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With the enhancement in the world of wireless communications, the need for multipurpose devices has increased. This need can be fulfilled with reconfigurable antennas In this paper, frequency reconfigurable microstrip patch antenna is presented. In this design it makes use of two patches with same shapes in order to tune for multiple frequencies. The antenna design make use of micro strip feeding technique, PIN diode is used for switching between the patches to tune for different frequencies. The antenna is capable of resonating at a frequency of 2.4574GHz and 5.907GHz, when On State. It will generate a frequency 3.296GHz. When OFF state. This antenna is simulated and measured using CST 2018 software.

There are many applications using the small MIMO antenna structure for performance improvement. The Long Term Evolution (LTE) and Wi-Fi wireless modems are good example of the MIMO based modeling. Many coding techniques have been designed for enhancing the performance of the MIMO channels. This paper has presented the comprehensive study of the Coding techniques used for MIMO system specially using the Space Time Block Codes (STBC). Basically the coding techniques are used for improving the estimation of the MIMO Channel states information (CSI). Various design challenges of the channel estimation for wireless communication are addressed and problems are identified. The comparison of various SCBC based MIMO channel estimation methods have been tabulated based on the BER and MSE performances.

In recent time, world have seen a rapid growth in wireless communication. Development in antenna from single band to dual band and multi band had made the antenna system more compact. A frequency reconfigurable microstrip antenna using a PIN diode for multiband operation is using many application and hot research area. In this paper, reconfigurable microstrip patch antennas and their types like frequency, polarization, radiation pattern and gain are described.