Study On Left-Handed Transmission Line Based Coupled-line

Left-handed transmission lines are fabricated by human hands which exhibit highly unusual properties that both the permittivity and permeability are negative.In the case of left-handed transmission line,the electric field-magnetric field–wave vector(?) build the unusual left-handed traid wave.Left-handed transmission line in the low frequency phase has a great deal of slow-wave-factor,so we can use left hand transmission line to design miniaturization microwave devices.However,resherch on the left hand transmission line and left hand coupled-line is still in the exploratory stage,especially in the numerical method of extracting left-handed transmission line and left-handed coupled-line dispersion curves.This paper proposed the thesis mainly extracted left-handed transmission line and left-handed coupled line characteristic from the the scattering parameters.The periodic Bloch-Floquet boundary is applied to the periodic solution accurately to calculate the complex propogated constant of symmetrical left-handed coupled-line and asymmetric left-handed coupled-line.The complex propagation constant of the coupling line,established a strict formula of solving and Mathematica program is used to implement the above method.First of all,this paper designed the different series capacitor and shunt inductor,the thesis is also applied to extract the dispersion curves including c/?-mode of the left-handded transmission line and left-handeded coupled lines with different number of perodic structure cell.When the number of periodic structure cell reaches ten,the dispersion curves of left-handed transmission line and left-handeded coupled-line convergence.The dispersion curves based on the lumped equivalent circuit model are nearly identical with periodic solution with one unit cell structure proposed by this paper,but the dispersion curves have not been convergence.The lef-handed couplded-line constructed by different series capacitors can synthesize different coupling bandwidth in the left-handed bound-mode region.The lef-handed couplded-line designed by different shunt inductors can synthesize different forward coupling in the left-handed wave-guide mode region.Finally the symmetric left-handded coupled-line and asymmetric left-handeded coupled-line are frabracated by standard CMOS 130 nm 1P8 M technologies and measured with THz on-wafer measurement system.This paper designed three different types of directional coupler,the first type is the directional coupler constructed by one left-handed transmisiong line and one right-handed transmission line.This directional coupler can achieve 3-d B cupling with the 38-dB isolation.The second type is the directional coupler constructed two symmetric left-handed transmission lines.This directional coupler can realize 10-dB forward coupling with the length of 0.108 ?_g.Compared with the convntiaonal forward coupler,the left-handed forward couplers can enchance the forward coupling.The last type is the directional coupler constructed two asymmetric left-handed transmission lines.This coupler can reduce the coupler size due to the structure of the inductor coupling.This paper also derived the fout-port mircrowave device measured method.by using two-port vector network analyzer.Finally,this paper designed the miniaturized antenna using symmetrical left-haned coupled-line with defected ground structure.Compared with the single left-handed transmission line antenna,this antenna can realize higher radiation efficiency and peak gain.The antenna chip size is only 165 ?m×90 ?m.