Research Terms
This monolithic, wideband RF filter easily reconfigures for different bandwidths and performs better than many electrically coupled RF filters. Radiofrequency filters enable numerous electronic devices to communicate via wireless signals and prevent undesired signals from creating background noise and interference. Projections for the market for tunable RF filters show growth from $89 million in 2020 to $148 million by 2025. Monolithic RF filters, which operate with only the integrated circuit processes of a single silicon chip, are beneficial for designing and manufacturing electronics and minimizing device sizes. Acoustic coupling allows for this monolithic integration, but available acoustically coupled designs do not perform as well as electrically coupled designs, having smaller bandwidths and larger insertion loss.
Researchers at the University of Florida have developed an acoustically coupled RF filter that uses aluminum-scandium-nitride film to improve performance. The film’s greater electromechanical coupling gives the filter a bandwidth and tuning range larger than what available acoustically coupled RF filters have achieved.
High-performance, monolithic RF filter for electronic devices that allows dynamic reconfiguration of a large bandwidth and frequency range, useful for emerging multi-band 5G wireless systems
This high-performance, acoustically coupled RF filter has a monolithic design suitable for use in the reconfigurable RF front ends of multi-band wireless systems. The acoustically coupled filter uses ferroelectric aluminum-scandium-nitride film that has strong electromechanical properties to allow for large bandwidth reconfigurability within the 2.3GHz wideband. Using ferroelectric Al-Sc-N film with 30 percent Sc content facilitates dynamic reconfiguration of the filter’s bandwidth and frequency using a DC voltage.
This acoustic resonator easily configures via ferroelectric switching to filter wide-spectrum frequencies for 5G devices and tactical communication systems. The number of electronic devices that are internet-enabled has been increasing each year. Beyond mobile phones, all sorts of devices from thermostats to refrigerators connect with each other across a network called the Internet of Things (IoT). As more consumer electronics use internet communication, wireless networks must handle more users and devices and deliver higher speeds. Hence, the global market for 5G services, valued at more than $41 billion in 2020, continues to increase rapidly. Due to size and cost constraints, many consumer electronics must use resonators tuned to precise frequencies, which limits their functionality in 5G networks that integrate multiple frequency bands.
Researchers at the University of Florida have developed a digitally tunable acoustic wave resonator for processing signals in multi-band 5G communication systems. The resonator can tune and re-tune to different frequencies over a wide range, enabling 5G-integrated electronics such as radios and tactical communication devices.
Digitally configurable acoustic resonator with wide-spectral coverage for 5G-capable devices
This acoustic wave resonator is digitally configurable because of the ferroelectric properties of its transducer. The resonator consists of a substrate, a first electrode, a composite stack, and a second electrode. The ferroelectric properties of the scandium-doped aluminum nitride film layers in the composite stack allow an applied DC current to tune (and later re-tune) the transducer for particular frequencies. The inherent configurability of the resonator makes it suitable for signal processing in network-capable devices such as 5G radios or in tactical communication systems.
This device is a high-performance resonator that sustains a high resonator quality factor and is smaller, lighter, and consumes less power than other super-high-frequency resonators. The super-high-frequency wave band is used for a number of important civilian and military applications including high-resolution radar, high-bandwidth satellite, and tactical communications. High-performance resonators are critical components in super-high-frequency wireless transceivers. The resonator quality factor, a measure describing the ability of a resonator to store energy, limits key performance metrics such as frequency stability and power loss. Currently, there are only a few resonators that can sustain a high resonator quality factor when used for super-high-frequency wireless transceivers, and these devices are bulky, require external circuitry, and consume significant power.
Researchers at the University of Florida and Sandia National Laboratories developed a high-performance resonator for use in super-high-frequency wireless transceivers. This super-high-frequency resonator (over 50 GHz) can sustain a high resonator quality factor and is smaller, lighter, and consumes less power than comparable devices.
High-performance resonator to be used in super-high frequency wireless transceivers for applications such as high-resolution radar and high-bandwidth satellite communications
This device is a high-performance resonator for use in super-high-frequency wireless transceivers. This device has a self-amplified silicon and silicon-germanium nanowire-nanofin resonator architecture that leads to built-in amplification of resonator quality factor by several orders of magnitude while reducing the SWAP by 2 orders of magnitude. Unlike other high-performance super-high-frequency resonators, this device does not require external amplification or circuitry.
This high-speed, selective, nonlinear signal processor uses a mechanical wave-mixing matrix to synthesize multi-band frequencies, enabling a tremendous boost in the spectrum resources through accessing white bands in cm- and mm-wave spectrums. To accommodate the increasing number of wireless users and their explosive demand for higher communication data rates, emerging wireless systems, such as the 5G wireless network, target system-level transformation to exploit multi-band communication schemes over ultra- and super-high-frequency (UHF and SHF) regimes. Multi-band communication systems rely on spread-spectrum communication schemes that distribute wide-band signals among several distinct carrier-aggregated frequencies over an extended spectrum to accommodate enhanced communication data rates. Realization of spread-spectrum wide-band communication systems requires a phase-synchronous set of frequency references to serve as local oscillators at each carrier frequency and facilitate a coherent combination of data from multiple carriers without signal distortion. Such a reference set is currently realized through exploiting several standalone resonators, besides phase locked loop (PLL) based synthesizers, that impose additional burden on the integration, complexity, and power consumption of the systems. Furthermore, with the inevitable increase in the number of constituent sub-carriers and extension of communication bands into higher frequencies, beyond the UHF, the PLL-based synthesizer solutions are not efficient, due to the significant degradation in the phase-noise with increased output-to-input frequency ratios.
Researchers at the University of Florida have developed a fully-mechanical synthesizer that employs nonlinear acoustic wave-mixing processes to realize a phase-synchronous frequency reference chain over multiple bands, without the need for PLLs. This device enables operation of multi-band 5G wireless communication systems in carrier-aggregation mode through using a single frequency reference, reducing the complexity and power consumption of the system.
High-frequency signal processing unit that synthesizes multiple frequencies throughout the entire UHF and SHF ranges for 5G multi-band telecommunications systems with ultra-low power consumption
This phononic signal processing system uses nonlinear acoustic wave propagation to synchronize signals of varying frequencies for efficient multi-band, carrier-aggregated communications systems. Waveguides that support certain vibration modes at desired frequency are cross-couple on geometrically engineered semiconductor and piezoelectric regions. These regions feature perforations that enhance the elastic anharmonicity of the material, allowing them to exhibit acoustic wave-mixing properties. The perforations also provide acoustic band-gap around specific frequencies, which isolates the local excitations from nonlinearly generated signals. Since the system employs mechanical wave-mixing to process signals, this frequency synthesizer is substantially immune to electromagnetic interference and frequency-pulling effects at ultra-high and super-high frequencies (UHF and SHF), thereby increasing the stability of frequency references in multi-band wireless systems in the cm- and mm-wave spectrums.
These nano-electromechanical systems (NEMS) barcodes use nano-sized arrays to create microscopic, non-cloneable labels and IDs with unprecedented immunity to counterfeiting. Businesses and other institutions rely on barcodes and other identifiers (i.e. radiofrequency IDs) to monitor and track their inventory for authenticity verification, supply chain management, and automated purchasing and check-out of products. Barcodes dominate the field of automatic identification and data capture (AIDC) because they are easy to use, effective and cheap. However, available barcode systems are vulnerable to counterfeiting and other forms of exploitation, which is particularly problematic when tracking valuable or sensitive items, such as electronics or prescription painkillers. Researchers at the University of Florida have developed a nano-electromechanical systems barcode generator that layers or engraves tiny barcodes directly onto a substrate or product, such as mechanical parts, plastic and glass packaging, food and medicine, and medical devices. The microscopic size lends itself to clandestine barcodes and the layering process includes a protective layer; both attributes make the barcodes highly immune to cloning or tampering. In addition, mechanical removal and reapplication of the barcode results in irreversible physical damage.
Non-cloneable, nano-sized barcode generation for AIDC
The barcode, fingerprint, labeling or watermark device comprises a substrate, a microscopic array of identification dots engraved on a substrate, plus other layers that may include an interdigital transducer, a piezoelectric layer, and passivation or protective layers. The interaction of acoustic waves within the nanostructure dots generates distinct resonance modes that stand out in the frequency response. The pattern generated by each nanostructure represents a spectral signature, which can be detected and identified by a receiving device. Because of the nature of the nanostructure, it cannot be removed from the substrate without irreparable physical damage, unlike a traditional barcode. In addition, the barcode can be clandestine due to its nano-size. Furthermore, the materials used in the barcode are bio-degradable, meaning it can be safely used for biomedical applications.
This nano-acoustic resonator employs a ferroelectric transducer to enable the radio frequency (RF) front-end module necessary for the realization of 5G wireless communication networks. The majority of Americans today use a cellphone as a primary source for wireless communication. Each cellphone has at least 40-50 bulk acoustic resonator-based RF filters; these are used in Wi-Fi, GPS, Bluetooth, data/voice transceivers. In 2018, 440 million users subscribed to wireless carriers in the United States and this number keeps increasing. With the advent of the internet of things, more “smart” cars and household devices are communicating among themselves, and this requires our wireless networks to handle more users/devices at increasingly higher speeds. To prevent interference between devices and to increase data speed significantly, communication networks aim to scale the frequencies of certain wireless communication signals to extremely high frequencies in the millimeter wave (mm-wave) spectrum. In order to enable operation at mm-wave frequencies, the piezoelectric transducers used in the bulk acoustic resonator technology need to be miniaturized to sub-100nm thickness. Available thin-film resonator technology cannot achieve this thickness miniaturization because of their inherent material processing limitations such as nucleation, crystallization and texture development at such low thicknesses. Therefore, on scaling to the mm-wave frequency spectrum, the current piezoelectric films cannot preserve the critical electromechanical properties necessary for the effective operation of resonant devices.
Researchers at the University of Florida have developed a nano-acoustic resonator with a thin film ferroelectric transducer that exhibits superior piezoelectricity even at thicknesses less than 10 nm. This nanoscale resonator technology is capable of extreme frequency scaling, thus enabling 5G mm-wave wireless mobile systems.
Nano-acoustic resonator that achieves extreme frequency scaling for faster, clearer wireless communications
This nano-electro-mechanical (NEM) resonator creates monolithic cm- and mm-wave RF front ends and frequency references for 5G wireless communications systems. Resonators consist of a piezoelectric material in between two electrodes. The frequency of a bulk acoustic resonator is inversely proportional to its piezoelectric film thickness. For a resonator to operate in the mm-wave spectrum, the piezoelectric film thickness must be less than 100nm. This resonator uses an atomically engineered hafnium-zirconium oxide (Hf0.5Zr0.502) ferroelectric transducer. An atomic layer deposition process forms the Hf0.5Zr0.502 layer, ensuring better control of the thickness and uniformity of the film. This layer has a thickness in the range of 2nm to 20nm, well below the maximum thickness limit for mm-wave signal processing. Hf0.5Zr0.502 is already available in the current CMOS process material bank. Thus, with Hf0.5Zr0.502 transducer, this nano-acoustic resonator enables the first monolithic integration of acoustic frequency references/RF filters on chips operating in mm-wave bands.
This high-performance bulk acoustic resonator provides narrow frequency filtering that can be used in the most advanced wireless mobile systems. Full-duplex wireless communication front-ends are one of the key-enabling systems for 5G and beyond. However, the current full-duplex technology faces a fundamental challenge of self-interference between the transmitter and receiver signals. As 5G networks redefine the telecommunications industry, smartphones and other devices will have faster speeds and more reliable connections. Under these advanced networks, non-reciprocity and compatibility with complementary metal-oxide semiconductor (CMOS) technology are still demands that wireless communication devices need to meet in order for them to perform at their highest potential.
Researchers at the University of Florida have developed a non-reciprocal frequency limiter using asymmetrically transduced micro-electro-mechanical resonators with extreme miniaturization capabilities. It has the ability to receive narrowband frequencies and be compatible with CMOS technology. This technology forms a vital design for wireless communication systems, enabling them to meet the high data requirements of the emerging 5G communication systems and beyond.
Non-reciprocal frequency Limiter with CMOS compatibility to make emerging 5G systems more efficient
This non-reciprocal frequency limiter with reconfigurable non-reciprocity uses micro/nano-electro-mechanical resonators to create an architecture that paves the way for the design of CMOS compatible UHF-SHF non-reciprocal filters necessary for future full-duplex systems. The design uses the input power of the resonator-2 in the electrically couple filter architecture to reconfigure the non-reciprocal nature of the filter. Two independent transducers with dissimilar electromechanical coupling and power handling capabilities allow the design of an asymmetric resonator with non-reciprocal behavior. This device enables fully CMOS-compatible non-reciprocity, where the non-reciprocity is reconfigurable (tunable) with respect to input power. A limiter such as this has significant and valuable potential for use in wireless mobile systems and IoT.
This crystal-based waveguide enables excitation of large amplitude harmonic acoustic waves without signal distortion, establishing high quality factor (Q) resonators to improve narrow band communication in electronic devices. Wireless communication industries often employ multi-band carrier aggregation techniques to satisfy the demand for higher data rates and communication capacity and to improve network performance. Developers seek high Q resonators to perform the requisite frequency synthesis. However, available devices have a limited ability to meet major resonator performance metrics consistently during extreme frequency scaling. In order to maintain high Q performance, certain resonator designs improve acoustic energy localization by geometrically suspending the propagating region using narrow tethers or anchors. These, however, can cause signal distortions in power-intensive extreme frequency applications. With these drawbacks, available resonators lack the lithographical frequency scalability necessary for transmitting configurable data communication over a wide frequency spectrum while preserving high Q performance at narrow bands.
Researchers at the University of Florida have developed an acoustic waveguide that utilizes a crystal structure to facilitate development of high Q performance resonators without the need for geometrical suspension through narrow tethers or rigid anchors. This enables devices to synthesize frequencies efficiently across a wide frequency spectrum including narrow bandwidths, expanding wireless communication capacity and improving network performance.
High quality factor resonators with improved power handling that enhance narrow bandwidth communication in electronic devices such a routers, internet of things devices, and military equipment
This acoustic waveguide features a crystallographic orientation in single crystal silicon that enables excitation of large amplitude harmonic acoustic waves without generation of higher harmonics, thereby improving a resonator’s power handling capacity. Its single crystal silicon substrate lowers acoustic dissipation to reduce signal quality factor degradation during extreme frequency scaling. It does not require geometrical suspension through narrow tethers or rigid anchors. The design utilizes dispersive energy trapping to localize acoustic energy uniformly within the electromechanical transduction area, which is a fundamental requirement for frequency scalability.