Composite Right/Left-Handed (CRLH) Microstrip Resonant Antennas

by Bo Zhao

Institution: University of Cincinnati
Department: Engineering : Electrical Engineering
Degree: MS
Year: 2005
Keywords: CRLH; Left-handed; Right-handed; Zeroth Order Resonator
Record ID: 1771736
Full text PDF: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1123784412


The left-handed metamaterials have the negative permittivity e and permeability µ simultaneously. This provides the left-handed metamaterials various new properties in comparison with the traditional right-handed (RH) material. The discovery of the LH material became one of breakthroughs in the science. Many applications for the left-handed metamaterials are possible. Extensive research has been carried out or is being carried on. The goal of this thesis is to design a new type of the microstrip resonant antenna with small physical size by the Composite Right/Left-Handed (CRLH) transmission line (TL). This is coincident with the trend of the modern integrated circuit technology. The CRLH TL is the concrete application of the LH metamaterial. It can be implemented by the series microstrip unit cells. In this thesis, the CRLH TL theory is interpreted carefully. The verification is done by the ADS momentum simulation. The good agreement between the theoretical expectation and the simulation results is observed. One important application of the CRLH TL is the zeroth order resonator (ZOR) antenna. Unlike the traditional microstrip transmission line, the CRLH TL can have zeroth order resonant model and the zeroth order resonant frequency does not rely on the CRLH TL’s physical length, but on the resonance frequency of its shunt anti-resonance circuit. This unique property makes it possible to design a small size antennas. A 2.4 GHz ZOR antenna is designed with CRLH TL. It has low S11 minimum, high radiation frequency, and very compact size. The area is almost tenth of the conventional microstrip rectangular antenna. The antenna has radiation center frequency of 2.401 GHz, which is close to the expected frequency as from the CRLH TL theory. The S11 minimum in center frequency is -30.529 dB. The radiation efficiency is found at 96.190%. The size of the antenna is approximately 17mm long and 9mm wide, and the area is about 153 square mm.