Date of Award:

5-2016

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Electrical and Computer Engineering

Committee Chair(s)

Reyhan Baktur

Committee

Reyhan Baktur

Committee

Jake Gunther

Committee

Charles M. Swenson

Committee

Regan Zane

Committee

T. C. Shen

Abstract

A CubeSat is a very small satellite that has been achieving growing interests in space exploration. The base unit of CubeSats 1U, which is a cube with 10 cm on each side. In applications, CubeSats can be deployed as just 1U, or multiple unites can be stacked together to form a larger CubeSat for extended functionality. Due to their small sizes, it is challenging to fit antennas onto CubeSats because the antenna always fights for surface real estate with solar cells. The challenge is further aggravated when an antenna is required to have high gain such as more than 20 dB because the size of the antenna grows in accordance to the gain.

This doctoral dissertation presents a comprehensive study to answer the question of "Can it be possible to integrate a high gain optically transparent antenna array directly on top of solar cells?". The answer to such question is extremely important because it solves the issue of allocating the antenna and solar cells on a CubeSat. After asserting the feasibility of such an integration of antenna with solar cells, the thesis shows detailed guideline on how to integrate a single transparent antenna element and antenna array on solar panels.

On the element level, the thesis presents research in assessing the effects between a planar antenna integrated on the solar cell and the photovoltaic cell. A series of experiments were designed to perform assessments for antennas operating from 5 to 10 GHz. It is concluded that a commercial triple junction space-certified solar cell normally would decrease the gain of the antenna to 2-3 dB and is not affected by the working states of solar cells. The shadow of the antenna casts on solar cells, however, is not significant (less than 2%). The thesis also provides a model of a common space solar cell that helps to explain the gain loss. The model was validated by experimental data, and it was utilized to predict a possible custom design of solar cell where with a minimal design modification, it would facilitate less gain loss of the antenna integrated on top.

On the array level, the research surveys different high gain antenna array design and then focus on an optimal sub-wavelength reflectarray design. The final antenna array design is a 30 cm by 20 cm, X band (8.475 GHz) reflectarray that shows 94% transparency, 24 dB gain, and higher than 40% aperture efficiency. The design is then prototyped and tested on actual solar panel. The measurement of the reflectarray placed on the solar panel showed a gain of 22.46 dB and an aperture efficiency of 29.3%. While those results are considered excellent, the thesis continues to address the reasons for reduction of the antenna's performance due to the solar panel, through both theoretical analysis and experiments.

Checksum

90d3f914e5701538403d2ddbdee11e56

Download

Share

COinS

Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .