HIGH DATA RATE RADIO TRANSMITTER FOR CUBE SATELLITES by Peter Brent Henderson A project submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Electrical Engineering Approved: ________________________ ________________________ Dr. Jacob Gunther Dr. Reyhan Baktur Major Professor Committee Member ________________________ Dr. Bedri Cetiner Committee Member UTAH STATE UNIVERSITY Logan, Utah 2009 ii Copyright © Peter Brent Henderson 2009 All Rights Reserved iii ABSTRACT High Data Rate Radio Transmitter for Cube Satellites by Peter Brent Henderson, Master of Science Utah State University, 2009 Major Professor: Dr. Jacob Gunther Department: Electrical and Computer Engineering There is a growing interest among universities and industry in the field of Cube Satellites (CubeSats). These are very small satellites, about the size of a shoebox, which can be launched into space at a much lower cost than typical large satellites. CubeSats are generally low earth orbit (LEO) satellites, which mean they orbit at about 500 km above earth. Due to the small nature of these satellites, large, powerful radio communication links cannot be used. This is becoming an increasing constraint on the abilities of CubeSats. This report describes the research, design, and implementation of a high data rate downlink radio for CubeSat systems. Such a downlink connection will allow for a much larger library of payload options for these CubeSat systems. The implementation of a high data rate downlink has the science and university communities interested as well as the government and many commercial industries. This report presents the design of a transceiver system based on a common radio iv transmitter design. In the following chapters, the process of selecting various components with a goal to minimize overall power consumption and physical size, while maximizing transmitter power, is discussed. The design of a prototype transceiver system is detailed, and the results from various tests on the system are presented. (94 pages) v ACKNOWLEDGMENTS More than just my own efforts have gone into making this project not only a success, but possible. I am truly grateful for the opportunity that Dr. Gunther offered me to work on this project and to assume such a critical role in this project’s success. His council and guidance, as well as his trust in my engineering decisions, have made this project not only very educational, but exciting and enjoyable. I am also grateful for the support and assistance from the staff and other professors in the Electrical and Computer Engineering Department at Utah State University. I am especially grateful to Heidi Harper who would bend over backwards to insure I have the proper equipment for this project. Justin Hamm and Trent Johnson also aided in every way possible to provide updated computer equipment, cables, and other technical supplies and software. It was also nice to work with Mary Lee Anderson through all the graduate hoops relative to satisfying the graduate requirements. I would like to thank Microwave Vector for their generous donation of two band pass filters for this project. The assistance provided by my mother, Lael Henderson, has also played a critical role in all of my education. Not only her prayers and continual concern, but also her direct financial assistance has made going to graduate school and supporting a family at the same time possible. I am truly grateful for her love, never ending encouragement, and faith in my school efforts. Last, I would like to acknowledge the fact that not only all of my graduate work, vi but also my undergraduate work, would not have been possible without the patience and direct assistance by my wife, Emily. I hope that through this schooling effort, all of her efforts in raising two children with minimal presence of their father will pay off. I look forward to only having one full-time job and being able to focus my evenings and weekends not on school work, but on my family, catching up on the last five years of their lives, as well as being there for each new and exciting event to come in their lives. Peter Henderson vii CONTENTS Page ABSTRACT ....................................................................................................................... iii ACKNOWLEDGMENTS .................................................................................................. v! LIST OF TABLES ............................................................................................................. xi! LIST OF FIGURES .......................................................................................................... xii LIST OF ACRONYMS ................................................................................................... xiv CHAPTER ! 1. INTRODUCTION .........................................................................................................1 A. Background of Cube Satellites.................................................................................1 B. Need for Higher Rate Downlinks ............................................................................5 C. Project Proposal .......................................................................................................6 D. Chapter Overview ....................................................................................................6 2. PROJECT OVERVIEW ................................................................................................8 A. High-Level System Design ......................................................................................8 1) Adopted Transmitter Methodology ....................................................................8 2) Goals of Transmitter Design ............................................................................10 3) Board Layout ...................................................................................................11 B. Project Timeline .....................................................................................................11 1) Proof of Concept ..............................................................................................11 2) Flow of Project .................................................................................................12 3) Gantt Chart .......................................................................................................12 3. RESEARCH AND INITIAL EFFORTS .....................................................................14 A. Component Selection .............................................................................................14 viii 1) Objectives and Design Requirements ..............................................................14 2) Available Components .....................................................................................15 a) Maxim Integrated Circuits .........................................................................15 b) Analog Devices Incorporated ....................................................................17 3) Decision Matrix on Component Selection .......................................................18 4) Additional Components Required ....................................................................18 5) Carrier Frequency Selection ............................................................................22 B. Evaluation Kits .......................................................................................................24 C. Test Equipment and Software Packages ................................................................24 1) Lab Equipment .................................................................................................24 2) AFE Viewer Design .........................................................................................25 3) Software ...........................................................................................................29 4. DESIGN .......................................................................................................................31 A. RFIC Subsystem Design ........................................................................................31 1) Power ...............................................................................................................32 2) RF Considerations ............................................................................................33 3) Additional Circuits Required for Operation ....................................................33 B. AFE Subsystem Design .........................................................................................34 1) Power ...............................................................................................................35 2) RF Considerations ............................................................................................36 3) Digital Considerations .....................................................................................36 4) Additional Circuits Required for Operation ....................................................36 C. PAD Subsystem Design .........................................................................................37 D. PA Subsystem Design ............................................................................................38 E. RF Switch Subsystem Design ................................................................................38 F. Band Pass Filter Selection .....................................................................................39 G. Power Subsystem Design .......................................................................................40 1) Power Supply Requirements ............................................................................40 2) Initial EMI Considerations ...............................................................................42 H. Full RFFE System Design .....................................................................................42 1) Overall Design .................................................................................................42 ix 2) Schematic .........................................................................................................44 3) PCB Layout ......................................................................................................45 I. Antenna Selection ..................................................................................................46 J. Adapter Board Design ............................................................................................46 5. RESULTS ....................................................................................................................48 A. Evaluation Kit Results ...........................................................................................48 1) Individual .........................................................................................................48 a) RFIC ...........................................................................................................48 b) AFE ............................................................................................................52 c) PAD............................................................................................................57 d) PA ..............................................................................................................58 e) RF Switch...................................................................................................60 2) Joint ..................................................................................................................60 B. RF Frontend CCA ..................................................................................................64 1) Manufacturing ..................................................................................................64 2) Operational Findings ........................................................................................68 3) Performance Measurements .............................................................................69 6. CLOSING ....................................................................................................................71 A. Conclusion .............................................................................................................71 1) TX Power .........................................................................................................71 2) Overall System Power ......................................................................................71 B. Future .....................................................................................................................71 1) Changes for Following Revisions ....................................................................71 2) Remaining Work to Be Done ...........................................................................73 REFERENCES ..................................................................................................................74 APPENDIX ........................................................................................................................78 APPENDIX: DATA CD ....................................................................................................79 x A. AFE Viewer Software ............................................................................................79 B. RFFE Schematic ....................................................................................................79 C. RFFE PCB Layout .................................................................................................79 D. Adapter Board Schematic ......................................................................................79 E. Adapter Board PCB Layout ...................................................................................79