 Hello everyone. Namaste. Welcome to the topic of special antennas that is smart antenna. Learning outcomes. At the end of this video you will be able to define smart antenna. You will be able to explain types of smart picture. Okay, what is smart antenna at all? In the types of antenna I talked about smart antenna, what it is? So, what is smart antenna? Let us see what it is. Smart antenna also known as adoptive array antennas. So, as name indicates adoptive and array means the antenna elements put together is then array is forms an antenna array. Adoptive is adjusting the pattern of the array. So, its name is adoptive array antenna. So, smart antenna also known as adoptive array antennas. The this concept of adoptive array antenna will be much clear when I explain you the working and with the examples. And digital antenna array is also the name for smart antenna. Also there are the names as multiple antennas and it is also recently called as MIMO multiple input multiple output. Antenna arrays with smart signal processing algorithms are used to identify the spatial signal signatures which is direction of arrival signal. So, the arrays are used with signal processing algorithms for detection of direction of arrival of signal. So, these are used to calculate beam forming vectors which are used to track and locate the antenna beam on the mobile or target. Smart antennas are different than reconfigurable antennas. Most of the times it happens that reconfigurable antennas are confused with smart antennas, but they are different from smart antenna. Both of them have similar capabilities, but the single element antennas are called as reconfigurable antennas and not the antenna arrays. So, when it comes to antenna arrays it is a smart antenna, but it comes to simple element then or a single element antenna then it goes it comes to the reconfigurable antennas. What is the objective of the smart antenna? The objective is to maximize the gain in the desired direction and another objective is to minimize the gain in the direction of interference. So, in the direction of interference we are going to nullify or we want the null or we want the minimum radiation, whereas in the direction of maximum gain where in the direction where the actual target is there in that direction I want the maximum gain. So, here smart antenna when I say as I am saying we want the maximum gain in the desired direction if this is the desired user. So, in this direction we want maximum gain whereas in interfering user we want null in that case. So, that is what is the requirement of the objective. Working of smart antenna, technical aspects involve number of elements fade with the signals which are adoptively processed. So, there are number of elements that means the antenna array those are fade with the signals which are adoptively processed which are processed adoptively one after the other in space and with the space time filtering types of smart smart antennas. So, there are basically two types of smart antennas adoptive array antenna and switched beam array antenna. Let us see first the adoptive array antenna. It is the core system component in mobile networks. Adoptive array antenna is a core system component in mobile networks. Adoptive array as the name is there adoptive it allows the antenna to steer the beam to any direction of interest while simultaneously nulling the interfering signal. So, adopting in the sense what it is allowing or steering the beam in the direction of interest and nullifying the or nulling the beam in the direction of interfering signals. This adoptive antenna array can track and locate the signals. Here the diagrammatically it is shown where you can see these are the antennas and this is the these are the weightages provided to it all sum together there is the adoptive algorithm is there. The output of this is the beam forming signal. This beam forming signal given here and whatever desired signal is given here. The error signal when fed to adoptive algorithm the adoptive algorithm will adopt in such a way that it provides the maximum gain in the desired direction and null in the interfering direction. This is what is the adoptive array antenna system. So, it can locate and track the user signals that is users as well as interference is it can customize an appropriate radiation pattern for each individual user. So, for each user it can create or customize the radiation pattern. Now, let us see the difference between what is the difference between the conventional array and beam forming array. See if this is the radiation pattern of one antenna this is radiation pattern of the other antenna likewise these are the individual radiation patterns. So, if I see all the antennas radiation pattern this is a complete one it is a case of conventional array. But if I say this is of the beam forming array. So, the beam forming array is making the radiation to increase or the more is the gain in a desired direction where the main beam is where the target is in that case you can see the main beam you can see the larger lobe you can see the higher gain. Whereas, in other directions you can see the side lobes which have very less gain. So, this is the difference between the conventional array and beam forming array in terms of radiation. Another type of the antenna which is a switched beam array antenna. As the name itself indicates switched beam that means the radiation beam is getting switched. So, switched beam array antenna have several fixed beam patterns and only the decision need to be made which beam is to be accessed at a given point of time. The aim of the switched beam system is increasing the gain according to the location of the user. So, based on the location of the user increase the gain of that particular beam let me show you diagrammatically. So, these are the multiple beams that you can see, but only active beam is this one. This is for these beams are formed due to antenna array and this is the here if user is there this beam is active at a particular point of time. So, multiple fixed beams with one beam turned on towards the desired signal that is the switched beam antenna or switched beam array or I can also say single beam is steered to the desired signal single beam is getting steered to the desired signal. Comparison between switched and the adaptive array antenna if I see you can see here switched beam array antenna will be giving the maximum gain for the desired user for interfering users or for interference it is there are the minor loops, but in case of adaptive scheme you can see the for the desired user the maximum gain is there, but at the same time for interfering users there is a null. So, that is what is the adaptive scheme. So, it is adopting in that way. So, this is the difference between the switched antenna and adaptive array antenna. You can see here based on the criteria I can differentiate between switched beam and adaptive array. So, here on based on the integration switched beam is easy to implement it and it has a low cost. Whereas adaptive antenna array system the trans receiver complexity is there so that the cost is high and hard less hardware redundancy is there in adaptive arrays. Based on range and coverage if I compare switched beam has more coverage compared to conventional system and less coverage compared to adaptive array. Whereas adaptive arrays more coverage is there compared to switched beam system. If I talk in terms of interference rejection there is a difficulty in the switched beam in distinguishing between desired signal and interferer and does not react to the moment of interferers. Whereas in adaptive array as you have seen in the lobe also focusing is narrower and it is capable of nulling the interfering signals as I have shown in the previous slide here it is capable of nullifying the or nulling the applications are the different applications are mobile communications, cellular and wireless networks, satellite communications, wireless sensor network, military application and electronic warfare these are the different applications of smart antenna. These are the references used for preparing this video. Thank you.