Keiju Yamada

High-performance laminated thin-film shield with conductors and magnetic material multilayer

This paper presents a laminated shield consisting of conductors and a magnetic material multilayer. The laminated shield provides a high shielding performance in an ultrahigh-frequency (UHF) band because the magnetic materials have high permeability and multi reflection occurs in the shield. Furthermore, the shielding performance is enhanced at the ferromagnetic resonance (FMR) frequency of the magnetic materials because the magnitude of complex permeability is maximized owing to the large imaginary part of permeability. We examined the shielding mechanisms of the laminated shield and a conductor shield by impedance calculation. The shielding performance obtained by impedance calculation coincides with that obtained by finite element method (FEM) simulation. The laminated shield is fabricated using a CoNbZr thin-film layer with a thickness of 0.2 μm and two Cu layers with a thickness of 0.4 μm. The measured shield effectiveness of the laminated thin-film shield is 27 dB higher than that of the conductor shield at a frequency of 470 MHz, which is similar to the results of impedance calculation and FEM simulation.

Grounding design for low-cost ball grid array package with high shielding effectiveness

This paper presents grounding design for shielded packages to obtain high shielding effectiveness at low cost. Shielded packages are required for high-speed LSIs in mobile handsets and should have not only shield layers with high conductivity but also ground pattern arrangement on interposers. While arranging a ground area on an interposer is indispensable for high shielding effectiveness, a large ground area increases the number of wiring layers and raises the cost. Therefore, investigation of the relationship between the grounding design and the shielding effectiveness is important. In the present work, several kinds of fine-pitch ball grid array (FBGA) packages were designed and fabricated. Each package is different in terms of the design of the contacts between shield layers and ground patterns on the interposer. The grounding design, especially the maximum distance between the contacts, affects the magnetic shielding effectiveness (MSE).

Millimeter-wave band slot antenna on shielded BGA package

High-speed short-range wireless communication systems utilizing the 60-GHz band are expected. An installation of a 60-GHz transceiver into a mobile terminal with high packaging density is one of the promising usages. Electromagnetic noise in the mobile terminals is an important issue, because it may degrade the communication quality of the 60-GHz transceiver. This paper presents a novel antenna-in-package solution realizing both efficient radiation of millimeter waves and high shielding effectiveness to electromagnetic noises. The antenna is composed of U-shaped slots cut on the shielded ball grid array package. The antenna is designed to have a wide-angle radiation characteristic in the horizontal plane. The measured antenna gain of the fabricated antenna is from 2.9 to 5.2 dBi in the frequency range from 57 to 65 GHz.

Design of an electrically small antenna using a broadside-coupled split ring resonator

An electrically small planar antenna using a broadside-coupled split ring resonator (BC-SRR) with a simple structure is presented. Due to the capacitance between the two SRRs in the BC-SRR, the resonant frequency of the antenna is lowered without increasing the size of the antenna. The proposed antenna resonates at 2.45 GHz and 7.31 GHz. At 2.45 GHz, the dimension of the SRR in the proposed antenna is as small as 0.012λ<inf>0</inf>× 0.082λ<inf>0</inf>, where λ<inf>0</inf> is the wavelength in vacuum. The radiation efficiency is 24% at 2.45 GHz.

Anisotropic Magnetic Shielding Effectiveness of Magnetic Shielded Package

In this paper, an analysis method and a measurement method for anisotropic magnetic shielding effectiveness (MSE) are discussed. Some magnetic sensors and memories require small magnetic shielded packages to decrease the influence of external magnetic noise. Whereas, the packages are applied for the external noise from various directions, sensitivity of the magnetic device in the package is affected by the direction and intensity of applied field noise. Influenced by the directions of external and internal magnetic fields, MSE of the shielded package varies several dozen decibels. Therefore, understanding the anisotropic MSE of the shielded package is indispensable for designing a shielded package that prevents malfunctions attributable to external magnetic noise. The

Semiconductor package and mobile device using the same

3 \times 3

WIRELESS DEVICE, AND INFORMATION PROCESSING APPARATUS AND STORAGE DEVICE INCLUDING THE WIRELESS DEVICE

MSE matrix and the directivity of MSE are introduced as evaluation indicators of the anisotropic MSE. The MSE matrix and the directivity of MSE revealed that the MSE of the fabricated package varied significantly, from 24 dB to more than 60 dB, according to the direction of external field and internal field.