No abstract

In this research, we present a Tri-strip monopole antenna for LTE, WLAN (Wireless Local Area Network) and WIMAX (Wireless interoperability for microwave access) Applications. This is due to the fact that wireless applications is not needed to connect all operating frequencies simultaneously, Which will effect improving functionalities without increasing size of antenna. A miniaturized triple wideband coplanar waveguide-fed patch antenna with the defected ground structure isused for LTE, WLAN and WIMAX applications. The proposed antenna with overall size of 40 mm×40 mm×1mm and the design simulation are carried on a Rogers RT/ duroid 5880 substrate using HFSS v.13.0 simulation software. The proposed antenna shows the gain of 9dB at notch band frequency therefore it is good for its working conditions. Moreover, the proposed antenna is fabricated with a new metamaterial approach by placing the unit cell we have observed the triple band notch characteristics and depth in resonant frequency. There is enhancement in gain and radiation patterns, return loss is analyzed and parametric analysis is presented for optimization of antenna. The average gain that is observed through the band is 3.5dB and the average radiation efficiency that is observed for the model is 94%.

OFDM based wireless systems are spectrally efficient but they are vulnerable to Inter carrier interference (ICI). The rapid variation of the channel can induce ICI. ICI will significantly increase the difficulty of OFDM channel estimation. ICI due to carrier frequency offset can be mitigated by accurate frequency synchronization but ICI due to fast fading channel is more difficult to handle. This kind of ICI can be easily reduced by increasing the sub carrier spacing. In this paper we proposed an OFDM system which will use Variable Sub carrier Bandwidth (VSB) with Variable Bit Loading (VBL) to minimize the effect of ICI due to channel estimation error. We investigate the performance of such VSB-VBL OFDM system with Fixed Subcarrier Bandwidth (FSB-OFDM) system based on Signal Interference to Noise Ratio (SINR) and Symbol Error Rate (SER).

In the Modern communication field, transmitting data through compact antennas like Microstrip patch antennas plays a major role. For Mobile radiolocation, satellite services, medical applications at Terahertz frequency range. Designing antennas for such applications at this frequency must have less weight and good characteristics. For this, graphene is the best suitable material for design due to its electrical, optical, and thermal conductivity properties. So, The Graphene-Based drilled substrate patch antenna 500 X 500 X 40 µm presents the simulation in the terahertz frequency. The prosed antenna structure is well suitable in the ISM (Industrial Scientific and Medical) band 1.36 THz-1.64THz 2.4 ~ 2.5 GHz. Its gives a high gain -20dB. Their Properties have been analyzed with CST for full-wave Simulations.