Syed Abdullah Nauroze

A Novel Solar and Electromagnetic Energy Harvesting System With a 3-D Printed Package for Energy Efficient Internet-of-Things Wireless Sensors

This paper discusses the design of a novel dual (solar + electromagnetic) energy harvesting powered communication system, which operates at 2.4 GHz ISM band, enabling the autonomous operation of a low power consumption power management circuit for a wireless sensor, while featuring a very good “cold start” capability. The proposed harvester consists of a dual port rectangular slot antenna, a 3-D printed package, a solar cell, an RF-dc converter, a power management unit (PMU), a microcontroller unit, and an RF transceiver. Each designed component was characterized through simulation and measurements. As a result, the antenna exhibited a performance satisfying the design goals in the frequency range of 2.4–2.5 GHz. Similarly, the designed miniaturized RF-dc conversion circuit generated a sufficient voltage and power to support the autonomous operation of the bq25504 PMU for RF input power levels as low as −12.6 and −15.6 dBm at the “cold start” and “hot start” condition, respectively. The experimental testing of the PMU utilizing the proposed hybrid energy harvester confirmed the reduction of the capacitor charging time by 40% and the reduction of the minimum required RF input power level by 50% compared with the one required for the individual RF and solar harvester under the room light irradiation condition of 334 lx.

Additively Manufactured RF Components and Modules: Toward Empowering the Birth of Cost-Efficient Dense and Ubiquitous IoT Implementations

In this review, the particular importance and associated opportunities of additively manufactured radiofrequency (RF) components and modules for Internet of Things (IoT) and millimeter-wave ubiquitous sensing applications is thoroughly discussed. First, the current advances and capabilities of additive manufacturing (AM) tools are presented. Then, completely printed chipless radio-frequency identification (RFID) systems, and their current capabilities and limitations are reported. The focus is then shifted toward more complex backscattering energy autonomous RF structures. For each of the essential components of these structures, that encompass energy harvesting and storage, backscattering front ends, passive components, interconnects, packaging, shape-chaging (4-D printed) topologies and sensing elements, current trends are described and representative stateof- the-art examples reported. Finally, the results of this analysis are used to argue for the unique appeal of AM RF components and systems toward empowering a technological revolution of costefficient dense and ubiquitous IoT implementations.

3D printed reconfigurable helical antenna based on microfluidics and liquid metal alloy

This paper demonstrates a new approach to build 3D reconfigurable antennas at an extremely low cost and the first 3D printed reconfigurable helical antenna based on microfluidics and liquid metal alloy (LMA). With the fused deposition modeling (FDM) 3D printing technique, 3D microfluidic channel can be fabricated in a short production cycle cost-effectively. EGaIn, a non-toxic LMA, is filled into a 3D printed helix channel and form the helical antenna. As the gain of the antenna is determined by the number of turns of the helix which is controlled by the volume of LMA, the gain of the antenna can be tuned when needed. A more than 4 dB gain increase around 5 GHz is measured with the prototype when the number of turns of helix increases from 2 to 8 (0.2 mL LMA volume change), which demonstrates the reconfigurability of the proposed helical antenna.

Inkjet-printed substrate integrated waveguides (SIW) with “drill-less” vias on paper substrates

In this paper, an inkjet-printed substrate integrated waveguide (SIW) on commercially available cellulose paper is implemented for the first time. Unlike traditional inkjet-printed SIWs, it does not require any etching process to form the conductive side walls and utilizes the porosity of the paper to get through-substrate conduction. The frequency response of the waveguide along with its performance under bending is discussed in this paper, verifying that such a structure would be particularly suitable for Quality of Life and Internet of Things applications.

Novel 3D-printed “Chinese fan” bow-tie antennas for origami/shape-changing configurations

This paper presents a novel approach to realize 3D-printed flexible reconfigurable antennas, along with a proof-of-concept tunable bow-tie antenna inspired from Chinese origami fan. Stereolithography (SLA) printing, a low-cost high-performance additive manufacturing technique, is utilize to enable the easy fabrication of origami structure prototypes and the structure is metallized using a liquid metal alloy (LMA) to facilitate folding without breakages. The proposed bow-tie antenna features a frequency tuning range from 896 MHz to 992 MHz and bandwidth reconfigurability. This reconfigurable antenna can be applied to various dynamically changing scenarios such as wireless communications, collapsible/portable radars, wearable applications.

On-package mm-wave FSS integration with 3D-printed encapsulation

This work outlines the design, simulation, and fabrication of a millimeter-wave (mm-wave) frequency selective surface (FSS) integrated directly onto a 3D-printed die encapsulation. The cross-shaped slot FSS is designed to function as a bandpass filter centered at 77 GHz for on-package tunability. Stereolithography (SLA) 3D printing is used to fabricate encapsulations for silicon dies attached to a metallic QFN leadframe. Surface profilometry is used to assess the roughness of the SLA-printed surfaces, yielding roughness 25× lower than standard fused deposition modeling (FDM) 3D printing techniques. Finally, inkjet printing is used in a post-process fashion to fabricate the package-integrated FSS directly onto a 3D-printed die encapsulation as a proof-of-concept demonstration.

Novel 3D printed liquid-metal-alloy microfluidics-based zigzag and helical antennas for origami reconfigurable antenna “trees”

The first-of-its-kind origami antenna “tree” model is introduced in this paper, enabling the integration of multiple 3D antennas with a minimal interference and an on-demand reconfigurability of frequency, polarization and radiation pattern to optimize performance in dynamically changing environments. EGaIn, a liquid metal alloy(LMA) is used to switch between antennas and to enable flexible implementations. An origami structure, the zipper tube, coupled with Voronoi topology implementations is utilized as the scaffolding structure facilitating the mechanical tuning of the radiation pattern while minimizing storage requirements. The “tree” was fabricated by 3D printing, enabling on-demand fast-prototyping and low-cost manufacturing. A proof-of-concept two-antennas “tree” (zigzag/helical antenna) was presented, featuring a dual-band (3GHz/5GHz) operability and different polarizations (linear/circular) along with varying radiation patterns with “tree” compression. The “tree” can be applied to various dynamically changing scenaria such as wireless communications, collapsible/portable radars, satellite communications, while it can also realize numerous other reconfigurable RF components, such as filters, reflectors and shielding structures.

Inkjet-printed “4D” tunable spatial filters using on-demand foldable surfaces

A state-of-the-art fully Inkjet-printed tunable frequency selective surface on cellulose paper is presented, which uses a Miura origami structure for an on-demand linear variation in inter-element distance and the effective length of the resonant dipole elements, resulting in an observable shift in the operational frequency of the structure. The dipole elements are placed on the foldlines along with special “bridge-like” structures to realize first-of-its-kind truly flexible conductive traces over sharp bends. Simulation and measurement results show that the Miura-FSS can be tuned to a wide range of frequencies and features a large angle of incidence rejection.

Additive manufacturing technologies for near-and far-field energy harvesting applications

This paper reviews the fabrication and design of two different types of energy harvesting systems, that utilize ambient energy to power up connected wireless modules. A 3D/inkjet-printed origami-style (morphing) cube with orthogonally-placed patch antennas is presented which enhances the nodes diversity reception capabilities. The cube changes its shape upon heating up to 60°C. In contrast, the presented near-field energy harvester utilizes the ambient RF energy of a handheld two-way radio to convert the RF signal with an efficiency of 82.5%. For proof-of-concept purposes, an E-field energy harvesting receiver is fabricated on a flexible LCP substrate with inkjet printing technology featuring an open-circuit voltage of 17.87V for an output power of 43.2 mW for the E-field energy harvester placed 7 cm away from a 1W Walkie-Talkie transmitter.

A novel printed stub-loaded square helical antenna

A novel planar printed stub-loaded square helical (PSLSH) antenna is presented for 2.4GHz WLAN applications. Unlike conventional stub loaded helical (SLH) antennas, the input impedance of the proposed antenna is real. Therefore, a simple quarter-wave transformer can be used to match this antenna. Simulation results show that the antenna has a maximum gain of 10 dBi, a front-to-back ratio of 12dbi, a 70° half-power beam width and a good axial ratio. The volume of PSLSH antenna is 75% less than conventional axial mode helical antennas and 17% less than SLH antennas. Furthermore, the usable bandwidth of PSLSH antenna (46%) is significantly higher compared to SLH antenna (10%).