Radio Frequency System Research Articles

Design of a Novel SiP Integrated RF Front-End Module Based on SOI Switch and SAW Filter

This paper proposes a novel System-in-Package (SiP) integrated architecture that incorporates Silicon-On-Insulator (SOI) switches and Surface Acoustic Wave (SAW) filters within the chip, aiming to fulfill the demands for miniaturization and multi-functionality for application in emerging wireless technologies. The proposed architecture not only reduces the integration complexity but also considers the architectural design of the integrated module, impedance matching techniques, and signal integrity for carrier aggregation (CA) technology realization. The feasibility of employing SOI switches and SAW filters based on SiP design has been validated through the trial production of a Sub-3GHz radio frequency (RF) front-end diversity receiver module. The resulting RF front-end module demonstrates exceptionally high packaging density and enhanced communication reliability, rendering it suitable for diverse applications in miniaturized RF systems.

Effect of Radio Frequency Energy for Intervention Processing on the Quality of Intact Eggs

During conventional pasteurization, eggs are submerged for 60 min at 56.7 °C, a lengthy and costly process that affects egg quality. Radio frequency (RF), a means to pasteurize eggs without affecting quality, is a novel option based on fast volumetric heating; however, there is scarce information about the quality of such treated food. This research consisted in a comprehensive quality study on eggs treated with RF. The RF system was operated at 40.68 MHz, 40 W and 16 W (8 min total), and 42 rpm. The quality assessment included the determination of Haugh unit, yolk index, compression strength, albumen turbidity, albumen and yolk pH, and yolk color. Additional analyses were conducted to quantify the mineral composition of the eggshell (40.68 MHz, 40 W, 42 rpm, 5.5, 8.5, and 10 min); these samples were observed by SEM. The results showed that RF did not significantly (p > 0.05) change any quality parameters. The mineral composition remained constant in processed eggs. The SEM images of RF-treated eggs showed some smooth spots; however, these areas could exist due to the high variability of the eggshells. RF is an option to process intact eggs, maintaining their fresh quality and keeping the integrity of the eggshell to ensure the food safety of the internal egg components.

Approach to Validate ISPM-15 Compliance for Commercial Treatment Certification of Dielectric Standard Heating of Bulk Solid Wood Packing Materials using Radio Frequency

Abstract To substantially reduce the risk of alien invasive species moving to new geographic areas, phytosanitary treatment of wood packaging materials (WPM) in compliance with the International Standard of Phytosanitary Measures No. 15 (ISPM-15) is required by trading partners. Approved treatments include conventional heating, methyl bromide and sulfuryl fluoride fumigation, and dielectric heating (DH). The DH standard was officially adopted in 2013 but has not been practiced commercially due primarily to insufficient operational validation at commercial scale. In 2022, we converted our 50-kW radio frequency (RF) unit with a 1,200-board foot capacity from an oscillator electromagnetic field power generator to a solid-state power supply, which allows for selective power input adjustments during treatment; we also switched from a five-plate to a three-plate winged electrode system to improve heating uniformity. Each loading cycle can treat sufficient material to build ∼94 standard Grocery Manufacturers Association pallets. Our research team characterized the dielectric heating pattern and options for monitoring wood temperatures over a wide-ranging test matrix of WPM that varied by wood species, dimension, moisture content, and loading configuration. We found that this upgraded RF system markedly reduced treatment times and improved heating uniformity, allowing us to develop methods that can be used to verify compliance with ISPM-15 for improved technology transfer to industry. We also discuss the operational cost of RF treatment and make general cost comparisons to conventional heat treatment for WPM.

In-pack radio frequency heating of liquid whole egg: Effect of agitation on heating rate and uniformity

In-pack radio frequency (RF) heating of liquid whole egg (LWE) was performed using a 27.12 MHz parallel-plate radio frequency (RF) system. To do this, 600 mL of LWE was subjected to RF heating in a RF-transparent plastic bag (140 mm×180 mm). Experiments were conducted at two different electrode gap settings (98 and 103 mm) with and without orbital movement in the horizontal plane. The effect of agitation on heating rate and uniformity was investigated for varying rpm’s (120 and 140 rpm) for a constant orbit diameter (35 mm). An orbital shaker was specially designed and coupled with the RF system for this purpose. Fiber optic probes were used to continuously measure the temperature of LWE at four different internal locations. Temperature uniformity index (TUI) was calculated to evaluate the uniformity of heating. Coagulation of LWE around the headspace was inevitable when the package was stationary during the treatment. Agitation brought about by orbital movement prevented the coagulation. Drastic improvement in heating rate and uniformity was observed upon orbital movement of LWE at all conditions.

Regulating the structure and gelling properties of maize starch by non-thermal effect of low intensity radio frequency wave

To verify whether there is a non-thermal effect in the radio frequency (RF) treatment process, it's very important for effectively excluding the thermal effect. Native maize starch (MS) slurry was treated under a specific electric field intensity while maintaining the sample temperature at 25 ± 2 °C for different times (1, 2, 4 and 8 h), which would effectively eliminate the influence of thermal effect on starch. A corresponding low electric field intensity of 3.3–3.4 kV/m was established after adjusting the electrode gap to be 220 mm of the 27.12 MHz RF system. Samples treated without RF-wave for the same time (1, 2, 4 and 8 h) were used as controls. The differences between the effect of these two treatments on the multi-scale structural and gelling properties of starch samples were investigated. Results showed that the low intensity RF-wave treatment enhanced the short-range structural order. A higher degree of order value and the double helical structure were observed from Fourier transform infrared (FTIR) spectra and solid state 13C nuclear magnetic resonance (13C NMR). Moreover, compared to control MS, the crystallinity of low intensity RF-treated starch significantly increased though the crystal pattern remained unchanged. Low intensity RF-wave treated starch had no significant difference in loss modulus, energy and distance of inter-double helices hydrogen bond, and pasting properties (i.e. TV, SB and BD) when compared with control sample. The effect of low intensity RF wave on starch without heating was insufficient to cause macroscopic property changes. These results provide valuable insights into the structural changes of starch treated by low intensity RF-wave and verify that the non-thermal effect of RF waves may be primarily achieved through the dipole polarization mechanism.

DESIGN AND SIMULATION OF S-BAND MICROWAVE AMPLIFIER FOR SATELLITE COMMUNICATIONS SYSTEM

This paper presents a novel design of S-band monolithic microwave integrated circuit (MMIC) amplifiers based on GaAs MESFET HFET-1102 transistors used in radiofrequency (RF) and microwave communications systems. Based on the Chebyshev gain response, an analytical method is used to design a two-stage lumped microwave amplifier. The matching networks constituted by lumped elements are transformed into T inductive networks, and the resulting amplifier is optimized using RF simulator software. In the following step, the lumped optimized amplifier is transformed into a distributed amplifier and implemented on Rogers TMM3 substrate largely used in microwave circuits. The final MMIC amplifier is stable in the frequency band (2-4 GHz), and excellent performances are obtained in terms of very high gain, reaching a peak of 35 dB, low input (S11) and output reflection (S22) coefficients, and very good output/input isolation (S12). For its RF characteristics, the proposed MMIC amplifier presented in this work is very suitable for space telecommunications in low earth orbit (LEO) satellites onboard receivers.

Survey on Optical Wireless Communication with Intelligent Reflecting Surfaces

Optical Wireless Communication (OWC) technology has gained significant attention in recent years due to its potential for providing high-data-rate wireless connections through the large license-free bandwidth available. A key challenge in OWC systems, similar to high-frequency Radiofrequency (RF) systems, is the presence of dead zones caused by obstacles like buildings, trees, and moving individuals, which can degrade signal quality or disrupt data transmission. Traditionally, relays have been used to mitigate these issues. Intelligent Reflecting Surfaces (IRSs) have recently emerged as a promising solution, enhancing system performance and flexibility by providing reconfigurable communication channels. This paper presents an overview of the application of IRSs in OWC systems. Specifically, we categorize IRSs into two main types: mirror array-based IRSs and metasurface-based IRSs. Furthermore, we delve into modeling approaches of mirror array-based IRSs in OWC and analyze recent advances in IRS control, which are classified into system power or gain optimization-oriented, system link reliability optimization-oriented, system data rate optimization-oriented, system security optimization-oriented, and system energy optimization-oriented approaches. Moreover, we present the principles of metasurface-based IRSs from a physical mechanism perspective, highlighting their application in OWC systems through the distinct roles of light signal refraction and reflection. Finally, we discuss the key challenges and potential future directions for integrating IRS with OWC systems, providing insights for further research in this promising field.

Virtual cavity probe for the real-time identification of cavity burst-noise type in superconducting radio-frequency systems

Burst-noise events are primary trip sources at the China Accelerator Facility for superheavy Elements (CAFE2), characterized by a rapid burst noise in the cavity pick-up signal categorizable into three distinct types: flashover, electronic quench (E-quench), and partial E-quench. Herein, we design an algorithm identifying the burst-noise event types in real time to realize a real-time discrimination of the three types of burst-noise events. This algorithm is based on a virtual cavity probe constructed with the forward and reflected signals of the cavity and integrated into a field-programmable gate array (FPGA). Moreover, we introduce an innovative method for calibrating the transmission delay in channels. This FPGA-based low-level radio-frequency algorithm identifies the burst-noise event type in real time. Its effectiveness has been validated in the CAFE2 facility, offering valuable data support for future advancements in machine learning-based fault classification and dark-current characterization.

RF technology in wireless communications:From transceiver architecture to subsystem specifications

Radiofrequency (RF) technology is essential to wireless communication.The demand for RF technology research is growing as mobile, satellite, radar, and other fields advance. In recent years, the development of 5G and 6G technologies has raised the bar for in-depth RF technology research, requiring greater frequency and data transmission efficiency, among other things. In addition to providing a brief overview of the transceiver's components, the signal chain, and an introduction to the major RF technologies, this paper will concentrate on the architecture of RF transceivers in RF systems and the specification of sub-systems. It will also include references for the RF sub-system specifications and integration techniques. The comprehensive study of communication technology will benefit greatly from an in-depth grasp of the transceiver's capabilities. Lastly, an overview of the layout and features of RF transceivers is provided, along with a prediction of the future application-focused path of RF technology.

Extended applications of the small-scale radio frequency system for improving the heating performance of multi-component rice

With the changing lifestyles and the rapid development of the prepared food industry, there are many different multi-component rice-based foods on the market today. Further, manufacturers of multi-component foods prepare different types of rice products and provide them to markets and restaurants. In this study, the multi-component rice was heated by a self-built small 50 Ω, 13.56 MHz radio frequency (RF) heating system to explore the effective scheme for improving heating uniformity. The dielectric properties (DPs) of the single-component material (cooked rice, carrot, and sausage) were first measured and the heating rates were recorded at a selected input power level of 500 W and electrode gap of 80 mm. Based on the above results and the occurrence of edge effect, three types (I, II, and III) of the multi-component test samples were designed to compare the heating performances and the quality changes after RF treatment with three different electrode gaps (70, 80, and 90 mm). Results demonstrated that the Type-I sample arrangement resulted in a relatively shorter treatment time and a lower heating uniformity index as compared to the other two sample arrangements (Types of II and III). It also resulted in a more uniform temperature distribution and better-quality retention than that was possible with the single-component treatment. Thus, the layered scheme (Type-I) based on the DPs of the material could effectively improve the RF heating uniformity of multi-component food.

IoT-based trusted wireless communication framework by machine learning approach

The traditional Radio-Frequency Systems (RFS) authentication methods, designed to ensure secure data transmission on the web, may not always effectively prevent adversaries from gaining access to concealed IDs or asymmetric cryptography through infiltrative, side-channel, training, and computer attacks. In contrast, Unaccounted Information (UAI) has the potential to exploit irregularities in production systems to automatically identify microchips, offering a highly robust and cost-effective security solution. This approach introduces RFS-UAI, a deep neural network-based system that efficiently manages wireless node identification by leveraging synthetic RFS characteristics of remote controls (Tx) learned through supervised methods in Wireless Sensor Networks (WSN). Unlike traditional methods that require the development of specialized transistors for UAI or semantic segmentation, this approach utilizes the existing asymmetrical RFS communication networks. Similar to the way the human brain processes information, Rx handles the entire device identification process at the gateway. According to test results, which include assessing process capability at a specified 65 nm threshold voltage and characteristics such as Local Oscillator (LO) misalignment and I-Q disparity using a probabilistic model with 52 hidden units, the system can distinguish up to 4800 transmitters with a remarkable 99.9 % accuracy under various channel conditions, all without the need for regular preambles. This recommended method can serve as a standalone security measure or be integrated into a biometric identification system.

Impact of beam coupling impedance on crab cavity noise induced emittance growth

Crab cavities will be deployed as a part of the High Luminosity Large Hadron Collider (HL-LHC) upgrade to mitigate the luminosity reduction induced by the crossing angle at the main experiments (ATLAS and CMS). Two prototype crab cavities have been installed in the CERN Super Proton Synchrotron (SPS) in 2018 for studies with proton beams. An issue of concern is the transverse emittance growth induced by noise in the crab cavity radio frequency (rf) system, which is anticipated to limit the performance of the HL-LHC. In measurements conducted in the SPS in 2018, the crab cavity noise-induced emittance growth was measured to be a factor of 4 lower than predicted from the existing analytical models. In this paper, it is shown that the observed discrepancy is explained by damping effects from the beam coupling impedance, which were not included in the models up to now. Using the van Kampen mode approach, a new theory is developed, suggesting that the impedance can separate the coherent tune from the incoherent spectrum leading to an effective reduction of the crab cavity rf noise-induced emittance growth. This mechanism is validated in tracking simulations using the SPS impedance model as well as in dedicated experimental measurements conducted in the SPS in 2022. The implications for the HL-LHC project are discussed. Published by the American Physical Society 2024

A comprehensive investigation on industrial radio frequency (RF) drying: Modeling and optimization strategies for carrot slice processing

Radiofrequency (RF) drying is a revolutionary technique gaining prominence in the food industry. The present study delves into the drying of carrot slices within industrial settings, employing cutting-edge RF technology. The entire drying operation was optimized using response surface methodology, and the effect of process parameters on the physico-chemical properties of carrot slices was noted. Optimized process parameters were found to be at the initial moisture content of 89.86% with an electrode distance of 210 mm and a thickness of carrot slice at 4.75 mm. Page model was found to be most suitable as it explains most of the variations in the moisture ratio. High moisture diffusivity was noted for RF-treated samples which indicates faster drying rates. This project on optimizing and modeling carrot slice drying in industrial RF systems holds immense industrial relevance, promising increased efficiency, improved product quality, and sustainable practices in vegetable processing.

Design of high gain MMIC amplifier for LEO satellite communication systems

In this paper, we present a novel design of S-band monolithic microwave integrated circuit (MMIC) amplifier based on GaAs Mesfet HFET-1102 transistor used in radiofrequency (RF) and microwave communications system. Basing on Chebyshev gain response an analytical method is used to design two stages lumped microwave amplifier. The matching networks constituted by lumped elements are transformed to T inductive networks and the resulting amplifier is optimized using RF simulator software. Thelumped optimized amplifier is then transformed to distributed amplifier and implemented on Rogers TMM3 substrate, largely used in microwave circuits. The proposed MMIC distributed amplifier is stable in the frequency band (2–4 GHz) and excellent performances are obtained in terms of very high gain reaching a peak of 34.23 dB, minimum input return loss (S11) of −8.85 dB at f=2.62 GHz, minimum output return loss (S22) of −12.21 dB at f=2.05 GHz and very good output/input isolation (S12) lower than −51.99 dB. For its excellent performances, the proposed MMIC distributed amplifier, is very suitable for use in space telecommunications as in Low Earth Orbit (LEO) satellites onboard receivers where the high gain amplifier is very important to assure the success of the space missions.

Facial tightening using a novel vacuum-assisted microneedle fractional radiofrequency system: A prospective, randomized, split-face study.

The microneedle fractional radiofrequency system (MFRS) is able to rejuvenate facial appearance by heating and coagulating certain depth of skin tissue. To evaluate the safety and efficacy of a novel vacuum-assisted MFRS for facial contour tightening. This prospective, randomized, split-face study included 21 patients who underwent three treatments with a vacuum-assisted MFRS at 1-month intervals. Half of the face was treated with the MFRS; the other half was untreated (control). Facial volume changes and wrinkles were objectively measured using a three-dimensional imaging system and VISIA-CR. Volume changes of the treated midface were -0.24 ± 0.75, -0.59 ± 0.92, and -0.55 ± 0.65 mL at 1, 3, 6 months follow-up; however, measurements of the control side were 0.08 ± 0.70, -0.08 ± 0.53, and - 0.10 ± 0.86 mL, indicating significant reductions (p < 0.05). The number of facial wrinkles on the treated side was significantly reduced to 12.44 ± 4.85 at 3 months and sustained at 6 months (11.11 ± 4.100) compared to the control side (14.89 ± 5.26 and 13.22 ± 4.44, respectively; p < 0.05). No long-term side effects occurred. The vacuum-assisted MFRS is safe and effective and is recommended for improving facial tightening and reducing wrinkles. This technology is sufficient to ensure the insertion depth, thus helping to improve the treatment accuracy and safety. The MFRS provides sustained effects for at least 6 months.

Advancing Green Communications: The Role of Radio Frequency Engineering in Sustainable Infrastructure Design

A thorough examination of the role of radio frequency (RF) engineering is crucial for promoting sustainability in communications infrastructure. This review explores the complex interplay between environmental concerns in communication systems and RF engineering. It examines RF engineering approaches and strategies that support the design, implementation, and preservation of environmentally friendly infrastructure, including the integration of renewable energy sources into RF systems, and the prospects and challenges associated with employing RF technologies for fostering sustainable actions in the communications industry. The major findings revealed the importance of RF engineering as it relates to reducing carbon footprints, lowering energy consumption, and enabling environmental sustainability in communication networks. RF engineering is an essential driver of sustainability in the communications industry, considering that it supports the integration of renewable energy sources, optimization of power usage, and improvement of spectrum efficiency. Therefore, the adoption of eco-friendly practices and utilization of RF technological innovations can potentially support a more sustainable and greener digital ecosystem.

A self‐quadruplexing antenna for quad‐band wireless applications

AbstractThis paper presents a compact self‐quadruplexing antenna (SQA) designed through the utilization of substrate‐integrated rectangular cavity (SIRC) technology for quad‐band applications. It operates at four distinct frequencies, which are 3.29, 4.27, 5.20, and 5.72 GHz. The antenna's maximum gains were estimated to be 5.09, 6.46, 5.79, and 6.21 dBi at their respective operating frequencies. The proposed antenna has minimum 24.42 dB isolation among the any two resonance frequencies. Moreover, variation in the patch length enables individual control over all resonant frequencies. The proposed antenna exhibits high isolation, compactness, and independent impedance control, making it well‐suited for compact and planar radio frequency systems.

Developing a combined rotating and air-circulating system for improving radio frequency heating uniformity and controlling Aspergillus in almond kernels

It is important to improve radio frequency (RF) heating uniformity for developing effective pathogen control protocols before storage of almonds. The purpose of this study was to design a combined rotating and air-circulating system (CRACS) in the RF cavity for improving sample temperature uniformity during pasteurization, drying, and cooling of almond kernels. The results showed that the optimal rotating speed of 15 r/min and loading volume ratio of 60% of CRACS were determined to achieve the required RF pasteurization level. The pasteurization protocol was developed based on the above selected parameters of CRACS, RF heating/drying, and forced air cooling. Compared to the five-layer container (five single layers stacked vertically) used for RF pasteurization of almond kernels, the RF heating uniformity in almond kernels using CRACS was clearly improved, resulting in moisture content reduction of only 0.70% wet basis (w.b.). The pasteurization validation curve of almond kernels in CRACS was closer to the predicted survival one based on the cumulative thermal lethal time model, suggesting that CRACS was suitable for the effective RF pasteurization of almond kernels. The moisture content and color values of almond kernels after RF pasteurization were beneficial for maintaining their long-term storage and stable quality. This CRACS in the RF system may provide a practical and effective technology for pasteurizing almond kernels.

Transverse emittance growth due to rf noise in crab cavities: Theory, measurements, cure, and high luminosity LHC estimates

The High-Luminosity LHC (HL-LHC) upgrade with planned operation from 2029 onward has a goal of achieving a tenfold increase in the integrated number of recorded collisions thanks to a doubling of the intensity per bunch (2.2×1011 protons) and a reduction of β* (the β value in the two high luminosity detectors, namely ATLAS and CMS) to 15 cm. Such an increase in recorded collisions would significantly expedite new discoveries and exploration. Crab cavities are an important component of the HL-LHC upgrade and will contribute strongly to achieving an increase in the number of recorded collisions. However, noise injected through the crab cavity radio frequency (rf) system could cause significant transverse emittance growth and limit luminosity lifetime. We presented a theoretical formalism relating transverse emittance growth to rf noise in an earlier work. In this follow-up paper, we summarize measurements in the super-proton synchrotron (SPS) at CERN that validate the theory, we present estimates of the emittance growth rates using state-of-the-art rf and low-level rf (LLRF) technologies, and we set the rf noise specifications to achieve acceptable performance. A novel dedicated feedback system acting through the crab cavities to mitigate emittance growth will be required. In this work, we develop a theoretical formalism to evaluate the performance of such a feedback system in any collider, identify limiting components, present simulation results to validate these studies, and derive key design parameters for an HL-LHC implementation of such a feedback system. Published by the American Physical Society 2024

Social and environmental transmission spread different sets of gut microbes in wild mice

Gut microbes shape many aspects of organismal biology, yet how these key bacteria transmit among hosts in natural populations remains poorly understood. Recent work in mammals has emphasized either transmission through social contacts or indirect transmission through environmental contact, but the relative importance of different routes has not been directly assessed. Here we used a novel radio-frequency identification-based tracking system to collect long-term high-resolution data on social relationships, space use and microhabitat in a wild population of mice (Apodemus sylvaticus), while regularly characterizing their gut microbiota with 16S ribosomal RNA profiling. Through probabilistic modelling of the resulting data, we identify positive and statistically distinct signals of social and environmental transmission, captured by social networks and overlap in home ranges, respectively. Strikingly, microorganisms with distinct biological attributes drove these different transmission signals. While the social network effect on microbiota was driven by anaerobic bacteria, the effect of shared space was most influenced by aerotolerant spore-forming bacteria. These findings support the prediction that social contact is important for the transfer of microorganisms with low oxygen tolerance, while those that can tolerate oxygen or form spores may be able to transmit indirectly through the environment. Overall, these results suggest social and environmental transmission routes can spread biologically distinct members of the mammalian gut microbiota.