Chi-Kai Shen

Modeling and Analysis of Bandwidth-Enhanced Multilayer 1-D EBG With Bandgap Aggregation for Power Noise Suppression

A circuit model of multilayer electromagnetic bandgap (EBG) structure with application on bandgap aggregation design is investigated in this paper. A design concept for bandgap aggregation is merging the lowest two bandgaps into an equivalent wide bandgap by narrowing central passband. This goal could be achieved by optimizing pitch and arrangement of power/ground vias. The theoretical circuit model which only focuses on cutoff frequencies is proposed for efficient bandgap prediction. The accuracy of the proposed model is validated by comparison with full-wave simulation and measurement results. By using the circuit model, mechanism of bandgap aggregation can be explained well, and the influence of structural parameters can also be studied easily. Furthermore, effect on limiting excitation of propagation modes by narrowing central passband is also validated for merging adjacent bandgaps. Test boards with unit cell size 2.03 mm × 3.94 mm are fabricated and measured to validate the design concepts. Both simulation and measurement show the wide bandgap in insertion loss results, which ranges from 1.27 GHz to above 10 GHz by merging even higher bandgaps.

Miniaturized and bandwidth-enhanced multilayer 1-D EBG structure for power noise suppression

A one-dimensional multilayer electromagnetic bandgap (EBG) structure is investigated for size reduction and bandwidth enhancement. A design concept for bandwidth enhancement of the multilayer EBG structure focuses on merging multi-bandgap into one wide bandgap by making inner passbands as narrow as possible. Such goal could be achieved by optimizing the arrangement of power/ground vias. It is also shown that the first band would drop slightly and the third band would be raised significantly with the proper vias arrangement. In addition, size reduction is due to large capacitance characteristics of multilayer structure. The proposed ten-layer structure results in bandgap from 1.6 GHz to 6.3 GHz with merging first two bandgaps. Test boards are also fabricated and measured to validate the design concepts and simulation results. Wider bandgap for insertion loss results, which ranges from 1.27 GHz to above 10 GHz, is better than dispersion diagram due to higher bandgaps.

Compact hybrid open stub EBG structure for power noise suppression in WLAN band

A compact hybrid open stub EBG structure for broadband power noise suppression is proposed. With an additional lumped component on proper locations of open stub, the proposed EBG structure could offer a wider bandgap to cover the whole associated WLAN bands or an aggregated bandgap ranging from WLAN band to above 10 GHz. A 1-D equivalent circuit model is also developed with validation by full-wave simulation and adopted to investigate design concepts. Test board is fabricated with 0402 capacitor and measured for verifying simulation results. The proposed EBG structure with single broadband design offers bandgap from 2.4 GHz to 6.1 GHz with 89.7% fractional bandwidth, and the one with bandgap aggregation design provides bandgap from 2.4 GHz to 10.8 GHz with 127.3% fractional bandwidth. The unit-cell area of proposed EBG is about 6.6 times smaller than traditional mushroom with the same lower bound cutoff frequency for WLAN band.

An efficient partition analysis for electromagnetic interference estimation of high-speed input/output differential interfaces

To estimate electromagnetic interference (EMI) results of differential high-speed input/output interfaces more quickly, an partition method is proposed by separating system into source generation part and radiation part. Also, the partition analysis can help find contribution of differential-mode (DM) and common-mode (CM) to the unwanted radiation. A measurement validation on HDMI assesses the computational efficiency of proposed analysis by comparing with that of conventional full-wave simulation.

EBG-Based Grid-Type PDN on Interposer for SSN Mitigation in Mixed-Signal System-in-Package

A novel electromagnetic bandgap (EBG)-based grid-type power distribution network (PDN), or grid-type EBG (GT-EBG), is proposed for interposer PDN. The behavior of the proposed EBG structure at cutoff frequencies is first analyzed, and a simplified circuit model is proposed to help control the bandgap behavior. Then the proposed design is realized with the integrated passive device process and validated by measurement. The measured stopband ranges from 7.5 to 15 GHz with an isolation level of −40 dB and 70% fractional bandwidth. In general, the GT-EBG consisting of different numbers of power/ground lines could be embedded in grid-type PDN for different bandgaps.

Design and modeling of an absorptive frequency selective surface with several transmissive bands

An absorptive frequency selective surface (AFSS) which allows signals transmitted in some specific bands is proposed. The transmitting characteristic is rare among AFSS design in the past and can be used to shield the whole package of mixed signal systems. The proposed AFSS provides above 97% absorption at 5.6 GHz in the Wi-Fi band and allows at least half power transmission below 1.84 GHz and above 8.95 GHz, which covers GPS band, most of GSM bands and X-band. Additionally, the proposed work is polarization independent and stable for oblique incident waves up to 45 degrees for both TE and TM polarizations. It is worth to note that clear design concepts and closed-form formulae based on a simple equivalent circuit model are provided, as well as useful design procedures.

Post-fabricated EBG tape on electronic devices for RFI mitigation in WLAN bands

A thin tape with double-stacked electromagnetic bandgap (EBG) structure is proposed for RFI suppression in this paper. This thin EBG tape sticks on only single side of parallel-plate structure formed by printed-circuit board (PCB) and chassis, which is named as single-sided EBG tape (SS-EBG tape). SS-EBG tape provides a RFI solution in a post-fabricating way and can be fabricated with PCB process. Test boards are fabricated with different kinds of excitation and adopted to validate design concepts. By using double-stacked structure, SS-EBG tape has two bandgaps from 2.18 GHz to 2.51 GHz and from 4.8 GHz to 5.63 GHz. In Wi-Fi bands application, SS-EBG tape can provide additional 10 dB suppression level.

Power distribution network modeling for 3-D ICs with TSV arrays

A coupling node insertion method (CNIM) is proposed to handle electrical coupling between top metals of on-chip interconnects and silicon substrate surfaces in three-dimensional integrated circuits (3-D ICs). This coupling effect should not be neglected especially as metal area is intentionally increased in order to reduce resistance values. In this paper, we illustrate how to build the CNIM model and incorporate it into power distribution networks. The CNIM model is validated by comparing our results to the one obtained from a full-wave simulator. The differences between two approaches are within 5% but our computation time is shorter than that required by a full-wave simulator.