University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 5-2015 Wide Band Embedded Slot Antennas for Biomedical, Harsh Environment, and Rescue Applications Yun Seo Koo University of Tennessee - Knoxville, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Biomedical Commons, and the Electromagnetics and Photonics Commons Recommended Citation Koo, Yun Seo, "Wide Band Embedded Slot Antennas for Biomedical, Harsh Environment, and Rescue Applications. " PhD diss., University of Tennessee, 2015. https://trace.tennessee.edu/utk_graddiss/3379 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Yun Seo Koo entitled "Wide Band Embedded Slot Antennas for Biomedical, Harsh Environment, and Rescue Applications." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Doctor of Philosophy, with a major in Electrical Engineering. Aly E. Fathy, Major Professor We have read this dissertation and recommend its acceptance: Syed K. Islam, Seddik M. Djouadi, Seung J. Baek Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) Wide Band Embedded Slot Antennas for Biomedical, Harsh Environment, and Rescue Applications A Dissertation Presented for the Doctor of Philosophy Degree The University of Tennessee, Knoxville Yun Seo Koo May 2015 Copyright © 2015 by Yun Seo Koo. All rights reserved. ii DEDICATION To my beloved son, Brandon Inhoe Koo (9.21 2012 ~ 12.6 2014) iii ACKNOWLEDGEMENTS I would like to express my deepest and sincere gratitude to my advisor, Dr. Aly E. Fathy for providing me the inspiration that led to the completion of this dissertation. His extensive experience, superior knowledge, and expertise in the field of RF and Microwaves, have been extremely helpful in solving various technical problems throughout my research. Furthermore, his continued support and patience helped me complete my PhD degree. I would like to extend my sincerest thanks to my beloved parents Yeon Geon Koo and Young-Sook Kang, without whose continued love and support throughout my entire life, I would not be able to complete this work. Special thanks to my wife Yun Hyung Choi and children Anthony, Brandon, Celine for their devoted love and patience for me throughout the years. I also wish to express my sincere thanks to my committee members, Dr. Syed Kamrul Islam, Dr. Seddik M. Djouadi, and Dr. Seung J. Baek for their support and great suggestions. Also, I would like to appreciate to Dr. Jeffrey Phillips, Dr. Robab Kazemi, Dr. Quanhua Liu to finish the hyperthermia applicator project and Dr. Richard Fink, Dr. Ahmad Hoorfar for helping me to design antennas under protection. Thanks also go to all my lab collaborators, IT staff, supervisors and colleagues Sungwoo Lee, Mohamed Awida, Yazhou Wang, Song Lin, Ki Ryung Shin, Essam Elkhouly, Reza Ghahremani, Haofei Wang, Lingyun Ren, Mohamed Saleh, William Rhodes, Justin Forbes and many others at the University of Tennessee. iv ABSTRACT For many designers, embedded antenna design is a very challenging task when designing embedded systems. Designing Antennas to given set of specifications is typically tailored to efficiently radiate the energy to free space with a certain radiation pattern and operating frequency range, but its design becomes even harder when embedded in multi-layer environment, being conformal to a surface, or matched to a wide range of loads (environments). In an effort to clarify the design process, we took a closer look at the key considerations for designing an embedded antenna. The design could be geared towards wireless/mobile platforms, wearable antennas, or body area network. Our group at UT has been involved in developing portable and embedded systems for multi-band operation for cell phones or laptops. The design of these antennas addressed single band/narrowband to multiband/wideband operation and provided over 7 bands within the cellular bands (850 MHz to 2 GHz). Typically the challenge is: many applications require ultra wide band operation, or operate at low frequency. Low frequency operation is very challenging if size is a constraint, and there is a need for demonstrating positive antenna gain. v TABLE OF CONTENTS CHAPTER I Introduction .................................................................................................. 1 1.1. Examples of Embedded Antennas .......................................................................... 4 1.1.1. Embedded Antennas in Concrete ................................................................. 4 1.1.2. Implantable Microstrip Antennas for Medical Implants .............................. 5 1.1.3. Antenna Embedded in Low Permittivity Metamaterial ............................... 8 1.1.4. Gain Enhanced of Embedded Microstrip Antennas ................................... 11 1.1.5. 2.4GHz printed antennas embedded in small UAV wings ......................... 13 1.2. Examples of Embedded Antennas ........................................................................ 16 1.2.1. Example I: Antenna for Hyperthermia Treatment ..................................... 17 1.2.2. Example II: Embedded Antenna in Harsh Environment ............................ 17 1.2.3. Example III: Antennas for Vital Sign Detection through Debris and Rubbles ....................................................................................................... 18 1.3. Challenges in Designing Embedded Antennas and systems................................. 20 1.4. Contributions in Designing Embedded Antennas and Systems ............................ 21 CHAPTER II Development of a High SAR Conformal Antenna for Hyperthermia Tumors Treatment ..................................................................................... 22 2.1. Examples of Embedded Antennas ........................................................................ 22 2.2.1 Hyperthermia Treatment ............................................................................ 22 2.2. Hyperthermia Research by RF Engineers ............................................................. 23 2.2.1 IMS Frequency Band for Hyperthermia Treatment ................................... 23 2.3. Properties of Tissues ............................................................................................. 24 2.4. Hyperthermia Antenna Development ................................................................... 27 2.4.1. Hyperthermia Antenna Requirement .......................................................... 27 2.4.2. State of Art ................................................................................................. 28 2.5. Antenna Design for Hyperthermia Applicator ...................................................... 34 2.5.1. Hyperthermia Antenna Requirement .......................................................... 35 2.5.2. Microwave Hyperthermia Control Unit ..................................................... 38 2.5.3. Phantom Tissue Model ............................................................................... 42 2.5.4. Methodology .............................................................................................. 42 2.6. Antenna Design for Hyperthermia Applicator ...................................................... 43 2.6.1. Return Loss ................................................................................................. 43 2.6.2. Electric Field Patterns ................................................................................ 46 2.6.3. SAR Patterns .............................................................................................. 48 2.6.4. Effects of Patches within the Slot of the Conformal Antennas .................. 50 2.6.5. Effects of Body Curvature .......................................................................... 52 2.7. Conclusion ............................................................................................................ 54 CHAPTER III Wideband Embedded Slot Antenna .......................................................... 56 3.1. Background ........................................................................................................... 56 3.1.1. Survey of Low Profile Antennas ................................................................ 56 3.1.2. Slot Antennas as a Viable Candidate ......................................................... 59 3.2. Microstrip Slot Antennas ...................................................................................... 60 3.3. Our Proposed Solution and their advantages ........................................................ 66 3.3.1. Antenna Structure ....................................................................................... 66 vi 3.3.2. Parametric Study ........................................................................................ 69 3.4. Numerical and Experimental Results .................................................................... 76