Planar Compact Dual-Band Coupled-Line Balun with High Isolation

A planar circuit structure, which is based on three cascaded pairs of coupled lines, an open stub, and an isolation resistor, is proposed in this paper to design a compact dual.band balun with high isolation. This circuit features equal power division with out of phase, all ports matching, high isolation between two outputs, compact structure, and inherent impedance transformation. The closedform design equations are derived based on the traditional transmission.line theory and even.(odd.) mode analysis. A practical dual.band balun, which operates at 0.9/1.8GHz, is designed and fabricated to validate the function of equal power division with out of phase and high isolation between two outputs. The consistency between the simulated and measured results verify the design theory.

Dynamic State Estimation Based Protection of Mutually Coupled Transmission Lines

Mutually coupled lines create challenges for legacy protection schemes.In this paper,a dynamic state estimation based protection(EBP)method is proposed to address these challenges.The method requires GPS synchronized measurements at both ends of the line and a high fidelity model of the protected line.The paper presents the dynamic model of the protected line and its impact on the performance of the protection scheme.Numerical simulations prove that the method can correctly identify faults,independent of position and type.The work also demonstrates the advantages of the proposed method versus legacy protection functions such as distance protection and line differential.These advantages include reliable and faster detection of internal low impedance faults,inter-circuit faults,and high impedance faults,even in cases of 1)partially coupled lines and 2)lack of measurements in adjacent lines.

Multi-Band Bandpass Filter Using Novel Topology for Next-Generation IoT Wireless Systems

The design of single-and quad-band Bandpass Filter(BPF)topology has been presented in this paper for next-generation Internet of Things(IoT)devices.The main topology is constructed using the Split Ring Resonator(SRR),separated by the Anti-Parallel Coupled Line Structure(APCLS).A detailed analysis of APCLS has been presented,which is further used to construct the single-and quad-band BPF.The single-band BPF design consists of SRR loaded with APCLS.The developed single-band BPF displays a dual-mode response with a center frequency of 2.65 GHz and a measured fractional bandwidth of 17.17%.Moreover,a quad-band bandpass filter has been achieved using the same topology with minor modification in the SRR and APCLS electrical parameters.The developed quad-band BPF generates a dual-mode response having center frequencies of 1.2,2.4,3.5,and 4.7 GHz with the measured fractional bandwidth of 13%,26%,16%,and 5%,respectively.Two prototypes have been fabricated on the highfrequency substrate to validate the proposed topologies.Very high rejection in the stopbands region,little in-band insertion loss,and very selective passband have been measured for single-and quad-band BPFs.The measured and simulated results are well correlated.

Equivalent Pi-Network Model of Lossy and Dispersive Coupled Transmission Lines

An equivalent circuit representation is presented for a set of coupled transmission lines. An ap- proximation of the hyperbolic secant function allows a simple derivation of a staged model that accounts for the complex frequency dependent parameters. The model converts the T-ladder network into a i-r-network with controlled sources. The equivalent circuit based approach presented here is not only intriguing but also enhances the computed accuracy and efficiency. Numerical simulations verify the accuracy of this approach for both time and frequency domain responses.

A novel model for a planar wideband Marchand balun

A new lumped element model for conventional Marchand baluns is presented. Analyzed by the even- and odd-mode method, the equivalent equations are derived for ）./4 coupled lines. Based on the proposed 5th-order lumped equivalent circuit for ）./4 coupled lines, the self-inductance, mutual inductive coupling and the capacitance can be calculated according to the even- and odd-mode characteristic impedance, therefore, the model parameters of the balun can be easily gained from the derived equations. To verify the model, a GaAs monolithic wideband Marchand balun was implemented and tested. The EM simulation and experimental results show a good agreement with the model simulation. This model is available in a wide frequency range and makes the design procedure of the Marchand balun faster and easier.

FDTD technique based crosstalk analysis of bundled SWCNT interconnects

The equivalent electrical circuit model of a bundled single-walled carbon nanotube based distributed RLC interconnects is employed for the crosstalk analysis. The accurate time domain analysis and crosstalk effect in the VLSI interconnect has emerged as an essential design criteria. This paper presents a brief description of the numerical method based finite difference time domain （FDTD） technique that is intended for estimation of voltages and currents on coupled transmission lines. For the FDTD implementation, the stability of the proposed model is strictly restricted by the Courant condition. This method is used for the estimation of crosstalk induced propagation delay and peak voltage in lossy RLC interconnects. Both functional and dynamic crosstalk effects are analyzed in the coupled transmission line. The effect of line resistance on crosstalk induced delay, and peak voltage under dynamic and functional crosstalk is also evaluated. The FDTD analysis and the SPICE simulations are carried out at 32 nm technology node for the global interconnects. It is observed that the analytical results obtained using the FDTD technique are in good agreement with the SPICE simulation results. The crosstalk induced delay, propagation delay, and peak voltage obtained using the FDTD technique shows average errors of 4.9%, 3.4% and 0.46%, respectively, in comparison to SPICE.