Abstarct: Frequency beam scanning is the inherent characteristics of the leaky wave antenna. Today, beam scanning has special importance in Search Radar. Some systems operate at a specific frequency, due to limitations. Therefore, frequency beam scanning is not efficient in these systems. But if the beam is controlled by another parameter except frequency, such as the varactor diode bias, or magnetic excitation of ferrite materials and … , so the antenna will use in more systems. In this project, the beam of the leaky wave antenna is controlled using variable capacitor (varactor diode) in the angular range -53 to +39 degrees at a specific frequency. It should be noted that we need mextamaterial structures for negative angles. Here it is possible by using the Substrate Integrated Waveguide. It is important that the realized gain is kept at the desirable level at all angles during beam scanning. Also, capacitor values are selected to minimize return loss. Then, in the second part, we introduce the structure of the leaky wave antenna, which, in addition to the beam scanning capability, also has a circular polarization, So that the circular polarization remains during beam scanning in a large part of the scanned area. The challenge in the constant-frequency beam scanning of a circular polarized antenna is that the polarization is not maintained due to the change of phase constant. In this thesis, the beam of the antenna is steered by a frequency jump and using varactor diode in the angular range -21 to +21 degrees, which maintains circular polarization in -18 to +21 degrees. In this section, realized gain is kept at the desirable level during beam scanning without matching network. It has been tried to use the lowest number of varactor diode as possible as.