This thesis focuses on a type of antenna known as the reflectarray antenna. In particular, it looks at the design of an active reconfigurable reflectarray antenna, which has not received much attention in the reflectarray community. Potential applications include deployment as a high gain, reconfigurable antenna for communication links, and as a spatial power combiner. The reflectarray element is an aperture-coupled patch that accepts a linearly polarized wave, phase shifts and amplifies the guided-waves in the transmission lines, and then re-radiates an orthogonally polarized wave. Stability analysis of the element, experimental results of the designed phase shifter and simulation and experimental results of the element are presented. Fabrication details of a 48 element reflectarray and challenges faced during experimental characterization of the elements are also discussed. The two dimensional beamforming capability and amplifying nature of the array are successfully demonstrated and veri fied, indicating robustness to phase errors and oscillating elements.

This thesis focuses on a type of antenna known as the reflectarray antenna. In particular, it looks at the design of an active reconfigurable reflectarray antenna, which has not received much attention in the reflectarray community. Potential applications include deployment as a high gain, reconfigurable antenna for communication links, and as a spatial power combiner. The reflectarray element is an aperture-coupled patch that accepts a linearly polarized wave, phase shifts and amplifies the guided-waves in the transmission lines, and then re-radiates an orthogonally polarized wave. Stability analysis of the element, experimental results of the designed phase shifter and simulation and experimental results of the element are presented. Fabrication details of a 48 element reflectarray and challenges faced during experimental characterization of the elements are also discussed. The two dimensional beamforming capability and amplifying nature of the array are successfully demonstrated and veri fied, indicating robustness to phase errors and oscillating elements.

The advances in modern communication systems have brought about devices with more functionality, better performance, smaller size, lighter weight and lower cost. Meanwhile, the requirement for newer devices has become more demanding than ever. Tunability and flexibility are both long-desired features. Tunable devices are ‘smart’ in the sense that they can adapt to the dynamic environment or varying user demand as well as correct the minor deviations due to manufacturing fluctuations, therefore making it possible to reduce system complexity and overall cost. It is also desired that electronics be flexible to provide conformability and portability. Previously, tunable devices on flexible substrates have been realized mainly by dicing and assembling. This approach is straightforward and easy to carry out. However, it will become a “mission impossible” when it comes to assembling a large amount of rigid devices on a flexible substrate. Moreover, the operating frequency is often limited by the parasitic effect of the interconnection between the diced device and the rest of the circuit on the flexible substrate. A recent effort utilized a strain-sharing Si/SiGe/Si nanomembrane to transfer a device onto a flexible substrate. This approach works very well for silicon based devices with small dimensions, such as transistors and varactor diodes. Large-scale fabrication capability is still under investigation. A new transfer technique is proposed and studied in this research. Tunable BST (Barium Strontium Titanate) IDCs (inter-digital capacitors) are first fabricated on a silicon substrate. The devices are then transferred onto a flexible LCP (liquid crystalline polymer) substrate using iv wafer bonding of the silicon substrate to the LCP substrate, followed by silicon etching. This approach allows for monolithic fabrication so that the transferred devices can operate in millimeter wave frequency. The tunability, capacitance, Q factor and equivalent circuit are studied. The simulated and measured performances are compared. BST capacitors on LCP substrates are also compared with those on sapphire substrates to prove that this transfer process does not impair the performance. A primary study of a reflectarray antenna unit cell is also conducted for loss and phase swing performance. The BST thin film layout and bias line positions are studied in order to reduce the total loss. Transferring a full-size BST-based reflectarray antenna onto an LCP substrate is the ultimate goal, and this work is ongoing at the University of Central Florida (UCF). HFSS is used to simulate the devices and to prove the concept. All of the devices are fabricated in the clean room at UCF. Probe station measurements and waveguide measurements are performed on the capacitors and reflectarray antenna unit cells respectively. This work is the first comprehensive demonstration of this novel transfer technique.