Taras Kushta

Resonance stub effect in a transition from a through via hole to a stripline in multilayer PCBs

We present results of study of the resonance stub effect occurring in a transition from a through via hole to a stripline in a multilayer printed circuit board (PCB). This effect for via structures including ground vias is estimated by numerical simulations and measurements in the frequency band up to 20 GHz. Ways to alleviate problems in the design of interconnections embedded in multilayer PCBs due to the resonance stub effect and possible applications of the effect in microwave filtering are traced.

An accurate experimental method for characterizing transmission lines embedded in multilayer printed circuit boards

We have developed an accurate method for measuring the complex propagation constant and characteristic impedance of transmission lines embedded in multilayer printed circuit boards. It is based on mathematical error-removal schemes using two different length transmission lines and an advanced via-hole structure that minimizes coupling. Consequently, associated errors, due to discontinuities and interference can be effectively eliminated, and the frequency dependencies of the transmission line parameters can be clarified in wide frequency bandwidths. We verified the validity of this method in frequency ranges up to at least 18 GHz, by comparing the determined values with the theory derived from transverse electromagnetic (TEM) approximations.

New 3-D Design of Filtering Components Using Multilayer Board Technologies

In this paper, a contribution to development of three-dimensional (3-D) techniques using multilayer boards for design of passive circuit components is presented. Shown approach gives a possibility to obtain compact devices with an improved EMI performance. A distinguishing point of this approach is a shield via structure which serves as both a vertical transmission line and an appropriate element of a passive such as short- or open-circuited stub, as for an example. Here bandpass and bandstop filters designed by the use of stub elements obtained as a part of the shield via structure are demonstrated. Simulation and measurement data obtained for the filters demonstrate a high performance of such components and a perspective direction in development of compact and cost-effective devices.

Miniaturized bandpass filters based on multilayer substrate technologies

Novel concept of bandpass filters focused on their miniaturization, cost-effectiveness and high integration in a chip-package system has been discussed in the paper. This concept is based on a three-dimensional architecture, in which both a vertical transition and a planar transmission line disposed in a multilayer substrate, are used as building blocks of the filters. Here, the vertical transition is formed as a specific coaxial wave guiding structure by a signal via, being inner conductive boundary, and ground vias, serving in the role of an outer conducive boundary.

Suppression of conducted noise coupling in a board with digital and RF circuits by a ferrite film plated on an interposer

This paper presents evaluation results of conducted noise suppression effect of a ferrite film directly plated on an interposer substrate in the long-term evolution (LTE) communication band. A test board for evaluations has an IC with digital and RF circuits which is designed for investigations of electromagnetic noise coupling at the IC chip level. Firstly, we have confirmed effectiveness of a ferrite film onto an interposer in suppression of conducted noise from a digital circuit to a board by simulations. Then, we have verified that the ferrite film reduces conducted noise coupling to the RF circuit, occurring inside the board, by measurements of In-phase/Quadrature (I/Q) signals and high frequency voltages of power supply lines.

Novel compact bandpass filters for high-density packaging applications

In this paper, a new concept providing not only compactness of a filtering component, but also its effective integration in a chip-package system has been presented. This concept is based on a three-dimensional (3-D) design approach and an anisotropic artificial dielectric of a high permittivity formed in a predetermined area of a multilayer substrate used to construct the component. In the 3-D approach, a planar transmission line segment and a resonator formed vertically in the substrate are applied.