Search

In this paper a modeling approach for predicting the electrical behavior of nonresonant and resonant structures under the influence of the absorption of moisture into the dielectric is presented. The paper focuses on the encapsulation materials used for printed circuit boards (PCBs) as a case study. For the investigated cases, analytical modeling shows that the loss of electrical insulation resulting from moisture absorption has minimal effects on the losses in transmission lines (TMLs), which would only cause system failure when combined with other aging effects. However, potential cases are discussed where the loss of electrical insulation could be significantly increased. Full-wave modeling shows that moisture absorption can cause the detuning of passive components, specifically antennas and impedance-controlled TMLs, that can have significant effects on system performance. Antenna resonance frequencies shift by up to 3-5%. [ABSTRACT FROM AUTHOR]

In compact wireless modules, electromagnetic (EM) interactions occurring between planar antennas and transmission lines (TML) sharing the same substrate may cause a high amount of undesired coupling and may also detune the antenna characteristics. In this paper, an approach for defining a block-out region around the planar antenna, where no components should be placed is developed, thereby ensuring that the antenna characteristics remain within tolerable limits when the antenna is integrated at board level. This region is comparable to the reactive near-field, but is determined by evaluating the reactive EM power density excited on the ground plane and deducing a threshold value. Its boundary will be termed the EM antenna boundary. Furthermore, a method for efficient estimation of EM coupling from the antenna to terminated TMLs routed outside the EM antenna boundary is developed. This method is based entirely on a postprocessing step to field simulations, i.e., the coupling is calculated based on the previously computed magnetic field distribution excited by the antenna on the ground plane. The coupling model uses the theory of field excited TMLs together with the Baum–Liu–Tesche integral equations for obtaining the terminal voltages of the TML and, hence, the coupling terms. [ABSTRACT FROM AUTHOR]

Through-silicon vias (TSVs) in low, medium and high resistivity silicon for 3-D chip integration and interposers are modeled and thoroughly characterized from 100 MHz to 130 GHz, considering the slow-wave, dielectric quasi-TEM and skin-effect modes. The frequency ranges of these modes and their transitions are predicted using resistivity-frequency domain charts. The impact of the modes on signal integrity is quantified, and three coaxial TSV configurations are proposed to minimize this impact. Finally, conventional expressions for calculating the per-unit-length circuit parameters of transmission lines are extended and used to analytically capture the frequency dependent behavior of TSVs, considering the impact of the mixed dielectric (silicon dioxide–silicon–silicon dioxide) around the TSVs. Excellent correlation is obtained between the analytical calculations using the extended expressions and electromagnetic field simulations up to 130 GHz. These extended expressions can be implemented directly in electronic design automation tools to facilitate performance evaluation of TSVs, prior to system design. [ABSTRACT FROM PUBLISHER]

In this paper, a stripline model is presented for coupled signal lines routed between a power and a ground plane based on multiconductar transmission line (MTL) theory. Through a suitable diagonalization of the MTL equations for striplines, the transverse electromagnetic (TEM) parallel-plate mode is decoupled from the stripline mode. In this way, stripline models that are obtained assuming ideal planes at ground potential can be extended to take into account the nonideal behavior of the planes. The presented model is applied to represent mode conversion due to vias, holes in the reference planes, and terminations of the stripline. Influence of inhomogeneous media is discussed. [ABSTRACT FROM AUTHOR]