DEVELOPMENT OF MICROWAVE/MILLIMETER-WAVE ANTENNAS AND PASSIVE COMPONENTS ON MULTILAYER LIQUID CRYSTAL POLYMER (LCP) TECHNOLOGY A Thesis Presented to The Academic Faculty by Ramanan Bairavasubramanian In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of Electrical and Computer Engineering Georgia Institute of Technology May 2007 DEVELOPMENT OF MICROWAVE/MILLIMETER-WAVE ANTENNAS AND PASSIVE COMPONENTS ON MULTILAYER LIQUID CRYSTAL POLYMER (LCP) TECHNOLOGY Approved by: Dr. John Papapolymerou, Advisor Dr. Bernard Kippelen School of Electrical and Computer School of Electrical and Computer Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. John Cressler Dr. George Papaioannou School of Electrical and Computer School of Sciences Engineering University of Athens (Greece) Georgia Institute of Technology Dr. Andrew Peterson Date Approved: 30 March 2007 School of Electrical and Computer Engineering Georgia Institute of Technology To my parents iii ACKNOWLEDGEMENTS Thisresearchwouldnothavebeenpossiblewithouttheguidance, help, support, andfriend- ship of many people at different stages, to whom I owe a huge debt of gratitude. I express my sincerest thanks to: • My parents, Bairavasubramanian and Meenakshi, and my sister, Lavanya, for their unending love, support, patience, and encouragement • My uncle and aunt, Viswanathan and Vasanthi, for their love and for helping me to shape my career • My adviser, Prof. Papapolymerou, for his guidance on various research problems, for garnering financial support, and for constantly encouraging to strive for the best • Prof. Cressler,Prof. Peterson,Prof. Kippelen,andProf. Papaioannou,forservingon my defense committee, and for their evaluations and suggestions that helped improve this work • Dr. Ponchak, for his help with antenna measurements • Prof. Tentzeris, Prof. Laskar, Dr. Pinel and their research groups for their collabo- ration on certain sections of this research • Friends and colleagues for their help, support, fellowship, and for the many stress- relieving hours of pointless discussions • The staff of ECE, GEDC, and MiRC cleanroom, for their administrative and opera- tional assistance iv TABLE OF CONTENTS DEDICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x LIST OF SYMBOLS AND ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . xv SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xviii I INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Trends in wireless systems . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 SoC Vs SoP approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.3 SoP material technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.4 Liquid crystal polymer technology . . . . . . . . . . . . . . . . . . . . . . 6 1.5 Object of this thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.6 Contributions and organization . . . . . . . . . . . . . . . . . . . . . . . . 8 II DUAL-FREQUENCY/DUAL-POLARIZATION PATCH ANTENNA ARRAYS 10 2.1 Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.2 Overview of the existing technology . . . . . . . . . . . . . . . . . . . . . 11 2.3 Microstrip-fed patch antenna arrays . . . . . . . . . . . . . . . . . . . . . 13 2.3.1 Array design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.3.2 LCP multilayer fabrication . . . . . . . . . . . . . . . . . . . . . . 16 2.3.3 Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2.4 Aperture-coupled patch antenna arrays . . . . . . . . . . . . . . . . . . . 22 2.4.1 Array design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2.4.2 Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.4.3 Efficiency calculations . . . . . . . . . . . . . . . . . . . . . . . . . 31 2.5 Polarization-reconfigurable antenna arrays using RF MEMS switches . . 33 2.5.1 MEMS characteristic features. . . . . . . . . . . . . . . . . . . . . 34 2.5.2 MEMS-integrated array design . . . . . . . . . . . . . . . . . . . . 34 2.5.3 MEMS fabrication . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 v 2.5.4 Results and discussions . . . . . . . . . . . . . . . . . . . . . . . . 39 2.6 Chapter summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 III SINGLE LAYER MICROSTRIP LOW-PASS AND BAND-PASS FILTERS . . 42 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 3.2 Low-pass filters using stepped impedance resonators . . . . . . . . . . . . 43 3.2.1 Lumped element design . . . . . . . . . . . . . . . . . . . . . . . . 43 3.2.2 Lumped element-microstrip transformation . . . . . . . . . . . . . 45 3.2.3 Measurements and discussions . . . . . . . . . . . . . . . . . . . . 47 3.3 Band-pass filters using folded open-loop resonators . . . . . . . . . . . . . 52 3.3.1 Coupling matrix synthesis. . . . . . . . . . . . . . . . . . . . . . . 52 3.3.2 Filter specifications and design . . . . . . . . . . . . . . . . . . . . 55 3.3.3 Experimental results . . . . . . . . . . . . . . . . . . . . . . . . . . 61 3.3.4 Unloaded quality factor calculations . . . . . . . . . . . . . . . . . 64 3.4 Chapter summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 IV MULTILAYER MICROSTRIP BAND-PASS FILTERS . . . . . . . . . . . . . 70 4.1 Modular filters using non-resonant nodes . . . . . . . . . . . . . . . . . . 71 4.1.1 Modular coupling scheme . . . . . . . . . . . . . . . . . . . . . . . 71 4.1.2 Multilayer design . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 4.1.3 Fabrication and measurements . . . . . . . . . . . . . . . . . . . . 75 4.2 Filters using dual-mode resonators . . . . . . . . . . . . . . . . . . . . . . 76 4.2.1 Coupling scheme and coupling matrix . . . . . . . . . . . . . . . . 78 4.2.2 Slotted patch resonator . . . . . . . . . . . . . . . . . . . . . . . . 78 4.2.3 Multilayer configuration . . . . . . . . . . . . . . . . . . . . . . . . 79 4.2.4 Fabrication and measurements . . . . . . . . . . . . . . . . . . . . 83 4.3 Chapter summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 V INTEGRATION OF PASSIVE CIRCUITS . . . . . . . . . . . . . . . . . . . . 86 5.1 V-band example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 5.1.1 Background. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 5.1.2 Duplexer development . . . . . . . . . . . . . . . . . . . . . . . . . 88 5.1.3 Antenna development . . . . . . . . . . . . . . . . . . . . . . . . . 92 vi 5.1.4 Duplexer/Antenna integration . . . . . . . . . . . . . . . . . . . . 96 5.2 X-band example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 5.2.1 Duplexer development . . . . . . . . . . . . . . . . . . . . . . . . . 99 5.2.2 Antenna development . . . . . . . . . . . . . . . . . . . . . . . . . 105 5.2.3 Duplexer/Antenna integration . . . . . . . . . . . . . . . . . . . . 107 5.3 Chapter summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 VI CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 APPENDIX A DUAL-BAND FILTERS . . . . . . . . . . . . . . . . . . . . . . . 112 APPENDIX B ASYMMETRIC MODULAR FILTERS . . . . . . . . . . . . . . . 117 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 vii LIST OF TABLES 2.1 Return loss characteristics of the 14 GHz microstrip-fed array. . . . . . . . . 19 2.2 Return loss characteristics of the 35 GHz microstrip-fed array. . . . . . . . . 20 2.3 Radiation pattern characteristics of the 14 GHz microstrip-fed array. . . . . 21 2.4 Radiation pattern characteristics of the 35 GHz microstrip-fed array. . . . . 21 2.5 Return loss characteristics of the 14 GHz aperture-coupled array. . . . . . . 29 2.6 Return loss characteristics of the 35 GHz aperture-coupled array. . . . . . . 30 2.7 Radiation pattern characteristics of the 14 GHz aperture-coupled array. . . 31 2.8 Radiation pattern characteristics of the 35 GHz aperture-coupled array. . . 31 2.9 Efficiency calculations of the 14 GHz aperture-coupled array. . . . . . . . . 32 2.10 Comparison between this work and other contemporary research on multi- layer antenna arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2.11 Switch configurations for the polarization-reconfigurable antenna array. . . 35 2.12 Comparison between this work and other contemporary research on recon- figurable antenna systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 3.1 Theoretical expression and value of the lumped elements . . . . . . . . . . . 45 3.2 Comparison of performances achieved from ideal lumped components, full wave simulations and measurements − C-band (Design 1) . . . . . . . . . . 49 3.3 Comparison of performances achieved from ideal lumped components, full wave simulations and measurements − X-band (Design 2) . . . . . . . . . . 49 3.4 Comparison of performances achieved from ideal lumped components, full wave simulations and measurements − Ka-band (Design 3) . . . . . . . . . 51 3.5 Comparison of performances achieved from ideal lumped components, full wave simulations and measurements − V-band (Design 4). . . . . . . . . . 51 3.6 Comparison of C-band filter performance reported in this work with other printed low-pass filter implementations available in the literature. . . . . . . 51 3.7 Performance specifications for the single-layer band-pass filter prototypes. . 56 3.8 Coupling elements for the prototypes with topology as in figure 3.10. . . . . 56 3.9 Physical dimensions of the single-layer band-pass filter prototypes. . . . . . 59 3.10 Simulated and measured S-parameter characteristics of the X-band prototype. 62 3.11 SimulatedandmeasuredS-parametercharacteristicsoftheKa-bandprototype. 63 3.12 Simulated and measured S-parameter characteristics of the V-band prototype. 63 viii 3.13 Q calculations for the X-band folded open-loop resonator based on simula- u tions with f0 = 10.07 GHz and β = 0.6951. . . . . . . . . . . . . . . . . . . 66 3.14 Q calculationsfortheX-bandfoldedopen-loopresonatorbasedonmeasure- u ments with f0 = 10.07 GHz and β = 0.6321. . . . . . . . . . . . . . . . . . 66 3.15 Q calculations for the Ka-band folded open-loop resonator based on simu- u lations with f0 = 35.35 GHz and β = 0.9361. . . . . . . . . . . . . . . . . . 68 3.16 Q calculations for the Ka-band folded open-loop resonator based on mea- u surements with f0 = 35.44 GHz and β = 0.8485. . . . . . . . . . . . . . . . 68 4.1 Elements of the coupling matrix. . . . . . . . . . . . . . . . . . . . . . . . . 74 4.2 Resonator Arrangement for the prototypes. . . . . . . . . . . . . . . . . . . 83 5.1 Applications that could utilize the V-Band. (taken from [91]) . . . . . . . . 87 5.2 Performance specifications for the V-band duplexer. . . . . . . . . . . . . . 89 5.3 Physical dimensions of the V-band patch antenna. . . . . . . . . . . . . . . 93 5.4 Physical dimensions of the V-band slotted patch antenna. . . . . . . . . . . 95 5.5 Performance specifications for the X-band duplexer. . . . . . . . . . . . . . 100 5.6 Coupling type and method utilized to realize the X-band duplexer. . . . . . 101 5.7 Physical dimensions of the X-band wide-slot antenna. . . . . . . . . . . . . 106 A.1 Comparison of full-wave simulation and measurement results for the dual- band filters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 A.2 Performance comparison of the dual-band WLAN filters implemented in this research with other published works. . . . . . . . . . . . . . . . . . . . . . . 116 B.1 Physical parameters of the designed second order filters with reference to Figure B.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 ix LIST OF FIGURES 1.1 Examples of convergent systems. . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Functionality segregation in a SoP-based RF system. . . . . . . . . . . . . . 3 1.3 Exploded pictorial representation of a typical SoP-based system. . . . . . . 3 1.4 Cross section of a typical SoP-based system. . . . . . . . . . . . . . . . . . . 4 1.5 LTCC-based multilayer module. . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 Generic multilayer architecture of the microstrip-fed antenna array. . . . . . 14 2.2 Topview(withalllayersinterlaced)ofthemicrostrip-fedantennaarray. The inset shows an enlarged portion of the feedline containing the 200 µm gap (on the left side branch of the main feedline). By moving the gap to the right ride branch, the polarization can be switched. The configuration shown here 0 will result in radiation patterns with E-field polarized along the 135 axis. . 15 2.3 Illustration of a typical LCP bonding process. . . . . . . . . . . . . . . . . . 17 2.4 Photo of the Karl-Suss wafer bonder. . . . . . . . . . . . . . . . . . . . . . . 17 2.5 Left: Photo of fabricated 2x1 microstrip-fed array. The 14 GHz array is not visible, as it is embedded. Right: Photo demonstrating flexibility. . . . . . . 18 2.6 Return loss - 14 GHz microstrip-fed array. . . . . . . . . . . . . . . . . . . . 19 2.7 Return loss - 35 GHz microstrip-fed array. . . . . . . . . . . . . . . . . . . . 20 2.8 2-D radiation patterns - 14 GHz microstrip-fed array. . . . . . . . . . . . . . 20 2.9 2-D radiation patterns - 35 GHz microstrip-fed array. . . . . . . . . . . . . . 21 2.10 Generic multilayer architecture of the aperture-coupled antenna array. . . . 23 2.11 Aperture-coupledantennaarray. Left: Topviewwithallthelayersinterlaced. Right: Sideview. ThethicknessoftheLCPsubstratesusedareh1 = 228µm; h2 = 127 µm; h3 = 102 µm. . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2.12 Development of the aperture-coupled array. Top Left: one-port ‘End Ele- ment’. Top Right: two-port ‘Any Element’. Bottom: Linear Array with one ‘End Element’ and one ‘Any Element’. Several such linear arrays can be combined using a corporate feed to form a planar array [Refer Fig. 2.11]. Theparallelfeedlinewithoutportsineachcaseisforexcitingtheorthogonal polarization making this a dual-polarization system. . . . . . . . . . . . . . 25 2.13 Simulated return loss of the ‘end element’ - 14 GHz array. . . . . . . . . . . 26 2.14 Simulated S-parameter characteristics of the ‘any element’ - 14 GHz. . . . . 27 2.15 Images of the fabricated aperture-coupled array. . . . . . . . . . . . . . . . 28 2.16 Return loss - 14 GHz aperture-coupled array. . . . . . . . . . . . . . . . . . 29 x