Design and Analysis of a Phased Array Microstrip Antenna for a Low Earth OrbitCommunication Satellite

摘要

A Naval Postgraduate School spacecraft design class proposed a multiple beam,phased array, microstrip antenna as part of the preliminary design of a low earth orbit communication satellite. The antenna must provide coverage over the satellite's entire field of view while both uplink and down-link operate simultaneously on the same 1-band frequency. This thesis assesses the feasibility of the antenna proposed in that preliminary design. Design tradeoffs for a microstrip array constrained by both available surface area and a limited mass budget are examined. Two different substrate materials are considered in terms of weight and performance. Microstrip patch theory is applied to array element design and layout and antenna array theory is applied to determine phase and amplitude coefficients. The focus of the design is on obtaining the desired beam shape and orientation, given antenna size constraints. A corporate feed method is discussed and a general design presented. Antenna performance is predicted through the use of a computer model based on Modal Expansion theory and results are plotted in a series of graphs which demonstrate the limitations of the proposed design. Microstrip antenna, Low earth orbit communication, Modal expansion theory, L-band, Satellite.