Integration of a 4x8 Antenna Array with a Reconfigurable 2-bit Phase Shifter using RF MEMS Switches on Multilayer Organic Substrates David J. Chung, Dimitrios E. Anagnostou, G. Ponchak, Manos Tentzeris, and John Papapolymerou Georgia Institute of Technology, School of Electrical and Computer Engineering, 85 Fifth Street, Technology Square Research Building, Atlanta, GA 30308 Introduction As water is a crucial factor for sustaining life, the study of its distribution around the globe has also been a great importance. Satellites have been deployed with antennas operating at 14 GHz to observe the rainfall. In the past, high-gain parabolic reflectors have been used frequently for space missions with a cost of low efficiency, large size, heavy weight, and difficulty in deploying. In order to overcome these troubles, microstrip arrays antenna have been developed. Though they have higher insertion loss, meaning less efficiency, they will be significantly lighter, smaller, and simpler [1], [2]. Recently, NASA has been collaborating with Georgia Institute of Technology to develop advanced, low cost, light weight, and large surface area antennas that can be deployed in space. Previous works show multi-functional small arrays [3], [4], but the size has been limited, and the possibility of expanding the structure is small. In this paper, Liquid Crystal Polymer (LCP) is used as the substrate, which enables the fabrication of a flexible, low cost, and light weight antenna. Using LCP, an attempt to expand from the previous works has been accomplished by constructing a 4x8 antenna array made of two 4x4 sections being fed with a reconfigurable 2-bit phase shifter. Each reconfigurable phase shifter is enabled by eight RF MEMS switches and the two 2-bit phase shifter together, allow a 6° phase shift in the final design. Antenna Design The unit design is based on a 4x4 antenna array. We can see in Fig. 1, the S11 response of a 4x4 array. The resonance is at a frequency about 13.9 GHz shown by the line corresponding to thick foam and the measurements match the simulation results. The thick foam (~2 inches) was placed on the patches to facilitate the measurements when positioning the probes, and did not interfere with the free-space results as the relative permittivity is very close to 1. In order to verify that the resonance indeed represents radiation that takes place and does not originate from anywhere along the feed network or the slots, the patch layer was attached to a thick metal plane. With the metal plane on top of the patches, the reflection coefficient was measured (Fig. 1). The results showed a cancellation of the occurring resonance which verifies that the radiating elements are the metal 93 1-4244-0878-4/07/$20.00 ©2007 IEEE