A systematic numerical method to analyze hybrid networks composed of linear/nonlinear lumped elements and transmission lines with distributed sources

Author(s):  
Satoshi Ichikawa ◽  
Ryuichirou Tanaka

A transmission line (TL) is simply a medium that is capable of guiding or propagating electromagnetic energy. The transmission line stores the electric (E) and magnetic (M) energies and distributes them in space by alternating them between the two forms. This means that at any point along a TL, energy is stored in a mixture of E and M forms and, for an alternating signal at any point on the TL, converted from one form to the other as time progresses. Transmission line is usually modelled using lumped elements (i.e., inductors for magnetic energy, capacitors for electric energy, and resistors for modelling losses). The electrical characteristics of a TL such as the propagation constant, the attenuation constant, the characteristic impedance, and the distributed circuit parameters can only be determined from the knowledge of the fields surrounding the transmission line. This chapter gives a brief overview of various transmission lines, with more detailed discussions on the microstrip and the SIW.


2011 ◽  
Vol 9 (1) ◽  
pp. 804-809
Author(s):  
Eduardo Coelho Marques Costa ◽  
Sergio Kurokawa ◽  
Jose Pissolato

Author(s):  
Mohamed Ribate ◽  
Rachid Mandry ◽  
Jamal Zbitou ◽  
Larbi El Abdellaoui ◽  
Ahmed Errkik ◽  
...  

In this paper, the design of a Broadband Power Amplifier for UHF applications is presented. The proposed BPA is based on ATF13876 Agilent active device. The biasing and matching networks both are implemented by using microstrip transmission lines. The input and output matching circuits are designed by combining two broadband matching techniques: a binomial multi-section quarter wave impedance transformer and an approximate transformation of previously designed lumped elements. The proposed BPA shows excellent performances in terms of impedance matching, power gain and unconditionally stability over the operating bandwidth ranging from 1.2 GHz to 3.3 GHz. At 2.2 GHz, the large signal simulation shows a saturated output power of 18.875 dBm with an output 1-dB compression point of 6.5 dBm of input level and a maximum PAE of 36.26%.


2018 ◽  
Vol 5 (6) ◽  
pp. 180011 ◽  
Author(s):  
Chuan Wu ◽  
Bo Yan ◽  
Guizao Huang ◽  
Bo Zhang ◽  
Zhongbin Lv ◽  
...  

A numerical method to simulate air flow around a bundle conductor line by means of the FLUENT software is presented and verified by a wind tunnel test for aerodynamic characteristics of a twin bundle conductor line. The lift and drag coefficients of the leeward sub-conductor of a twin bundle conductor varying with its relative position in the wake zone to the windward one under different wind velocities are numerically determined by the presented method. A user-defined subroutine of ABAQUS software is developed to apply the aerodynamic loads on each sub-conductor and the electromagnetic force between sub-conductors. The numerical simulation method for wake-induced oscillation of a bundle conductor line is proposed. By means of the numerical method, wake-induced oscillation processes of twin bundle conductor transmission lines under different parameters, including current intensity, spacer layout, span length and wind velocity, are numerically simulated. Moreover, the effects of those parameters on the oscillation characteristics of the lines, such as vibration mode, frequency, amplitude and motion trace, are discussed. The results obtained provide a fundamental basis for the understanding of wake-induced oscillation behaviour of twin bundle conductor transmission lines and the development of control technique for wake-induced oscillation.


2013 ◽  
Vol 5 (3) ◽  
pp. 213-220 ◽  
Author(s):  
Miguel Durán-Sindreu ◽  
Jordi Bonache ◽  
Ferran Martín ◽  
Tatsuo Itoh

The implementation and application of single-layer fully-planar extended-composite right-/left-handed transmission lines (E-CRLH TLs) in substrate-integrated waveguide (SIW) technology are presented. The multiband CRLH behavior of these artificial lines is explained by considering the lumped element equivalent circuit model. The potential of these lines for dual-band and quad-band applications is demonstrated by designing and fabricating a quad-band Y-junction power divider and two dual-band band-pass filters. The main relevant advantage of SIW-based E-CRLH TLs over other E-CRLH lines is fabrication simplicity, since only a single metal layer must be etched and lumped elements are avoided. The fabricated prototypes exhibit very reasonable performance. It is remarkable that for dual-band band-pass filters, standard Chebyshev responses can be obtained to a very good approximation.


2012 ◽  
Vol 4 (4) ◽  
pp. 463-472 ◽  
Author(s):  
Adnen Rajhi ◽  
Said Ghnimi ◽  
Ali Gharssallah

A simple and efficient numerical inversion Laplace transform (NILT) algorithm is implemented in MATLAB environment based on the quotient difference method to solve the problem of electromagnetic (EM) field coupling to lossy or lossless multi-conductor transmission lines (MTL) illuminated by an EM incident field. Two major points are treated in this work for the lossy MTL system excited by an incident EM field; the first one is the optimum equivalent circuit taking into consideration the different physical concepts based on the transmission line theory and the second point deals with the choice and implementation of the numerical method for less computing time and for efficient results. In this paper, the effect of the EM coupling is treated and it is based on the superposition effect of each distributed voltage current sources using the NILT numerical method. Results of the near end and far end voltages and currents for an MTL system are presented and displayed for two types of microwave (MW) structures in the time domain for the case of a plane wave excitation. It has been shown that a non-homogeneous MW structure or multilayered system with a specific choice of the dielectric constant has an advantage for less transient EM coupling due to the external EM field.


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