Wireless Sensor Network (WSN) has been a source of attraction for many researchers as well as common people for the past few years. The use of WSN in various environmental applications like monitoring of weather, temperature, humidity, military surveillance etc. is not limited. WSN is built on hundreds to thousands of nodes where each node is a sensor whose main role is to sense data. These nodes are restricted to various constraints like power, energy, efficiency and deployment. The location of deployment influences the efficiency of data transmission. In this paper we briefly discuss on localization process in WSN and the classification of localization methodologies, namely centralized localization and distributed localization. The various techniques like ToA, TDoA, AoA and RSSI that are used to estimate the distance among the nodes are studied in detail. The localization issues categorized under proximity-based, range-based and range-free localization are discussed in detail. This paper also focuses on how the nodes with GPS can contribute to the localization process. The merits and demerits of using GPS have also been looked into. The various approaches of range-based techniques like Bounding box, SumDistMinMax, geometric methods, general techniques have been discussed briefly. We will also discuss on how the factors like path loss, noise, propagation, device measurements, connectivity, power control and tracking can influence the measurements in localization. In the tracking process we have briefly discussed about the variants of Kalman filter that can be used in detecting the direct path, strongest path and undirected path. This paper as a whole is just a brush up of the localization methodologies used in wireless sensor networks. This paper may give idea to the researchers to develop efficient algorithms to localize nodes with accuracy adapting to different techniques with respect to the environment and applications to be designed.

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In this paper, a Microstrip Patch Antenna (MPA) is about to be designed. A dielectric material known as the substrate is sandwiched between a metallic patch and ground in an MPA. In comparison to the substrate and ground, a patch is smaller in size. The resonant frequency and dielectric constant value affect the size of a microstrip patch antenna. The proposed technology is a multi- input and multi-output microstrip patch antenna technology for wireless communications. The term "multiple inputs and multiple outputs" (MIMO) refers to a wireless technology that transfers more data between the transmitter and receiver at once to speed up data transmission and reduce mistakes. In essence, this idea refers to wireless network technology enabling access points or wireless routers to have many antennas. Simulating all antenna parameters, such as VSWR, balance, efficiencies, far field, and s-parameters, using CST Microwave Studio is the only way to verify the proposed antennas' performance.