Conventional package lid induces additional unintentional radiation due to the resonances between the conventional metal lid and ground plane on package board. In this paper, a novel package lid is proposed based on the gap waveguide theory, which adopts mushroom-type electromagnetic bandgap structures to mitigate the increased unintentional emission. In addition, a scalable equivalent circuit model is presented as an assistance for designing the proposed package lid. Both the simulation and measurement results confirm that the proposed lid can significantly reduce the unintentional radiation within the specific frequency range as designed.

High electromagnetic interference (EMI) radiation is becoming a critical problem as the operating frequency of the electronic devices increases rapidly. In this paper, the mushroom type electromagnetic band gap (EBG) structure attached on the bottom of the heatsink is proposed to suppress high EMI radiation of packages within a specific frequency range. To confirm the effects of the novel heatsink with mushroom-type EBG structure, full-wave simulation and measurement in the semi-anechoic chamber (SAC) have been carried out to validate and quantify EMI radiation suppression. The proposed novel heatsink with mushroom-type EBG structure can keep EMI radiation at a low level, which offers the remarkable suppression by approximately 10 dB on average in the frequency range from 9.2 GHz to 15.8 GHz in simulation and by approximately 8 dB on average in the frequency range from 9.8 GHz to 15.6 GHz in measurement.

Package lid is usually mounted above the integrated circuits (ICs) to protect the die and improve the thermal performance. However, the package lid may be an unintentional radiation contributor due to the resonance of package lid and package substrate. In this paper, based on a typical wire-bonded ball grid array (WB-BGA) package, perfect magnetic conductor (PMC) packaging is used to suppress the electromagnetic interference (EMI) radiation caused by the package lid. Lid of nails (also called pin surface) is utilized to realize the PMC condition within a certain frequency range. The simulation results confirm that the lid of nails can effectively reduce the radiated emission from the lid in the frequency range as designed.

Heat sink is widely mounted on the integrated circuits to optimize thermal performance. Unfortunately, the cavity resonance between heat sink and package substrate could lead to severe radiation problem, causing that the product fail to satisfy the relevant electromagnetic interference (EMI) standards. It is a critical challenge to simultaneously obtain the excellent radiation attenuation and desirable thermal performance. In order to solve the problem, a combination of ring-shaped absorbing material and flat-shaped graphite is proposed in this paper. Based on a typical wire-bonded package, the effect of graphite on mitigating radiation and optimizing the thermal performance is investigated. As the graphite size varies from 20 to 45 mm, temperature reduction 5 degrees C and radiation attenuation 10 dB absorption bandwidth is realized. The experiment for EMI radiation is conducted in a semianechoic chamber, and the results of simulation and experiment matched well.

Package lid is usually mounted above the complex package substrate to protect die, control warpage and provide a better heat dissipation. Unfortunately, the resonance of radio frequency (RF) signal between package lid and package substrate usually causes serious radiation problem, which could prevent the products from satisfying the relevant EMI standards. In this paper, based on a conventional wire-bonded ball grid array (WBBGA) package with a package lid, a lid covered by resistive graphene films is proposed to mitigate the radiation emission. The resistive graphene lid achieves radiation attenuation about 10 dB on average and the related process is introduced in detail.

Heat sink is widely amounted above the package substrate for heat distribution. Unfortunately, the resonance between heat sink and package substrate leads to the severe electromagnetic radiation, and results the product not satisfying the relevant EMI (electromagnetic interference) standards. It is a critical to simultaneously obtain the excellent radiation mitigation and desirable thermal management. In this paper, a combination of ring-shaped absorbing material and flat-shaped graphite is proposed. This paper investigates the effectiveness of graphite to mitigate radiation and optimize thermal performance based on a typical wire-bonded (WB) package. The experiment for EMI radiation is conducted in a semi-anechoic chamber. A good agreement between simulation and measurement is obtained.

Plane-pair partial element equivalent circuit (PEEC) (PPP) is a faster analytical method for calculating the impedance properties of plane-pairs PDN structure. In this paper, PPP method is employed to simulate the loop inductance of multi-slots plane-pair structure. The influence of slots fill area ratio on loop inductance is studied. The experimental work is carried out and the results agree well with the simulated ones.

Plane-pair partial element equivalent circuit (PEEC) (PPP) is a fast analytical method for calculating the impedance properties of plane-pairs PDN structure. In this paper, PPP method is employed to simulate the loop inductance of multi slots plane-pair structure. The influence of slots fill area ratio on loop inductance is studied. The experimental work is carried out and the results agree well with the simulated ones.

The effects of shorting vias on suppressing common-mode radiation in different frequency range are investigated based on a typical wire-bonded ball grid array (WB-BGA) package. Conventional shorting vias provide a short return path for common-mode currents so as to reduce the radiation effectively at low frequencies. However, the suppression is limited at higher frequencies due to the excess parasitic inductance. Therefore, a novel concept of absorptive shorting vias is presented for suppressing radiation in high frequency range.