Research On The Metamaterial Antenna

With the continuous updating of wireless communication systems, a variety of wireless electronic devices have become increasingly demanding. As the front end of the wireless communication, antennas are constantly made toward miniaturization, wideband, high gain direction. Although conventional microstrip antenna can not meet the requirements of the times, but the research on the antenna opens up a new path because of the found of Left-handed Materials(LHM). As a form of LHM, the composite left/right-hand(CRLH) trans-mission line has been widespread concerned because of its good characteristics. And we try to design the miniaturized and wideband antennas on the basis of the analysis of the CRLH-TL theory.Firstly, this article briefly describes the development process of left-handed materials (LHM), as well as the background and significance of the metamaterial(MTM) antennas, and concisely describes the current research on the metamaterial antennas. Then this paper briefly introduces the basic theories about the metamaterial antenna design.Secondly, this paper analyzes the negative order and the zero-order resonator based on the principles of the CRLH-TL. At the same time, we summed up several implementations antenna bandwidth extension technique, and a novel structure of a coplanar waveguide (CPW)-fed antenna is presented. A method to extend the bandwidth of metamaterial (MTM) antennas based on the CRLH-TL is proposed. A prototype of the proposed antenna has been constructed and experimentally studied. The measured return loss bandwidth (-10 dB) is enhanced from 240 MHz (1.63-1.87 GHz) to 840 MHz (1.67-2.51 GHz), which corresponds to the fractional bandwidth of 14.0% and 40.2%. Measured peak gain and measured radiation efficiency are up to 4.13 dB and 83.69% at the operating frequency of 2.09 GHz. Because of wide bandwidth, good radiation characteristics, and acceptable peak realized gains, the proposed antenna is very suitable for GSM/UMTS/LTE/WLAN wireless communication systems.Lastly, this paper introduces some technologies of antenna miniaturization. And then, we design an asymmetric coplanar waveguide (ACPW)-fed miniaturized antenna contains two unit cells of the CRLH-TL based on the principles of the CRLH-TL. We change the resonant frequency by adjusting the constitutive parameters and merging its two resonance frequencies into a single band for the purpose of the bandwidth enhancement. It can be seen from the simulation results obviously that the antenna’s operating frequency band is 1.91-2.06 GHz(150MHz). The size of the proposed antenna is only 17.7× 25 × 1.6 mm3, and it has the advantages of the simple structure and so on. But the antenna has low realized gain because of its small size. This design effectively extends the bandwidth without increasing the size and complexity of the antenna.