Coupled Strip Lines Research Articles

Ka-Band Wide-Angle Scanning Phased Array with Dual Circular Polarization

A wide-angle scanning phased array with dual circular polarization in the Ka-band is presented in this paper. To improve the scanning capability of the phased array, the microstrip element is modified by loading many metal posts at its center and periphery. In addition, a stripline coupler is designed to achieve dual circularly polarized (CP) radiation, and the inner conductor of the subminiature micro-push-on (SSMP) connectors for feeding the coupler is extended to the top layer of the multilayer element by introducing an open stub, which simplifies the assembly process between the SSMP connector and multilayer printed circuit board (PCB) due to through-hole soldering instead of blind-hole soldering. The proposed element can cover a frequency range from 28 GHz to 30.5 GHz with a relative bandwidth of 8.5% in the Ka-band. An 8 × 8 phased array is constructed based on this proposed element, and a wide-angle scanning range from −65° to +65° is obtained for the dual circular polarization. The proposed array has a gain fluctuation of 5.1 dB and an axial ratio (AR) of less than 3.3 dB during beam-steering. The prototype is fabricated and measured, with a good agreement between the measured and simulated results. The proposed phased array can be applied in a Ka-band millimeter-wave (MMW) communication system.

Ultra-Wideband Dual-Circularly Polarized Crossed-Dipole Antenna With Stripline Coupler and Parasitic Elements for Vehicular Sensing and Communications

Ultra-Wideband Dual-Circularly Polarized Crossed-Dipole Antenna With Stripline Coupler and Parasitic Elements for Vehicular Sensing and Communications

3D конструкции связанных линий и их применение в CВЧ устройствах

The review discusses 3D designs of coupled strip lines and their application in microwave devices. It is noted that 3D designs of coupled strip lines have advantages over other strip structures due to the possibility of forming a strong electromagnetic coupling between the strips. This result is achieved by simple technological methods, such as installing a vertical substrate with soldering (or welding) of conductors oriented horizontally and vertically on the substrates, respectively. The article briefly covers the history of development and provides a classification of these structures. The advantages and disadvantages of devices built based on such structures are analyzed. Methods for analyzing them and improving their characteristics are considered. It is emphasized that three-dimensional designs of coupled strip lines represent a promising direction in the development of microwave technologies and can be widely used in various devices.

Design of Absorptive Common-Mode Filters Based on Coupled Stripline λ/4 Resonator

Design of Absorptive Common-Mode Filters Based on Coupled Stripline λ/4 Resonator

A Compact Broadside Coupled Stripline 2-D Beamforming Network and Its Application to a 2-D Beam Scanning Array Antenna Using Panasonic Megtron 6 Substrate.

This article presents a 4-way 2-D butler matrix (BM)-based beamforming network (BFN) using a multilayer substrate broadside coupled stripline (BCS). To achieve the characteristics of a compact, wide-bandwidth, high-gain phased array, a BCS coupler is implemented using the Megtron 6 substrate. The compact 2-D BFN is formed by combining planarly two horizontal BCS couplers and two vertical BCS couplers. The BFN is proposed without a crossover and without a phase shifter, generating phase responses of ±90° in the x- and y-directions, respectively. The proposed BFN exhibits a wide operating band of 66.7% (3-7 GHz) and a compact physical area of just 0.25 λ0 × 0.25 λ0 × 0.04 λ0. The planar 2-D BFN is easily integrated with the patch antenna radiation elements to construct a 2-D multibeam array antenna that generates four fixed beams, one in each quadrant, at an elevation angle of 30° from the broadside to the array axis when the element separation is 0.6 λ0. The physical area of the 2-D multibeam array antenna is just 0.8 λ0 × 0.8 λ0 × 0.04 λ0. The prototypes of the BCS coupler, the 2-D BFN, and the 2-D multibeam array antenna were fabricated and measured. The measured and simulated results were in good agreement. A gain of 9.1 to 9.9 dBi was measured.

Parametric Modeling of Coupled Stripline Coupler with Arbitrary Operating Frequency and Coupling Coefficient in Silicon-Based 3D RF Integration

Parametric Modeling of Coupled Stripline Coupler with Arbitrary Operating Frequency and Coupling Coefficient in Silicon-Based 3D RF Integration

1-D and 2-D Beam Steering Arrays Antennas Fed by a Compact Beamforming Network for Millimeter-Wave Communication

In this article, a new Beamforming Network (BFN) realized in Broadside Coupled Stripline (BCS) is proposed to feed 1 × 4 and 2 × 2 arrays antenna at 28 GHZ-Band. The new BFN is composed only of couplers and phase shifters. It doesn't require any crossover compared to the conventional Butler Matrix (BM) which requires two crossovers. The tight coupling and low loss characteristics of the BCS allow a design of a compact and wideband BFN. The new BFN produces the phase differences of (±90°) and (±45°, ±135°) respectively in x- and y-directions. Its integration with a 1 × 4 linear array antenna reduces the array area by 70% with an improvement of the gain performance compared with the conventional array. The integration with a 2 × 2 array allows the realization of a full 2-D beam scanning. The proposed concept has been verified experimentally by measuring the fabricated prototypes of the BFN, the 1-D and 2-D patch arrays antennas. The measured 11.5 dBi and 11.3 dBi maximum gains are realized in θ0 =14° and (θ0, ϕ0)=(45°,345°) directions respectively for the 1-D and 2-D patch arrays. The physical area of the fabricated BFN is only (0.37λ0 × 0.3λ0 × 0.08λ0), while the 1-D array and 2-D array antennas areas without feeding transmission lines are respectively (0.5λ0 × 2.15λ0 × 0.08λ0) and (0.9λ0 × 0.8λ0 × 0.08λ0).

A 2-D Beam Scanning Array Antenna Fed by a Compact 16-Way 2-D Beamforming Network in Broadside Coupled Stripline

A 2-D beam scanning array antenna fed by a compact 16-way 2-D beamforming network (BFN) designed in Broadside Coupled Stripline (BCS) is addressed. The proposed 16-way 2-D BFN is formed by interconnecting two groups of 4x4 Butler Matrix (BM). Each group is composed of four compact 4x4 BMs. The critical point of the design is to propose a simple and compact 4x4 BM without crossover in BCS to achieve a better transmission coefficient of the 16-way 2-D BFN with reduced size of merely 0.8λ0 × 0.8λ0 × 0.04λ0. Moreover, the complexity of the interface connection between the 2-D BFN and the 4x4 patch array antenna is reduced by using probe feeding. The 16-way 2-D BFN is able to produce the phase shift of ±45°, and ±135° in x- and y- directions. The 2-D BFN is easily integrated under the 4x4 patch array to form a 2-D phased array capable of switching 16 beams in both elevation and azimuth directions. The area of the proposed 2-D beam scanning array antenna module has been significantly reduced to 2λ0 × 2λ0 × 0.04λ0. A prototype operating in the frequency range of 4-6GHz is fabricated and measured to validate the concept. The measurement results agree well with the simulations.

A simple decoupling method applied in gain improvement of a planar array antenna

AbstractA 4 × 4 patch array antenna based on loading shorting vias is proposed in this letter. The excitation method of the array antenna adopts stripline coupling feed, leading to a strong mutual coupling between the adjacent elements. The realized gain and impedance match are deteriorated seriously. Then, eight groups of metallic vias are introduced to the array antenna. By adjusting their number and spacing, the radiation performance of the array antenna can be improved significantly. Finally, the experiment results show that the proposed array antenna resonates at 5.4 GHz. Compared with the antenna without shorting vias, one resonance point caused by the mutual coupling can be removed within 5.34 GHz to 5.46 GHz. The gain drops unexpectedly, which is improved as well.

Study of Dependence of Capacitance of Coupled Stripline on Stripwidth, Frequency and Spacing Between Two Striplines

In this present paper, we studied about the dependance of capacitance of coupled stripline on strip width, frequency and spacing between two striplines. Miniaturized microwave circuits fabricated by extension of integrated circuits (ICs) technology to microwave frequencies are known as Microwave Integrated Circuits (MICs). MICs promise a real revolution leading to both expansion of present markets of microwaves & opening of many new applications including host of non-military uses in India & abroad. With the advent of MICs planar Transmission Lines have been developed which have been proved to be very significant as regards the fabrication of various microwave-components such as: Directional Coupler, Filters, Isolator & Impedance transformers etc. The planar Transmission Lines are: Stripline, Microstripline, Slot line, Coplanar Striplines & their different variant forms such as inverted and suspended striplines & microstriplines etc. Among these microstripline is the most suited due to its open structure, low losses in gigaharz range of frequency, reduced size, improved reliability and eventual cost reduction in mass production. The microstrip transmission line consists of a narrow strip conductor separated from a conducting ground plane by an intervening supporting dielectric substrate as studied by Wheeler and others. The electromagnetic traveling through such structures suffers from some losses like: Conductor loss & Dielectric loss. There is a change of phase of the wave traveling through the structure also. This phase change (shift) depends on the width of metal strip, height of the dielectric substrate, permittivity of the substrate and operating frequency. The present study is devoted to this objective i.e. we have to study the variation of Phase-Shift of the wave within the structure with width of the stripline, height & effective permittivity of the structure & frequency.

3D Printed Dual-Band Microwave Imaging Antenna

Microwave imaging utilizes low-power near-field electromagnetic fields at microwave frequencies to detect the internal structure of an object. Sufficient resolution through the thickness is crucial in biomedical applications to detect small objects of concern. Parameters such as the frequency of microwave signals, the design, and the material of the antenna are the most important factors to consider for microwave-based biomedical sensing. The proposed antenna yields merits of: compactness in size, ease of fabrication, wider impedance bandwidth, simple design, and good RF performance. An Asymmetric-fed Coupled Stripline (ACS) antenna is 3D-printed on an FR4 substrate with return loss measurements ranging from 2 GHz to 20 GHz. The impedance bandwidth is obtained between 6 GHz to 8 GHz and 15 GHz to 17 GHz. The proposed microwave antenna was simulated using Ansys HFSS. The parameters are designed to ensure optimum radiation efficiency. The radiation patterns obtained were omnidirectional in H-plane and bidirectional in E-plane.

Evaluation of Spurious Emission of New System of Wireless Power Transfer

The operation of system of wireless power transfer is considered in the paper. System design is based on the use of coupled strip lines. Considered system is distinguished from known coupled strip line by the coiling of strip lines into spiral. Mentioned approach ensures the softening the demands of mutual positioning the system elements and it leads to space saving. The main attention within the system of wireless power transfer operation is paid to spurious emission. It was shown the negative affect of system under consideration onto biological objects is negligible at relative high value of wireless transferred power

Синтез связанных полосковых линий с гетерогенным диэлектрическим заполнением

Using the example of coupled strip lines with horizontally and vertically arranged strip conductors, the solution of the inverse problem of finding relative permittivity according to a given ratio of phase velocities of in-phase and antiphase waves propagating in the lines is shown. Per unite capacitances are defined as the sum of partial capacitances in the selected subdomains of the strip structure, in which the accumulated energy of the electric field was calculated. Examples of the synthesis of coupled line structures with a given ratio of phase velocities are shown.

Directional microwave coupled-line couplers with high lateral coupling level

Classic сoupled-line couplers with a high lateral coupling level by type of directivity are counterdirectional. Restrictions on their synthesis are imposed by the gap between transmission lines, which must be extremely small (tens of microns), the difference in the phase velocities of even and odd modes, which must be compensated and others. This makes it difficult of manufacturing couplers. Described in technical literature сoupled-line couplers with a high lateral coupling level with changed types of directivity are either quite bulky or have small dimensions due to the use of discrete inductors and capacitances, which complicates the technological process with surface mounting when implementing the final device. In this article we propose a compact сoupledline coupler with a high lateral coupling level, which implements power transfer to a single port (0 dB, crossover). The coupler topology uses periodic loops that are located between сoupled-line. The equivalent circuit of the coupled lines was calculated and analyzed for a single periodic stub. This allowed us to determine the necessary parameters and dimensions of the topology. The device is narrow-band (3 GHz ± 5 %), transmission coefficient minus 0.44 dB at the center frequency of 3 GHz, isolation for isolated ports is not less than 35 dB. The proposed compact coupler with a coupling level of 0 dB suits building distribution circuits in which it is necessary to exclude the intersection of transmission lines. The information on the synthesis of the 3 dB co-directional microwave coupler on coupled strip lines with lateral electromagnetic coupling is given. The coupler is characterized by a high isolation level with an isolated port, not less than 40 dB. The imbalance of the amplitudes between the working (through and connected) and the input port is minus (3.4 ± 0.8) dB.

Wideband stripline compact directional coupler with lumped-element compensating filter

This paper presents a design and fabrication of a wideband high power stripline directional coupler. The coupler has 50 dB coupling in the frequency range of 30 to 520 MHz. The design method consists of two steps. At the first step, a stripline coupler is designed by combination two directional coupler and connecting the through ports to each other. Then miniaturizing technique is used to compact the dimensions. At the second step, two lumped-element filter compensating circuits are used in series with the coupling and isolating ports of the coupler to flatten the overall coupling response of the coupler over multioctave frequency bands. This coupler is fabricated on Rogers 4003 substrate with dielectric constant of 3.55. The dimensions of the coupler are 25 × 28 mm2 which are very compact considering its operation frequency. The measurements have a good agreement with predicted results which is verifies the feasibility of the directional coupler.

An experimental research of the ultra-wideband pulse propagation in a transdirectional coupler based on coupled striplines

The propagation of short picosecond pulses in coupled strip lines with a phase velocity ratio of odd and even modes of 3:1 is considered. The feature of the separation of the input pulse between the three output ports without significant loss of energy due to reflection from the input in transdirectional couplers based on coupled strip lines is experimentally shown. As a result of the analysis, it was found that the spectral components of the pulse are separating between the ports of the transdirectional coupler.

Расчетно-экспериментальный метод анализа волн в нерегулярных связанных полосковых линиях с сосредоточенными неоднородностями

Расчетно-экспериментальный метод анализа волн в нерегулярных связанных полосковых линиях с сосредоточенными неоднородностями

Influence of stripline coupling on the magnetostatic mode line width of an yttrium-iron-garnet sphere

We study the effect of stripline coupling on the damping of magnetostatic modes in an yttrium-iron-garnet sphere. Both the magnetostatic dispersion and line width display a pronounced dependence on the YIG-stripline separation, with the coupling dominating the line width for small separations. By suppressing the coupling effect we use a broadband technique to measure both the Gilbert damping, α = (6.5 ± 0.5) × 10−5, and the inhomogeneous broadening which is mode dependent and as small as 0.075 MHz. Our study therefore reveals the importance of, and a method for, exploring the influence of coupling on damping, which may be useful for future device characterization and design.

Dependence of high density nitrogen-vacancy center ensemble coherence on electron irradiation doses and annealing time

Negatively charged nitrogen-vacancy (NV−) center ensembles in diamond have proved to have great potential for use in highly sensitive, small-package solid-state quantum sensors. One way to improve sensitivity is to produce a high-density NV− center ensemble on a large scale with a long coherence lifetime. In this work, the NV− center ensemble is prepared in type-Ib diamond using high energy electron irradiation and annealing, and the transverse relaxation time of the ensemble—T2—was systematically investigated as a function of the irradiation electron dose and annealing time. Dynamical decoupling sequences were used to characterize T2. To overcome the problem of low signal-to-noise ratio in T2 measurement, a coupled strip lines waveguide was used to synchronously manipulate NV− centers along three directions to improve fluorescence signal contrast. Finally, NV− center ensembles with a high concentration of roughly 1015 mm−3 were manipulated within a ~10 µs coherence time. By applying a multi-coupled strip-lines waveguide to improve the effective volume of the diamond, a sub-femtotesla sensitivity for AC field magnetometry can be achieved. The long-coherence high-density large-scale NV− center ensemble in diamond means that types of room-temperature micro-sized solid-state quantum sensors with ultra-high sensitivity can be further developed in the near future.

Optimization of Coupled Stripline Microinductors in Power Supply on Chip Applications

Coupled inductors offer significant advantages over their uncoupled counterparts; however, with these advantages come a number of additional design caveats. The factors affecting the design and optimization of coupled stripline microinductors for PwrSoC applications are outlined, which include device area, the number of coupled phases, duty cycle, paralleling of coupled inductors, switching frequency, as well as thermal and saturation constraints. Results of this analysis are presented and discussed along with guidelines for the design of coupled stripline microinductors, which show that paralleling coupled inductors is the best route toward higher output current. Analytical models predict a peak inductor efficiency of 86.8% and 86.3% for fabricated 3 and 5-phase coupled stripline microinductors with an Ni45Fe55 core, respectively. Models are verified by measurements on prototype 3 and 5-phase converters with parallel coupled stripline microinductors over a range of operating conditions.