Abstract-In this paper, inkjet-printed UHF and microwave circuits fabricated on paper substrates are investigated for the first time as an approach that aims for a system-level solution for fast and ultra-low-cost mass production. First, the RF characteristics of the paper substrate are studied by using the microstrip ring resonator in order to characterize the relative permittivity ( ) and loss tangent (tan ) of the substrate at the UHF band for the first time reported. A UHF RFID tag module is then developed with the inkjet-printing technology, proving this approach could function as an enabling technology for much simpler and faster fabrication on/in paper. Simulation and well-agreed measurement results, which show very good agreement, verify a good performance of the tag module. In addition, the possibility of multilayer RF structures on a paper substrate is explored, and a multilayer patch resonator bandpass filter demonstrates the feasibility of ultra-low-cost 3-D paper-on-paper RF/wireless structures.

loss tangent measurements 8 2.3 Liquid Crystal Polymer: Properties and benefits for RF Applications 9 2.4 Summary 10 CHAPTER 3: CONDUCTIVE INK-JET PRINTING RF MODULES 11 3.1 Conductive ink-jet printing technique 11 3.2 Curing of Conductive Ink 12 CHAPTER 4: BENCHMARKING PROTOTYPES 14 4.1 RFID Antenna Design Challenges 14 4.2 Serial Stub Feeding Structures for RFID Antenna 15 4.2.1 Design Approach 15 4.2.2 Antenna circuit modeling 19 4.2.3 Measurement Results and Discussion 22 4.2.4 Effect on Antenna parameters when placed on 24 Common Packaging Materials 4.3 Bowtie T-match RFID Antenna 27 v 4.3.1 Design Approach 4.3.2 Results and Discussion 4.4 Monopole Antenna 4.4.1 Design Approach 4.4.2 Results and Discussion 4.4.3 Antenna Gain Measurement 4.5 RFID/Sensor Integration CHAPTER 5: CONCLUSION REFERENCES vi

Abstract-In this letter, a novel electromagnetic band-gap structure (EBG) with single-ring resonators is inkjet-printed on the commercially available photo paper using conductive nano-silver ink. The printed EBG array is placed above a copper sheet, forming an artificial magnetic conductor (AMC) reflector at the designed frequency range (2.4 2.5 GHz). A microstrip monopole antenna is backed with the designed AMC reflector and is tested in free space and in contact with a human phantom. The antenna gain of a conventional microstrip monopole on human phantom is as low as 9 dBi. The gain of the proposed AMC backed monopole, measured on a human phantom is 0.95 dBi. The measurements demonstrate superior performance of the proposed monopole with EBG array compared to a conventional microstrip monopole antenna when they are considered for wearable applications.Index Terms-Artificial magnetic conductor (AMC), electromagnetic band-gap (EBG) structure, inkjet printing, personal area networks (PANs), wearable antenna, wireless body area networks (WBANs).

| This paper discusses the evolution towards the first integrated radio-frequency identification (RFID)-enabled wireless sensor network infrastructure using ultra-high frequency/ radio frequency (UHF/RF) RFID-enabled sensor nodes and inkjetprinted electronics technologies on flexible and paper substrates for the first time ever. The first sections highlight the unique capabilities of inkjet printed electronics as well as the benefits of using paper as the ultra-low-cost, conformal and environmentally friendly substrate for the mass-scale ubiquitous implementation of the first RFID-enabled wireless sensing applications.Various inkjet-printed antenna configurations are presented for enhanced-range compact RFID-enabled sensing platforms in Brugged[ environments up to 7 GHz, followed by the discussion of their 2-D integration with integrated circuit (IC) and sensors on paper. This integration is extended to a power-scavenging Bsmart-shoe[ batteryless integrated RFID module on paper that could be used for autonomous wearable sensing applications with enhanced range. The paper concludes discussing the details for establishing for the first time an asynchronous wireless link between the aforementioned RFID-tags and a widely used commercial wireless sensor network (WSN) mote using a simplified protocol; a paramount step that could potentially create ubiquitous ultra-low-cost sensor networks and large-scale RFID implementations eliminating the need of expensive RFID reader infrastructure and linking RFIDs to the mature level of WSNs.

Abstract-For the first time, we demonstrate the feasibility of realizing ultrawideband antennas through ink-jetting of conductive inks on commercially available paper sheets. The characterization of the conductive ink as well as of the electrical properties of the paper substrate are reported for frequencies up to 10 GHz. This letter is one step further toward the development of low-cost, environment-friendly conformal printed antennas/electronics for ad hoc wireless sensor networks operating in rugged environments.