for CubeSat Communications

Cube satellites or CubeSats are attractive for use in space research and education programs. This is because of their low-cost, short development time, and ease of deployment. Moreover, CubeSats are able to communicate with each other, and assemble into swarms to carry out different functions such as wide area measurements and sensing. These capabilities require CubeSats to be equipped with an efficient, high gain, wideband and small antenna to facilitate communication links with each other and with ground stations. However, the limited real estate, power and communication opportunities of CubeSats pose real challenges to any antenna designs. Specifically, designs are required to meet the size and weight restrictions of CubeSats while yielding high gain and wide bandwidth. To date, CubeSats employ wrapped-up wire dipole antennas that require deployment after launch. However, this adds complexity and there is a risk they might not deploy, which increases the likelihood of mission failure. They also have low total gain and narrow bandwidth. One approach to avoid deployment failure is to use micro-strip patch or slot antennas. However, they have low gains and narrow bandwidth. Moreover, their performance on CubeSats is unknown

Developing Cost-Effective and High-Speed 40 Gbps FSO Systems Incorporating Wavelength and Spatial Diversity Techniques

Free-space optical (FSO) communication systems are being anticipated to offer promising alternatives to existing radio networks in delivering high-speed data access to end-users. Ease of installation, robust features, and cost-effective operation have been the hallmark of FSO systems, and these features will play an obvious role in deciding the ways in which futuristic smart communication models will operate. Despite these arrays of features, FSO links suffer severe performance degradation due to channel-induced impairments caused by atmospheric effects such as rain, haze, and fog. In this work, we have investigated and compared the performance of 40 Gbps FSO links for different channel conditions ranging from clear weather to severe attenuation by incorporating spatial and wavelength diversity as performance booster techniques. The use of an erbium-doped fiber amplifier (EDFA) with FSO links has also been proposed here. Using performance metrics like bit error rate (BER) and eye patterns, it has been found that the use of EDFA not only helps in compensating for the link losses but also aids in realizing an all-optical processing based last-mile access system. The proposed FSO system will be capable of bridging the existing backbone fiber networks with end-users with minimal changes to the existing hardware regime, thereby proving to be extremely cost-effective in sharp contrast to radio-frequency generations which require major infrastructure overhaul

Telemetry, tracking and command subsystem for LibyaSat-1

In this paper we present the design and the analysis of Telemetry, Tracking and Command Subsystem (TT&CS) for Libyan imaging mini-satellite (LibyaSat-1). This subsystem is the brain and the operating system of any satellite or spacecraft as it performs three important functions; tracking mini-satellite position, monitoring mini-satellite health and status and processing received and transmitted data. Moreover, the uplink and downlink budgets for s-band and x-band antennas are presented. We also designed s-band C-shaped patch antenna for command receiver (2.039 GHz). Electromagnetic simulation was performed to this antenna High Frequency Structure Simulator (HFSS). Our results show that the s-band C-shaped patch antenna achieves high gain of 6.45 dB and wide bandwidth; i.e., 1500 MHz. The achieved simulated return loss is -19.6 dB at a resonant frequency of 2.039 GHz

S-band Planar Antennas for a CubeSat

This paper studies the suitability of shorted patch and CPW-feed square slot antennas for CubeSat communications. To study the effect of the CubeSat body on the antennas performance, we have simulated both antennas in the High Frequency Structure Simulator (HFSS) with and without the CubeSat body. Compared to CPWfeed square slot antenna, the shorted patch antenna achieves higher gain and wider bandwidth. We have also re-dimensioned both antennas to shift their resonant frequencies to 2.45 GHz using Quasi Newton method in HFSS. This thus enables their use in the unlicensed ISM band. The repurposed shorted patch has smaller return loss; e.g., -27.5 dB (without CubeSat), higher gain; e.g., 5.3 dBi and wider bandwidth than the repurposed CPW-feed Square slot antenna. Lastly, further enhancement in the gain of re-dimensioned CPW-feed square slot antenna shows an increase of total gain from 2 to 2.52 dB

A survey and study of planar antennas for pico-satellites

Works on pico-satellites have gained momentum recently, especially those that consider pico-satellites as part of a much larger constellation or swarm. This feature allows pico-satellites to provide high temporal resolution of observational data and redundancy. In particular, it reduces the need for satellite-to-ground communications and, hence, helps save energy and allows the execution of distributed processing algorithms on the satellites themselves. Consequently, satellite-to-satellite or cross-link communication is critical. To realize these advantages, the cross-link antenna employed on pico-satellites must meet many criteria, namely, small size, lightweight, low-power consumption, high gain, wide bandwidth, circular polarization, and beam steerability. To date, no works have examined the suitability of existing planar antenna designs for the use on pico-satellites. To this end, this paper contributes to the literature by focusing on microstrip patch and slot antennas that have the ability to achieve high gain, beam steering, and wide bandwidth. This paper reviews 66 planar antenna designs, which includes 38-patch and 28-slot antennas. In addition, we provide an extensive qualitative comparison of these antennas in terms of their mass, size, gain, beam steerability, type of polarization, operating frequency band, and return loss. In addition, we have evaluated three antenna designs that best address the pico-satellite challenges on a common platform. We find that the asymmetric E-shaped patch antenna design is the most suitable for the use on 2U CubeSats. This is because of its small size ( $34times 13$ mm $^{2})$ and high gain (7.3 dB). In addition, the E-shaped patch antenna yields a wide −10-dB bandwidth of 2300 MHz and a small return loss of −15.2 dB

A Printed Yagi Antenna for CubeSat with Multi-Frequency Tilt Operation

In this paper, a printed Yagi antenna with an integrated balun is proposed for CubeSat communications. The printed antenna is mechanically adjustable to realize three functional states at different operating frequencies in the L‐band and S‐band respectively. Three different angle deployments are proposed at 10°, 50° and 90°, so that the antenna operates at three different operating frequencies, namely 1.3 GHz (L‐band), 2.4 GHz (S‐band) and 3 GHz (S‐band). The measured results of the fabricated antenna are well matched with the simulation, having frequencies of 2.82–3.07 GHz, 1.3–1.4 GHz and 2.38–2.57 GHz, with similar radiation patterns. The measured gain of the antenna is 8.167 dBi at 2.4 GHz, 5.278 dBi at 1.3 GHz and 6.120 dBi at 3 GHz. Keeping within the general theme of cheap off the shelf components for CubeSats, this antenna design allows the CubeSat designers to choose from three popular frequencies, through a simple angle configuration. The main contribution of this work lies with the reconfigurable frequency, relatively high gain and simplicity of design

Antenna Designs for 5G/IoT and Space Applications

Antenna design has received renewed attention in the last few years [...

Single Layer Unit Cell with reduced phase sensitivity for X-band Reflectarray Applications

In this paper a single layer multi-resonant unit cell with a reduced phase sensitivity for X-band wideband reflectarrays is presented. The unit cell employs a Jerusalem cross and four pairs of concentric square loops and is arranged in a rectangular grid. The proposed unit cell achieves a reflection phase response of 426° and a reduced reflected phase sensitivity. This results in low quantization phase errors of ±6.17° and element bandwidth of 13% at 12GHz by considering a 45° margin error. Finally, the proposed unit cell presents linear and parallel phase curves ranging from 10 to 14GHz, showcasing its potential for wideband reflectarrays applications operating in X-band