Cube Satellites, aka CubeSats, are a class of nano satellites that have gained popularity recently, especially for those that consider CubeSats as an emerging alternative to conventional satellites for space programs. This is because they are cost-effective, and they can be built using commercial off-the-shelf components. Moreover, CubeSats can communicate with each other in space and ground stations to carry out many functions such as remote sensing (e.g., land imaging, education), space research, wide area measurements and deep space communications. Consequently, communications between CubeSats and ground stations is critical. Any antenna design for a CubeSat needs to meet size and weight restrictions while yielding good antenna radiation performance. To date, a limited number of works have surveyed, compared and categorised the proposed antenna designs for CubeSats based on their operating frequency bands. To this end, this paper contributes to the literature by focusing on different antenna types with different operating frequency bands that are proposed for CubeSat applications. This paper reviews 48 antenna designs, which include 18 patch antennas, 5 slot antennas, 4 dipole and monopole antennas, 3 reflector antennas, 3 reflectarray antennas, 5 helical antennas, 2 metasurface antennas and 3 millimeter and sub-millimeter wave antennas. The current CubeSat antenna design challenges and design techniques to address these challenges are discussed. In addition, we classify these antennas according to their operating frequency bands, e.g., VHF, UHF, L, S, C, X, Ku, K/Ka, W and mm/sub-mm wave bands and provide an extensive qualitative comparison in terms of their size, -10 dB bandwidths, gains, reflection coefficients, and deployability. The suitability of different antenna types for different applications as well as the future trends for CubeSat antennas are also presented.

Flexible substrates have become essential in order to provide increased flexibility in wearable sensors, including polymers, plastic, paper, textiles and fabrics. This study is to comprehensively summarize the bending capabilities of flexible polymer substrate for general Internet of Things (IoTs) applications. The basic premise is to investigate the flexibility and bending ability of polymer materials as well as their tendency to withstand deformation. We start by providing a chronological order of flexible materials which have been used during the last few decades. In the future, the IoT is expected to support a diverse set of technologies to enable new applications through wireless connectivity. For wearable IoTs, flexibility and bending capabilities of materials are required. This paper provides an overview of some abundantly used polymer substrates and compares their physical, electrical and mechanical properties. It also studies the bending effects on the radiation performance of antenna designs that use polymer substrates. Moreover, we explore a selection of flexible materials for flexible antennas in IoT applications, namely Polyimides (PI), Polyethylene Terephthalate (PET), Polydimethylsiloxane (PDMS), Polytetrafluoroethylene (PTFE), Rogers RT/Duroid and Liquid Crystal Polymer (LCP). The study includes a complete analysis of bending and folding effects on the radiation characteristics such as S-parameters, resonant frequency deviation and the impedance mismatch with feedline of the flexible polymer substrate microstrip antennas. These flexible polymer substrates are useful for future wearable devices and general IoT applications.

CubeSats have revolutionized the way scientists and students perceive space. The majority of CubeSat communication is greatly limited by the AX.25 standards, the small communication window, the available transmission power, and the available bandwidth at VHF/UHF band. As a result, CubeSat radios could only establish low data rate links which restrict the communication capabilities of a CubeSat mission. In this paper, a brief review of current Software Defined Radios used in space missions is given. In addition, two different design methodologies for Software Defined Radios for CubeSats are proposed that can be used as guideline for CubeSat developers. Finally, a High Data Rate Software Defined Radio for the UOW CubeSat project is presented that address all the above limitations. The radio operates at S-band, employs Quadrature Amplitude Modulation with a maximum data rate of 60Mbps consuming 2.6 Watts in transmit mode and 0.4 Watts in receive mode. The digital signal processing functions and the mode control of the radio are orchestrated by a Field Programmable Gate Array System-on Chip. The analog Radio Frequency domain is accommodated by a 4-layer Printed Circuit Board with dimensions of 92mm x 88mm. The goal of the UOW CubeSat radio is an adaptive, on-flight reconfigurable communication platform that will revolutionize the current communication capabilities of the CubeSats and expand nanosatellites mission perspectives.

This article presents a compact wideband high gain patch antenna for CubeSat. The proposed metal-only antenna mainly consists of an upper patch, a folded ramp-shaped patch and shoring pins connecting the antenna with the ground plane. By adjusting the lengths and widths of two arms of the upper F-shaped patch, a second resonant frequency is generated, and hence, the −10 dB bandwidth is increased. Moreover, the effect of arms’ lengths and widths on reflection coefficients, operating frequency and bandwidth is presented. To validate the design and the simulation results, a prototype metal-only patch antenna was fabricated and tested in a Chamber. A good agreement between the simulated and measured results is achieved. The measured results show that the fabricated prototype achieves a −10 dB bandwidth of 44.9% (1.6–2.7 GHz), a small reflection coefficient of −24.4 dB and a high efficiency, i.e., 85% at 2.45 GHz. The radiation performance of the proposed antenna is measured, showing a peak realized gain of 8.5 dBi with cross polarization level less than −20 dB at 2.45 GHz and a 3 dB gain bandwidth of 61.22%.

In this paper, a dual-band folded-end dipole antenna is proposed for plastic CubeSat platforms. The proposed antenna has a compact structure which is integrated in a miniaturized satellite i.e. CubeSat without any deployment mechanism. This is achieved by folding the dipole antenna around the CubeSat circumference. In addition, by folding the dipole, the antenna provides a dual-band performance centered at 2.5GHz and 4.7GHz, respectively. The folded-end dipole forms a square loop with a gap of tunable width which can be adjusted to tune its impedance. Finally, the measured gain of the proposed design is 7dBi and 4.3dBi with a -10dB bandwidth of 500MHz and 250 MHz at S and C-band, respectively.

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.