In this thesis, the RF front-end was done at K/Ka (18-27 GHz/26.5-40 GHz) bands used for satellite communication and satellite TV . In this study, vertical polarized signal transmission and horizontal polarized signal reception were performed. The design is set to be compatible with TURKSAT 4B . RF front-end is consist of an offset dish providing high gain and low side lobe level (SLL) for collecting the signal, a circular horn antenna which is compatible with RHCP (Right Hand Circular Polarization) and LHCP (Left Hand Circular Polarization) polarizations at the focal point of the dish, to separate dual polarization an orthomode transducer (OMT) and a transmit reject filter to prevent the receiver from the strong signal generated at the transmitter side (cross-pol). In the design waveguide structures is used to work in microwave frequencies and for high power delivery requirements. AWR Microwave Office, Computer Simulation Technology (CST) and MATLAB (Matrix Laboratory) programs are used for simulation, optimization and calculations.