Theory And Technology Of CSRR And EBG Structure For Noise Suppression In High-speed Mixed Circuit System

With the rapid development of integrated technology and system in packagetechnology, the requirements of mixed signal system, such as high-performance,miniaturization, low cost and high reliability, are increased simultaneously. Becausethe operating rate of the high-speed digital circuits is increasing, the applicationfrequency range of the RF/microwave circuits is becoming high and the size of thepackage structure is decreasing, some problems, such as signal integrity (SI), powerintegrity (PI) and Electromagnetic Compatibility (EMC), also become more serious.Therefore, it is imperative to suppress the noise propagation effectively while keepingthe SI and EMC behaviors in high-speed mixed circuit system.CSRR (Complementary Split Ring Resonator, CSRR) and EBG(Electromagnetic Bandgap, EBG) structure, as typical meta-material structure, havesome characteristics such as bandgap, simple structure, ease of processing and systemintegration. Therefore, they have attracted more concerns and applied in the design ofmicrowave and millimeter-wave circuit system. However, the applications of CSRRand EBG structure in the high-speed mixed signal system are not enough.In this paper, the noise suppression methods in high-speed mixed circuit systemby using CSRR and EBG structure are investigated. The main research work andinnovations are summarized as follows:(1) An improved planar EBG structure is proposed. For the traditional planarEBG structure, the noise mitigation level can be strengthened by adding the numberof resonator unit cells. Meanwhile, the ripple level is large owing to the inherentbehavior of periodic structure. In this paper, DGS (Defected Ground Structure, DGS),open stub and suprline resonators are loaded on the planar EBG structure, therefore,the noise isolation level is increased in the stopband. The periodic structure isdistributed according to the chebyshev function, thus, the return loss in the passbandcan be decreased. The order of the filter is only three that can minimize the size ofthe filter significantly. By introducing these methods to improve the noisesuppression characteristics, the trades off between the transmission behaviors and thesize of planar EBG structure can be solved effectively.(2) A power distribution network (PDN) is presented by using localizedtopology, CSRRs and embedded capacitance. Owing to the bandgap behaviors ofCSRR and the large capacitance of substrate, the SSN propagation between thepower and ground planes can be prohibited sufficiently. The noise can mitigatedfrom0.41GHz to15GHz with the suppression level of-60dB. The maximumisolation level can reach-130dB in the stopband. In comparison with the globalstructure, the influence on the continuity of return current path can be minimized andthe SI performance can be kept by localized topology. In addition, the equivalentcircuit model is developed to guide the PDN structure design. (3) A PDN structure is proposed by employing CSRRs and localized planarEBG structure. Compared with typical EBG structures, the noise isolation behaviorscan be improved effectively with the presented NBCSRR type EBG structure.Moreover, the transmission characteristics of partial EBG structure are similar to theglobal EBG structure. That is, the number the EBG unit cells are reduced and theinfluence on the SI performance is minimized with the partial EBG. In comparisonwith the referenced board, the proposed PDN structure can decrease the EMIradiated energy and minimized the impact on the adjacent circuits. The cost thestructure is reduced because FR-4material is used for the substrate. Moreover, theequivalent circuit model is also presented to guide the PDN structure design.(4) A common-mode filter for high-speed differential signal line is designedwith the improved CSRRs. By introducing the slot in the double split CSRRs, theinductance is decreased and the capacitance is increased. Then, the common-modenoise can be mitigated with increased bandwidth and large isolation level. For thedifferential signal of differential line, the magnitude and orientation of the currentare opposite and the energy is cancelled, the CSRRs are unexcited and thedifferential signal is passed through. The waveguide wavelength of the proposedCSRR resonator is decreased that can reduce the size of the filter.All the samples are fabricated on the single-layered or multi-layered printedcircuit board (PCB) to validate our proposed works, their measured results agreewell with the simulated ones.