Sökning: "Active antenna array"
Visar resultat 11 - 15 av 27 avhandlingar innehållade orden Active antenna array.
11. Antenna array systems : electromagnetic and signal processing aspects
Sammanfattning : A simple and commonly used model of an array antenna consists of identical sensors, which are equidistantly located along a line. But in reality the array antennas do not look this way. The elements are not perfectly positioned, and sometimes they are even placed on a curved surface (conformal arrays). LÄS MER
12. Shape and material optimization for antenna applications
Sammanfattning : In this thesis, a gradient-based method for shape and material optimization fortwo antenna applications is presented: minimization of the active reflectioncoefficient for conformal array antennas; and minimization of the totalscattering cross section for cylindrical scatterers. The sensitivity of theobjective function with respect to changes of the shape and material of the geometry isexpressed in terms of the original field problem and an adjoint field problem. LÄS MER
13. Submillimeter-Wave Waveguide Frontends by Silicon-on-Insulator Micromachining
Sammanfattning : This thesis presents novel radiofrequency (RF) frontend components in the submillimeter-wave (sub-mmW) range implemented by silicon micromachining, or deep reactive ion etching (DRIE). DRIE is rapidly becoming a driving technology for the fabrication of waveguide components and systems when approaching the terahertz (THz) frequency range. LÄS MER
14. Polymer-Based Micromachining for Scalable and Cost-Effective Fabrication of Gap Waveguide Devices Beyond 100 GHz
Sammanfattning : The terahertz (THz) frequency bands have gained attention over the past few years due to the growing number of applications in fields like communication, healthcare, imaging, and spectroscopy. Above 100 GHz transmission line losses become dominating, and waveguides are typically used for transmission. LÄS MER
15. Integrated Antenna Solutions for Wireless Sensor and Millimeter-Wave Systems
Sammanfattning : This thesis presents various integrated antenna solutions for different types of systems and applications, e.g. wireless sensors, broadband handsets, advanced base stations, MEMS-based reconfigurable front-ends, automotive anti-collision radars, and large area electronics. LÄS MER