Study On The Design Of Novel Left-Handed Transmission-Line And Its Characteristics

The left-handed material is a metamaterial with simultaneously negative permittivity and negative permeability. It has many extraordinary properties and potentials for applications. At present, it becomes one of hot research areas in the electromagnetic field and microwave region. In this dissertation, based on the application of the left-handed materials in microwave field, we design types of novel transmission line with left-handed characteristics using all kinds of structures. First, the left-handed materials can be realized based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous wires, which exhibits a frequency region in the microwave regime with simultaneously negative values of effective permeability and permittivity. The wave has left-handed properties transmitting in the double negative materials. Subsequently, the effective circuit of the double negative materials was proposed in the transmission line. That is, series capacitors and shunt inductors obtain a negative refractive index. To these methods, some design is porposed in this paper.In Chap. 3, we transform the 3-D split ring resonators into plane SRR and CSRR according etching techniques. The 3-D wires are also changed to shorted stub and series capacitors. These modifications which get neative permeability and permittivity can realize left-handed properties in the transmission line. In Chap. 4, we also design the new structures with SRR. Combining SRR and DGS and using neative permeability effected by the SRR, the new structures get a new stop band include stop band by DGS. And then, there is an important change for the influence of width of DSG on working frequency of the traditional DGS structure, because of the adding SRR. We renounce the use of SRR in Chap. 5 and design the CLRH with left-handed properties again using common structure, just like interdigital capacitor, gap capacitor and stub. At last, we realize the special properties for the CLRH. When the stopband between the two passband is closed, the frequency which connects left-handed passband to right-handed passband is called zero-order resonat frequency. The physical length is not depending on the working frequency at the zero-order resonat frequency.Accroding the up methods, the main innovative works of this paper are as follows:1. The novel composite right/left-handed transmission line with SRRs and CSRRs is designed. This line transmits electromagnetic waves which have left-handed characteristics and easily processed. On the other hand, the frequencies of the passbands are changed especially adjusting the resonating units, because that the CSRR and SRR are different in the physical unit and the pass bands achieved by SRR and CSRR are located in different region.2. The novel transmission line that consists of rectangular SRR and a dumbbell-shaped DGS is designed. The main feature of this SRR-based DGS is remarkable dual-stop-band characteristics for adopting the SRR. Different from the conventional dumbbell-shaped DGS, the resonant frequencies of the stop band increase with the increasing widths of the gap and the SRR. This significantly properties were not found in the similar structure.3. A simple structured composite right/left-handed transmission line is designed, in which the meander lines, the rectangular patch and the T-DGS instead of the traditional interdigital capacitors and gap capacitors. For adopting the new resonating structure, the bandwidth of pass bands is relative wide. So this new structure with two left-handed pass bands and two right-handed pass bands have multi-band-pass characteristics.4. The composite right/left-handed transmission line with zeroth-order resonance is designed with balanced resonance conditions by the spiral inductor. Without volume enlarged, the transmission line with the new design thought, the proposed structure is that the mender line closed the stop band between the right and left pass bands. As a resonator at zeroth-order resonance frequency point, it is independent of the physical length so that the resonator can be arbitrarily small.