Dual Resonant Frequencies Research Articles

Wearable transceiver with composite test-beds for breast cancer diagnosis

Abstract The dual-band wearable antennas are built with reinforced epoxy materials printed on textile fabrics for use in the diagnosis of breast tumors. Microwave Imaging Device has incorporated these recommended antennas. These slots were designed and tested by the (Agilent N99917A) Microwave Analyzer for the wearable cotton and polyester materials. The dual resonant frequencies 4.85 GHz and 3.21 GHz were offered. Thus these wearable antennas did not result in a lack of reflection on the tissue. Therefore these antennas deliver a low profile, broadband structure and also the large coverage area. Consequently, its measurement analysis was approved for these proposed prototypes.

Dual band transceiver of 1x2 grid pattern printed on fabric woven and cancer detection by composites

Abstract The dual band wearable wideband antennas have been fabricated by reinforced epoxy materials, which have been printed on textile woven for breast tumor diagnosis application. These proposed antennas have been implemented by Microwave Imaging Device. These microstrip slots have been constructed on the wearable cotton and polyester materials and tested by (Agilent N99917A) Microwave Analyzer. They have been offered the dual resonant frequencies 5.22 GHz and 2.67 GHz respectively. Therefore, these wearable antennas have not emitted the reflection loss on the woven materials. Hence, these proposed antenna have a low profile, wideband structure and also provides the wide coverage area. Therefore, these proposed prototypes have been authorized their measurement analysis.

Input voltage selection method of half-bridge series resonant inverters for all-metal induction heating applications using high turn-numbered coils

All-metal induction heating (IH) systems have been introduced to heat both ferromagnetic and non-ferromagnetic pots using dual resonant frequencies. They are designed for heating ferromagnetic pots using a first harmonic operation mode (FHOM) and for heating the non-ferromagnetic pots using a third harmonic operation mode (THOM). All-metal IH systems employing dual resonant frequencies consist of an IH inverter and a power factor correction (PFC) circuit to transfer desired power to pots by increasing the input voltage of the IH inverter. In this paper, the input voltage is designed to obtain an efficiency-optimized operating point. To obtain an appropriate input voltage, power loss analyses are conducted using first harmonic approximation (FHA). Based on analysis results, the input voltage of the IH inverter can be selected to improve its power conversion efficiency. A 2-kW half-bridge series resonant inverter prototype is implemented to verify the effectiveness of the proposed design by heating ferromagnetic pots using the FHOM with a 2-kW transfer power and by heating non-ferromagnetic pots using the THOM with a 1-kW transfer power.

Miniaturized Dual-Resonant Helix/Spiral Antenna System at MHz-Band for FSK Impulse Radio Intrabody Communications

In this article, a miniaturized dual-resonant antenna system at MHz-band operating at around 20 and 50 MHz is proposed for frequency-shift keying impulse radio (FSK-IR) intrabody communications. This antenna system comprises a swallowable helix-coil in-body antenna with a hollow cylindrical shape of 10 mm diameter and 30 mm length, and two single band on-body matched planar spiral-coil antennas with a compact size of 79 mm $\times\,\,72$ mm $\times\,\,2.8$ mm. For in-body antenna design, a nonuniform helical pitch structure is utilized to produce dual-resonant frequencies. The soft ferrite magnetic sheet with high relative permeability and low dissipation factor is used as a flexible conformal substrate to realize antenna miniaturization without lumped element loading. Simulation results for antenna performance, electromagnetic field distribution, and specific absorption rate are presented with different tissue-type phantoms, as well as an anatomical numerical human model. In addition, experimental verification of antenna performance and implant transmission characteristics is also conducted in a liquid phantom. At an implant depth of 50 mm, the measured maximum transmission coefficients are −33 and −45 dB at the dual-resonant frequency bands, respectively. Simulation and measurement results demonstrate that the proposed dual-resonant antenna is suitable for the FSK-IR system and can be expected to realize a data rate as high as 10 Mb/s for biomedical implant applications at MHz-band.

Dual Resonant Sum Frequency Generations from Two-Dimensional Materials.

We propose dual resonant optical sum frequency generation (SFG), where the two most singular resonances could be selected, and report for the monolayer (1L-) WSe2 when one (ω1) of two excitation pulses is resonant to A exciton and their sum frequency (ω1 + ω2) to D exciton. The dual resonant SFG confirms that, under an irradiation of ω1 and ω2 pulses with the same fluence of ∼1.4 × 1010 W/m2, its signal intensity could be enhanced about 20 times higher than the resonant SHG (i.e., 2ω1 to the D excitonic absorption). Further, the dual resonant SFG intensity of 1L-WSe2 is found to be 1 order of magnitude higher than the single resonant SFG intensity of 1L-WS2 under the same condition of two-pulse irradiation. Finally, observations of the dual resonant SFG are thoroughly examined using real-time time-dependent density functional theory (rt-TDDFT), and the relevant nonlinear optical characteristics are scrutinized using the Greenwood-Kubo formalism.

Double‐layer metasurface‐based low profile broadband X‐band microstrip antenna

In this paper, a novel technology based on double-layer metasurfaces is proposed in order to broaden the bandwidth of microstrip antennas, which has been verified in X-band linearly polarised and circularly polarised antennas. Referring to the conventional metasurface antenna that employs slot-coupled feeding, these designs add an extra metasurface between the radiation patch and the ground plane so as to establish dual resonance modes, TM10 and TM20. Following the adoption of the composite right/left-handed transmission lines principle, this technique aims to adjust the propagation constant in the right-hand region by introducing parallel inductors and capacitors to widen the dual resonant frequencies' interval, thereby realising a broadband antenna. In addition, the interlayer metasurface may also be utilised as a director to balance the E-field of the radiation patch. A linearly polarised double-layer metasurface antenna with a size of 0.8 0.8 0.058 (wavelength in free space at the centre frequency) is filled with F4B substrate with a dielectric constant of 2.2. It finally realises an impedance matching bandwidth (VSWR 2) from 8.41 to 11.67 GHz, occupying about 32.47 of the centre frequency. This circularly polarised antenna attains both an impedance matching bandwidth of 32.44 (i.e. 8.29–11.5 GHz) and an axial-ratio bandwidth of 19.72 (i.e. 9.6–11.7 GHz).

Design and Development of Single & Dual Resonant Frequency Antennas for Moisture Content Measurement

The microstrip antenna is designed for the measurement of soil moisture content for agriculture applications. In this paper, the single and dual-band microstrip antennas are designed, simulated and fabricated. The simulated results are compared and analysed with measured results for both designed for different types of feeds. It is found that the simulated and measured results are similar and better. Therefore, the fabricated antennas can be used for the soil moisture content measurement for agriculture applications. The dual resonant frequency antennas results are better than the single band antenna, it covers wide band thus, and it can be applied for wide applications.

Defected Ground Structure Printed Antenna with Triangular Slot

Double Layer Single Feed dual resonant frequency patch antenna is presented in this paper. After design the patch, we are etched triangular and rectangular slots at the top and bottom layer of the patch. After design the antenna structure, we got a remarkable result and the operating frequencies are used for the various applications of microwave Communication. Two triangular slots are designed at the top layer from the both sides of the patch with one rectangular slot from the bottom layer and also one h-type slot is introduced at the middle portion from the rest at bottom layer to obtain the desired resonant frequency. The different shapes of the patch used to improve the gain bandwidth performance of the antenna. We get two operating frequencies for this triangular shaped printed antenna. 1st frequency is applicable for microwave radiometry from aircraft to measure ocean wind speed and rain characteristics in hurricanes and the other is used to design BeO POWER CHIP RESISTOR which is applicable for Microwave and RF high power communication, microwave amplifiers and power dividers. This paper includes an extensive analysis of simulated results for this above mentioned microstrip printed patch antenna. All results are simulated and verified by the network analyzer. Due to the basic characteristics of proposed printed antenna, it is suitable for the applications in long distance radio telecommunication systems. It is also applicable for satellite communication and microwave relay systems.

Double-Elliptical Micro-Strip Patch Antenna for Higher Design Flexibility and Miniaturization

Micro-Strip Patch Antenna (MSPA) finds large scale applications in various fields of communication. Elliptical shaped patch antenna is a prominent category among MSPAs. Possibility of circular polarization and dual resonant frequencies makes the Elliptical Micro-strip Patch Antenna (EMPA) widely accepted in modern communication devices. The present work aims to identify the constraints in further advancements in the design of EMPA and propose a novel shape to overcome these constraints. Minimizing the patch area and increasing the number of degrees of freedom in design were found to be the challenges. To overcome these challenges, a newly shaped patch called ‘Double-Elliptical Patch (DEP)’ is proposed for designing ‘Double-Elliptical Micro-strip Patch Antenna (DEMPA)’. A double-ellipse is a combination of two half-ellipses either with the same minor axis and different semi-major axes or with the same major axis and different semi-minor axes. The DEP has an additional degree of freedom in design compared to elliptical patch, which leads to greater design flexibility. In the present work, a DEP with the same horizontal major axis and centrally given feed was designed using Ansoft HFSS software. The semi-minor axis of upper half-ellipse was varied by keeping the semi-minor axis of lower half-ellipse a constant. The radiation properties of DEMPA were found to be similar to that of corresponding EMPA and this was achieved with less patch area. The maximum percentage reduction in patch area was 10.714%. The DEMPA covered the entire frequency range of Ultra Wide Band (UWB).

Design Techniques for Elliptical Micro-Strip Patch Antenna and Their Effects on Antenna Performance

Elliptical Micro-strip Patch Antenna (EMPA) has been emerged as a peculiar and significant category among the different shaped micro-strip patch antennas because of its circular polarization and dual-resonant frequency features with a single feed. Elliptical and its derived shapes such as semi-elliptical, half-elliptical, slotted-elliptical and elliptical ring are found to be particularly instrumental for bandwidth enhancement and these antennas find great applications in Ultra Wide Band (UWB) and Super Wide Band (SWB) communications. Compared to antennas with circular or rectangular shapes, the design of EMPA is a research area of high potential as there is higher flexibility in its design due to more degrees of freedom. The reported literature in the field of EMPA is very less and there is ample scope for new researchers to work on. This review paper is an attempt to summarize and critically assess the-state-of-the-art design techniques as reported in literature and understand their effects on performance of elliptical patch antenna for suggesting new research fronts in the field of EMPA.

Design and analysis of dual band integrated hexagonal shaped microstrip UWB antenna

<span class="s22">In this paper, we proposed a hexagonal shaped </span><span class="s22">microstrip</span><span class="s22"> ultra-wideband (UWB) antenna integrated with dual band applications. The antenna design consists of a hexagonal shape patch with two folded Capacitive Loaded Line Resonators (CLLRs) on the left edge of the patch antenna. This hexagonal structure is used to implement UWB applications (3.1-10.6 GHz). A rectangular ground</span><span class="s22">,</span><span class="s22"> and two CLLR are also used on t</span><span class="s22">he bottom of antenna to obtain</span><span class="s22"> the extra dual resonant frequency at 2.4 GHz and 9.1 GHz for </span><span class="s22">B</span><span class="s22">luetooth and radar applications respectively. The proposed design is implemented using FR4 epoxy substrate. The relative permittivity of the substrate is 4</span><span class="s22">.4. The overall size of designing</span><span class="s22"> antenna is 26 × 30 mm2 with 1.6 mm as thickness and fed by standard feed line of 50 Ω </span><span class="s22">microstrip</span><span class="s22">. The results obtained from the simulation indicate that the designed antenna attains a good bandwidth from 1.1 GHz – 10.69 GHz with VSWR < 2 and return loss < -10 </span><span class="s22">dB.</span><span class="s22"> The proposed geometry is s</span><span class="s22">imulated by using the </span><span class="s22">Ansoft</span><span class="s22"> HFSS </span><span class="s22">simulator working on the principle of FEM and results are also analyzed.</span>

A Compact Broadband Antenna with Dual-Resonance for Implantable Devices.

A compact broadband implantable patch antenna is designed for the field of biotelemetry and experimentally demonstrated using the Medical Device Radiocommunications Service (MedRadio) band (401–406 MHz). The proposed antenna can obtain a broad impedance bandwidth by exciting dual-resonant frequencies, and has a compact structure using bent metal radiating strips and a short strategy. The total volume of the proposed antenna, including substrate and superstrate, is about 479 mm3 (23 × 16.4 × 1.27 mm3). The measured bandwidth is 52 MHz (382–434 MHz) at a return loss of −10 dB. The resonance, radiation and specific absorption rate (SAR) performance of the antenna are examined and characterized.

Design of dual-band microstrip patch antenna with right-angle triangular aperture slot for energy transfer application

This work focusing on the dual-band antenna design with rectifying circuit for energy transfer system technology for enhancement gain performance. The air gap technique is applied on this microstrip antenna design work to enhance the antenna gain. The work begins with designing and analyzing the antenna via the CST Microwave Studio software. After validation on acceptable performance in simulation side is obtained, the return loss, S11 of the antenna is measured using vector network analyzer equipment. The rectifier circuit is used to convert the captured signal to DC voltage. This projected dual-band antenna has successfully accomplished the target on return loss of −44.707 dB and −32.163 dB at dual resonant frequencies for 1.8 GHz and 2.4 GHz, respectively. This proposed antenna design benefits in low cost fabrication and has achieved high gain of 6.31 dBi and 7.82 dBi for dual-band functioning frequencies.

Novel D SRR‐based dual band antenna for WiMAX/C applications

AbstractA novel miniaturized D shape split ring resonator (SRR) antenna is proposed for dual band (3.6 GHz and 4.7 GHz) applications. This proposed antenna structure has dimensions of 18 × 20 × 0.8 mm3 which is built on FR4 dielectric constant ( ε r=4.4). This antenna consists of top and bottom side dual SRR creating dual band resonant frequency which is excited from microstrip line as monopole and slotted partial ground plane for better impedance matching. The microstrip line (monopole) is creating a resonance frequency at 4.7 GHz and the SRR is responsible for creating resonance frequency at the frequency of 3.6 GHz. The parametric study of microstrip line and the position of SRR has been analyzed. The D shape SRR in the monopole is generating another resonating frequency at 3.6 GHz. The metamaterial property of proposed D shape SRR is also verified to validate the resonance frequency. The antenna radiation measurement is carried out in Antenna Research Centre (ARC) FKE, Universiti Teknologi MARA, Malaysia. Both simulated and measured results agreed well. Measured gain achieved with this dual band antenna is around 2‐3 dB.

An underwater parametric array source transducer composed of PZT/thin-polymer composite

The source transducers for parametric array (PA) sound are required to radiate the primary wave with high intensity and directivity so as to generate nonlinear interactions between strong acoustic waves at different frequencies effectively, resulting in so-called PA sound. Thickness-mode piezoelectric transducers using 1–3 lead zirconate titanate (PZT) polymer composites were used to produce wide-bandwidth PA sound due to their ability to generate high-intensity, high-frequency sound beams over a relatively wide frequency band. The small mechanical quality factor of 1–3 PZT polymer composites results in high damping of the polymer matrix leading to a transducer with relatively flat frequency response but yet decreased-power efficiency. A PZT polymer composite that can enhance the power efficiency of a PA source transducer over a wide frequency bandwidth was proposed. This is achieved by adopting thinner polymer matrix layers and PZT rods with dual resonance frequencies. A transducer demonstrated ultrasonic sound up to 197 and 203 dB (re = 1 μP) at 98 and 135 kHz, respectively. The power efficiencies were 50% at 98 kHz and 33% at 135 kHz. PA sound was successfully generated up to 150 dB (re = 1 μP) at 30 kHz with a half-power beam width of 3.4°.

Power harvesting through flexible rectenna at dual resonant frequency for low power devices

In Wireless power transmission, the transmission of electrical energy can be done without using any conductor or lead. After the simulation of wearable antenna, two resonant frequencies are obtained, i.e. 9.94 GHz and 7.35 GHz. For the designing of antenna, instead of using glass epoxy material, textile material is used having dielectric constant 1.7. The places where it is difficult to transfer the electrical energy, textile antenna is useful in those places. Ambient radio frequency can be converted in DC signal through the rectifier. All the graphs related to rectenna, such as return loss, output voltage and current at load are presented in this paper. Textile antenna for energy harvesting is de-signed in CST software and further rectenna circuit can be designed in Pspice Software.

Dual-Band and Low-Profile Differentially Fed Slot Antenna for Wide-Angle Scanning Phased Array

A novel dual-band slot antenna with low profile is proposed. The slot antenna is constructed on dual-layer substrates, in which a metal cavity is fabricated by metalized vias. The antenna is fed by a differential scheme, so it can be easily integrated with other systems. The proposed antenna can operate at dual resonant frequencies because of the metal cavity and the radiating slot. A corresponding differential feeding network is constructed on another substrate. The half-power beamwidth of the slot antenna's radiation pattern is wide in the electric plane ( E -plane), and it is suitable to be applied to wide-angle scanning phased arrays. The phased array built by the slot antenna can realize wide-angle scanning within 3 dB peak gain fluctuation in the E -plane at both frequencies. Measured results show that the phased array can scan from –67° to 69° at 5.02 GHz and from –62° to 64° at 5.58 GHz.

Design and fabrication of simple and frequency-adjustable dual-band and triple-band antennas

A novel dual-band antenna and a triple-band monopole antenna were developed and fabricated on an Al2O3 ceramic substrate with a thickness of 0.4 mm. An L-shaped electrode structure with two branches of different lengths was designed for the antenna with two resonant frequencies, and a W-shaped structure with triple branches of different lengths was designed for the antenna with three resonant frequencies. The two antennas had simple structures, and the resonant frequency could be easily adjusted by changing the length of each branch. A stub was added to both antennas at the input microstrip line to control the input impendence, which gave the antennas better radiation (S11) properties. For the L-shaped antenna, the designed dual resonant frequencies were 2.4 and 3.5 GHz and for the W-shaped antenna, the designed triple resonant frequencies were 2.4, 3.5, and 5.7 GHz. The lengths of the radiation lines, the length of the ground plane, and the length between the tuning stub and the two radiation lines were used as design parameters. Different design parameters were changed to determine how this would affect the antennas’ characteristics. We found that the different parameters had large effects on the return loss (S11) value, and that stub length had a large effect on the resonant frequencies and return loss values.

A LLC resonant converter with dual resonant frequency for high light load efficiency

ABSTRACTThis paper presents a new approach to achieve high light-load efficiency for inductor-inductor-capacitor (LLC) resonant converters. Compared with the conventional LLC resonant converters, an additional active resonant network is employed to give the proposed converter another resonant frequency and another steady state. Thereby, the proposed converter has advantages of narrow switching frequency range and high light-load efficiency. The operation principle and the resonant network switching strategy of the proposed converter are analysed, as well as the design considerations. A 1.2-kW prototype with silicon carbide (SiC) MOSFETs is built to verify the proposed converter. The peak efficiency is tested as 94.4% at 680 kHz. Especially, the light-load efficiency is improved from 89% to 91%.

Quantifying seismic vulnerability, dynamical shear strain and liquefaction of the Quaternary deposits in the Doon valley near the Main Boundary Thrust in the Northwest Himalaya, India

Erosion and deposition are two conjugate surface dynamical processes that affect differently to the soft soil site characteristics of Quaternary deposits in the Doon valley and at its northern topographic transition zone near the Main Boundary Thrust (MBT). During an impending large magnitude earthquake, what would be the seismic vulnerability and liquefaction susceptibility of the soft soil at both the regions? We quantified Seismic Vulnerability Index, effective dynamical shear strain and the expected ground deformation in the valley soft soil through H/V site characteristics using seismic ambient noise data. At the in-accessible topographic transition zone near the MBT, site effects were studied using Moderate and Light magnitude earthquakes recorded by three Broad Band Seismographs (BBS). Results show unique dual peak mean resonant frequencies (1.11 and 1.38 Hz) and amplification factors (1.69 and 1.51) at the topographic transition zone, which highlights a bimodal distribution of site effects, where the top soil formation is influenced by erosion and deposition due to topographic slope instability apart from fluvial re-working. Here, relatively compact Oldest Doon gravel is present in the foothill terraces with the re-worked fluvial deposition of the Youngest Doon gravel. However, in the valley and its terraces the soft soil formed under fluvial environ is relatively thick (10 to < 535 m) and show a distinct single peak mean amplification factor >2 and mean resonant frequency of 1.1 Hz.The spot resonant frequencies increases from 1 Hz to more than 6 Hz from the HFT region to the MBT, while the amplification factor decreases from 14 to 1. In general, the valley soft soil is susceptible for liquefaction because the estimated dynamical shear strain is 15–25 millistrains under medium (2.2 m/s2, 225 years) and long (4.6 m/s2, 2500 years) term strong motion conditions, which is much higher than the soil plasticity limit of ten millistrains that lead to liquefaction. Dynamical shear strain distribution with depth at eight boreholes in the valley indicate ∼20 m is the liquefaction potential depth, where the pore pressure induced peak shear strain exceeds the threshold shear strain of 0.01% during the passage of seismic waves. Isolated locations in the valley like that at Dharmawala (H1), where all site parameters are very high, and would be hazardously vulnerable to liquefaction. However near the MBT the liquefaction possibility of soft soil is less, but would experience ground deformation of more than 50 cm.