Symmetric Stripline Research Articles

A compact four-band high-isolation quad-port MIMO antenna for 5G and WLAN applications

A miniaturized quad-port multiple-input-multiple-output (MIMO) antenna, generating four-band and high port isolation properties, is developed for 5G and wireless local area network (WLAN) applications. The realized MIMO antenna consists of four elements. Each element combines multiple L-shaped and rectangular branches with concave grounds, so that good impedance matching in four frequency bands is reached. The four elements are orthogonally placed to reduce current coupling. Moreover, four pairs of rotationally symmetrical strip lines are added to further improve the isolation between the units at low frequency. The antenna has been optimized to achieve a compact size of 39 mm × 39 mm × 1.6 mm, covering three 5G bands (2.6/3.5/4.8 GHz) and the 5.8 GHz WLAN band. In addition, inter-port isolation is better than 21.5 dB. Furthermore, the measured envelop correlation coefficient is smaller than 0.012 in the desired bands. Measurements also show that the radiation patterns and gains of the fabricated antenna agree well with the simulated ones. The diversity gain is as good as 9.94 dB. Moreover, the channel capacity loss is satisfactory, being below 0.4 bits/s/Hz. Satisfactory efficiency and diversity performance are realized. These facts indicate that the antenna system is a promising candidate for MIMO usage on 5G and WLAN devices.

Technical realization of the device for integrated monitoring of the parameters of the microwave path

Two designs of a microwave sensor have been developed for a device for built-in monitoring of microwave path parameters, built on the basis of a broadband quadrature measurement method. The first sensor design is made on the basis of a symmetrical strip line, the second - on the basis of a segment of a coaxial line. Each of the microwave sensor designs consists of three parts: a directional coupler and two non-directional measuring probes. The microwave sensor is designed to operate in the 1 - 2 GHz frequency range. The paper also proposes a variant of the circuitry implementation of the built-in microwave control device, which implements the procedure for broadband automatic measurement of the complex reflection coefficient and the power level in the microwave path based on the method of quadrature measurements. The device solves the problem of long-term automatic monitoring of parameters and timely detection of the beginning degradation of the antenna-feeder path.

Design of 4 × 4 and 8 × 8 Filtering Butler Matrices Utilizing Combined 90° and 180° Couplers

In this article, a novel design approach for designing 4×4 and 8×8 filtering Butler matrices is proposed. The matrices, composed of combined 90° couplers and 180° filtering couplers as well as phase shifters, provide incremental phase shifts and a bandpass filter performance. The detailed design process and synthesis method for the Butler matrices are presented. A three-layer symmetrical stripline structure is used to realize the Butler matrix, allowing a fully planar structure without interlayer connections. For experimental verification, two prototype 4×4 and 8×8 filtering Butler matrices, operating at the center frequency of 2.4 GHz with a bandpass response, are devised, manufactured, and tested. The test results match well with the simulation ones. Based on the measurements, array factors have been calculated, which further indicate the acceptance of the measured results.

Modeling the distribution line form of surface electromagnetic wave and calculating the transmission coefficient of a symmetric strip line

The work is devoted to the analysis of the dependence of the dielectric properties of highly conducting anisotropic materials from the magnitude and the direction of the magnetic field. A nonlinear model of propagation of a surface electromagnetic wave in a planar bismuth waveguide located in a quantizing magnetic field is considered. As a result of the simulation of the shape of the magneto-optical experiment line, a software package in the JavaScript language for calculating the dielectric constant and the bismuth conductivity tensor for each direction (binary, bisector and trigonal) is presented.

System for wireless power transfer

The issues of wireless power transfer over short distances are considered. The approach may be used for wireless charging of batteries in unmanned vehicles. It is proposed to use the technique of microstrip structures for power transfer. The microstrip structures form a directional coupler on symmetrical strip lines when approaching by front parts. The length of the interaction lines is chosen several times longer than a quarter of the wavelength. Ballast resistors are excluded from the circuit. This approach leads to small losses of power transfer when the distance between microstrip structures changes over a wide range. Modeling of the operation of the power transfer system has been carried out, an experimental sample has been made and experimental studies have been carried out. The simulation and experiment are well accorded.

Расчет коэффициента пропускания симметричной полосковой линии и моделирование формы линии распространения поверхностной электромагнитной волны

Расчет коэффициента пропускания симметричной полосковой линии и моделирование формы линии распространения поверхностной электромагнитной волны

Symmetric stripline duplexer

The compact duplexer using the symmetric stripline and containing the fifth-order comb filters in transmit channel TX (2300–2370 MHz) and receive channel RX (2510–2580 MHz) is constructed, and the characteristics of obtained duplexer are measured. This duplexer is built using dielectric material Al2O3 (Alumina, polikor) with high thermal conductivity that makes it possible to use the operating power of 10 W at small dimensions 57´11.8´4 mm. The losses in bandpass of TX and RX filters did not exceed 3 dB during the filter attenuation at adjacent channel frequencies of no less than 60 dB. It is shown that the selection of the width of metallized strip at the base of quarter-wave resonators makes it possible to change the duplexer width for attaining the required value. The circuit of coupling of resonators with loads used in this design made it possible to obtain a sufficiently high level of isolation from each other for RX and TX channels of duplexer. This level does not exceed 60 dB. The finite thickness of internal conductors of stripline amounting to 16 mm is taken into account while building the duplexer that results in good agreement between the simulation and measurement results.

Combline filters designed on symmetric stripline

Problems arising during the design of stripline combline filters, which until quite recently were considered as all-stop microwave structures, are considered. It has been shown that the electromagnetic coupling coefficient of quarter-wave stripline resonators increases with the value of material permittivity er, the operating frequency, and the thickness of the filter resonators. For er = 92 and a thickness of stripline resonators of 4 mm, it exceeds 12% at frequencies higher than 2.2 GHz. Two alternative versions of combline filters have been designed: a filter with a coupling strip and a filter without a coupling strip. Experimental data for a nine-resonator combline filter with a thickness of 4 mm, er = 9.7, and the center frequency f 0 = 2.4 GHz are presented. A method for increasing the selectivity of combline filters with the same number of resonators is proposed. It has been found that amplitude–frequency responses of stripline combline filters are near-symmetric, unlike the responses of microstrip combline filters.

Theoretical Model of the Stripline Measurement Cell for Doped Diamond Films

A method for measurement of electrophysical properties of delta-doped diamond samples loaded into the measurement cell based on symmetrical stripline is demonstrated. The simulation of S-parameters of the measurement cell with doped diamond samples is carried out. The influence of the carrier density on the transmission characteristics of the symmetric stripline with doped diamond film is investigated. An increase of the carrier density in the doped diamond film from 5·1019 m-3 to 1022 m-3 leads to frequency shift of transmission characteristic minimum from 15.85 GHz to 16 GHz and increasing of incretion losses from -15 dB to -25 dB.

Coupling coefficient of quarter-wave resonators as a function of parameters of comb stripline filters

The relationship of the coupling coefficient of quarter-wave resonators operating on the main resonance frequency f0 as a function of different parameters of comb filters made of sections of symmetric striplines has been analyzed. It has been found out that the coupling coefficient increases with the rise of relative dielectric permittivity of striplines, their thickness and the resonance frequency. The measured characteristics of the stripline 4-resonator comb filter with central frequency f0 = 2.4 GHz built on dielectric material with er = 9.7 are also presented.

A new measurement method for electrode gain in an orthogonally symmetric beam position monitor

The new beam position monitor (BPM) system of the injector at the upgrade project of the Hefei Light Source (HLS II) has 19 stripline beam position monitors. Most consist of four orthogonally symmetric stripline electrodes. Differences in electronic gain and mismachining tolerance can cause changes in the beam response of the BPM electrodes. This variation will couple the two measured horizontal positions, resulting in measuring error. To alleviate this effect, a new technique to measure the relative response of the four electrodes has been developed. It is independent of the beam charge, and the related coefficient can be calculated theoretically. The effect of electrode coupling on this technique is analyzed. The calibration data is used to fit the gain for all 19 injector beam position monitors. The results show the standard deviation of the distribution of measured gains is about 5%.

Design and experimental investigation of stripline antennas

The results of development and experimental investigation of several centimeter-wave planar antennas are presented. The antennas contain a multichannel stripline power divider and a 2D periodic array of slot radiators excited by symmetric strip lines. A single-polarization antenna, an antenna with two linear polarizations, and an antenna with two circular polarizations are analyzed. The results of measuring the basic parameters of these antennas (the gain, the radiation pattern, and the cross-polarization level) are presented. Specific features of the design of such antennas and possible means of improvement of their performance characteristics are discussed.

Closed-Form Expressions for the Current Densities on the Ground Planes of Asymmetric Stripline Structures

In this paper, closed-form expressions for the current density on the ground planes of an asymmetric stripline structure are derived. The derivation utilizes image theory in order to obtain a suitable quasi-static Green's function for this asymmetric geometry. For the special case of a symmetric stripline geometry and the limiting case of a microstrip line, it is demonstrated that the results obtained here reduce to previously derived results. As expected, it is illustrated that the current densities on the ground planes of an arbitrary asymmetric stripline are bounded by the current distribution of a symmetric stripline and that of a microstrip line. The validity of the analytical results is investigated by comparing to numerically obtained results. Finally, expressions are presented for the total ground-plane currents as fractions of the total current on the signal trace

A variational calculation for higher order mode cutoff frequencies of a symmetrical strip line by conformal mapping

AbstractThe cutoff frequencies of higher order modes in a symmetrical strip line are calculated using the variational finite‐element method combined with conformal mapping. Conformal mapping is used to improve the modeling of the infinite transverse extents of a strip line. Then the finite‐element method is employed to solve the variational equation in the transformed finite region. Comparisons with numerical results found in the literature validate the presented method. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 32: 449–452, 2002.

Excitation and Reception of Electromagnetic, Magnetostatic and Spin Waves in Ferrite Films

The paper presents a new universal formulation of electromagnetic fields in microwave ferrite-dielectric waveguiding structures from the given magnetic field distribution of an external source. The solution is derived from the linearized Landau-Lifshits equation using an orthogonality condition for eigenwaves of a magnetization. The magnetization excited in ferrite is obtained in an electrodynamic, magnetostatic or dipole-exchange approximation, depending on the approximation used for eigenwaves. Results are applied for the formulation and the analytical solution of self-consistent electrodynamic problems of an excitation and a reception of waves in ferrite films by transmission lines of an arbitrary type. Numerical calculations are performed for filters and delay lines on the base of symmetric strip-lines using surface and forward volume magnetostatic waves in ferrite films.

Low-cost printed collinear array antenna

This paper presents the design and antenna-prototype measurements of a low-cost antenna for DECT and LMDS system base stations (3400 to 3600 MHz). The specified pattern must be omnidirectional in the horizontal plane, having a maximum at the horizon. To produce this pattern, a linear array of printed patches, placed on both sides of a planar feeding structure, is designed The feeding structure is a symmetrical stripline, made with low-cost materials and designed to simplify the implementation tasks as much as possible.

Enhanced stripline scanning array

Previous work demonstrating the successful beam scanning of a three-element array, with integral low bias strength ferrite phase shifters, is extended to show significant improvement by implementing the structure as symmetrical stripline. The maximum beam scan angle is increased by 30% over that of the microstrip array.

Excitation and Reception of Electromagnetic, Magnetostatic and Spin Waves in Ferrite Films - Abstract

The paper presents a new universal formulation of electromagnetic fields in microwave ferrite-dielectric waveguiding structures from the given magnetic field distribution of an external source. The solution is derived from the linearized Landau-Lifshits equation using an orthogonality condition for eigenwaves of a magnetization. The magnetization excited in ferrite is obtained in an electrodynamic, magnetostatic or dipole-exchange approximation, depending on the approximation used for eigenwaves. Results are applied for the formulation and the analytical solution of self-consistent electrodynamic problems of an excitation and a reception of waves in ferrite films by transmission lines of an arbitrary type. Numerical calculations are performed for filters and delay lines on the base of symmetric strip-lines using surface and forward volume magnetostatic waves in ferrite films.

Impedance Control of Conductors Acting as Transmission Lines in Printed Boards for High‐frequency Digital Applications

High‐frequency performance of printed boards (PBs) — a term which encompasses printed wiring boards (PWBs) and printed circuit boards (PCBs) — is becoming increasingly important in digital circuits and knowledge of the electrical characteristics associated with conductors acting as transmission lines is essential. This paper is an introduction to the electrical theory associated with transmission lines and develops the fundamental principles into formulae of use to PB users, designers and manufacturers. Established equations for calculating propagation delay and characteristic impedance based on physical parameters of conductor configurations are then summarised. The concept of ‘critical conductor length’ is proposed as a method of ascertaining whether control of characteristic impedance is required for a particular transmission line. The paper uses the surface microstrip configuration as a vehicle for mathematical analysis but the analysis is equally applicable to other transmission line configurations such as embedded microstrip, symmetrical stripline and dual stripline for which the associated physical parameter equations are included.

Interband magnetooptic absorption line shape in bismuth

The results of an investigation of the transmission of a symmetric bismuth stripline at T=80 K at the laser wavelength λ=10.6 µm in magnetic fields up to B=8 T are reported. A set of parameters is obtained for the energy spectrum of the L electrons of bismuth by modeling the shape of the experimental curve on the basis of a modified Baraff model. The values of the parameters in the McClure-Choi model are found from an analysis of the field positions of the maxima of the mageto-optic oscillations.