Research On The Application Of Left-handed Structures In Microwave Passive Components

Since left-handed materials have been successfully realized by special structures in 2002, left-handed materials, as a new kind of metamaterials with the characteristic of simultaneous negative permittivity and negative permeability, they gradually show significant application potentials in microwave components and microwave circuits design. Generally, various structures which realize the left-handed materials are defined as left-handed structures. In recent years, the most common structure to achieve left-handed materials are divided to split ring resonator (SRR) and composite right/left-handed transmission (CRLH) structure based on transmission line theory. In this thesis, the composite right/left-handed transmission line structure and the simplified composite right/left-handed transmission line (SCRLH) structure is analyzed firstly. And then their application in microwave passive components is investigated, such as directional couplers, filters, antennasThe original works and valuable results of this thesis are as follows:1. The traditional composite right/left-handed transmission structure based on the transmission line theory is analyzed first of all. An ultra-wideband (UWB) filter based on the CRLH structure is designed, which can improve the in-band and out-of-band performance.2. A new kind of CRLH/SCRLH directional couplers is proposed which has superior characteristics, such as strong coupling, compact size, and broad bandwidth.3. The zero order resonators characteristics and its realization are studied in this thesis. Then, a narrow-band bandpass filter with two zero order SCRLH resonators are designed, which has compact size, wide out-of-band rejection bandwidth.4. An improved CRLH zero order microstrip antenna and improved SCRLH zero order resonance antenna are designed and fabricated. The results show that they have characters of compact size, easily frequency adjustment.5. Recently, the design of ultra-wideband antenna with band-notched characteristics is a hot spot. In this thesis, the SCRLH resonator is used for the notched band of the UWB antenna. A new (UWB) antenna with dual notched bands utilizing a simplified composite right/left-handed (SCRLH) resonator is proposed.