A direction finding of conducted interference using the coupled transmission lines

With increased wire density of integrated circuits and with increased speed of signal, crosstalks due to couplings of wires and wave distortions due to impedance mismatches have become a problem. For the transient analysis of these signals, using the wave digital filter representation of the wires, simulation methods consider them as coupled transmission lines. However, the existing methods construct a digital model depending on the load of the circuits to be analyzed. This paper represents the loss‐less coupled lines of the circuit to be analyzed by equivalent circuits using ideal transformer interconnections and uncoupled transmission lines. Then its power supply and load, its ideal transformer interconnections and its uncoupled transmission lines are modeled individually by digital filter models thus representing the entire circuit with a wave digital filter. Also, digital models are presented for the cases when coupled transmission lines contain lumped parameter elements and branchings. Furthermore, it is shown that lossy symmetrical coupled lines can be represented by equivalent circuits using ideal transformer interconnections and lossy uncoupled lines, and their wave digital filter representations are given. Finally, a wave digital filter representation of a network containing lossy symmetrical coupled lines is given. It is used as a model for wirings on a GaAs substrate, and examples of its transient response analyses are given.

Coupled transmission lines are experimentally characterised by using 4-port s-parameter measurements in the broad frequency band (up to more than the 20 GHz). The test patterns are designed and fabricated by using a BGA package process. Symmetrical coupled transmission lines are decoupled into two eigen modes that can be readily determined from the measured s-parameters. Then signal transient and crosstalk noise are directly determined from the measured s-parameters. It is shown that not only are the transmission line parameters frequency-variant, but also the frequency-variant effects and non-ideal characteristics of transmission lines have substantial effect on the signal transients and crosstalk noises.

An overview of standard macromodeling techniques (i.e., employ poles but no phase shifts) for transient simulation of high-speed interconnects is first presented. Then, the limitations of these standard macromodeling techniques (e.g., high model order and slow convergence) are discussed. In order to overcome these limitations, generalized method of characteristics (MoC) techniques include the physical phenomenology of phase shift (time delay) in addition to the system poles, thereby making it possible to model single and coupled transmission lines using far fewer terms than when standard macromodeling techniques are employed. Since MoC techniques incorporate the time delay into the model, causality is also guaranteed. In this paper, the MoC idea is extended by developing a hybrid phase-pole macromodel (HPPM) for the modeling of more complex interconnects with embedded discontinuities. Unlike other generalized MoC techniques that have only been applied to single and coupled transmission lines, the HPPM macromodel can be applied to larger portions of the system that contain multiple cascaded transmission lines and discontinuities. The HPPM parameters can be extracted from either measured or simulated transient data. Comparisons between a standard macromodel and the HPPM show that the HPPM has significant advantages in terms of reduced macromodel orders.

This paper describes a computational model based on lumped elements for the mutual coupling between phases in transmission lines without the explicit use of modal transformation matrices. The self and mutual parameters and the coupling between phases are modeled using modal transformation techniques. The modal representation is developed from the intrinsic consideration of the modal transformation matrix and the resulting system of time-domain differential equations is described as state equations. Thus, a detailed profile ofthe currents and the voltages through the line can be easily calculated using numerical or analytical integration methods. However, the original contribution of the article is the proposal of a time-domain model without the successive phase/mode transformations and a practical implementation based on conventional electrical circuits, without the use of electromagnetic theory to model the coupling between phases.

Transmission line port de-embedding is critical in characterization and modeling for high-speed digital systems. De-embedding technique for single-ended transmission lines has been developed and widely used. However, few de-embedding techniques for coupled transmission lines have been reported in the literature. In this paper, a de-embedding technique for coupled transmission lines using a single-ended TRL (Thru-Reflect-Line) calibration pattern is proposed. It is based on directly obtaining VNA (Vector Network Analyzer) error correction data from measurement and post data processing. As accurate de-embedding is related to the equipments used in the measurement, the proposed technique is verified on two different VNAs with different architectures including a three-sampler VNA and a four-sampler VNA. Good agreement of de-embedded mixed-mode S-parameters has been achieved on both VNAs.

In this paper, -15 dB branch-line hybrid was realized. In the case of-15 dB coupling power, the characteristic impedances of transmission lines were 49.20 Omega and 276.689 Omega and it was discussed to realize the high characteristic impedance of 276.689 Omega using coupled transmission lines. Using the method suggested, the problem how to realize the high characteristic impedance of 90deg transmission lines will be solved.

This paper presents an alternative derivation of delay extraction for lossy transmission lines based on the method of characteristics and a network formulation. The resulting model consists of ideal transmission lines, controlled sources, and delayless networks, which are approximated by rational polynomial functions. The approach has been implemented in Hspice and is demonstrated for single and coupled transmission lines.

Analytical frequency-domain expressions for single and coupled transmission lines with triangular input waveforms are first developed. The inverse Fourier transform is then used to obtain an expression for the time-domain triangle impulse responses for frequency-independent transmission line parameters. The integral associated with the inverse Fourier transform is solved analytically using a differential-equation-based technique. Closed-form expressions for the triangle impulse responses are given in the form of incomplete Lipschitz-Hankel integrals (ILHI) of the first kind. The ILHI can be efficiently calculated using existing algorithms. Combining these closed-form expressions for the triangle impulse responses with a time-domain convolution method using a triangle impulse as a basis function, provides an accurate and efficient simulation method for very lossy transmission lines embedded within linear and nonlinear circuits.

A new class of miniaturized nonreciprocal leaky-wave antenna (LWA) is proposed for wide angle scanning via magnetic tuning. A design is proposed based on coupled composite right left handed (CRLH) transmission lines (TLs) on a ferrite substrate for miniaturization with an external magnetic field control. Coupled TLs were previously utilized in a nonreciprocal LWA design with separate transmitter (TX) and receiver (RX) ports. In this work, CRLH TLs are employed to realize miniaturization, nonreciprocal properties and wide-angle scanning at the same time. To design the LWA, a circuit model was developed with the nonreciprocal propagation properties analytically calculated. For experimental validation, a 15-unit-cell prototype with a unit-cell length of only λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> /20 was manufactured and tested. The TX and RX beams were independently scanned in the E-plane up to 80° by changing the bias field ±50 Oe. The associated antenna gain varies between 3.5 and 5 dB at the operating frequency of 1.79 GHz as the beam is scanned. This is unlike traditional LWAs that achieve beamscanning via frequency control. Additionally, measured isolation between TX and RX ports was ~ 10 dB.

An analytical transmission line (TL) coupling model is used for evaluating the susceptibility of a DUT in the near-field of a noise source in comparison to a far-field excitation. For this purpose, appropriate field solutions of a λ/2 dipole antenna are used in combination with the TL coupling equations of a short TL. The analytical model is validated by accurate 3D field simulations. A coupling ratio is defined to quantify the difference between the near and far-field coupling. The evaluation of the coupling ratio results in the conclusion that standard EMC-test may highly underestimate the near-field disturbance level of a noise source, in the meantime, testing in the near-field may overestimate the required protection measures with respect to the EMC test standard in the far-field. The size of the DUT also influences the coupling ratio.

A Transmission Line Transformer (TLT) can be used to transform high-voltage nanosecond pulses. These transformers rely on the fact that the length of the pulse is shorter than the transmission lines used. This allows connecting the transmission lines in parallel at the input and in series at the output. In the ideal case such structures achieve a voltage gain which equals the number of transmission lines used. To achieve maximum efficiency, mismatch and secondary modes must be suppressed. Here we describe a TLT based on parallel plate transmission lines. The chosen geometry results in a high efficiency, due to good matching and minimized secondary modes. A second advantage of this design is that the electric field strength between the conductors is the same throughout the entire TLT. This makes the design suitable for high voltage applications. To investigate the concept of this TLT design, measurements are done on two different TLT designs. One TLT consists of 4 transmission lines, while the other one has 8 lines. Both designs are constructed of DiBond™. This material consists of a flat polyethylene inner core with an aluminum sheet on both sides. Both TLT's have an input impedance of 3.125 Ω. Their output impedances are 50 and 200 Ω, respectively. The measurements show that, on a matched load, this structure achieves a voltage gain factor of 3.9 when using 4 transmission lines and 7.9 when using 8 lines.

In this paper, we present an efficient method of simulating the transient response of frequency-dependent nonuniform lossy coupled transmission lines, which are terminated in active nonlinear loads. The transient simulation is carried out by applying the recursive convolution integration with impulse response functions derived from the orthogonal expansions of the transmission-line characteristic impedance and wave propagation functions in both time and spatial domains. Transient responses of nonuniform coupled transmission lines with skin-effect parameters are simulated for illustrations. The accuracy and efficiency of the discrete-time analysis are substantiated with exact analytical solutions. >

The most efficient method of simulating the transient response of frequency-dependent nonuniform lossy coupled transmission lines which are terminated in active nonlinear loads is presented. The transient simulation is carried out by applying recursive convolution integration with the impulse response functions derived from the orthogonal expansions of the transmission-line characteristics in both time and spatial domains. Transient responses of nonuniform coupled transmission lines with skin-effect parameters are simulated for illustrations. The accuracy and efficiency of the discrete-time analysis are substantiated with exact analytical solutions.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The waveform relaxation method has been shown to be both efficient and accurate when applied to coupled transmission lines with conductor losses. In this paper, the method is generalized to include the dielectric loss surrounding the transmission lines. The distributed loss model assumes that the conductance matrix is approximately diagonal and its product with the resistive matrix is a scalar matrix. Computational results using the model is presented and compared with HSPICE solutions.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A novel method is developed to reconstruct the physically structures of a nonuniform couple transmission lines from layer peeling algorithm and genetic algorithm. Base on the time domain reflection (TDR) measurement, the impedance profile of the device under test (D.U.T) is first derived by layer peeling transmission line synthesis. Then, the genetic algorithm (G.A.) is employed to extract the parameter of the lumped/distributed circuits in high-speed digital circuit. As a result, the system characteristic can be easily obtained by the extracted model and SPICE circuit simulation software.