Research Terms
This neural implant device delivers deep brain stimulation and treatment drugs to specified neural targets to treat common neurological disorders. Neurological disorders afflict millions of people in the United States, with the most common disorder, epilepsy, affecting 3.4 million people. Deep brain stimulation can treat neurological disorders such as Parkinson’s disease, depression, epilepsy, and obsessive-compulsive disorder with some success. However, available deep-brain-stimulation electrode devices target anatomical regions but not specific neuronal tracts, and they do not have the ability to deliver drugs. Additionally, these deep-brain-stimulation electrode implants are not compatible with MRI scans, making monitoring of post-operative patients difficult.
Researchers at the University of Florida have developed a neural implant that can deliver deep brain stimulation and treatment drugs to specific neuronal tracts. This neural implant device, made entirely from carbon nanofiber and polymer, is MRI-compatible.
MRI-compatible neural implant that delivers targeted deep brain stimulation and therapeutics for neurological disorders
This neural implant device is an all-in-one, MRI-compatible implant with optical, electrical, microfluidic, and wireless functionalities used to treat neurological disorders. This device is composed entirely of carbon nanofiber and polymer, making it completely MRI-compatible. It incorporates optogenetics to selectively target genetically-defined populations of neurons for deep brain stimulation in vivo and has microfluidic channels that allow for precision drug delivery and sampling. Additionally, the device includes fluorescent microendoscopy, providing high resolution, real-time imaging of neurons in deep tissue. These features allow for the effective treatment of neurological disorders and provide unprecedented insights into the fields of neuroscience and neurodegeneration.
This cylindrical radial superlattice structure utilizes concentric alternating non-magnetic/magnetic layers to compose a low loss radio frequency conductor. Radio waves are used to transmit information in many devices including mobile phones, GPS, wireless internet, and television. When transmitting or receiving a signal, these devices must carry a radio frequency electric current through their circuits to translate radio signal into sound, video, or information. Unfortunately, high frequency currents cause magnetic interferences called the skin and proximity effects. These effects result in increased conductor loss and, therefore, more power consumption and signal loss, ultimately greatly reducing battery life in the mobile devices and deteriorating communication quality. Researchers at the University of Florida have developed a cylindrical radial superlattice structure composed of concentric alternating non-magnetic and magnetic layers for improved radio frequency resistance suppression. This alternating structure reduces the eddy current effect and the skin effect at the targeted frequency and allows the superlattice conductor to be used in manufacturing of low loss radio frequency components especially for 5G communication and millimeter wave applications.
Low resistance conductor improves performance of radio and microwave frequency transmissions
The cylindrical radial superlattice structure is composed of alternating concentric permalloy (i.e., nickel-iron, nickel-iron-cobalt, etc.) and non-permalloy (i.e., aluminum, copper, etc.) layers. The permalloy layers and non-permalloy layers are designed to produce negative permeability and positive permeability, respectively, at the target frequency. This results in an eddy current canceling effect, suppressing radio frequency conductor loss, and improving power efficiency and signal integrity.
This magnetic conductor uses a mixture of nanoscopic ferromagnetic and non-ferromagnetic materials to provide more tunable, wireless control and greater electrical conductivity for increased current flow. Ferromagnetic materials, when used as conductors, have dynamic frequency-dependent properties that can deliver a great degree of tunability to better control the conductors. However, they have much lower electrical conductivity than most commonly used conductor materials, limiting their utility as conductors.
Researchers at the University of Florida have designed a ferromagnetic conductor that uses a combination of ferromagnetic and non-ferromagnetic conductive metals in a lattice structure to provide a high degree of non-contact magnetic control. Furthermore, since it uses metals instead of semiconductors in the current flow layer, it can facilitate applications requiring a higher current.
Transconductor with magnetic field control for high-current applications
By combining ferromagnetic and non-ferromagnetic materials in a nano-superlattice structure, the magnetic field effect transconductor (M-FET) uses the properties of ferromagnetic metals without sacrificing conductivity. The non-contact magnetic field control of M-FET is more efficient than the traditional physical and electrical field control. Furthermore, M-FET's current flow layer uses a metal conductor rather than a semiconductor as in other conductors. Hence it is able to handle levels of current that are too high for a semiconductor. This higher level of current in turn, reduces relative noise.
This low-maintenance, passive wireless sensor uses a microelectromechanical system (MEMS) and radiofrequency waves to measure static and dynamic pressures accurately for applications in harsh environments, such as gas turbines. Many industries require pressure sensors that maintain accurate operation even when subject to severe environmental hazards. However, these harsh environments often damage the pressure sensors, which then demand regular maintenance. Notably, this problem occurs in high-temperature gas turbines, which are powered by the hot gases produced by burning fuel. Pressure fluctuations in the air flow across the turbine blades and vanes cause high cycle fatigue, the primary source of component failure in gas turbines. A sensor that can properly measure pressure in this harsh environment would better detect local pressure fluctuations and aid in preventing high cycle fatigue. Although optical sensors successfully measure pressure in harsh environments, they are quite expensive, use fragile filaments, and are difficult to package.
Researchers at the University of Florida have developed a sensor that functions wirelessly and passively to detect both static and dynamic pressure in high-temperature environments. The sensor can apply to a variety of applications requiring pressure measurement in the presence of high temperatures, such as gas turbines, jet engines, or nuclear power generators.
Passive wireless pressure sensor that maintains operation in extreme environments
This microelectromechanical system (MEMS) sensor is both passive, meaning no internal energy sources such as batteries are required, and wireless. A diaphragm on the sensor deflects either downward or upward based on the surrounding pressure. The sensor attaches to an area of interest and uses radio frequency electromagnetic signals to communicate the current pressure of the environment with a computer-based simulation that analyzes the signals to determine the area’s fluid flow. This sensor can determine both static and dynamic pressures and also can detect uncontrolled fluid flow early, preventing any damage to engines or other equipment.
This metaconductor skin combines multiple ferromagnetic and non-ferromagnetic layers into a flexible superlattice structure that wraps radiofrequency (RF) components such as conductors, transmission lines, 3-D antennas, or waveguides to improve signal integrity and power efficiency at high frequencies. The global market for RF components is projected to exceed $17.5 billion by 2022. As the growing number of electronic devices crowd out lower frequencies, new devices must increasingly operate within higher frequency bands in order to facilitate the high-speed, high-quality communications required by rising internet service demands. Due to the skin effect, however, resistance increases as operating frequencies increase. Conductors become less effective and suffer from poor signal integrity, leading to higher signal loss, noise, and longer circuitry delays that reduce the performance of electronic devices. Available conductors with reduced resistance and improved RF signal loss often use special alloy materials that require costly, complex production processes. Additionally, most resistance reduction by these conductors comes at frequencies below 10 GHz, which is not effective within the higher frequency spectra that promising future applications will operate, such as millimeter wave frequencies of over 30 GHz.
Researchers at the University of Florida have developed a flexible metaconductor skin that wraps around conductors and other interconnecting components to decrease resistance and signal loss in RF electronics used in high-frequency applications. The superlattice structure utilizes different ferromagnetic materials and dimensions in order to yield low resistance at targeted frequency ranges.
Flexible ferromagnetic or non-ferromagnetic superlattice structure that wraps around radiofrequency components in conductors, transmission lines, 3-D antennas, waveguides, and others to reduce signal loss at targeted frequency ranges
This flexible magnetic/non-magnetic substrate functions as a metaconductor by covering conducting or non-conducting radiofrequency (RF) components to provide conductors with superior signal integrity for Ku, K, Ka, and millimeter wave frequency broadband applications. The skin consists of multiple layers of ferromagnetic and non-ferromagnetic materials arranged in a nanoscale lattice structure. By cancelling out the magnetic flux generated by the alternating current flowing within, the skin eliminates the eddy current effect. Layers of the metaconductor skin wrap around a conductor, reducing the resistance in the conductor and significantly improving signal integrity and power efficiency.
This spherical monopole antenna with a tapered feeding line improves wireless data transmission quality. Antennas are used in a variety of devices, from surveillance to health monitoring systems. Although planar monopole antennas show good bandwidth performance, they suffer from loss of data (lossiness) in signals received and distortion in the signals transmitted. Available 3-D super wideband antennas (SWB) provide better omnidirectional signals, but are expensive to manufacture. Researchers at the University of Florida have developed a 3-dimensional wideband antenna capable of transmitting and receiving high quality data that is inexpensive to manufacture. This antenna can be applied in nearly any wireless data device or system, and is positioned to capture a large portion of the $31 billion telecommunications market.
Super wideband antenna with improved wireless signal transmission and reduced manufacturing costs
This spherical super wideband (SWB) monopole antenna consists of a conductive sphere as a main radiator, a tapered feeding line and a polyurethane mold. The diameter of the conductive sphere can be adjusted to determine the low frequency cutoff. The 3D tapered feeding line is fabricated using polyurethane and multidirectional UV lithography. Using the tapered feeding line between the coaxial and the sphere greatly enlarges the upper cutoff. By enlarging both the upper and lower cutoff ranges, UF researchers have created an SWB antenna that provides a better omnidirectional radiation pattern with low cost.
This nanoscale, multi-layer magnetic and non-magnetic superlattice functions as a low-loss, broad bandwidth radio or microwave frequency conductor, or metaconductor. The conduction loss of radio or microwave is greatly influenced by the conductivity of the materials. The industry of high performance and high-speed electronic devices is rapidly growing and places a great importance on operating efficiently at high frequencies. Researchers at the University of Florida have developed conductors composed of alternating nanometer-thick layers of magnetic and non-magnetic materials that lessen the effect eddy currents have on conductive loss. Experimental results show an improvement of more than three times in the figure of merit (frequency versus effective resistivity) as compared to devices available on the market. This metaconductor can be applied to a number of existing products, such as radio or microwave frequency transmission lines, transformers, and resonators.
Low-loss conductor improves performance and power efficiency of radio and microwave frequency transmissions
This magnetic and non-magnetic superlattice is designed to produce negative-permeability and positive permeability, respectively, at the frequency of interest, which cancels the generated eddy currents and suppresses radio or microwave frequency conductor loss. The permeability of the magnetic material varies with changing frequencies, while the permeability of the non-magnetic material is fixed. The ratio of layer thicknesses between the magnetic and non-magnetic layers determines the operational frequency and makes the superlattice customizable for specific applications. The metaconductors can be composed of different materials combinations or different geometries to increase the operational bandwidth. This technology can be applied to either cylindrical or planar metaconductors.
This multiferroic thin film material controls magnetization and ferroelectricity at room temperature by substituting strontium (Sr) ions with iron (Fe) ions in SrTiO3 thin films. With applications within the micro-electromechanical system (MEMS) and radio frequency (RF)/microwave system market, multiferroic thin film materials are expected to attract significant commercial interest. The global MEMS market is expected to grow at an annual rate of 12.3 percent through 2019. As the rate of MEMS and RF/microwave applications increases in automotive and consumer electronics and in industrial and healthcare sectors, so will the demand for next generation multiferroic thin films. Available multiferroic thin films require multiple structure phase transitions using piezoelectric materials, while their high frequency properties, such as loss tangent, and response time, etc. are not very promising. This prevents such films from being used for high frequency applications. Researchers at the University of Florida have created iron substituted SrTiO3 thin films that allow the formation of single phase multiferroic structures and that control magnetization and ferroelectricity at room temperature with very low dielectric loss and high magnetodielectric coefficients. This improvement has the potential to meet the increasing demand for multiferroic thin films in RF/microwave and MEMS applications.
Multiferroic thin film material that controls magnetization and ferroelectricity at room temperature for RF/microwave and MEMS applications.
Commonly used ABO3-type structures of multiferroic materials are limited to exhibiting sequential structure phase transitions. By substituting part of Sr with iron in SrTiO3 thin films, researchers at the University of Florida have developed multiferroic materials exhibiting single crystal multiferroic structures at room temperature. Material dielectric loss is low and the electromagnetic coupling is high in the high frequency range, which makes the material extremely useful for RF/microwave and MEMS applications. Experimental results indicate that iron substituted multiferroic thin films control magnetization and ferroelectricity at room temperature.
This electrospun nanofibrous tissue scaffolding system with magnetic nanoparticles embedded in the nanofibers can be used to actively stimulate cell culture or cell differentiation in vitro. A major problem in human healthcare is tissue and organ failure and the unavailability of adequate tissue or organ replacements. In the United States, this organ shortage yearly has deprived thousands of patients of a better quality of life and has caused a substantial increase in the cost of alternative medical care. Tissue engineering is emerging as a solution as it enables the creation of necessary biomaterials to meet such a shortage. Researchers at the University of Florida have developed a mechano-active nanofibrous scaffold system for in vitro active cell culture using electrospun nanofibers, magnetic particles and an electromagnet. This wirelessly driven active cell culture system, remotely actuated, provides mechanical stress and strain on culturing cells in response to external alternating current magnetic fields.
A mechano-active nanofibrous scaffold system for in vitro cell culture and tissue differentiation
The electrospinning of nanofibers can be used to generate a magnetic nanofibrous membrane containing polycaprolactone and iron oxide nanoparticles. By embedding the magnetic nanoparticles in the nanofibers of the membrane, researchers can mechanically actuate the nanofibrous scaffolding membrane, controlling the resonant frequency to either enhance or suppress cell culture or cell differentiation. This wirelessly driven active cell culture system can stimulate cells remotely.
This smart cat’s eye system uses integrated radiofrequency identification (RFID) tags and low-power environmental sensors to communicate important traffic and road condition information to drivers, autonomous vehicles, law enforcement officers, or emergency crews, thereby establishing a simple and reliable infrastructure for an on-road smart transportation network. The application of advanced information technology to transportation brings tremendous potential for improvements in efficiency, safety, and flexibility for motorists, leading the smart transportation market to a projected $220 billion by 2021. Available autonomous vehicles use a combination of optical and infrared cameras, LIDAR (Light Detection and Ranging or a remote sensing method that uses light in the form of a pulsed laser to measure ranges), and ultrasonic sensors to mimic humans’ interaction with their environment while driving. These are expensive, use a lot of power, and are prone to malfunction or experience the same limitations a person’s vision might have.
Researchers at the University of Florida suggest a much less complex solution to alleviate driving problems associated with poor visibility or road cover: a smart cat’s eye. The “cat’s eye” for the road is a reflective marker typically used to indicate lanes and other road information. UF researchers have developed the Global Assistant for Transportation On the Road - Electronic Yellow Eye (Gator-Eye), a smart transportation system that offers a low-cost, feasible, and reliable infrastructure for providing active feedback of road conditions, accidents, or traffic situations to drivers and autonomous vehicles via an on-road communications network.
Smart, reflective road markers and processers that incorporate RFID tags and low-power environmental sensors for vehicle navigation and hazard detection
The Gator-Eye units replace conventional cat’s eye reflectors along the road and include integrated radio frequency identification (RFID) tags with unique IDs that communicate important traffic and road condition information to vehicles that would also have RFID tags and an RFID reader. The tags may be passive, configured for identification, or be active, configured to provide sensor data, in response to interrogation by an RFID reader in a vehicle or waypoint. The tag could sense lane position, temperature, moisture, ambient pressure or traffic conditions. The RFID communication relays the information to motorists or autonomous vehicles regardless of on-road weather conditions or lane visibility. Waypoints (powered by traffic lights, for example) collect the real-time road data from the Gator-Eye systems and relay it to a central server. The processed information goes out to other vehicles, authorities, or emergency crews, notifying them about road conditions, accidents, hazards, etc.
This Fractal Rectangular-Reactive Impedance Surface can be utilized to reduce an antenna’s size and achieve compact high-gain antennas for high-efficiency wireless communication systems. Planar antennas have become highly desirable for wireless communication systems in recent years due to the ease of fabrication and integration as well as compactness and low-profile characteristics. The desirable electrical and physical characteristics can be achieved through the substrate design. Use of a reactive impedance surface as a substrate for planar antennas enhances the bandwidth and radiation characteristics of an antenna. Researchers at the University of Florida have developed a Fractal Rectangular-Reactive Impedance Surface that can reduce the antenna size while still creating compact high-gain antennas. Any type of antenna can be integrated on top of the FR-RIS while still maintaining efficiency and size reduction.
Fractal Rectangular-Reactive Impedance Surface (FR-RIS) for antenna miniaturization for high-efficiency wireless communication systems
Using this Fractal Rectangular-Reactive Impedance Surface (FR-RIS) structure reduces antenna size, increases inductive impedance, and achieves compact high-gain antennas for high-efficiency wireless communication systems. In contrast to the Conventional Rectangular-Reactive Impedance Surface (CR-RIS), this Fractal Rectangular-Reactive Impedance Surface (FR-RIS) does not have rectangular metal patches between the two substrates. Instead the unit cell of the FR-RIS shows a scalable fractal-rectangular shape. A gap between the metal patches produces inductance, capacitance, and determines the resonant frequency. Increasing or decreasing the length or width of the gap between the unit cell of the FR-RIS changes the fractal patterns without changing the total size of the unit cell, which allows for antenna miniaturization. University of Florida researchers have reduced an antenna by 20 percent using FR-RIS .
This glass interposer replaces traditionally used silicon in integrated circuits and system-on-package (SOP) platforms. Silicon interposer technology is subject to high substrate loss in the radio frequency/microwave range and is costly to manufacture. University of Florida researchers have discovered a glass interposer that provides the unique advantage of dual functionality as a hosting medium for high quality radio frequency (RF) components and the conventional use as an interconnecting layer. The glass interposer would be a good hosting medium for high quality RF components such as bandpass filters, integrated antennas and supporting modern devices required for SOP and system-on-a-chip (SOC) technologies. Therefore, this improved interposer is applicable to a range of electronic products including inductors, capacitors, resonators, antennas, and transformers.
Glass interposer as hosting medium and interconnecting layer in system-on-package and system-on-a-chip systems
The glass interposer layer can be fabricated using the Corning fusion process. This process produces a pristine surface in addition to a thin and strong glass. Through glass vias (TGV) can be formed by laser drilling, reactive ion etching, or electrical discharge. The dual functionality of the interposer allows for integration of high quality RF components such as metamaterial circuits and substrate integrated waveguides on the glass layer. When combined with these advanced microwave technologies, the interposer allows device compactness and superior interconnect architecture that can’t be achieved with currently used silicon interposers.
This mouth guard uses sensors to provide real-time data readout of vital signs and potential injuries sustained while playing sports. The market size for wearable fitness monitors, mainly wristbands and smartwatches, has increased by 90 percent in recent years. Although these devices monitor certain vital signs such as heart rate, they cannot record health information near the head such as concussions and heat stroke. The Centers for Disease Control estimates that 1.6 to 3.8 million concussions occur in sports and recreational activities annually. University of Florida researchers have created a wearable device that aids the identification, quantification, and management of head, heat, and heart-related injuries that may occur during physical activity. This device could include a software counterpart for data display and cloud storage for user tracking, and could help physicians noninvasively collect samples to test for diabetes and cancer.
Smart mouth guard that collects data on many common sports injuries and prevents serious aliments
This device utilizes 11 sensor channels to collect data regarding the user’s heath. This data can be sent to a master device such as a smart phone, tablet, or computer where it can be viewed and analyzed in order to ensure the safety of the user. Most wearable impact technology uses only a 6-axis inertial sensor whereas the mouth guard uses 9-axis inertial sensors to monitor lateral force and angular momentum. This allows the user to detect dangerous levels of force they may have experienced during physical activity, and it uses the Earth’s magnetic field to compensate for errors that may occur over long periods of use. The mouth guard collects data points about the user’s heart rate and blood pressure using an infrared sensor, monitors the core body temperature using a temperature sensor, measures biting force using a capacitive pressure sensor to prevent bruxism, and detects biological markers in the user’s saliva to noninvasively test for diseases.
This omnidirectional patch antenna minimizes a camera pill’s blind spots to improve the view of the gastrointestinal tract during a wireless capsule endoscopy (WCE). Endoscopic procedures help doctors identify pathologies, cancers, and internal bleeding locations within the gastrointestinal tract. WCEs offer additional benefits compared to standard endoscopic procedures, as they do not require any sedation and provide better visualization of the small intestine. In fact, the market for capsule endoscopy systems is expected to exceed $1 billion by 2026. However, the size of the camera pill endoscopes can be difficult for patients to swallow and can also lead to blockages in the gastrointestinal tract. Additionally, the emitted signals transmitting the internally captured images can experience electromagnetic interference, causing blind spots.
Researchers at the University of Florida have developed an omnidirectional patch antenna that is 50 percent smaller than the antenna used in many available camera pills for WCEs. This will improve the design of camera pills to make them easier to swallow and less likely to cause blockages, while equipping them for reliable 360-degree coverage of the stomach and intestines to reduce the occurrence of blind spots.
An improved patch antenna for smaller, easier to swallow camera pills that enable better, more reliable visualization of the stomach and intestines
Microstrip patch antennae facilitate signal transmission in a wide range of electronic devices. This patch antenna folds to create an omnidirectional radiation pattern. The folded patch forms an electromagnetically shielded space near the ground plane of the patch antenna. This space can accommodate electronic circuits or integrate with a printed circuit board to protect them from electromagnetic interference. The antenna then tunes to satisfy input impedance matching without requiring an extra matching circuit.
This mouth guard uses sensors to provide real-time data readout of vital signs and potential injuries sustained while playing sports. The market size for wearable fitness monitors, mainly wristbands and smartwatches, has increased by 90 percent in recent years. Although these devices monitor certain vital signs such as heart rate, they cannot record health information near the head such as concussions and heat stroke. According to Statistic Brain Research Institute, 35 million Americans between the ages of 5 and 18 play team sports, and at the high school sports level alone, there were more than 250,000 reported concussions in 2009. University of Florida researchers have created a wearable device that aids the identification, quantification, and management of head, heat, and heart-related injuries that may occur during physical activity. This device could include a software counterpart for data display and cloud storage for user tracking, and could help physicians noninvasively collect samples to test for diabetes and cancer.
Smart mouth guard that collects data on many common sports injuries and prevents serious aliments
This device utilizes 11 sensor channels to collect data regarding the user’s heath. This data can be sent to a master device such as a smart phone, tablet, or computer where it can be viewed and analyzed in order to ensure the safety of the user. Most wearable impact technology uses only a 6-axis inertial sensor whereas the mouth guard uses 9-axis inertial sensors to monitor lateral force and angular momentum. This allows the user to detect dangerous levels of force they may have experienced during physical activity, and it uses the Earth’s magnetic field to compensate for errors that may occur over long periods of use. The mouth guard collects data points about the user’s heart rate and blood pressure using an infrared sensor, monitors the core body temperature using a temperature sensor, measures biting force using a capacitive pressure sensor to prevent bruxism, and detects biological markers in the user’s saliva to noninvasively test for diseases.
This design for compact antenna arrays maintains high antenna gain and efficiency for use in small devices. Microstrip patch antennas are well known for their performance, robust design, easy fabrication, low profile, and low costs. They are commonly used in various applications including medical, satellites, military systems, aircrafts, and missiles. In applications where high gain is required and area is a constraint, the dimensions of the antenna and the number of antennas used play a crucial role. When more than one antenna is used, each radiating element will affect the gain of the other antenna because of mutual coupling. The effect increases as the distance between the radiating elements is reduced. Available antenna array designs with complementary meander line slots require complex fabrication processes and create large resonant frequency mismatch between the antenna elements due to their asymmetric structure. Researchers at the University of Florida have discovered that the addition of point symmetric complementary meander line (PSC-ML) slots in antenna arrays effectively reduces mutual coupling between closely placed antenna elements. This design makes it possible to create compact antenna arrays while maintaining high antenna gain and efficiency for use in small devices.
Point symmetric complementary Meander Line slots to reduce mutual coupling of micro-patch antennas
The design of the PSC-ML slots effectively reduces the mutual coupling between antenna elements; thereby increasing the overall gain and efficiency of the antenna array. The design works by increasing isolation between the antenna elements. A pair of micro-machined meander line slots are placed in a complementary point symmetric fashion on the ground plane of the antenna array. The PSC-ML slots serve as a band-stop filter and suppress surface currents and mutual coupling between the antenna elements. The point symmetric design of the complementary meander line slots allows for high isolation improvement while also removing resonant frequency mismatch. The PSC-ML architecture is frequency scalable for use in different antenna array applications. The number of meander turns can be increased to further reduce the slot size and distance between the antenna array elements.
This omnidirectional, wireless helix antenna provides power to implanted medical devices and capsule endoscopes, while allowing these devices to better relay health information for easier diagnosis and treatment. Every year in the U.S., more than $85 billion is spent on implanted medical devices, including $5.5 billion and $4.5 billion on defibrillators and pacemakers, respectively. These implanted devices and other medical technologies, such as wireless capsule endoscopes, need to be able to communicate information back to healthcare providers who use this data to diagnosis illnesses and make treatment decisions. Wireless capsule endoscopes allow for better visualization of the gastrointestinal tract than traditional endoscopes. Their performance, however, suffers from antennas that provide spotty coverage. University of Florida researchers have addressed this problem by developing a durable dual mode antenna with improved efficiency and omnidirectional radiation capabilities and wireless power transmission.
A wireless, rechargeable antenna that facilitates the communication of health information by implanted medical devices and capsule endoscopes
Researchers at the University of Florida have designed a dual-functional helix antenna with wireless communication and power receiving capabilities for medical implants. The antenna is designed on a flat liquid crystalline polymer (LCP) substrate and rolled up into a cylindrical shape. This cylinder operates as a far-field antenna for wireless communication and also serves as an inductive element for near-field wireless power transmission. The antenna can be used to charge the sensor using the wireless charging station or a cellphone with wireless power delivery capability such as near field communication (NFC).
These two types of glass interposer integrated antennas for in-plane/out-of-plane and point-to-point directional communications achieve high-speed intra-/inter-chip and board communications in 3D-IC. Three dimensional integrated circuits are becoming more complex. Many emerging 3D-IC have tens to hundreds of integrated components on a single chip, and these various components need to communicate with each other quickly and efficiently. Recent wireless interconnect technologies for data transmission in 3D-IC minimize cross talks and delay caused by mechanical contacts such as wire bonding and Through Silicon Vias. However, these technologies are expensive and can pose reliability issues, and antennas designed on silicon interposers have shown lower antenna gain and efficiency in the high frequency range. Researchers at the University of Florida have developed glass interposer integrated antennas that achieve high antenna gain and efficiency and enable far-field communications for long distance intra-/inter-chip and board data transmission. These glass interposer integrated antennas show strong potential for their use in wireless interconnects, leading to high-speed wireless data transmission and clock synchronization in 3D-IC.
Glass interposer integrated antennas for compact, high-speed wireless interconnects
To achieve wireless interconnects that will lead to high-speed wireless data transmission, University of Florida researchers propose two types of antennas – a dual-mode Through Glass Via antenna for in-plane/out-of-plane communications and a reflector antenna with a pillar array for point-to-point directional communications. A 3D integrated circuit comprises the package substrate, the glass interposer with Through Glass Vias interspersed, and multiple chips and components. For the dual-mode, Through Glass Via (TGV) antenna, in-plane communication is achieved by using the TGV as a monopole antenna, a class of radio antenna consisting of a straight rod-shaped conductor. A circular-shaped disc connected to the TGV produces in-plane communications. The reflector antenna is made up of a TGV and disc much like the dual-mode antenna, but it also contains a pillar array on one side of the TGV connected to the ground plane. This pillar array acts as a reflector of electromagnetic waves produced by the monopole antenna, resulting in a directional radiation pattern enabling point-to-point directional communications.
This highly efficient wireless power transfer (WPT) system uses a rollable metamaterial screen to improve power transfer efficiency (PTE), even in misaligned conditions. There is a high demand for wireless charging in the modern electronics market, leading to active research and development of wireless power transfer (WPT) technologies. Current WPT systems employ the inductive charging approach, limiting power transfer distance and efficiency. Alternatively, magnetic resonance coupling-based WPT enables a greater power transfer range. However, an increase in misalignment levels and transfer distance between the transmitting and receiving coils leads to a decline in PTE. The use of metamaterials to improve transfer efficiency has increased due to their electromagnetic properties, such as evanescent wave amplification and negative refractive characteristics. The placement of metamaterial structures between transmitter and receiver coils increases the efficiency of the WPT systems. Nevertheless, the bulky architectures often lead to substrate loss and do not comply with the technology trend of reduced size, weight, and power.
Researchers at the University of Florida have developed a high-efficiency wireless power transfer (WPT) system based on magnetic resonance coupling, placing a rollable metamaterial screen between transmitter and receiver coils. The screen configures to amplify and focus the magnetic field between transmitter and receiver coils in a non-contact fashion, significantly improving power transfer efficiency (PTE).
Transfers electrical power wirelessly via magnetic resonant coupling, enhanced by the rollable and tunable metamaterial screen, maximizing power transfer efficiency
This wireless power transfer (WPT) system utilizes a rollable metamaterial screen to enhance power transfer efficiency (PTE). The system transfers electrical power wirelessly via magnetic resonant coupling operating at 4.5 MHz. The screen is between the transmitting and receiving coils, focusing the magnetic field and significantly improving the PTE. This slab has a fully expanded area of 750 mm x 750 mm and a thin structure with low power losses and excellent rollability. As a result, it is highly compact and portable and does not require any designated space when not in use. Additionally, the metamaterial screen consists of multiple unit cells with tunability properties, enabling them to change the direction of the magnetic field depending on the location of the receiving coil. This feature provides compensation for misalignment between coils, preserving PTE. Each unit cell comprises a square spiral resonator fabricated on a flexible polyethylene substrate, conferring lower power losses than traditional split-ring resonators.
These patch antennas leverage a multilayered copper/cobalt design to improve received signal power by reducing loss associated with alternating current oscillating at radiofrequency (RF). 5G cellular networks offer faster data rates and higher capacities than previous networks, enticing 1.6 billion consumers onto 5G networks as of 2023. However, their operation in the 24-36 GHz band of RF frequencies suffers from antenna power losses, which increase as more antenna array elements are added. These RF losses stem from the confinement of RF current to the surface of traditional nonmagnetic conductors such as copper. One mechanism to counteract this surface confinement is to set the magnetic permeability of the material as close to zero as possible. This is achievable by layering the copper conductor with a material possessing a very different magnetic permeability, forming a metaconductor with unusual properties attributed to the misalignment of the magnetic permeabilities of the layers. This breakthrough was successfully applied to reduce RF losses antenna transmission lines, but it remains important to reduce RF losses in other antenna components as well, especially in the patch antennas found in mobile phones.
Researchers at the University of Florida have developed a metaconductor patch antenna design constructed of stacked layers of nanometer-thin copper and ferromagnetic cobalt. The competition between the positive magnetic permeability of the copper and the negative magnetic permeability of cobalt results in a small effective magnetic permeability, reducing RF losses by destroying the surface confinement effect.
Suppresses power loss in patch antennas operating at 5G compatible radiofrequencies
Patch antenna arrays consist of many planar array elements connected to a receiver/transmitter by feedlines. Each of these carries alternating current at frequencies on the GHz scale, seven orders of magnitude greater than the alternating current supplied by wall outlets. Unsurprisingly, these high frequencies cause power loss for each array component. This power loss can be quantified via the skin depth of the component, which measures how deep into the surface the alternating current can manifest.
The skin depth is inversely proportional to the frequency of the current, resulting in the surface confinement effect at RF frequencies. This means only a tiny fraction of the conductor’s cross-sectional area very near the surface can transmit current, corresponding to significant power loss. Increasing the skin depth counteracts this power thanks to the inverse dependence of the skin depth on the effective magnetic permeability of the material. This quantity can be customized in multilayered structures by including materials with magnetic permeabilities of opposite sign. The metaconductor patch antenna design layers a few nanometers of nonmagnetic, conducting copper with ferromagnetic cobalt to achieve low effective magnetic permeability and boosted skin depth. As a result, it delivers signal power 6 decibels higher than a copper-only design for a typical 5G operating frequency.
This efficient, cost-effective device produces superior-quality nanoporous membranes and three-dimensional nanoporous structures used in medical-tissue scaffolding. Since these membranes and structures are formed by stacking directionally controlled nanofibers using the unique stamp-thru-mold process, the membranes and 3-D scaffolds can have nanoscopic morphology with microscopic size control in lateral and vertical dimension. They provide a solid structure that mimics the environment found in the human body, which is useful for human cell and tissue culture. The device uses a mechanical patterning approach rather than photolithography or other approaches involving chemicals. This powerful feature puts at the user’s disposal biocompatible materials that previously could not be employed to manufacture micropatterned nanoporous membranes due to chemical contamination concerns. Researchers are increasingly mindful of the shortcomings of 2-D cell culture and their effect on the value and relevance of their studies. The device can control the porosity of the membranes and the dimension of 3-D nanoporous structures, and can customize the composition of each layer (e.g., installing gradients to direct cell growth) at the nanofiber production stage. These superior membranes and 3-D nano scaffolds are more versatile, reliable and better suited to uses such as cell culture and tissue scaffolding. The system of production is not only faster but is also more cost-effective and manufacturable.
Device that uses stamp-thru-mold process to pattern an electrospun nanoporous membrane and 3-D tissue scaffold
Electrospun nanoporous membranes are membranes created from a substance (usually a polymer)that is electrically charged, then ejected in a pattern onto an opposite electrically charged plate. The opposite charges attract and the substance sticks to the surface of the plate in a specific pattern set by the user. The device developed by UF researchers uses a similar process with some important modifications and additional patterning processes. An electrospinning-stamp-thru-mold (ESTM) patterning technique is applied to mechanically define micro and meso patterns in the nanoporous membrane, resulting in 3-D nanoporous micro/meso scaffold, obviating the need for photoinitiators and/or solvents that may contaminate the product. The resulting stackable membranes are versatile and multifunctional, as fiber composition can be customized as needed and mimic the 3-D environment found in the human body, providing a desirable foundation for tissue scaffolding and cell culture.
These thicker nanofiber microstructures, especially beneficial for tissue scaffolding, are developed using an immersion lithography technique that overcomes limitations inherent in other nanofiber lithography. Nanofibers are extremely small fibers that can be constructed into specific patterns using a process called lithography. (Consider that a single human hair is about 50,000-100,000 nanometers thick.) In lithography, an ultraviolet light solidifies a prepared nanofiber pattern into a structure; some structures are used as a scaffold for tissue. The tissue scaffolding industry was valued at $3.5 billion in 2012. Flexible nanofiber structures are ideal for tissue scaffolding, as they are completely biocompatible and can be formed into many patterns via lithography. UV lithography in the medium of air has limited resolution due to diffraction of light; the alternative, the hydrogel embedded nanofiber tissue scaffold, is porous only on the bottom layer. Researchers at the University of Florida have developed an oil immersion lithography that decreases diffraction, increases resolution, and creates tissue scaffolds that are porous on all sides -- all in one step that reduces costs and minimizes human error. The superior result is a larger, thicker, and more stable 3D nanofiber microstructure.
Lithography that uses oil, improving quality and stability of 3D nanofiber microstructures
In this immersion lithography developed by UF researchers, nanofibers are immersed in an oil medium and are directly photopatterned in the oil medium using UV light. This creates a better substrate than air for many industries and uses, especially tissue scaffolding, and reduces the process to one step, improving accuracy. This photopatternable nanofiber can be used to mimic bio-inspired architectures. This electrospun nanofiber is compatible with a variety of substances.
