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In this article, an efficient approach based on the parallel alternating direction implicit (ADI) method is presented for the transient thermal simulation of liquid-cooled 3-D integrated circuits (ICs). To accurately characterize the thermal behaviors, a compact thermal model based on finite-difference approximation is established. The ADI method with linear time complexity is utilized to reduce computational cost, which can easily deal with large-scale problems. To suppress the oscillations of transient results in the case of large time steps, an effective technique using the exponentially expanding subtime steps is introduced, which improves the accuracy of results significantly. In addition, taking the advantage of parallel computing, the transient simulation is further accelerated by the parallel cyclic reduction (PCR) algorithm implemented on graphics processing units (GPUs). The accuracy and efficiency of the proposed method are demonstrated by several numerical examples. [ABSTRACT FROM AUTHOR]

In this article, an electrothermal co-design of substrate integrated waveguide (SIW) slot antenna array combined with fin-shaped heatsink is proposed. The antenna array is constructed by 4 $\times8$ SIW slot elements. The heatsink structure above the antenna array not only improves the radiation performance of the antenna array but also enhances the electromagnetic compatibility (EMC) and the heat dissipation capability of the whole structure. The measured realized gains over the operating frequency range increase from 15.4–18.1 to 16.1–19.7 dBi when the heatsink is mounted on the antenna array. Meanwhile, the enclosed heatsink reduces the hotspot temperature rise of the system by 57%. The measured results are in good agreement with the simulated ones. [ABSTRACT FROM AUTHOR]

In this article, the average power handling capability (APHC) of microstrip lines is studied which considers both the heat convection and self-heating effects (SHEs) with temperature-dependent resistivity. A modified parallel-plate model (MPM) is developed to improve the prediction accuracy of APHCs. First, an effective thermal conductivity is used as correction in the original parallel-plate model. After that, the impact of heat convection on the microstrip line is combined in MPM, which matters in realistic situations. Finally, MPM is extended to account for SHEs of metal lines with temperature-dependent resistivities. For validation, APHCs of several microstrip lines with different dielectric substrates are investigated. The results agree well with those simulated by the commercial multiphysics solver, which confirms the validity and accuracy of the model. [ABSTRACT FROM AUTHOR]

In this work, a novel Robin transmission condition (RTC)-enhanced discontinuous Galerkin (DG) method is proposed for the dc IR-drop analysis of power distribution networks with Joule heating effects included. Unlike the conventional DG method, the proposed DG method straightforwardly applied to discretize the second-order spatial partial differential governing equations for the electrostatic potential $\Phi $ and the steady-state temperature $T$. The numerical flux in DG used to facilitate the information exchange among neighboring subdomains introduces two additional variables: the current density $J$ for the electrical potential equation and the thermal flux $q$ for the thermal equation. To solve them, at the interface of neighboring subdomains, an RTC is presented as the second equation to establish another connection for solutions in neighboring subdomains. With this strategy, the number of degrees of freedom (DoFs) involved in the proposed RTC-DG method is dramatically reduced compared with the traditional DG method. The finalized matrix system is solved in an finite-element tearing and interconnecting (FETI)-like procedure, namely the unknowns are obtained in a subdomain-by-subdomain scheme. Finally, the accuracy and the efficiency of the proposed RTC-DG method are validated by several representative examples. [ABSTRACT FROM AUTHOR]

Crosstalk noise suppression is a crux in the high-speed integrated circuit design, which requires weak-coupling between transmission lines (TLs) over a wide band. To overcome the difficulty, this article presents a novel method to suppress the broadband crosstalk noise between a single TL and the differential pair based on spoof surface plasmon polaritons (SPPs). Due to the subwavelength feature of spoof SPP TLs, a natural mode mismatching between the spoof SPP TL and conventional microstrip (MS) brings a broadband suppression of near-field coupling. In order to verify the crosstalk suppression effect, four different kinds of prototypes are discussed and compared. The simulated and measured results in the frequency domain and time domain demonstrate that the proposed scheme achieves more than 83% far-end noise peak suppression than the traditional MS technology by replacing the single MS TL to the spoof SPP TL. Accordingly, the time-domain crosstalk noise is significantly suppressed without any extra costs, demonstrating its potential applications in ultracompact high-speed integrated circuits. [ABSTRACT FROM AUTHOR]

Due to the temperature-dependent resistivity of power distribution network (PDN) interconnects, a wiser and necessary strategy is to proceed the electrical–thermal cosimulation in order to include the thermal effects caused by Joule heating. As a natural domain decomposition method (DDM), in this article, a discontinuous Galerkin (DG) method is proposed to facilitate the steady-state electrical and thermal coanalysis. With the intention to avoid solving a globally coupled steady-state matrix system equations resulted from the implicit numerical flux in DG, the block Thomas method is deployed to solve the entire domain in a subdomain-by-subdomain scheme. As a direct solver, the block Thomas method is free of convergence problem frequently occurring in iterative methods, such as block Gauss–Seidel method. The capability of the proposed DG method in handling multiscale and complex 3-D PDNs is validated by several representative examples. [ABSTRACT FROM AUTHOR]

In this article, an efficient approach based on Laguerre-based finite-element method (LBFEM) is proposed for transient thermal simulation of integrated circuits (ICs) and packages. The unconditionally stable marching-on-in-order scheme is developed by the weighted Laguerre polynomials and Galerkin testing procedure. In order to handle complicated ICs and packages, the finite-element method (FEM) is employed for spatial discretization and to obtain the Laguerre coefficients. The treatment of different kinds of boundary conditions is also discussed in detail. The accuracy and efficiency of the proposed method are demonstrated by numerical examples. [ABSTRACT FROM AUTHOR]

This paper presents the fabrication process of a thin suspended membrane on normal low resistivity silicon (LRSi), which is then utilized to design millimeter-wave (mm-wave) transmission line and passive circuits with low loss. First, two redistribution metal layers are formed on a plain LRSi wafer with benzocyclobutene in-between. Then, the wafer is thinned down and etched from backside with a specific pattern. Based on this process, a volume is introduced underneath the front side structure and the lossy LRSi substrate is replaced by air, which is the ideal substrate with no loss. Using this method, the substrate loss that contributes the majority part of total loss in mm-wave circuits on LRSi is eliminated. As the operating frequency goes into mm-wave region, the circuit size is scaled down so that the suspended portion is so small that it will not increase the mechanical instability of the structure. Therefore, the proposed suspended membrane on LRSi technology provides an excellent platform to construct mm-wave components. A U-shaped slotline resonator formed on the first redistribution layer is proposed and its quality factors are studied in detail. A second-order bandpass filter is designed and implemented by cascading two such U-shape slotline resonators. The measured frequency responses exhibit good filtering performance, with fractional bandwidth of 13.9% at 126.8 GHz, midband insertion loss of 3.9 dB and passband return loss larger than 14.2 dB. It demonstrates that the proposed suspended membrane on LRSi technology is an excellent candidate for designing low loss mm-wave components. [ABSTRACT FROM AUTHOR]

Electrothermal characteristics of some novel 3-D carbon-based heterogeneous interconnects, consisting of vertical carbon nanotube bundle via and horizontal multilayer graphene, are investigated by utilizing in-house developed algorithm based on a finite-element method. With present fabrication capability, these heterogeneous interconnects can have larger electrical resistance but smaller thermal resistance in comparison with their Cu counterpart. Both the local on-chip interconnects for ballistic regime and global through-silicon via channel for diffusive regime are evaluated numerically, and their 3-D transient temperature distribution and hot spots are characterized and compared. During the electrothermal cosimulation, the anisotropic property of electrical and thermal conductivities of carbon nanomaterials is treated in an appropriate way. It is believed that this paper will be useful for the design as well as the realization of new generation carbon-based interconnects with high reliability and better thermal performance. [ABSTRACT FROM PUBLISHER]