Albert Chee W. Lu

Double-Stacked EBG Structure for Wideband Suppression of Simultaneous Switching Noise in LTCC-Based SiP Applications

We propose a novel electromagnetic bandgap (EBG) structure with a significantly extended noise isolation bandwidth, called a double-stacked EBG (DS-EBG) structure, fabricated on a low-temperature co-fired ceramic (LTCC) multilayer substrate. The DS-EBG structure was devised for wideband suppression of simultaneous switching noise (SSN) coupling in system-in-package (SiP) applications. Our design approach was enabled by combining two EBG layers embedded between the power and ground planes. The two EBG layers had different bandgaps from using different cell sizes. Enhanced wideband suppression of the SSN coupling was validated using a 11.4-GHz noise stop bandwidth with 30-dB isolation in time and frequency domain measurements up to 20GHz

Hybrid analytical modeling method for split power bus in multilayered package

As multiple chips are being integrated into a single package with increased operating frequency, switching noise coupling on power buses has become an important design issue. To reduce the noise coupling, a split power bus structure has been generally used in package substrates having multilayered power and ground planes. Consequently, there is an increasing need for an efficient method to analyze a split power bus in a multilayered package. This paper introduces a hybrid analytical modeling method for characterizing a split power bus in a multilayered package. The proposed method uses a resonant cavity model combined with a segmentation method. Furthermore, a port assignment technique and an associated calculation method for the equivalent circuit model parameter of the split gap are proposed. The proposed port assignment technique and the analytical equation make it possible to analyze a split power bus, especially in a multilayered package. To verify the proposed method, multilayered test packages are fabricated and tested by means of frequency-domain measurements. In addition, an optimal power bus design method was successfully demonstrated for suppressing noise coupling between chips on a single package. Finally, the proposed method and optimal power bus design method was verified using a series of frequency-domain and time-domain measurements

Ultrathin and Flexible Screen-Printed Metasurfaces for EMI Shielding Applications

An ultrathin, lightweight, and flexible metasurface for band-stop electromagnetic interference (EMI) shielding purpose has been designed and fabricated using screen-printing technology. Using a 1.8 GHz band-stop EMI shield as a design example, a prototype of a screen-printed metasurface has been validated using measured and numerically computed results. Hence, screen printing can be an attractive option for flexible and lightweight shields that can be easily applied on the walls and windows of a room to block specific wireless communication band so as to protect critical electronics instruments from possible EMI.

3D strip meander delay line structure for multilayer LTCC-based SiP applications

Recently, the timing control of high-frequency signals is strongly demanded due to the high integration density in three-dimensional (3D) LTCC-based SiP applications. Therefore, to control the skew or timing delay, new 3D delay lines will be proposed. For frailty of the signal via, we adopt the concept of coaxial line and proposed an advanced signal via structure with quasi coaxial ground (QCOX-GND) vias. We will show the simulated results using EM and circuit simulator.

Efficiency of differential signaling on cavity noise suppression in applications with reference plane change

We present the effect of reference plane change of signal traces on cavity noise generation and signal quality deterioration. Also, the efficiency of differential signaling in reducing the power plane noise and the alleviation of signal integrity deterioration, which are caused by power/ground plane resonance, are investigated with the analytical cavity noise coupling model and measurement.

Modeling and characterization of wire bonding for RF applications

This paper describes a design methodology for improving the electrical performance of wire bonding. Adjacent power or ground wires are used to provide return paths in a coplanar configuration, thereby minimizing impedance mismatch. Design space exploration based on full-wave electromagnetic analysis is performed to achieve an optimized topology. The methodology has been demonstrated for both parallel and fanout bonding topologies for high frequencies up to 10 GHz. With advances in wire bonding technology, particularly fine pitch bonding, a coplanar configuration is highly feasible. The proposed methodology can be applied to lead frame, leadless chip carrier, COB and advanced BGA packages.

Analysis of noise suppression techniques using embedded capacitor on split power bus in multi-layer package

An embedded capacitor for noise suppression on a power bus is analyzed and compared with a discrete capacitor by full wave simulation from 40 MHz to 5 GHz. In this paper, the design methodology of the power bus is demonstrated by analyzing self and transfer impedance characteristic of the embedded capacitor.

60-GHz LTCC antenna array with microstrip to CPW transition

We present an antenna array design at 60 GHz on low-temperature co-fired ceramic (LTCC) with a microstrip to coplanar waveguide (CPW) transition. The design consists of aperture-coupled microstrip patch antennas on LTCC Heraeus HL2000 with small embedded air holes to synthesize a lower dielectric substrate. The arrays are excited through a microstrip-line feed network with quarter-wave matching via a microstrip to CPW transition. The transition is designed so that the antenna can be measured with the patch facing upwards while reducing the effect of the probe station. An open cavity is made to ensure the microstrip-line is also placed away from the probe station plate. Good agreement between simulated and measured return loss with simulated gain of 14dB is achieved.

Noise Isolation in LTCC-Based X/Ku-Band Transceiver SiP Using Double-Stacked Electromagnetic Bandgap Structure

We experimentally investigate the isolation effect of the noise coupling in X/Ku-band transceiver SiP fabricated on low-temperature co-fired-ceramic (LTCC) multilayer substrate, using a double-stacked electromagnetic bandgap (DS-EBG) structure. The fabricated transceiver SiP is composed of Ku- band transmitter and X/Ku-band receiver. To prevent the simultaneous switching noise coupling from digital circuits, a DS-EBG structure was designed and implemented to the transceiver SiP. The effect of DS-EBG, which gives 30 dB stopband over X/Ku-band ranges, was demonstrated through frequency and time domain measurement.

Tri-band frequency selective band-stop shield using screen printing technique

A tri-band frequency selective band-stop EMI shield is designed using various concentric rings with each ring resonating at the specific desired frequency. The shield is fabricated using roll-by-roll screen-printing process, making it suitable for large surface architectural shielding applications. The design is designed using full-wave simulation tool and the performance is validated experimentally.