Internal Transmission Line Research Articles

Coupling analysis of penetrated wire connecting two electronic devices using a time domain hybrid method

AbstractAn efficient time domain hybrid method is proposed, which integrate transmission line (TL) equations, finite‐difference time‐domain (FDTD) method, Norton and Substitution theorems together, to predict the EM fields coupling with the penetrated wire connecting two electronic devices. Within this method, the geometry of penetrated wire is divided into external and internal TLs according to the shielded enclosures of two devices firstly. Then the equivalent circuit model of penetrated wire is established by the Norton and Substitution theorems, which can represent the discontinuity of impedance between external and internal TLs and the transmitting of interference signals between terminal loads of the wire. Finally, the TL equations combined with FDTD method is utilized to compute the transient responses on external and internal TLs respectively. Numerical simulations of penetrated wire connecting two shielded enclosures in different environment are employed to verify the accuracy and efficiency of the presented method.

Unequal Power Dividers Using Uniform Impedance Transmission Lines with Stubs

This study proposes an impedance control method in transmission lines using open- or short-circuit stubs for unequal power dividers. The proposed method is based on the conversion of a two-port to a three-port transmission line, which is equivalent to multiplying the impedance at the internal transmission line by a scaling factor and then connecting open- or short-circuit stubs in parallel to each port on the three-port transmission line. To verify the effectiveness of the proposed method, Wilkinson and Gysel power dividers with splitting ratios of 9:1 and 5:1, respectively, using uniform impedance transmission lines with open- or short-circuit stubs at an operating frequency of 2 GHz were designed. The experimental measurements of the two power dividers agree well with those of the simulation.

An Embedded Double Reference Transmission Line Theory Applied to Cable Harnesses

In this paper, an embedded double reference transmission line theory (EDRTLT) is presented. This approach is based upon taking an arbitrary wire among the $\boldsymbol{n }$ wires constituting the harness and considering it as an internal reference conductor. Then, the initial transmission line (TL) of $\boldsymbol{n}$ wires above a ground reference is split into two coupled subsets of wires. The internal subset is composed of $\boldsymbol{n} - 1$ wires with the internal reference wire as the return wire. The per unit length (p.u.l.) parameters of this internal TL are calculated with respect to this internal reference wire. They do not depend on the ground reference. The external subset is composed of only the internal reference wire with the ground plane as a reference. As a result, any change of relative position of the bundle and the ground reference involves the p.u.l. calculation of a mono-conductor TL. This double reference TL theory is shown to be equivalent to the classical single reference approach and the corresponding p.u.l. parameters are approximately retrieved from those of the single reference TLs to form the EDRTLT. The results obtained by this theory are in good agreement with those obtained from the single reference case where all p.u.l. parameters are directly calculated using the ground plane as a single reference. The main advantage provided by the EDRTLT is to reduce the complexity of analysis of the bundle-to-ground interaction.

Novel microwave reactor equipment using internal transmission line (INTLI) for efficient liquid phase chemistries: A study-case of polyester preparation

In this work, we demonstrate the application of a novel type of microwave equipment using internal transmission line (INTLI) to liquid phase chemistries. Contrary to common cavity-based microwave equipment, where the reactor is exposed to a standing microwave field formed in a confined space, the INTLI technology allows for irradiation of the liquid phase from the interior of the reactor, thereby enabling better coupling of the microwave energy with the liquid mixture. The model reaction system studied is a polyesterification reaction of industrial relevance. The INTLI reactor is compared with a common type of multimode cavity in terms of specific energy consumption. The total specific energy consumption with the INTLI reactor is considerably lower owing to the ability to optimize/adapt the microwave power dissipated in the liquid mixture and to minimize the lost (reflected) power that is scattered off the liquid mixture and sent back toward the magnetron. For the studied reactor system and conditions, the total energy consumption with the INTLI reactor was up to a factor two lower (at the beginning of the reaction) compared to the multimode cavity. Optimized (lower) usage of microwave power during the process and effective scale up possibility are inherent advantages of the INTLI reactor technology over cavity-based microwave equipment.

Numerical Analysis of the Output-Pulse Shaping Capability of Linear Transformer Drivers

Output-pulse shaping capability of a linear transformer driver (LTD) module under different conditions is studied, by conducting the whole circuit model simulation by using the PSPICE code. Results indicate that a higher impedance profile of the internal transmission line would lead to a wider adjustment range for the output current rise time and a narrower adjustment range for the current peak. The number of cavities in series has a positive effect on the output-pulse shaping capability of LTD. Such an improvement in the output-pulse shaping capability can primarily be ascribed to the increment in the axial electric length of LTD. For a triggering time interval longer than the time taken by a pulse to propagate through the length of one cavity, the output parameters of LTD could be improved significantly. The present insulating capability of gas switches and other elements in the LTD cavities may only tolerate a slightly longer deviation in the triggering time interval. It is feasible for the LTD module to reduce the output current rise time, though it is not useful to improve the peak power effectively.

A new type NRD-guide receiving front-end in Ka-band

A new type millimeter-wave receiving frond-end using NRD-guide as internal transmission line is presented in this paper. The receiving frond-end consists of a NRD-guide crossbar balanced mixer, a NRD-guide LSE mode local oscillator and two impedance-converters at two input ports of the mixer circuit. Firstly, the propagation characteristics of some transmission modes often used in NRD-guide are given, and the conditions which these modes are applied as the operating modes are discussed. Secondly, the principle of the balanced mixed which is regarded as the key circuit unit in the receiving frond-end is analysed by using vector Green's function, and the conversion loss of the mixer is computed with an equivalent circuit in Ka-band. And then, from the view of obtaining the optimum performances of the whole receiving frond-end, some methods of designing local oscillator are expound. Some experimental results of the receiving frond-end at Kaband are given in the paper lastly. Because the frond-end have the impedance matching and converting circuits, it possesses better electrical performance. The integrated frond-end which have compact size and excellent shock strength is suitable for varied millimeter-wave system.