More Like this

1. 2D titanium carbide (MXene) for wireless communication

   https://doi.org/10.1126/sciadv.aau0920  

   Sarycheva, Asia ; Polemi, Alessia ; Liu, Yuqiao ; Dandekar, Kapil ; Anasori, Babak ; Gogotsi, Yury ( September 2018 , Science Advances)

   null (Ed.)

   With the development of the Internet of Things (IoT), the demand for thin and wearable electronic devices is growing quickly. The essential part of the IoT is communication between devices, which requires radio-frequency (RF) antennas. Metals are widely used for antennas; however, their bulkiness limits the fabrication of thin, lightweight, and flexible antennas. Recently, nanomaterials such as graphene, carbon nanotubes, and conductive polymers came into play. However, poor conductivity limits their use. We show RF devices for wireless communication based on metallic two-dimensional (2D) titanium carbide (MXene) prepared by a single-step spray coating. We fabricated a ~100-nm-thick translucent MXene antenna with a reflection coefficient of less than −10 dB. By increasing the antenna thickness to 8 μm, we achieved a reflection coefficient of −65 dB. We also fabricated a 1-μm-thick MXene RF identification device tag reaching a reading distance of 8 m at 860 MHz. Our finding shows that 2D titanium carbide MXene operates below the skin depth of copper or other metals as well as offers an opportunity to produce transparent antennas. Being the most conductive, as well as water-dispersible, among solution-processed 2D materials, MXenes open new avenues for manufacturing various classes of RF and other portable, flexible, and wearable electronic devices. 

   more » « less
2. Flexible and Stretchable Antennas for Biointegrated Electronics

   https://doi.org/10.1002/adma.201902767  

   Xie, Zhaoqian ; Avila, Raudel ; Huang, Yonggang ; Rogers, John A. ( September 2019 , Advanced Materials)

   Combined advances in material science, mechanical engineering, and electrical engineering form the foundations of thin, soft electronic/optoelectronic platforms that have unique capabilities in wireless monitoring and control of various biological processes in cells, tissues, and organs. Miniaturized, stretchable antennas represent an essential link between such devices and external systems for control, power delivery, data processing, and/or communication. Applications typically involve a demanding set of considerations in performance, size, and stretchability. Some of the most effective strategies rely on unusual materials such as liquid metals, nanowires, and woven textiles or on optimally configured 2D/3D structures such as serpentines and helical coils of conventional materials. In the best cases, the performance metrics of small, stretchable, radio frequency (RF) antennas realized using these strategies compare favorably to those of traditional devices. Examples range from dipole, monopole, and patch antennas for far‐field RF operation, to magnetic loop antennas for near‐field communication (NFC), where the key parameters include operating frequency,Qfactor, radiation pattern, and reflection coefficientS₁₁across a range of mechanical deformations and cyclic loads. Despite significant progress over the last several years, many challenges and associated research opportunities remain in the development of high‐efficiency antennas for biointegrated electronic/optoelectronic systems.

    

   more » « less
3. A Gel‐Free Ti 3 C 2 T x ‐Based Electrode Array for High‐Density, High‐Resolution Surface Electromyography

   https://doi.org/10.1002/admt.202000325  

   Murphy, Brendan B. ; Mulcahey, Patrick J. ; Driscoll, Nicolette ; Richardson, Andrew G. ; Robbins, Gregory T. ; Apollo, Nicholas V. ; Maleski, Kathleen ; Lucas, Timothy H. ; Gogotsi, Yury ; Dillingham, Timothy ; et al ( June 2020 , Advanced Materials Technologies)

   Wearable sensors for surface electromyography (EMG) are composed of single‐ to few‐channel large‐area contacts, which exhibit high interfacial impedance and require conductive gels or adhesives to record high‐fidelity signals. These devices are also limited in their ability to record activation across large muscle groups due to poor spatial coverage. To address these challenges, a novel high‐density EMG array is developed based on titanium carbide (Ti₃C₂T_x) MXene encapsulated in parylene‐C. Ti₃C₂T_xis a 2D nanomaterial with excellent electrical, electrochemical, and mechanical properties, which forms colloidally stable aqueous dispersions, enabling safe, scalable solutions‐processing. Leveraging the excellent combination of metallic conductivity, high pseudocapacitance, and ease of processability of Ti₃C₂T_xMXene, the fabrication of gel‐free, high‐density EMG arrays is demonstrated, which are ≈8 µm thick, feature 16 recording channels, and are highly skin conformable. The impedance of Ti₃C₂T_xelectrodes in contact with human skin is 100–1000× lower than the impedance of commercially available electrodes which require conductive gels to be effective. Furthermore, the arrays can record high‐fidelity, low‐noise EMG, and can resolve muscle activation with improved spatiotemporal resolution and sensitivity compared to conventional gelled electrodes. Overall, the results establish Ti₃C₂T_x‐based bioelectronic interfaces as a powerful platform technology for high‐resolution, noninvasive wearable sensing technologies.

    

   more » « less
4. A Direct-Conversion Digital Beamforming Array Receiver with 800 MHz Channel Bandwidth at 28 GHz using Xilinx RF SoC

   Sravan Pulipati, Viduneth Ariyarathna ( November 2019 , 2019 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems (COMCAS))

   null (Ed.)

   This paper discusses early results associated with a fully-digital direct-conversion array receiver at 28 GHz. The proposed receiver makes use of commercial off-the-shelf (COTS) electronics, including the receiver chain. The design consists of a custom 28 GHz patch antenna sub-array providing gain in the elevation plane, with azimuthal plane beamforming provided by real-time digital signal processing (DSP) algorithms running on a Xilinx Radio Frequency System on Chip (RF SoC). The proposed array receiver employs element-wise fully-digital array processing that supports ADC sample rates up to 2 GS/second and up to 1 GHz of operating bandwidth per antenna. The RF mixed-signal data conversion circuits and DSP algorithms operate on a single-chip RFSoC solution installed on the Xilinx ZCU1275 prototyping platform. 

   more » « less
5. Design of a Compact 24 GHz Antenna Array for Unmanned Aerial Vehicle-to-Vehicle (V2V) Communication

   Kakaraparty, Karthik ; Roy, Sunanda ; Mahbub, Ifana ( September 2022 , 2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (AP-S/URSI))

   This paper presents the design of a compact 4 × 4 antenna array suitable for unmanned aerial vehicle-to-vehicle (V2V) communication applications. The proposed antenna array can offer a narrow beamwidth, high gain, wide beam steering capability and is highly compact. The substrate material used is Rogers 5880 with a thickness of 0.2 mm, and copper is used for the patch and ground material with 0.14 mm thickness. The di-electric constant and the tangent loss of the Rogers substrate are 2.2 and 0.0004, respectively. 45° phase shifters are incorporated in the feeding paths to facilitate the beamsteering. The dimensions of the proposed antenna array are 32 × 32 × 0.48 mm 3 . The designed antenna array has the resonating frequency at 24 GHz and has a bandwidth of 0.83 GHz (3.5% fractional bandwidth). The measured far field gain of the designed antenna array is 16.7 dBi. The beamwidth derived from the array’s far-field radiation pattern is 14.6°, and the maximum beam steering range of the array is 102° along the θ axis. 

   more » « less