scholarly journals Directional microwave coupled-line couplers with high lateral coupling level

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 5-13
Author(s):  
I. A. Fanyaev
Keyword(s):  
Transmission Lines ◽  
Electromagnetic Coupling ◽  
Center Frequency ◽  
Technical Literature ◽  
Coupled Line ◽  
Coupled Lines ◽  
Lateral Coupling ◽  
The Difference ◽  
Strip Lines ◽  
Microwave Coupler

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.

scholarly journals Reconfigurable Negative Group Delay Circuit with a Low Insertion Loss Using a Coupled Line

2020 ◽  
Vol 20 (1) ◽  
pp. 73-79
Author(s):  
Girdhari Chaudhary ◽  
Yongchae Jeong
Keyword(s):  
Insertion Loss ◽  
Group Delay ◽  
Characteristic Impedance ◽  
Center Frequency ◽  
Pin Diode ◽  
Negative Group ◽  
Coupled Line ◽  
Coupled Lines ◽  
Low Insertion Loss ◽  
Negative Group Delay

This paper presents a design of a transmissive-type, low insertion loss (IL) negative group delay (NGD) circuit with a reconfigurable NGD. The proposed circuit consists of a series transmission lines (TLs) and shunt short-circuited coupled lines where an isolation port is terminated with a parasitic compensated PIN diode. Analytical design equations are derived to obtain the circuit parameters for the predefined NGD and IL. The low IL can be achieved because of the very high characteristic impedance of the short-circuited coupled lines. The TL terminated with a PIN diode is used to achieve the constant center frequency of reconfigurable NGD circuit. For experimental validation, the NGD circuit is designed and fabricated at a center frequency (<i>f</i><sub>0</sub>) of 2.14 GHz. In the measurement, the NGD varies from -0.5 ns to -2 ns with an IL variation of 2.08 to 3.60 dB at <i>f</i><sub>0</sub> = 2.14 GHz. The NGD bandwidth (bandwidth of GD less than 0 ns) varies from 90 MHz to 50 MHz. The minimum input/output return losses are higher than 10 dB for the overall tuning range.

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.

Wideband suppression of spurious response for microstrip filters based on coupled lines of incommensurate lengths

2014 ◽  
Vol 7 (6) ◽  
pp. 685-690
Author(s):  
Sang-Ho Lee ◽  
Hobyung Yoon ◽  
Jungje Ha ◽  
Yongshik Lee
Keyword(s):  
Design Procedure ◽  
Substantial Improvement ◽  
Center Frequency ◽  
Third Order ◽  
Compact Structure ◽  
Coupled Line ◽  
Transmission Zeros ◽  
Microstrip Filters ◽  
Coupled Lines ◽  
Spurious Response

This work demonstrates design methods that can achieve remarkable enhancement in the stopband response of microstrip coupled-line filters. The frequencies of resonance and/or the transmission zeros of a coupled-line section can be controlled by its length. Therefore, by constructing a filter with coupled lines of incommensurate lengths such that these frequencies do not overlap, substantial improvement in the stopband response can be obtained. Besides its compact structure and simple design procedure, an unprecedented performance is demonstrated experimentally in which the transmission level is maintained below −20 dB up to as high as 11.9 f0 for a third-order filter, where f0 is the center frequency.

scholarly journals Split striplines with adjustable parameters and devices based on them

2019 ◽  
Vol 30 ◽  
pp. 06015
Author(s):  
Nickolay Malyutin ◽  
Alexandra Malyutina ◽  
Georgiy Malyutin ◽  
Alexander Zabolotsky
Keyword(s):  
Frequency Analysis ◽  
Transmission Lines ◽  
Electromagnetic Coupling ◽  
Characteristic Impedance ◽  
Scattering Matrix ◽  
Wide Frequency Range ◽  
Strip Line ◽  
Frequency Range ◽  
Strip Lines

The split strip lines (SSL) with adjustable parameters and examples of devices based on them are examined. Changing the parameters of the split strip lines are carried out with the help of so-called controlling strips, coupled with parts of the split strip line and having a strong electromagnetic coupling with them. Between controlling strips and the screen the lumped regulating elements are included. In wide frequency range such strip structures can be considered as transmission lines with changeable characteristic impedance and changeable propagation coefficient. Frequency analysis of of scattering matrix S of controlled split strip lines with different circuits of strip inclusion is carried out. Examples of the use of split strip lines with adjustable parameters in the design of different devices were discussed.

Parallel-coupled stub-loaded resonator bandpass filter with ultra-wideband passband on multilayer liquid crystal polymer substrates

2015 ◽  
Vol 8 (8) ◽  
pp. 1183-1186 ◽  
Author(s):  
S. Almorqi ◽  
H. Shaman ◽  
A. Alamoudi
Keyword(s):  
Liquid Crystal ◽  
Bandpass Filter ◽  
Liquid Crystal Polymer ◽  
Ultra Wideband ◽  
Center Frequency ◽  
Coupled Line ◽  
Crystal Polymer ◽  
Quarter Wavelength ◽  
Coupled Lines ◽  
Chebyshev Filter

A multilayer bandpass filter with ultra-wideband passband is presented in this paper. The filter is designed to have a very wide passband with a fractional bandwidth of about 180% at a center frequency of 10.5 GHz. The filter consists of two sections of parallel-coupled lines loaded at the center with short-circuited stub. Each of the coupled line sections and short-circuited stubs is designed to be a quarter-wavelength long at the desired center frequency. As a result, the filter exhibited a selective filtering characteristic equivalent to a five-pole Chebyshev filter with a very low insertion loss. The proposed filter is realized and fabricated using multilayer liquid crystal polymer substrate. The design is successfully realized in theory and verified by full-wave electromagnetic simulation of the full layout and the experiment where excellent agreement is obtained.

MODELING THE FREQUENCY CHARACTERISTICS OF THE QUADRATURE THREE-LOOP L-BAND WAVELENGTH BRIDGE

2021 ◽  
Author(s):  
Л.В. АЛЕКСЕЙЧИК ◽  
Н.В. АНДРИЕВСКИЙ
Keyword(s):  
Transmission Lines ◽  
Electric Circuit ◽  
Wave Resistance ◽  
Frequency Characteristics ◽  
Excitation Mode ◽  
S Matrix ◽  
Scattering Matrices ◽  
Standard Wave ◽  
Strip Lines ◽  
Algebraic Summation

Представлены результаты численного моделирования частотныххарактеристик квадратурного трехшлейфового моста (КШМ) L-диапазона, выполненного на основе симметричной полосковой линии с воздушным заполнением. Цель работы - установление допустимого уровня вносимых тепловых потерь полосковых линий (или других типов линий передачи), не оказывающих заметного влияния на рабочие характеристики КШМ, удовлетворяющие требуемым параметрам. Метод расчета основан на принципе декомпозиции электрической цепи КШМ на шесть симметричных 6-полюсников, три из которых соответствуют нечетной моде возбуждения КШМ, а три других - четной моде возбуждения КШМ. Алгебраическое суммирование матриц рассеяния указанных мод позволило получить частотные характеристики результирующей S-матрицы рассеяния КШМ. Нормирование S-матрицы к стандартному волновому сопротивлению 50 Ом выполнено с помощью вычисления собственных значений матриц рассеяния эквивалентных 4-полюсников КШМ. Моделирование проведено в среде LabVIEW. The paper presents the results of numerical simulation of the frequency characteristics of the L-range quadrature three-loop bridge (QLB), based on the symmetric striped line with air filling. The purpose of the study is to establish the permissible level of introduced thermal losses of strip lines (or other types of transmission lines) that do not significantly affect the performance characteristics of the QLB, satisfying the required parameters. The calculation method is based on the principle of decomposition of the QLB electric circuit into six symmetric 6-poles, three of which correspond to the odd excitation mode of the QLB, and the other three correspond to the even excitation mode of the QLB. Algebraic summation of the scattering matrices of these modes made it possible to obtain frequency characteristics of the resulting S-scattering matrix of the qLb. The normalization of the S-matrix to the standard wave resistance of 50 Ohms was carried out using the calculation of the eigenvalues of the scattering matrices of equivalent 4-poles of the QLB. The simulation was carried out in the LabVIEW environment.

Analysis of Characteristic of Microstrip Signal Loss in Course of Signal Transmission

2011 ◽  
Vol 194-196 ◽  
pp. 2229-2232
Author(s):  
Qing Song Xiong ◽  
Zhao Hua Wu ◽  
Pin Chen ◽  
Sheng Zhang
Keyword(s):  
Line Width ◽  
Transmission Lines ◽  
Coupling Effect ◽  
Signal Transmission ◽  
Characteristic Impedance ◽  
Signal Loss ◽  
Scattering Parameters ◽  
Scattering Parameter ◽  
Conductor Loss ◽  
Strip Lines

The effect of loss of transmission line on the transmission signal can’t be ignored in microwave circuits. Based on the theory of loss and microwave network principle, the effect of the width, parallel length and space of transmission lines on the scattering parameters’ insertion loss is analyzed in perspective of scattering parameters of the odd mode and even mode. The simulation results show that: when the other parameters are fixed, both the characteristic impedance and the conductor loss decrease non-linearly with the line width broadening; due to the coupling effect between micro-strip lines, the first trough frequency of the scattering parameter S21 curved line, that is the point the signal energy attenuate most seriously, decreases linearly with line width broadening and increases non- linearly with line spaces broadening.

scholarly journals Analysis of Surface Degradation of Silicon Rubber Insulators after 30 Years in-Service

2020 ◽  
Vol 12 (4) ◽  
pp. 828-844
Author(s):  
Lunnetta Safura Lumba ◽  
◽  
Suwarno Suwarno ◽  
Keyword(s):  
Transmission Lines ◽  
Silicone Rubber ◽  
Thermo Gravimetric Analysis ◽  
Volcanic Area ◽  
Gravimetric Analysis ◽  
Aged Sample ◽  
Percentage Difference ◽  
Virgin Sample ◽  
The Difference

In recent years, polymeric insulators have been increasingly used for high voltage overhead transmission lines. The industry has replaced the insulators from ceramic to polymeric due to its lightweight and hydrophobic materials, not to mention the performance against pollutant contamination. In this study, an analysis of two 70 kV silicone rubber insulators is performed. The insulators had been in service for 30 years on transmission networks in volcanic area, exposed to intense UV solar radiation in midday, but also high precipitation occur throughout the year. The urge to understand better of polymeric aging behavior is important to improve the quality of the polymeric type insulators. In this study, these aged samples were then compared with virgin samples to identify the endurance and quality of polymer material. The surface deterioration and the change of chemical content were evaluated using advanced techniques, including Spectroscopy and Scanning Electron Microscopy (SEM), Energy-dispersive X-ray Analysis (EDX), Thermo-Gravimetric Analysis (TGA), and Fourier Transform Infrared (FTIR). Meanwhile, the hydrophobic and visual inspection were also conducted. The hydrophobicity was evaluated by measuring the contact angle and assessed using IEC62073. The aged samples are categorized as hydrophobic class 1 due to the angle value of more than 60o. Physicochemical results showed that the aged sample compared with the virgin simple did not differ significantly given that the aged samples have been in-service for 30 years. Based on TG/DTA result, the percentage difference of weight loss between virgin and aged sample only lower than 4%. Then, from EDX result, the atomic percentage differences of C and O component compared with virgin sample are 4%-10%. Furthermore, the FTIR spectra indicates a normal aging condition of the silicone rubber, the difference in peak value of Si-(CH3)2 and OH compared with virgin sample is 10%.

scholarly journals Closed-loop ring resonator topology for bandpass filter applications

2020 ◽  
Vol 17 (3) ◽  
pp. 1422
Author(s):  
Norfishah Ab Wahab ◽  
M. N. Md Tan ◽  
M. N. Hushim
Keyword(s):  
Transmission Lines ◽  
Closed Loop ◽  
Bandpass Filter ◽  
Ring Resonator ◽  
Single Mode ◽  
Ring Structure ◽  
Transmission Zeros ◽  
Quarter Wavelength ◽  
Coupled Lines ◽  
Loop Ring

<p class="Pa41">This paper presents a single mode pseudo-elliptic bandpass resonator based on closed-loop ring topology. The resonator is built from six quarter wavelength transmission lines to form a square closed-loop ring structure. This structure creates transmission zeros at the lower and upper sidebands so that high selectivity bandpass filter response is achieved. The advantage of this topology is that the design is less complex since no perturbation is needed on the ring lines for creation of transmission zeros. Higher-order filters can be constructed by introducing quarter-wavelength coupled-lines, coupled at both input and output of the closed-loop ring resonator. For proof of concept, the filters are designed at 10 GHz up to 3<sup>rd</sup> order, simulated using full-wave electromagnetic simulator on microstrip substrate, <em>FR-4</em> with characteristics given as <em>Ԑr </em>= 4.70, <em>h </em>= 1.499 mm and <em>tan δ </em>= 0.012.  The filters are simulated and responses are found to be agreeable with the proposed idea.</p>

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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