###### Abstract  
Microstrip patch antennas (MPAs) are widely used in satellite communication due to their low profile, compact size, and ease of fabrication. This paper presents a design of an X-band microstrip patch antenna using an electromagnetic band gap (EBG) structure for CubeSat applications. The X-band is preferred for CubeSat missions in high-speed communication, long distance or deep space because it allows communication at higher data rates, and the antenna is smaller than those used for lower frequency bands. In our study, the EBG elements are analyzed, modified and optimized so that the antenna can fit a 10 cm \(\times\) 10 cm surface area of a standard 3U CubeSat structure while providing a significant high gain and circular polarization (CP). A noticeable point of this research is that the simplicity of the antenna and the EBG structure are being maintained by just using a simple single-probe feed to achieve a total antenna efficiency exceeding 90%, and the measured gain of around 11.7 dBi at the desired frequency of 8.483 GHz. Furthermore, the measured axial ratio (AR) is around 1.4 dB at 8.483 GHz, which satisfied the lower-than-3 dB requirement for CP antennas in general. The simulation, analysis and measured results are discussed in detail. 3U cubesat; circular polarization; electromagnetic band gap +
Footnote †: journal: Electronics Letters  
0000-0001-5000-0000][PERSON]. [PERSON] 00000-0001-5000]D. [PERSON] 0000-0002-0002-0002-0002][PERSON]. [PERSON] 0000-  
antennas (MPAs) become essential, especially in CubeSat missions that require a higher data rate and more directive communication. At these frequency ranges, due to the shorter wavelength, the size and compactness of the antennas are not as critical as they are in lower frequencies, but the antenna gain becomes a key factor. There are various reported works related to X-band MPAs for CubeSat: [PERSON] et al. (2016) designed a compact, optimized circular polarization MPA array for payload Telemetry (TM); this antenna operates at 8.025-8.4 GHz with a measured gain of more than 10 dBi and a measured axial ratio (AR) of lower than 3 dB at 8.212 GHz. However, the design was quite complicated with feeding network and antenna elements on the feed layer, as well as a separate parasitic layer. A high-gain CP planar antenna with a superstrate integrated on top of the antenna radiator was introduced in ([PERSON] et al., 2016); the gain is 17 dBic; nevertheless, the feeding network is complicated with four different pins to provide differential signals for CP. Furthermore, the total height of this antenna exceeded the threshold specified in the CubeSat Design Specification (CDS) developed by California Polytechnic State University (Cal Poly) and Stanford University ([PERSON] et al., 2016). Even when applying to small satellite standards other than CubeSat, during the launch process, the satellite might experience a strong vibration that leads to a shifting, or even a detaching, of the superstrate and the four supporting standoffs if not mechanically reinforced. In the review article ([PERSON] et al., 2016), three topologies of low-, medium-, and high-gain X-band MPAs are presented. The medium-gain antenna (MGA) is a \(2\times 1\) patch array, in which a dual-feed network is applied for each element to create CP. This MGA reached a gain value of 9 dBi and fits well in a surface area of 2U (10 cm \(\times\) 20 cm). It is clear that in the above MPA designs, an array of elements or auxiliary components for the antenna radiator must be implemented to achieve good gain. Moreover, a feed network must also be used to create circular polarization, that can lead to additional insertion losses, phase imbalance issues, and fabrication complexity. The purpose of the present paper is to introduce a novel CubeSat microstrip patch antenna design that balances high gain, circular polarization, simplicity and robustness. The method of integrating an electromagnetic band gap (EBG) into the MPA is considered.