 Good afternoon everyone, myself Piyusha Shedgarh. In today's session, we will see the two types of an antenna array, broad side array and end fire array. These are the learning outcomes. At the end of this session, students will be able to define and explain the types of an antenna array. They will be able to distinguish between the broad side and end fire array antenna. These are the contents. Now, before going to start the types of an antenna array, you can pause video here for a second and recall that what is antenna array? Yes, an antenna array is an assembly of antenna elements arranged in an orderly fashion and these elements are usually identical elements. Similar elements are connected in an orderly fashion. Now, what is the broad side array antenna? It is considered as one type of an antenna array. So broad side array is defined as an array of elements for which radiation will be maximally occur perpendicular to the axis of an array. That is, you are observing the main beam or the major lobe which is perpendicular to the axis of the array. That is 5 becomes is equal to 90 degree. Now, the broad side antenna array will be formed. So it is formed by having a number of elements of the equal size connected in a line. These are equally spaced along a straight line or on axis. It is forming collinear points. These array are formed by taking the same phase for all the dipoles that is for the all elements. Now, what is the frequency range considered for the broad side array antenna? So, the generally the frequency range used for the broad side array antenna is from 30 megahertz to 3 gigahertz which having the range in between very high frequency and the UHF that is ultra high frequency band. Now, the broad side array construction is shown in this figure. So, this is the construction the number of elements are connected to each other. Arranged to the principal direction of the radiation it should be perpendicular to the antenna array axis and also it is perpendicular to the plane containing the array element. So, this shows the front view of the broad side array antenna. This is nothing but the side view of an array antenna shows the points are connected linearly and the radiation pattern of an antenna is perpendicular to the axis on which the array is existing. Now, the broad side array is strongly directional at the right angle to the plane of an array. So, if these two are the elements spaced by the spacing between these are provided as a lambda by 4 and the feeding point is provided at the center point. So, this is the example of the two element broad side array antenna. Now, how to consider the radiation pattern of an broad side array antenna? So, typical antenna length is considered as 2 to 10 wavelength whereas, the typical spacing between the each element is should be lambda or lambda by 2 and the radiation pattern if you observe this figure at the both degrees you are getting the major lobes that is at the two degrees you are getting the maximum lobe and at the two degrees you are getting the minimum lobe. So, these are called as a major lobes and these are the minor lobes and this is the array axis and the minor lobes are along this array axis whereas, the major lobe that is the principal lobe radiation will be considered which is perpendicular to the direction of an array axis. Therefore, the radiation pattern for broad side antenna is bi-directional and right angles to the plane and therefore, if you observe this figure the beam is very narrow and therefore, for the broad side antenna array you are getting the gain is high. Physical arrangement of the end fire array antenna is same as that of the broad side array antenna, end fire array is the second type of an antenna array. That is the number of elements are connected collinear with each other, but if you observe these elements the arrow shows the face of one of the element is in upward direction and the second element the arrow shows in the downward direction that is the face for this element is in the downward direction that means you can say that the magnitude of the currents in each element is same, but there is a face difference between these currents. So, if you observe the side view of this end fire array system it is shown in this figure. The end fire array what are the points considered for the end fire array there is no any radiation in the right angle to the plane of the array dipole spacing should have the lambda by 4 or 3 lambda by 4 that is the spacing between each element is provided by the distance lambda by 4 or 3 lambda by 4. It is helps to avoid the radiation which is perpendicular to the antenna plane, minor lobes are avoided and therefore the directivity is also increased. In end fire array beam becomes narrower with the increase the number of elements as you go on increasing the number of elements it having the directivity is higher. So, what is the radiation pattern for the end fire array antenna? So, if you observe this figure this is a single element consider this is the single element which having the beam is very wider and if you go on increasing the number of element there is a second element, third element, fourth element like that if you go on increasing the number of elements then the directivity is much greater as compared to the single element and if you observe the lobe of this pattern. So, this is the major lobe, but it is a wider one and it goes in the narrower one in this direction by increasing the number of element and therefore for the end fire array antenna the radiation pattern will be in only one direction and therefore you can say it as in unidirection. The major lobe occurs at one of the end where the maximum radiation will be observed while the minor lobes represents the losses. Now, let us differentiate between these two types of an antenna array that is broadside array and end fire array. So, broadside array is an array that gives a radiation pattern whose main beam is perpendicular to the axis of an array whereas, in case of end fire array antenna the array that gives a radiation pattern whose main beam is along the axis of an array. So, these two figures differ between the each type that is broadside array and the end fire array. So, here the feeding point is considered at the center point and at one of the end of the element whereas, it is connected to the till the last end of the element and the elements spacing is provided lambda by 4 where it is considered as the lambda by 2 in case of the broadside array antenna. In broadside array radiation pattern this major beam is perpendicular to the axis of array whereas, in case of the end fire array the major lobe is along the axis of an array. An array that gives a radiation pattern whose main beam is perpendicular to the axis of the array in case of the broadside array while in case of an end fire array the radiation pattern whose main beam is along the axis of the array. In broadside array the phase difference alpha can be shown equal to 0 whereas, in end fire array the phase difference is given by minus beta D where D is the difference between the each element and the beta is the phase shift. In broadside array the directivity value equal to 2 in end fire array it is equal to 4. The bandwidth between the first nulls is given by this equation plus or minus 2 lambda by N D radian. In case of an end fire array it is given by plus or minus 2 under root 2 lambda by N D where lambda is the wavelength N r the number of elements and D is the distance or the spacing between each element. The radiation pattern in broadside array is the bi-directional whereas, in end fire array the radiation pattern is unidirectional. All the elements are equally spaced along the array axis and fed with the current of equal magnitude and same phase in case of broadside array antenna whereas, the arrangement is same in end fire array antenna for the number of elements just for the phase is different in case of the end fire array. In broadside array the phi value is given by this equation whereas, in end fire array the phi value is given by this equation. Whereas, you know that alpha is equal to 0 by putting alpha equal to 0 phi becomes equal to beta D cos theta and in end fire array alpha by putting alpha equal to minus beta D phi becomes equal to beta D cos theta minus 1. So, this is the difference between the broadside array and end fire array antenna. These are the references used for today's session. Thank you.