A Survey: Slot Antenna and Antenna Array. Sudarshan Bhat 1 and Priyadarshini K Desai 2 1 BNM Institute of Technology,Bangalore,karnataka 2 BNM Institute of Technology,Bangalore,Karnataka 1 uniquesud@gmail.com, 2 priyadarshini.p.r@gmail.com Abstract: Slot are generally introduced in the antenna or antenna to improve the impedance matching, improve the bandwidth and gain. Sometimes slots are introduced in the ground planes, or between antenna elements to reduce the mutual coupling between elements. The antenna being an important element in a wireless communication technology, the design of the same with different requirements is important. This paper gives the survey of the slot antenna and antenna array constructed through waveguide and microstrip lines, to meet different antenna parameters as required in various wireless communication technology. . Keywords: slot antenna,slot antenna array, gain bandwidth, polarization. 1. Introduction Slotare produced by making a lengthened or prolonged slot cut of about 0.5 λ long and width usually very less than 0.5 λ in a conductive metal sheet and is often excited at the center or off the center. Shape of slot is usually available in the form circular or rectangular and these are in the form of width modification, due to which it is capable of being acted as a waveguide, coplanar waveguide (CPW), coaxial, slot line, or as a microstrip feeding schemes. Slot creation leads to obtaining a new resonating frequency Creating or introducing a slot in the bottom layers, of the microstrip antennasoffersincreases in antenna gain. The radiation pattern of the slot antennas is most of the omni directional, featuring omni directional gain around the azimuth plane with horizontal polarization. Slots creation the waveguide antenna, termed slotted waveguide antenna, is basically an array of slots, offers a very high gain and are capable of operating in the frequency range 300MHz to 30 GHz. For the lower microwave frequency as well as ultra-highfrequency, a slotted-cylinder antennais used. Slot introduction has an added advantage of getting different polarization, as a simple example , the complement of a dipole when placed in free space is a thin slot in an infinite ground plane, consider slot and dipole have same dimension , then the corresponding radiation will be same except that E- and H- fields are swapped, that is slot acts as magnetic dipole rather than an electric dipole . As a result, the polarization is rotated 90º, so that radiation from a vertical slot is polarized horizontally while aifvertical slot is introduced antenna gives the horizontally polarized signal. Thus, slot cutting or introduction forming slot antenna and slot antenna seems to have many advantages with respect to getting desired antenna parameters such as Journal of University of Shanghai for Science and Technology ISSN: 1007-6735 Volume 23, Issue 7, July - 2021 Page -56