Research On Miniature Integrated Antenna And Radio Frequency MEMS Technology

A number of Unmanned Aerial Vehicles (UAVs) presently exist, both domestically and internationally. The current trend in UAVs is to reduce the airframe size and enhance the integration of sensing and signal processing. Future mini-aircrafts, such as Micro Air Vehicle (MAV) and Nano-satellite, requires RF front-end modules with functional complexity, high density and low power consumption. The conventional approach to hardware integration becomes extremely difficult, however, technological feasibility follows from advances in several innovative micro-technologies in recent years. The research of this dissertation focuses on the compact antenna of UAV, silicon-based miniature antenna and distributed MEMS phase shifter.First, the research background of our antennas is presented. Reviewing of many articles, we design a compact circularly polarized (CP) microstrip antenna for UAV applications. The difficulty in our design is exploiting the range of fundamental limits to optimize the size-gain-beamwidth compromise. Experimental results show the 3dB axial ratio bandwidth is 0.6%, the half power beamwidth is ?5, and the gain is 5dBi. The antenna size reduction can be as large as 36%, as compared to that of the conventional CP design. The parameters of this antenna satisfy the requirement of transceivers in our UAV systems.Second, to develop integrated antennas for MAV and on-chip integration, a novel CPW-fed planar antenna on Si has been investigated. The measured impedance bandwidth of 3GHz antenna is 2.7% and beamwidth is about 80. In addition, this antenna reconfigurablility in terms of frequency range is studied using a set of MEMS switches. The MEMS-switched reconfigurable multi-band antenna would support satellite or MAV-based communications and radar applications.Third, the distributed MEMS phase shifters, a key element in miniature phased array antennas, are designed and fabricated. The detailed discussions supported by simulations about design issues related to Bragg frequency are presented. Besides, good performance, high reliability and low actuation voltage in our experiments, verifies the nice compromise between strength and resilience of AlSi membrane. The measured results demonstrate a phase shift of 286 at 36GHz with the actuation voltage of 25V, and an insertion loss less than 3dB over l-40GHz band. Finally, our integrated-MEMS phased array radar subsystem is introduced.