scholarly journals Differential Bi-Level Microstrip Directional Coupler with Equalized Coupling Coefficients for Directivity Improvement

Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 547
Author(s):  
Slawomir Gruszczynski ◽  
Robert Smolarz ◽  
Krzysztof Wincza
Keyword(s):  
Coupling Coefficient ◽  
Dielectric Layer ◽  
Directional Coupler ◽  
Capacitive Coupling ◽  
Coupling Coefficients ◽  
Coupled Line ◽  
Line Section ◽  
Measurement Results

In this paper, a bi-level microstrip differential directional coupler has been investigated. It has been shown that the equalization of coupling coefficients can be successfully made with the use of appropriate dielectric stack-up and conductor geometry. The application of additional top dielectric layer can ensure proper equalization of coupling coefficients by lowering the value of capacitive coupling coefficient to the value of the inductive one. The theoretically investigated coupled-line section has been used for the design of a 3-dB differential directional coupler. The measurement results are compared with the theoretical ones.

Application of RH and LH sections for reduction of coupling coefficients in two-section asymmetric directional couplers

2015 ◽  
Vol 8 (3) ◽  
pp. 559-565 ◽  
Author(s):  
Jakub Sorocki ◽  
Kamil Staszek ◽  
Ilona Piekarz ◽  
Krzysztof Wincza ◽  
Slawomir Gruszczynski
Keyword(s):  
Theoretical Analysis ◽  
Transmission Lines ◽  
Directional Coupler ◽  
Center Frequency ◽  
Coupling Coefficients ◽  
Directional Couplers ◽  
Coupled Line ◽  
Left Handed ◽  
Design Flexibility

A method allowing for reduction of coupling coefficients required for realization of two-section asymmetrical coupled-line directional couplers has been proposed. It has been shown that by connecting uncoupled left-handed and right-handed transmission lines between two coupled-line sections one can obtain greater design flexibility of the resulting circuit, simultaneously with the coupling reduction in coupled-line sections. Moreover, the proposed circuit features the properties of two-section asymmetric directional couplers offering wide operational bandwidth. The theoretical analysis has been verified by measurements of a 3 dB directional coupler operating at the center frequency f0 = 1.5 GHz having coupling imbalance δC = ±0.4 dB and bandwidth 0.75–2.3 GHz.

scholarly journals A balanced-to-balanced directional coupler based on branch-slotline coupled structure

Frequenz ◽  
2020 ◽  
Vol 74 (11-12) ◽  
pp. 427-433
Author(s):  
Yaxin Liu ◽  
Feng Wei ◽  
Xiaowei Shi ◽  
Cao Zeng
Keyword(s):  
Directional Coupler ◽  
Return Loss ◽  
Design Method ◽  
Differential Mode ◽  
Arbitrary Power ◽  
Measurement Results ◽  
Transition Structures ◽  
Coupled Structures ◽  
Better Than ◽  
Good Agreement

AbstractIn this paper, a balanced-to-balanced (BTB) branch-slotline directional coupler (DC) is firstly presented, which can realize an arbitrary power division ratios (PDRs). The coupler is composed by microstrip-to-slotline (MS) transition structures and branch-slotline coupled structures. The single-ended to balanced-ended conversion is simplified and easy to implemented by the MS transition structures, which intrinsically leads to the differential-mode (DM) transmission and common-mode (CM) suppression. Moreover, the different PDRs which are controlled by the widths of branch-slotlines can be achieved. In order to verify the feasibility of the proposed design method, two prototype circuits of the proposed coupler with different PDRs are fabricated and measured. The return loss and the isolation of two designs are all better than 10 dB. Moreover, the CM suppressions are greater than 35 dB. A good agreement between the simulation and measurement results is observed.

Modeling the Atmospheric Boundary Layer Wind Response to Mesoscale Sea Surface Temperature Perturbations

2014 ◽  
Vol 142 (11) ◽  
pp. 4284-4307 ◽  
Author(s):  
Natalie Perlin ◽  
Simon P. de Szoeke ◽  
Dudley B. Chelton ◽  
Roger M. Samelson ◽  
Eric D. Skyllingstad ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Coupling Coefficient ◽  
Eddy Viscosity ◽  
Sea Surface ◽  
Coupling Coefficients ◽  
Wind Response ◽  
Speed Response

Abstract The wind speed response to mesoscale SST variability is investigated over the Agulhas Return Current region of the Southern Ocean using the Weather Research and Forecasting (WRF) Model and the U.S. Navy Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS) atmospheric model. The SST-induced wind response is assessed from eight simulations with different subgrid-scale vertical mixing parameterizations, validated using Quick Scatterometer (QuikSCAT) winds and satellite-based sea surface temperature (SST) observations on 0.25° grids. The satellite data produce a coupling coefficient of sU = 0.42 m s−1 °C−1 for wind to mesoscale SST perturbations. The eight model configurations produce coupling coefficients varying from 0.31 to 0.56 m s−1 °C−1. Most closely matching QuikSCAT are a WRF simulation with the Grenier–Bretherton–McCaa (GBM) boundary layer mixing scheme (sU = 0.40 m s−1 °C−1), and a COAMPS simulation with a form of Mellor–Yamada parameterization (sU = 0.38 m s−1 °C−1). Model rankings based on coupling coefficients for wind stress, or for curl and divergence of vector winds and wind stress, are similar to that based on sU. In all simulations, the atmospheric potential temperature response to local SST variations decreases gradually with height throughout the boundary layer (0–1.5 km). In contrast, the wind speed response to local SST perturbations decreases rapidly with height to near zero at 150–300 m. The simulated wind speed coupling coefficient is found to correlate well with the height-averaged turbulent eddy viscosity coefficient. The details of the vertical structure of the eddy viscosity depend on both the absolute magnitude of local SST perturbations, and the orientation of the surface wind to the SST gradient.

Design and characteristics of reflectivity tunable mirror with MZI and loop waveguide on SOI

2021 ◽  
Author(s):  
Yutaka Makihara ◽  
Moataz Eissa ◽  
Tomohiro AMEMIYA ◽  
Nobuhiko Nishiyama
Keyword(s):  
Phase Shift ◽  
Coupling Coefficient ◽  
Integrated Circuit ◽  
Silicon Photonics ◽  
Silicon On Insulator ◽  
Zehnder Interferometer ◽  
Directional Couplers ◽  
Photonic Integrated Circuit ◽  
Active Elements ◽  
Measurement Results

Abstract To achieve a reconfigurable photonic integrated circuit with active elements, we proposed a reflectivity tunable mirror constructed using a Mach–Zehnder interferometer (MZI) with a micro heater and loop waveguide on a silicon photonics platform. In this paper, the principle of the operation, design, fabrication, and measurement results of the mirror are presented. In theory, the phase shift dependence of the mirror relies on the coupling coefficient of the directional couplers of the MZI. When the coupling coefficient κ2 was 0.5 and 0.15, the reflection could be turned on and off with a phase shift of π/2 and π, respectively. The reflection power of the fabricated mirror on the silicon on insulator (SOI) substrate was changed by more than 20 dB by a phase shift. In addition, it was demonstrated that the phase shift dependence of the mirror changes with the coupling coefficient of the fabricated devices.

scholarly journals A Novel Synthetization Approach for Multi Coupled Line Section Impedance Transformers in Wideband Applications

2022 ◽  
Vol 12 (2) ◽  
pp. 875
Author(s):  
Nan Zhang ◽  
Xiaolong Wang ◽  
Chunxi Bao ◽  
Bin Wu ◽  
Chun-Ping Chen ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Return Loss ◽  
Circuit Simulation ◽  
Characteristic Impedance ◽  
Fractional Bandwidth ◽  
Coupled Line ◽  
Variable Parameters ◽  
Line Section ◽  
Original Topology ◽  
Impedance Parameters

In this paper, a novel synthetization approach is proposed for filter-integrated wideband impedance transformers (ITs). The original topology consists of N cascaded coupled line sections (CLSs) with 2N characteristic impedance parameters. By analyzing these characteristic impedances, a Chebyshev response can be derived to consume N + 2 design conditions. To optimize the left N − 2 variable parameters, CLSs were newly substituted by transmission lines (TLs) to consume the remaining variable parameters and simplify the circuit topology. Therefore, there are totally 2N − N − 2 substituting possibilities. To verify the proposed approach, 25 cases are listed under the condition of N = 5, and 7 selected cases are compared and discussed in detail. Finally, a 75–50 Ω IT with 100% fractional bandwidth and 20 dB bandpass return loss (RL) is designed and fabricated. The measured results meet the circuit simulation and the EM simulation accurately.

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