Characteristics Of Microstrip Lines Research Articles

Development of a slow-wave artificial dielectric substrate-based microstrip line in X band

This paper presents a slow-wave artificial dielectric substrate for planar microstrip device miniaturization. The proposed substrate supports the improvement of the permittivity of a given substrate, and in turn offers guided wavelength reduction, leading to obtaining size reduction using low cost printed circuit board (PCB) process. In this structure, two rows of metal vias are located on either side of a microstrip line (ML), which are connected to the ground plane of the substrate. In addition, a row of metal mushroom-shaped vias is placed and connected at the center of the line, which is inserted inside the dielectric media. This would lessen the effective distance between the microstrip line and the ground, and so, the capacitance per unit length is increased leading to obtaining a slow-wave substrate. The proposed structure is numerically investigated using full wave software for specified parameters and the microstrip line characteristics are compared with those of the conventional line. A prototype of the introduced line is implemented and its measured propagation features, including phase constant and effective permittivity, are reported. Results show a perfect agreement with those of simulation, which confirms that a 50.6% longitudinal size reduction is feasible.

Development of an analytical method to determine the propagation characteristics of microstrip line on artificial perforated substrates

This paper presents an analytical method to investigate the propagation characteristics of a uniform microstrip line placed on porous substrates. The structure is periodic with a specified unit cell and the substrate is made of cascaded multi-layer dielectric slabs. The proposed method is started by solving wave equation by decomposing Helmholtz operator using appropriate eigen-functions and applying the associated boundary conditions of tangential electromagnetic fields of the unit cell. Then, using Floquet theorem, the equivalent propagation constant of a one-dimensional (1-D) periodic structure is obtained. In addition to, the proposed method is developed for two-dimensional (2-D) structures by a suitable transformation. Several practical structures are considered to verify the accuracy of the proposed method. The comparison of the proposed analytical model and measurement results and those obtained using simulation process provided by High Frequency Simulator Strctures (HFSS) are reported. It is shown that our method can be used for a wide variety of structures to quickly estimate the required parameters with a good accuracy.

Physicochemical Characteristics of Copper Microstrip Lines of Microwave ICs Passivated with Accelerated Argon Ions

It is found that there are difficulties in restoring the initial chemical activity of copper after passivation by means of ion-beam treatment. The physicochemical and electrical parameters of copper coatings passivated with accelerated medium-energy Ar ions, as well as the microwave characteristics of microstrip lines based on them, are investigated. The modes of ion-beam passivation leading to a significant increase in the chemical resistance of copper are ascertained. It is shown that depassivation of ion-passivated copper layers is possible in an oxygen plasma, in etching solutions with hydrofluoric acid, and by treatment with short ultraviolet radiation. Ion-beam passivation leaves the microwave characteristics of copper microstrip lines almost unchanged with an increase in their resistance to oxidation up to 100 times. The results suggest the possibility of using ion-beam passivation technology for the use of ion-passivated copper as an analog of gold in microwave microelectronic devices.

Laser-Scribed Lossy Microstrip Lines for Radio Frequency Applications

Laser-direct writing has become an alternative method to fabricate flexible electronics, whereas the resistive nature of laser-scribed conductors may distort the radio-frequency characteristics of circuits for high-frequency applications. We demonstrate that the transmission characteristics of microstrip lines are insensitive to the resistance of laser-scripted conductors when the sheet resistance is not above 0.32 Ω/□. On the other hand, the transmission and reflection characteristics of the MS lines can be simply modified through the accommodation of the resistance of the conductors, because a laser can trigger the sintering and melting of laser produced silver nanostructures. This could provide an alternative way to fabricate radio frequency (RF) resistors and promote their applications to flexible radio-frequency devices and systems.

Modeling of microstrip line characteristics with side grounded conductors near air–substrate boundary

The modeling of the microstrip line with side grounded conductors located near air-substrate boundary is performed. The dependences of per-unit-length delay and the characteristic impedance on a distance between the grounded conductors are calculated with a change in the height above the boundary and the burying into the substrate. The change of the points of zero sensitivity of the per-unit-length delay to the position of the side grounding conductors over and under the air-substrate boundary is investigated. The possibility of obtaining a minimum (up to zero) sensitivity of the impedance to the height of the side grounding conductors near the air-substrate boundary is revealed.

Analysis of Microstrip Line Fed Patch Antenna for Wireless Communications

AbstractIn this paper, theoretical analysis of microstrip line fed rectangular patch antenna loaded with parasitic element and split-ring resonator is presented. The proposed antenna shows that the dualband operation depends on gap between parasitic element, split-ring resonator, length and width of microstrip line. It is found that antenna resonates at two distinct resonating modes i.e., 0.9 GHz and 1.8 GHz for lower and upper resonance frequencies respectively. The antenna shows dual frequency nature with frequency ratio 2.0. The characteristics of microstrip line fed rectangular patch antenna loaded with parasitic element and split-ring resonator antenna is compared with other prototype microstrip line fed antennas. Further, the theoretical results are compared with simulated and reported experimental results, they are in close agreement.

Signal integrity analysis on discontinuous microstrip line

In high speed PCB design, microstirp lines were used to control the impedance, however, the discontinuous microstrip line can cause signal integrity problems. In this paper, we use the transmission line theory to study the characteristics of microstrip lines. Research results indicate that the discontinuity such as truncation, gap and size change result in the problems such as radiation, reflection, delay and ground bounce. We change the discontinuities to distributed parameter circuits, analysed the steady-state response and transient response and the phase delay. The transient response cause radiation and voltage jump.

Parasitic Compensation Design Technique for a C-Band GaN HEMT Class-F Amplifier

A class-F/inverse class-F load circuit design method that includes parasitic elements such as drain-source capacitance and bonding wire inductance has been developed. For the class-F load circuit design, a reactance function which has zeros at even harmonic frequencies and poles at odd harmonic frequencies is expanded to an -ladder circuit including parasitic elements through the use of the second Cauer canonical form. For the inverse class-F load circuit design, the zero points and the poles are exchanged. One stage of the -ladder circuit can be approximately replaced to a distributed circuit element for higher frequency operation. The proposed method allows parasitic compensation up to an arbitrary harmonic order by adding zeros and poles. Additionally, if distributed circuit elements are used, the method also compensates frequency dispersive characteristics of microstrip lines. According to the proposed method, a class-F amplifier using an AlGaN-GaN HEMT has been fabricated at 5.8 GHz. The fabricated class-F amplifier delivered high efficiency characteristics, with a maximum drain efficiency of 79.9%, a maximum power-added efficiency (PAE) of 71.4%, and an output power of up to 33.4 dBm at 5.86 GHz.

Numerical simulation of wave propagation in Y- and Z-type hexaferrites for high frequency applications

The dispersion characteristics of microstrip lines on magnetically anisotropic substrates are studied utilizing the Galerkin’s method in the spectral domain. Specifically, we calculate the differential phase shifts of devices consisting of Z-type (Zn2Z) and Y-type (Zn2Y) ferrites as a function of applied magnetic field. Our theoretical formulism is effective in modeling highly magnetically anisotropic materials, which are becoming increasingly important for the next generation of microwave devices. Such a theoretical treatment of anisotropic ferrite magnetic materials is presently unavailable in commercial numerical simulation tools.

A Comprehensive Technique to Determine the Broadband Physically Consistent Material Characteristics of Microstrip Lines

This paper describes a method to extract the relative complex dielectric permittivity from propagation coefficient measurements on microstrip lines. The material characteristics of microstrip lines fabricated on two different types of substrates commonly used in microwave circuit and printed circuit boards are investigated. The mechanisms that cause the effective permittivity of microstrip lines to be dispersive are explored. The technique includes creating closed-form effective permittivity equations to relate the effective permittivity of the microstrip lines to the real part of the dielectric permittivity of the substrate. Curve-fitting methods are used to create causal dielectric material models that relate the imaginary part of the dielectric permittivity to its real part. The methods developed in this paper can be used to characterize low-loss dielectric materials whose polarization is dominantly dipolar within the microwave frequency range in high-speed packaging applications.

Left-Handed Characteristics of Ferrite Microstrip Line Magnetized to Wave Propagation

Left-handed characteristics of microstrip line on the longitudinally magnetized ferrite substrate are investigated with both theoretically and experimentally. Transmission characteristics of the line are estimated by using an equivalent circuit model, and the high frequency structure simulator (HFSS) based on the finite element method. Experiments are undertaken using polycrystalline yttrium iron garnet substrate having 30 times 15 mm in thickness of 1 mm. Expected left-handed response within negative permeability region is found and agrees well with theory. Phase shifter tuned by the magnetic field is proposed as an application of the left-handed ferrite line.

Propagation characteristics of microstrip lines with 2D defected ground structures

A compact meander microstrip lines with 2D defected ground structures (DGS) and a microstrip line with a defected ground array (DGA) are proposed in this article. Their excellent bandgap characteristics are verified through simulation and measurements. Furthermore, the loss and slow-wave characteristics and the improved characteristic impedance of the meander microstrip lines with 2D DGS are analyzed and given. Also, a comparison of DGA and vertically periodic DGS is discussed. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.

Computation of Dispersion in Microstrip Line with Anisotropic Substrate and Overlay

This paper presents an analysis of frequency dependent propagation characteristics of microstrip lines with anisotropic substrate and overlay. The method involves setting up of the Green’s functions corresponding to the structure and formulating a dispersion relation in Fourier transform domain. The dispersion relation is constructed in a Galerkin’s procedure. Numerical results are also presented.

Analysis of Open Microstrip and Slot Lines with Semiconductor Substrates

The numerical study of open microstrip lines (MSLs) and slot lines (SLs) with n -Si substrates. Two methods of singular integral equations (SIE) were used in our calculations. The first method we used for solving a problem was based on TEM-approximation and the second method was electrodynamically rigorous. The algorithms that we applied in our computations allowed us to take into account the finite substrate width and the finite metal strip thickness. The electrodynamical characteristics of MSLs on the specific resistivity of the substrate material, the metal strip width, the distance between the metal strip and the substrate lateral edges were investigated in this article. Also the dispersion dependences were determined for the main and higher modes of a noncoplanar SL and coplanar SLs. We presented characteristics of open MSLs and SLs having different crosssections to show the algorithm efficiency. The calculated and measured results agreed when compared to one another.

Measurement and analysis for transmission characteristics of microstrip line covered with lossy magnetic sheet

AbstractFor EMI protection in high‐frequency regions beyond 1 GHz, composite materials made of rubber filled with soft magnetic metal powders have been used. With such materials, resonances in metal casings for amplifiers and coupling between transmission lines can be suppressed. In this paper, to provide a low‐pass‐type filter characteristic to the transmission line on a printed circuit board, a method is studied for covering a microstrip line (MSL) with such a composite material sheet and the necessary analysis is carried out. First, the propagation characteristics and the characteristic impedance of the MSL are derived numerically. Based on such information, the transmission and reflection characteristics as a filter are evaluated. Since the product of the complex relative permeability and the complex relative permittivity of the composite material sheet is larger than that of the substrate in this case, the quasi‐TEM mode approximation does not hold. Hence, the frequency domain finite‐difference (FDFD) method taking into account all electromagnetic field components is used for the analysis of the MSL. In the experiment, S11 and S21 of the MSL with its section coated with a composite material sheet are measured and compared with the analysis results. The computed results exhibit the same tendency as the measured data. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(11): 66–74, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10100

The effect of a thin ferroelectric film on the propagation characteristics of a microstrip transmission line

The properties of a microstrip line (MSL) on a bilayered substrate containing a thin ferroelectric layer are theoretically studied. The propagation parameters are calculated using an approach based on a two-dimensional full-wave electrodynamic model. The influence of the fringing electric field in the ferroelectric layer on the MSL characteristics is studied. It is shown that correct modeling of microwave devices based on bilayered substrates with ferroelectric layers must take into account the properties of these layers even despite very small thickness.

Coupling Characteristics of Microstrip Lines through an Elliptical Slot

AbstractMonolithic microwave integrated circuits are useful for miniaturization, weight reduction, and performance enhancement of components at microwave and millimeter‐wave frequencies. In this paper, a simple method is proposed for analysis of the coupling characteristics of laminated microstrip lines through an elliptical slot in the common ground plane. The results of the analysis by this method are presented and are compared with experimental values, demonstrating the effectiveness of the method. In this method, an elliptical slot is subdivided into infinitesimal rectangular slots. The characteristics of individual infinitesimally small rectangular slots are synthesized by means of the theory of multihole directional couplers to allow analysis of the coupling characteristics by an elliptical slot. The characteristics by individual slots are derived by means of the conventional theory. In this paper, the derivation is made more rigorous. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 85(1): 13–21, 2002

Characteristics of microstrip line on YIG–GGG substrate under arbitrary orientation of magnetization

AbstractThe propagation characteristics of a microstrip line printed on a YIG/GGG film are analyzed by the spectral‐domain approach for arbitrary orientation of the bias magnetic field. The nonreciprocal property of the YIG film is explored by studying the characteristics of the forward and backward wave. The change in differential phase shift with frequency obtained due to arbitrary orientation of the bias magnetic field finds application in microwave signal processing. © 2002 John Wiley & Sons, Inc. Microwave Opt Technol Lett 32: 29–35, 2002.

Formulas of microstrip with a truncated substrate by synthetic asymptotes: a novel analysis technique

A substrate is usually truncated far enough to avoid disturbing the microstrip-line characteristics. Such uneconomical practice is not necessary if the disturbances as a function of truncation are known in formulas and, therefore, are easily compensated. This paper derives the desired formulas from the novel technique of synthetic asymptotes. Truncation at both sides of a line is derived here with 3% average error. For the practical one-sided truncation at the edge of a chip or circuit board, the average error is only half at 1.5%.

QuasistaticRLCG parameters of lossy microstrip line for CAD application

This paper presents a closed-form model for primary line constants, i.e., R, L, C, and G, for a lossy microstrip line for CAD application. The present model easily determines the microstrip line characteristics, i.e., the effective dielectric constant, complex characteristic impedance, and total attenuation due to dielectric and conductor losses. The model has an average accuracy of 1% as compared to the experimental results and the results of other numerical methods. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 28: 209–212, 2001.