The Research Of Power Distributionnetwork And Structural Radiation Emission In High Speed Digital System

In the field of quick-developing electronic design, the electronic system composed by integrated circuit chip develops towards the direction of large-scale, small volume and high speed. Its power integrity and electromagnetic compatibility problems also become increasingly prominent to attract people's concern.Power distribution network and signal distribution network are two most important functional networks of the high-speed digital circuit system. Its power integrity and signal integrity are the barriers of the high speed digital circuit system to develop into high speed, high density, high power, low voltage and high current trend. At the same time, the accompanying electromagnetic radiation restricts the development of high-speed digital circuit system bringing the issues about electromagnetic leaks and the information security. Power distribution network is the core of the high speed digital system design which is the largest and the most complex interconnected structure in the system and it directly affects the power integrity, signal integrity and electromagnetic compatibility of the system. This paper focuses on the power integrity and structural radiation emission in the high speed digital system. The main contents and innovations are summarized as follows:1. Research on the power distribution network structure in the high-speed digital-circuit system. This paper analyzes the deep reason of the power integrity problem and the structure resonance characters of power distribution network. The frequency of multi-order high resonance is also being calculated. This paper has evaluated the positions and frequencies which can easily produce noises by the power distribution network structure. Based on the transmission line matrix method, the paper builds the electromagnetic radiation model of the power/ground plane in power distribution network. The result shows that the impedance in power distribution network is the key reason of the power integrity problem. The electromagnetic waves transmitted in the power/ground plane are transverse magnetic waves. The resonance could easily be produced when the frequencies of transverse magnetic waves and structure resonance are equal.2. This paper proposes an analyzing model of the electromagnetic radiation of power/ground planes structure based on the boundary element method. The pair of power plane and ground plane is the most important passive structure. This paper combines the boundary integration and discrete technologies to converts the three-dimensional problems into two-dimensional and the most important indicators (the impedance) in the PDN design has been calculated. According to the equivalent magnetic current theory, the radiated emission from the edge of power ground planes have been calculated and the influence of dielectric constant,dielectric layer thickness respective to the impedance and far field radiation emission has been analyzed. The result shows: the boundary element method can efficiently solve the impedance and radiated emission problems rapidly. The Dielectric constant and space of structure can affect the input impedance and edge diffuse radiation. The thicker of the dielectric layer is, the greater of the impedance and the radiation emission will be. The simulations and experiments have been used to verify the boundary element algorithm. Calculations, simulations and tests results are anastomotic with each other.3 A calculation model of edge diffuse radiation in power/ground plane structure based on dynamic injection noise analysis method was proposed.Concentrating on the current state of using a hypothesis of injecting noises to calculated the edge diffuse radiation of power/ground plane structure.This paper originally studied the influence of dynamic injecting noises into the power/ground plane edge diffuse radiation. According to the energy concentrating principle, the axisymmetric finite element method is adopted to extract the via holes' dynamically parasitic parameters, and uses the micro-strip line outside circuits to constitute a lumped circuit. By means of circuit simulation for acquiring the real-time noise of injecting power/ground plane and calculates the input impedance and emission of far-field radiation. Results show that the field-circuit combined method can effectively simulate the effects which dynamic injection noise have on the power/ground plane and the edge diffuse radiation; In high frequency,the axisymmetric finite element method can quickly and accurately extract via holes' parasitic parameters. Using the simulation for verifying, errors are controlled within 5%.4 A numerical method based on boundary integral has been propose to evaluate the effectiveness of decoupling capacitor on mitigating radiated emission from power/ground planes. Through the combing of field and circuit to deduce the boundary integral equation of voltage and current. the supplementary equation has been set up by setting the decoupling capacitor as the impedance boundary and to list the functions to calculate the input impedance and diffuse radiation of the pair of power/ground plane. This essay has also studied how the layout and the parasitic parameters of decoupling capacitors have influence on power integrity and electromagnetic radiation. It shows that the boundary integral numerical method can accurately evaluate the effects of the decoupling capacitor having on mitigating radiations. The decoupling capacitor can effectively mitigate the edge diffuse radiation and the effect is constrained by the capacity of the capacitor and parasitic parameters. The high-capacity decoupling capacitor is recommended at the low frequency and a large number of low-capacity capacitors in parallel are recommended at the high frequency.5 A electromagnetic radiation model based on the differential mode and common mode segmentation technology has been propose to evaluate the effectiveness of shorting via on mitigating radiated emission from power/ground planes. As for the common "ground-via" technology, this paper researches the effectiveness of shorting via from the perspective of the electromagnetic radiation and analyzes the mitigating mechanism. The influence that the switching of reference planes has on the signal transmission characteristics has been studied. The results show that the shorting via can effectively inhibit the differential-mode radiation. But when the common-mode radiation is greater than the differential mode radiation, the shorting via is not effective. When the short via is close to edge of the structure, the depression will be more effective. The distance between reference planes becomes closer and the signal transmission performance will be better.