Active Patch Array Design and Indoor Channel Modeling for Future Wireless Communications

iii First, I want to thank my advisor, Professor David Rutledge, for giving me this opportunity to pursue the PhD at Caltech, and to be a member of his research group. Without his valuable advice and guidance, without the many intuitive discussions with him during weekly group meeting, and without the excellent research environment he created in the RF and microwave group, this thesis would not have been possible. His keen insight, nice personality, unlimited patience and support made the work under his supervision a really enlightening and pleasant experience. I would also like to thank the Lee Center for Advanced Networking for the financial support of my research at Caltech. I would like to acknowledge those people who have given me lots of support and assistance at Caltech. I am grateful for the help of Kent Potter. Without his excellent mechanic work, our compact anechoic chamber would not have been made. Also, I cannot finish my indoor wireless channel measurement without his help on the automatic testing robot. Besides, I would like to thank Lawrence Cheung. He is really a sincere and kind person. He deserves much credit for his valuable assistance and help during th