The Macromodel Of The Transmission Line And Its Applications To Field-to-Wire Couplings

Field-to-wire coupling is a process during which the electromagnetic(EM)wave produces voltages and currents along the transmission line and at its terminal loads.The phenomenon is closely related to the electromagnetic compatibility(EMC)of an electronic system,as well as its immunity against high-power EM pulses and information security.The macromodel of a transmission line is a model in which equivalent lumped representations are utilized at the ports in order to characterize the distributed properties along the line.Thanks to its good modularity,it is an effective method for the analysis of field-to-wire coupling.In terms of irregular transmission lines,the present macromodels construct their S-parameters by means of full-wave algorithms or experimental measurements.Opencircuited voltages or short-circuited currents are required to consider the effects of the exciting EM fields.It is therefore of relatively low efficiency.Through associated theoretical derivations,the dissertation constructs the macromodel of the thin wires of arbitrary shape based on the algebraic equation of the method of moments(MoM).The effects of the exciting EM fields are considered through the reference current.When uniform or weakly non-uniform transmission lines are concerned,the proposed macromodel based on the MoM degenerates into the macromodel based on the classical transmission line equation.Currently,the research on field-to-wire couplings involving uniform transmission lines mainly focuses on the field of EMC and the effects of highpower EM pulses,while the attention on the information security of a transmission line is far from enough.Regarding weakly non-uniform transmission lines,the twisted-wire pair(TWP)is a popular topic.Some researches were conducted in depth separately in its radiated susceptibility(RS)and crosstalk.Few reports,however,are available which address the equivalence between the two coupling mechanisms.The dissertation studies the crosstalk between two pairs of parallel transmission lines.The potential risk of information leakage is proved by a reconstruction of the transmitting signals.Meanwhile,the macromodels of the TWP are utilized to study the equivalence between the crosstalk and the coupling of the external fields.The RS test of a TWP is equivalently fulfilled by means of crosstalk and the efficiency of the test is greatly improved.The main contributions of the dissertation are as follows:1.A macromodel of the thin-wire structure of arbitrary shape in free space or above the infinite conducting plane is proposed based on the MoM.Through a classic example,the accuracy of the proposed macromodel is verified.Furthermore,the terminal nonlinear loads and the geometric perturbation of the wire are studied,followed by a preliminary application of the proposed macromodel.2.On the basis of the macromodel of the uniform transmission line,the near-field coupling,namely crosstalk,between two pairs of parallel transmission lines is analyzed.‘One-recetpor method' and ‘two-receptor method' are proposed.The transmitting signals along the objective transmission line are reconstructed by corresponding algorithms.Numerical simulations are conducted to verify the effectiveness of the proposed reconstruction methods.The research theoretically proves the potential risk of information leakage along the parallel transmission lines.3.The macromodel of the TWP under the condition of external waves is built,together with the macromodel of the crosstalk between the straight wire and the TWP.After the simplification,approximation and match of the two macromodels,the equivalence between the two coupling mechanisms is proposed.Voltages and currents that are equivalent to those obtained in the presence of external waves are induced by crosstalk through well-controlled voltage sources at two ends of the feeding straight wire,thus equivalently fulfilling the RS test of the TWP.