Resonant Frequency Matching Research Articles

DESIGNING G-SHAPED MICROSTRIP PATCH ANTENNA FOR 5G APPLICATION

This paper presents the design and simulation of a G-shaped microstrip antenna operating at 3.7 GHz for 5G applications using ANSYS HFSS software. The antenna is fabricated on a substrate with dimensions 30x60 mm2. The G-shaped geometry is chosen for its compact size and improved bandwidth characteristics. The design process involves parameter optimization to achieve the desired resonant frequency and impedance matching. ANSYS HFSS simulations are utilized to analyze the antenna's performance in terms of return loss, radiation pattern, 3D polar plot and efficiency. The proposed antenna demonstrates promising characteristics suitable for 5G communication systems, offering wide bandwidth and efficient radiation properties with specific application in the S band frequency range. Key Words: G-shaped patch antenna, 3D polar plot, 5G, S band, ANSYS HFSS design.

Investigation of support transducer enabled higher-order radial bulk mode MEMS resonator and low phase noise oscillator

This work reports the successful excitation of a novel bulk acoustic mode whose actuation and sensing are facilitated by the support transducer topology (STT). The design methodology concurrently supports low motional impedance and high energy confinement features which are crucial for frequency reference components in Radio Frequency communication. A conventional bulk mode operating in the width extension (WE) mode is deployed to efficiently excite the higher-order radial mode using the STT design feature of resonant frequency matching. The thin-film piezoelectric on substrate support transducers excited in a WE mode is mechanically coupled to the bulk silicon allowing the acoustic energy of the MEMS resonator to be stored maximally in the high-quality factor (Q) resonant tank, thereby alleviating the overall losses due to low-Q of the piezoelectric thin film and electrode material. The resonator exhibits a Q of 19 728 at 63.56 MHz resonant frequency with a motional resistance (R m) of 368 Ω when measured in vacuum at a power level of 0 dBm. Under cryogenic measurement conditions, the device recorded a Q of 24 153 at 15 K. A standalone WE resonator is studied to put a spotlight on the quality factor enhancement technique using the STT. The STT enabled novel bulk mode enhances the overall Q by 320% and halves the R m. When implemented as an oscillator, its performance exceeds the Global System for Mobile communication standards phase noise (PN) requirements. PN of −136.95 dBc Hz−1 and −161.52 dBc Hz−1 at 1 kHz and 1 MHz offset, respectively, were recorded when normalized to a carrier frequency of 13 MHz.

Quartz tuning forks resonance frequency matching for laser spectroscopy sensing

In this paper, we report on the performance of quartz tuning fork (QTF) based laser spectroscopy sensing employing multiple QTFs. To avoid that resonance frequency mismatching of the QTFs degrades the sensor performance, two types of resonance frequency matching method are here proposed. A system based on the coupling of two sensing modules, one based on quartz-enhanced photoacoustic spectroscopy (QEPAS) and one on light-induced thermoelastic spectroscopy (LITES) technique, was realized to validate the proposed methods. Each module employed a different QTF (QTF1 and QTF2, respectively). Operating temperature or pressure of QTF2 were regulated to match the resonance frequency of QTF1, which operated at 25.0 °C and atmospheric pressure. Without regulation, the difference between QTF1 and QTF2 resonance frequencies was 2.42 Hz and the superposition coefficient η was only 54.7%. When the temperature regulation was carried out, at a QTF2 operating temperature of 67.5 °C, an optimal η value of 95.0% was obtained. For the pressure regulation approach, if operating QTF2 at pressure of 500 Torr, η reached a value of 97.2%. The obtained results show that the proposed two methods are effective in resonance frequency matching of QTFs for gas sensing systems.

A Fundamental Study to Observe Correlation at Molecular Level between Bio-Samples of Patients and Indicated Homoeopathic Medicines

Background: ‘Like cures like’ is the principle that is followed in homoeopathy. Substances which cause disorder in healthy individuals are used as medicines to treat similar patterns of disorder in sick persons. This article aims to find out whether any similarity picture exists at molecular level also that can make a selection of medicines based on scientifically measurable parameters. 
 Method: It consisted of getting frequency domain signatures for the dielectric functions of (i) bio-fluids (blood serums) of six arthritis patients and (ii) medicines selected for them on the basis of macroscopic similarity. Then, they were compared to find existence/absence of similarity between them. 
 Results: Medicines administered to the six patients were Rhus tox 200cH, Thuja 30cH, Medorrhinum 200cH. The dielectric loss at resonance for the bio-fluids of the patients and the medicines are given in the body of the article.
 Conclusion: It was observed that the patients who had beneficial results with their medicines have a similarity (resonance frequency matching) in spectral signatures of the two groups of substances i.e. bio-fluids (blood serum) of patients and the indicated remedies. This similarity was not evident in the cases where medicines failed to benefit the patients. These results are explorative and enthusiastic, but as the research is limited only to patients with arthritis, generalization could not be drawn. Further work with more rigor is required to establish the facts and apply generalizations to other disease condition. In future, this might be a new tool to integrate the fundamental research with clinical applications in homeopathy.

Non‐isolated LLC resonant converter with suppressed circulating current and automatic resonant frequency matching capability

This study proposed a novel non-isolated half-bridge Inductor-Inductor-Capacitor (HB LLC) resonant converter with automatic resonant frequency adjustment ability and a circulating current suppression auxiliary circuit. The proposed converter employs a hybrid modulation technique based on frequency modulation (FM) and pulse width modulation (PWM) to regulate the output voltage. At the nominal operating point, all the excellent attributes of a conventional LLC converter over the entire load range are maintained and output voltage control is achieved with FM. However, when the input voltage decreased to a level that LLC output voltage cannot be maintained with FM, the primary switches will operate at the minimum switching frequency and the auxiliary switch will be turned ON with PWM. The auxiliary switch is turned ON with zero-voltage switching and automatically matching the circuit resonant frequency with the switching frequency for optimal operation. The effective resonant inductor is energised directly from the dc bus storing more energy which is later released to the load to achieving high gain while maintaining the desired output voltage with a narrow frequency span. In addition, the converter exhibits low circulating current under an enhanced gain condition. Experimental results are presented on a 60 W prototype to validate the theoretical prediction. The proposed converter has a peak efficiency of 97%.

Light-weight, high-gain three-dimensional textile structural composite antenna

Due to the multiple dimensional and embeddable characterizations, the three-dimensional woven structure is of great potential as a platform for multifunctional composites. As an example of this concept, we proposed a light-weight and high-gain three-dimensional woven spacer microstrip antenna (3DWS-MA) for the first time by integrating microstrip antenna into 3D woven spacer composites. The single-element 3DWS-MA showed superb electromagnetic performance with the gain value of 7.1 dB, which is more than four orders of magnitude higher than traditional microstrip antenna (2.5 dB). Furthermore, the 3DWS-MA maintained proper resonant frequency and impedance matching after the impact of 18 J, exhibiting excellent structural integrity.

Novel Optimization Approach in Ultrasonic Machining: Unilateral Compensation for Resonant Vibration in Primary Side

Resonant frequency and impedance matching have great significance for the vibration performance and online monitoring of the rotary ultrasonic machining. Network compensation is a typical solution to match the resonant frequency and the impedance between the rotary ultrasonic holder (RUH) and the ultrasonic transducer. However, the traditional bilateral compensation method could adversely affect the rotary dynamic balance of the RUH. Currently, the existing unilateral compensation methods can only realize the resonant frequency matching. A novel unilateral compensation method that satisfies both the resonant frequency and the impedance matching is proposed. First, the impedance model of the RUH vibrating system is established according to its equivalent circuit. It is found that, without any compensation methods, the resonant frequency and the impedance between the RUH and the transducer have deviated. Second, the primary-series and primary-parallel compensation topologies are applied to the RUH system, and the expressions of compensation capacitance value, voltage gain, power transfer efficiency, and output active power are derived. The deviations of the resonant frequency and the impedance are eliminated with primary-series compensation topology; and as a result, the voltage gain is increased from 0.267 to 0.90, the output active power is 11.3 times than that without compensation. Third, the state-space model of primary-series topology is constructed. Finally, the above theoretical results are verified by the experimental results.

A High Fill-Factor Annular Array of High Frequency Piezoelectric Micromachined Ultrasonic Transducers

This paper presents a 1.2-mm diameter high fill-factor array of 1261 piezoelectric micromachined ultrasonic transducers (PMUTs) operating at 18.6 MHz in fluid for intravascular ultrasound imaging. At 1061 transducers/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , the PMUT array has a 10-20 times higher density than previous PMUT arrays realized to date. Aluminum nitride (AlN)-based PMUTs described in this paper are fabricated using a process compatible with the fabrication of inertial sensors, radio frequency (RF) resonators, and CMOS integrated circuits. The PMUTs are released using a front-side sacrificial etch through etching holes that are subsequently sealed by a thin layer of parylene. Finite element method and analytical results, including resonant frequency, pressure sensitivity, output acoustic pressure, and directivity are given to guide the PMUT design effectively, and are shown to match well with measurement results. Due to the PMUTs thin membrane (750-nm AlN/800-nm SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) and small diameter, a single 25-μm PMUT has approximately omnidirectional directivity and no near-field zone with irregular pressure pattern. PMUTs are characterized in both the frequency and time domains. Measurement results show a large displacement response of 2.5 nm/V at resonance and good frequency matching in air, high center frequency of 18.6 MHz and wide bandwidth of 4.9 MHz, when immersed in fluid. Phased array simulations based on measured PMUT parameters show a tightly focused high-output pressure acoustic beam.

Automatic resonant frequency matching of power amplifier by transformer loop sampling

A new automatic resonant frequency matching technique based on voltage detection by sampling the output transformer loop of the radio-frequency power amplifier (PA) in ultrasonic medical applications is proposed. The proposed automatic resonant frequency matching circuitry is composed of a single-loop coil added to a PA output transformer, voltage divider, diode detector and micro-controller unit for frequency adjustment. Using the proposed circuitry, the resonant frequency shift due to output load variations can be effectively tracked and compensated to provide optimised power transfer to a nonlinear load. For verification, a prototype ultrasonic medical application using a piezoelectric transducer is implemented and examined with silicone oil to check the resonance.

Photothermal response enhancement in heterogeneous plasmon-resonant nanoparticle trimers

The optical response of heterogeneous plasmonic trimer structures composed of a silver nanoparticle dimer and a central gold nanoparticle is investigated analytically and numerically. The plasmon resonance of the silver dimer is controlled through near-field coupling, resulting in plasmon resonance frequency matching of the silver dimer and gold monomer. This coupling condition makes it possible to increase the energy dissipation per unit volume in the gold particle by over two orders of magnitude compared to a single-particle system. It is predicted that pulsed illumination of a trimer consisting of two 80-nm-diameter silver particles and a 10-nm-diameter central gold particle can raise the gold particle temperature by 100 K using a pump fluence as low as $20\phantom{\rule{0.16em}{0ex}}\mathrm{nJ}/\mathrm{m}{\mathrm{m}}^{2}$ at a wavelength of 530 nm. This finding may have practical applications in photothermal therapy, fast thermal nonlinear optical modulation, and could enable new fundamental thermal studies at picosecond time scales.

Tunable coupled-mode dispersion compensation and its application to on-chip resonant four-wave mixing.

We propose and demonstrate mode coupling as a viable dispersion compensation technique for phase-matched resonant four-wave mixing (FWM). We demonstrate a dual-cavity resonant structure that employs coupling-induced frequency splitting at one of three resonances to compensate for cavity dispersion, enabling phase matching. Coupling strength is controlled by thermal tuning of one cavity enabling active tuning of the resonant frequency matching. In a fabricated silicon microresonator, we show an 8 dB enhancement of seeded FWM efficiency over the noncompensated state. The measured FWM has a peak wavelength conversion efficiency of -37.9 dB across a free spectral range (FSR) of 3.334 THz (∼27 nm), which is, to the best of our knowledge, the largest in a silicon microresonator to demonstrate FWM to date. This form of dispersion compensation can be beneficial for many devices, including wavelength converters, parametric amplifiers, and widely detuned photon-pair sources. Apart from compensating dispersion, the proposed mechanism can alternatively be utilized in an otherwise dispersionless resonator to counteract the detuning effect of self- and cross-phase modulation on the pump resonance during FWM, thereby addressing a fundamental issue in the performance of light sources such as broadband optical frequency combs.

Research on Efficiency of High Power Resonant Electric Vehicle Contactless Power Transfer Charger

Compared with traditional charging method, CPT (contactless power transfer) is more convenient and safe while having higher power lose. Therefore, the efficiency of CPT needs to be optimized. In this paper, PSSS (primary side series compensation and secondary side series compensation) model is used to study the efficiency optimization of a high-power CPT. The factors such as coil structure, resonant frequency, and load matching on high-power CPT charging equipment are studied by simulation and experiment. The results show that system efficiency is proportional to mutual inductance values; coil structure mainly affects the mutual inductance values; the mutual inductance of the coils is mainly affected by the diameter of the coils, the distance between the coils, the shape of coil, the number of turns, and so forth. As for the CPT charging system based on full-bridge inverter circuit, the efficiency of the system increases as the frequency increases in the range of 0–50 kHz, while decreases as the frequency is higher than 50 kHz. Load matching also affects the efficiency of high-power CPT charging equipment, and the load matching formula based on an equivalent circuit model is given.

Wireless power transfer in the presence of metallic plates: Experimental results

We demonstrate efficient wireless power transfer between two high Q resonators, especially in a complex electromagnetic environment. In the close proximity of metallic plates, the transfer efficiency stays roughly the same as the free space efficiency with proper designs. The experimental data fits well with a coupled theory model. Resonance frequency matching, alignment of the magnetic field, and impedance matching are shown to be the most important factors for efficient wireless power transfer.

A levitation instrument for containerless study of molten materials

A new aero-acoustic levitation instrument (AAL) has been installed at the Institute for Mineral Engineering at RWTH University in Aachen, Germany. The AAL employs acoustically stabilized gas jet levitation with laser-beam heating and melting to create a contact-free containerless environment for high temperature materials research. Contamination-free study of liquids is possible at temperatures in excess of 3000 °C and of undercooled liquids at temperatures far below the melting point. Digital control technology advances the art of containerless experiments to obtain long-term levitation stability, allowing new experiments in extreme temperature materials research and to study operation of the levitation instrument itself. Experiments with liquid Al(2)O(3) at temperatures more than 3200 °C, 1200 °C above the melting point, and with liquid Y(3)Al(5)O(12) far below the melting point are reported. Fast pyrometry and video recording instruments yield crystallization rates in undercooled liquid Al(2)O(3) as a function of temperature. Levitation of dense liquid HfO(2) at temperatures above 2900 °C is demonstrated. Capabilities are described for resonant frequency matching in the three-axis acoustic positioning system, acoustic control of sample spin, and position control of standing wave nodes to stabilize levitation under changing experimental conditions. Further development and application of the levitation technology is discussed based on the results of experiments and modeling of instrument operations.

Vertical comb-finger capacitive actuation and sensing for CMOS-MEMS

Abstract A new method for out-of-plane (vertical) electrostatic actuation and capacitive displacement-sensing that utilizes sidewall capacitance change of multiconductor comb fingers is analyzed and experimentally verified. Combining the inherited in-plane (lateral) actuation and sensing capacities of comb fingers, three-dimensional actuation/sensing can be realized. A maskless post-CMOS micromachining process is employed and the fabrication is compatible with standard CMOS processes. Applications include an three-axis microstage, a z -axis accelerometer and a lateral-axis gyroscope that use the proposed vertical comb-finger actuation/sensing method. The measured maximum vertical displacement of the microstage is 3.5 μm with a resonant frequency of 6.17 kHz. Measured sensitivity of the z -axis accelerometer is 0.5 mV/g with less than −40 dB cross-axis sensitivity, noise floor 6 mg/√Hz, and linear range from −27 to 27 g. The lateral-axis gyroscope design uses integrated comb drives for out-of-plane actuation, and is motivated by the desire to integrate three-axis gyroscopes on a single chip. The packaged gyroscope operates at atmospheric pressure with a sensitivity of 0.12 mV/ o /s and the resonant frequency of the drive mode is thermomechanically tuned between 4.2–5.1 kHz. Resonant frequency matching between the drive and sense modes is realized by integrating a polysilicon heater inside the spring beams.