Values Of Lumped Elements Research Articles

Development of a Compact Phase Shifter for the Decimeter Wavelength Range

This paper presents the results of a study aimed at miniaturizing a microstrip phase shifter with switched transmission lines. Two compact phase shifters have been obtained — one in which the classic section of the transmission line is replaced by a low-pass filter, and the second in which the power supply filters are made on SMD elements. When comparing the theoretical and experimental characteristics of phase shifters, a discrepancy has been discovered between them, which is associated with the difference in the dielectric constant of the substrates in the model and the prototype, as well as due to differences in the values of lumped elements and tolerances in the manufacture of prototypes.

CSRR inspired antenna using artificial neural network for sub 6 GHz 5G applications

The article investigates a compact low profile guitar shaped antenna loaded with co-directional complementary split ring resonator(CO-CSRR) based on negative permittivity metamaterial for sub-6 GHz 5G applications.The inclusion of metamaterial on the radiator produces two popular frequency bands n78 5G NR (3.13–4.01) GHz and n79 5G NR (4.98–6.19) GHz with gain of 5.75 dBi and 6.3 dBi respectively. The design is able to achieve high impedance bandwidth of 700 MHz and 1040 MHz at 3.6 GHz and 5.2 GHz with low return loss (S11 < -15 dB). The antenna offers simulated radiation efficiency of 93.9% at 3.6 GHz and 91.8% at 5.2 GHz making it suitable for 5G communication demands.The equivalent circuit of guitar shaped antenna is presented and the values of lumped elements are calculated. The metamaterial characteristic is verified by Nicholson Ross weir method. A neural network model is developed both in Regression predictive modelling and classification predictive modelling for the proposed guitar shaped antenna using feed forward Levenberg-Marquardt algorithm to predict return lossfor various dimensions of antenna. The model predictsthe data with 90.9% accuracy. The prototype of the antenna is designed with a compact size of 28 × 28 × 1.6 mm3, fabricated on FR4 substrate and experimentally verified.

An efficient modeling approach of 1D-planar metamaterials in the high-frequency regime

PurposeThe purpose of this paper is to present an alternative modeling approach in terms of the determination of a physically equivalent circuit model for one-dimensional (1D) planar metamaterials in the high-frequency regime, without a postprocessing optimization procedure. Thereby, an efficient implementation of physical relationships is aimed.Design/methodology/approachIn this paper, a method based on quasi-stationary simulations and mathematical conversions to derive the values for a physically equivalent circuit model is proposed. Because the electromagnetic coupling mechanisms are investigated in detail, a simplification for the considered multiconductor transmission line structure is achieved.FindingsThe results show that the proposed modeling approach is an efficient and physically meaningful alternative to classical full-wave simulation techniques for the investigated inhomogeneous transmission line structure in both the time domain as well as in the frequency domain. In the course of this, the effort is reduced while a comparable accuracy is maintained, whereby specific coupling mechanisms are considered in circuit simulations.Originality/valueThe process to obtain information about physically interpretable lumped element values for a given structure or to determine a layout for known ones is simplified with the aid of the proposed approach. An advantageous adaption of the presented procedure to other areas of application is well conceivable.

Compact Dual-Band Wilkinson Power Divider Design Using Via-Free D-CRLH Resonators for Beidou Navigation Satellite System

A compact dual-band Wilkinson power divider (WPD) using the via-free dual-composite right/left-handed (D-CRLH) resonators is presented for application in the Beidou navigation satellite system in this brief. First, by establishing an equivalent circuit model and using Bloch theory, a dual-band resonator is further analyzed to gain insight into its working mechanism, which can exhibit −90° phase shift at lower frequencies and +90° phase shift at upper frequencies, respectively. Then, to facilitate the design, ignoring parasitic parameters, a simplified circuit model retaining the physical meaning is presented, and the closed-form formulas for determining lumped element values of a dual-band characteristic are derived. Next, there is a significant rejection performance between two operating frequencies due to the inherent band-stop filtering effect of the D-CRLH resonator. Following that, the WPD is verified through experiments, showing excellent performance. Finally, based on this property, a dual-band feeding network (FN) is constructed by the combination of a WPD and a phase shifter with the proposed resonator. The simulated and measured results are found in good agreement with each other, which further demonstrated our proposed design conception.

The Investigation of the Volumetric Strip-Slot Transition with U-Shaped Slot Resonator

The application of volumetric strip-slot transition for the implementationof wireless devices with contactless frequency-selective transmission of microwave signals is relevant. This is due to the compactness of volumetric strip-slot transition achieved by the multilayer arrangement of its functional parts and of its electrical frequency-selective characteristics. At the same time the volumetric-modular design allows the replacement of its individual components which provides high functional flexibility of the device. Reducing of weight and dimensions of the volumetric strip-slot transition while maintaining its electrical characteristics is possible due to well-known methods used in microwave technology: 1) using of substrates with a high value of the relative permittivity, 2) due to the transition to higher frequency ranges. The authors of this paper present the third method for reducing of weight and dimensions of the volumetric stripslot transition by using a U-shaped slot resonator. The development of the equivalent circuit of the volumetric strip-slot transition and calculation of all its lumped elements are also presented. The values of such lumped elements as linear capacitance of the strip line, linear inductance of the strip line, characteristic impedance of the slot transmission line were determined. The value of the inductive inhomogeneity occurred when the slot resonator bends by 90 degrees was calculated and its S-parameters in the frequency range were simulated. Numerical electrodynamics simulation was performed to confirm the validity of the results of circuit simulation. Then the experiment research of the sample of the volumetric strip-slot transition with the U-shaped slot resonator was carried out. The theoretical and experimental results of the conducted researches of volumetric strip-slot transition with the U-shaped slot resonator are in good qualitative and numerical agreement with each other. The use of the U-shaped slot resonator provides an opportunity to achieve a 36% reduction of weight and dimensions parameters of the volumetric stripslot transition while maintaining its electrical characteristics.

The Multi-Mode Resonance in AlN Lamb Wave Resonators

The characteristics of the multi-mode resonance behavior of AlN Lamb wave resonators (LWRs) are theoretically and experimentally investigated for the first time in this paper. Adler’s approach and finite element method (FEM) are used to calculate the dispersive characteristics of the phase velocity ( $v_{p}$ ), group velocity ( $v_{g}$ ), effective coupling coefficient ( $k^{2}_{\text {eff}}$ ), and temperature coefficient of frequency for the first eight Lamb wave modes with different transducer configurations. The FEM is performed to take an insight into the mode shapes of the S0 mode and S1 mode specifically: the S0 mode is more contour-like and exhibits the largest $k^{2}_{\text {eff}}$ when $h_{\text {AlN}}/\lambda $ is close to 0.5; the S1 mode is strong in vertical direction and can enable high resonance frequency ( $f_{s}$ ) and large $k^{2}$ simultaneously when AlN thickness is very thin. Experimentally, AlN LWRs with different AlN thicknesses are designed and fabricated. The measured results are fitted into the multi-resonance BVD model so that the device performance parameters, as well as the equivalent, lumped element values are extracted and compared. By choosing different normalized AlN thicknesses, the performance of different Lamb wave modes varies largely due to the dispersive characteristics and agrees well with theoretically predicted acoustic characteristics. This paper lays the foundation for characterizing the multi-resonance behaviors of AlN LWRs and gives guidance on choosing the optimal design parameters and Lamb wave modes for different applications. [2018-0040]

A Novel Metamaterial Transmission Line With Adjustable Left-Handed Elements and Its Application to &lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;$H$ &lt;/tex-math&gt; &lt;/inline-formula&gt;-Plane Filter

This letter presents a metamaterial transmission line (TL) with enhanced designing flexibility. Interdigital fingers and rectangular slots are etched on the top and bottom metal plates to generate series capacitances and shunt inductances, respectively, which give rise to the composite right-/left-handed (CRLH) property. In this structure, the rectangular slots provide adjustable shunt inductances that facilitate the design of CRLH property compared with that in previous work. Furthermore, the increment of the shunt inductances also enables more compact size due to lower resonance. Examples are given to verify the advantages by comparing the dispersions, S-parameters, and extracted values of lumped elements for two types of CRLH TLs with various physical dimensions. In addition, a bandpass filter is implemented by the proposed CRLH TL with partial H-plane coupling structure. The filter is fabricated and measured, and the result shows a good agreement between the measurement and simulation.

Exact Performance Evaluation of RF Energy Harvesting with Different Circuit's Elements

ABSTRACTThis paper focuses on various design constraints of radio frequency energy harvesting circuit (RFEHC). Matching networks such as L- and Π-type are used to investigate the RFEHC performance. The simulation results show that the harvesting circuit yields improved output voltage while using a Π-type matching network of high-Q value. Further, a theoretical analysis of matching efficiency and voltage gain under different load conditions and lumped element values is discussed. A tradeoff between the maximum bandwidth and the maximum voltage gain is observed for a given load impedance. Moreover, the influence of various diode's parasitic on the RFEHC bandwidth is also discussed. This analysis shows that low series resistance, high junction capacitance, and high junction resistance of diode are the essential parameters to achieve wide bandwidth. In addition, a microstrip-fed monopole antenna is proposed for ambient RF harvesting. The output voltage varying between 750–800 mV has been obtained by capturing the ambient RF power from the nearby cell tower in the institute.

Compact dual‐band bandpass filters with stub resonating lines

AbstractSeveral new compact microstrip dual‐band bandpass filters using admittance inverters and open‐ended resonating stubs are introduced. Operating at the center‐band frequencies of 1.8 and 2.4 GHz, with moderate bandwidth passbands, the proposed devices are suitable for LTE mobile cellular networks and Wi‐Fi technologies. The design procedure includes the use of simple equations to extract the lumped element values of the circuit model. Next, the equivalent distributed layout which consists of 3 admittance inverters and 4 shunt‐connected stubs (two λg/2 and two λg/2) is presented. The design is adjusted to attain further enhancement in the electrical and physical characteristics. These include spurious passband suppression, layout miniaturization, and reduction in the capacitive coupling between stubs. Measured responses are compared with simulated results, and very good agreement is observed. These features make the proposed filters suitable for integration into various microwave planar technologies.

Mechanical and electrical impedance matching in a piezoelectric beam for Energy Harvesting

A piezoelectric beam is one of transducers for energy harvesting. It provides easy implementation and good performance in changing mechanical stress into electric voltage. In order to maximize output power, it is important to provide mechanical and electrical impedance matching. In the paper the authors proposed a methodology which allows to find values of lumped elements in an electromechanical model after completing appropriate measurements. Due to linear equations, it is possible to model a beam in both mechanical and electrical ways, and match the best load depending of frequency. The proposed model of a piezoelectric cantilever shows a potential use of these devices in micro scale as a cantilever which is a part of a silicon structure. Moreover, in the paper, the authors discuss mechanical aspects of using a weight as the way to tune the piezoelectric beam to a specific frequency. The electrical aspect of matching the source impedance with load, which is based on an electrical model of a piezoelectric transducer, is also presented. In the paper a mathematical model was verified by an experiment in which a laboratory stand equipped with a vibration generator, a piezoelectric energy harvester and acceleration sensors was used.

An ME-PC Enhanced HDMR Method for Efficient Statistical Analysis of Multiconductor Transmission Line Networks

An efficient method for statistically characterizing multiconductor transmission line (MTL) networks subject to a large number of manufacturing uncertainties is presented. The proposed method achieves its efficiency by leveraging a high-dimensional model representation (HDMR) technique that approximates observables (quantities of interest in MTL networks, such as voltages/currents on mission-critical circuits) in terms of iteratively constructed component functions of only the most significant random variables (parameters that characterize the uncertainties in MTL networks, such as conductor locations and widths, and lumped element values). The efficiency of the proposed scheme is further increased using a multielement probabilistic collocation (ME-PC) method to compute the component functions of the HDMR. The ME-PC method makes use of generalized polynomial chaos (gPC) expansions to approximate the component functions, where the expansion coefficients are expressed in terms of integrals of the observable over the random domain. These integrals are numerically evaluated and the observable values at the quadrature/collocation points are computed using a fast deterministic simulator. The proposed method is capable of producing accurate statistical information pertinent to an observable that is rapidly varying across a high-dimensional random domain at a computational cost that is significantly lower than that of gPC or Monte Carlo methods. The applicability, efficiency, and accuracy of the method are demonstrated via statistical characterization of frequency-domain voltages in parallel wire, interconnect, and antenna corporate feed networks.

Modeling and performance improvement of folded coupled lines in miniaturized Quasi-lumped directional couplers

An efficient modeling method for folded coupled inductors for application in quasi-lumped directional couplers designed in both symmetric and asymmetric structures has been proposed. The presented model takes into account the deteriorative effects which occur when coupled inductors realized as electrically short coupled-lines matched to the high impedance standard are folded into, for example, meander or spiral pattern. The deteriorative influence of coupled-lines' folding on the performance of the resulting directional coupler has been modeled as additional lumped inductors and capacitors on the schematic diagram of a quasi-lumped directional coupler's subsection. Moreover, it has been shown that this deteriorative influence can be substantially minimized when values of lumped elements constituting the directional coupler are appropriately changed. The proposed design procedure has been experimentally verified by measurements of two 3-dB single-section directional couplers designed in symmetric and asymmetric structures as quasi-lumped couplers with folded coupled inductors. The measurement results show a good agreement with both circuit and electromagnetic analysis which proves the correctness and usefulness of the presented methods. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:1–9, 2015.

Active Microwave Metamaterials Incorporating Ideal Gain Devices.

Incorporation of active devices/media such as transistors for microwave and gain media for optics may be very attractive for enabling desired low loss and broadband metamaterials. Such metamaterials can even have gain which may very well lead to new and exciting physical phenomena. We investigate microwave composite right/left-handed transmission lines (CRLH-TL) incorporating ideal gain devices such as constant negative resistance. With realistic lumped element values, we have shown that the negative phase constant of this kind of transmission lines is maintained (i.e., left-handedness kept) while gain can be obtained (negative attenuation constant of transmission line) simultaneously. Possible implementation and challenging issues of the proposed active CRLH-TL are also discussed.

An RF Circuit Model for Interdigital Capacitors-Based Carbon Nanotube Biosensors

We present improved RF circuit modeling of a biosensing element based on a single-walled carbon nanotube combined interdigital capacitors at microwave frequencies. From the resultant circuit, the lumped element values for biomolecular binding are accurately obtained. It is thereby found that the completed RF circuit model shows excellent agreement with measured results. This implies that the electrical properties of a specific biomolecular binding system can be quantitatively analyzed if an optimal RF circuit model is constructed. Finally, we suggest that the suggested methodology can be used to analyze other biomolecular sensing methods.

Quad-band negative-refractive-index transmission-line unit cell with reduced group delay

A generalised negative-refractive-index transmission-line (G-NRI-TL) lattice topology is used to design a quad-band phase-shifting cell with half the group delay of previous G-NRI-TL cells and perfect matching at all frequencies. The all-pass lattice topology reduces dispersion at the operating frequencies for lower group delay performance. Design equations are presented that determine the lumped element values necessary to match the structure while achieving a given phase at four arbitrary frequencies. This transmission-line cell is useful for implementing passive quad-band microwave elements with enhanced bandwidth performance.

Compact Wavelength Division Multiplexer Based on Microstrip Resonator Containing Effective Zero-Index Media

A compact wavelength division multiplexer (WDM) based on a microstrip resonator containing effective zero-index media is proposed. Both numerical simulations and microwave experiments demonstrate the crosstalk suppression phenomenon in this WDM. By properly adjusting the values of lumped elements, it is convenient to achieve crosstalk suppression over 10dB. Therefore, this compact WDM is promising for applications in modern microwave communication systems for its compact device volume and unique capability to suppress the crosstalk between WDM channels.

Synthesis of Reduced Equivalent Circuits for Transmission Lines

This paper presents a method for generating lumped models for symmetrical transmission-line two-ports. These models consist of an ideal transformer and frequency-domain approximations for two physical driving-point impedances. The lumped element values are obtained directly from the distributed parameters or propagation constant and characteristic impedance. The method is applied to dispersive transmission lines, skin effect and waveguides. It is shown that the equivalent circuit is superior in accuracy and number of elements compared to spatial discretizations like ladder approximation

A novel modeling method for defected ground structure using adaptive frequency sampling and its application to microwave oscillator design

This paper demonstrates new systematic approaches to equivalent circuit model extraction for defected ground structure (DGS) directly from full-wave frequency domain simulation. The DGS circuits being modeled may be either lossy or lossless. Adaptive frequency sampling (AFS) is used to minimize the computational effort of electromagnetic (EM) simulation while critically assisting in determining the cutoff frequency and attenuation pole location of the DGS circuits. A simple circuit model for lossy DGS circuits without any optimization of lumped element component values is presented. Furthermore, lossless circuit model relative complex along with a determined starting point of optimization of lumped element values is also presented in detail. The overall results are an efficient and accurate means to produce the complete equivalent models of DGS circuit for the design of various RF and microwave circuits such as oscillators that may require the high accurate nonlinear design procedures.

On the design of coupling networks for coupled oscillator arrays

Arrays of voltage-controlled oscillators can be coupled by means of a network so as to be mutually injection locked and thus oscillate as an ensemble. This ensemble may be used to excite the elements of a phased array antenna in such a manner as to radiate an agile beam. Design of the coupling network requires attention to three key parameters: the inter-oscillator coupling strength, the network bandwidth, and the oscillator loading. These parameters can be related to the network admittance matrix elements, which, in turn, are related to the lumped element values. This provides convenient formulas for use in designing networks, which provide the necessary values of the above three key design parameters.

Compact linear lead/lag metamaterial phase shifters for broadband applications

A compact one-dimensional phase shifter is proposed using alternating sections of negative refractive index (NRI) metamaterials and printed transmission lines (TL). The NRI metamaterial sections consist of lumped element capacitors and inductors, arranged in a dual TL (high-pass) configuration. By adjusting the NRI-medium lumped element values, the phase shift can be tailored to a given specification. Periodic analysis is applied to the structure and design equations are presented for the determination of the lumped element parameters for any arbitrary phase shift. To validate the design, various phase shifters are simulated and tested in coplanar waveguide (CPW) technology. It is demonstrated that small variations in the NRI-medium lumped element values can produce positive, negative or 0/spl deg/ phase shifts while maintaining the same short overall length. Thus, the new phase shifter offers some significant advantages over conventional delay lines: it is more compact in size, it exhibits a linear phase response around the design frequency, it can incur a phase lead or lag which is independent of the length of the structure and it exhibits shorter group delays.