Optimisation of Distributed Damping for Broadband HF Naval Antenna
Speaker: PD Dr.-Ing. Thomas Fickenscher, Helmut Schmidt University
When: 2008-09-15 14:00:00
Venue: 78-622
Host: Aleksandar Rakic
Abstract:Distributed damping is a desired feature for broadband shipboard HF fan wire antennas. Lumped resistors currently in use cause hazards due to the mechanical load of the antenna in heavy seas and due to their infrared signature. Optimisation of the distributed damping by using 3D field solvers is extremely time consuming when considering the whole ship structure.
In a first attempt the impact of distributed damping on the antenna matching and efficiency is studied for the case of a long thin broadband monopole antenna by means of an improved Fourier series analysis. The fundamental characteristics of the impact of distributed damping on antenna performance are investigated systematically. It is proved that distributed damping is superior to lumped damping in terms of radiated power and matching.
In a next step, the basic impact of the ship structure on the input impedance of the HF-fan-wire antenna is studied for a generic ship model. A simplified model is extracted which reflects the main resonances caused by the ship structure. This model is used for an optimisation of the damping distribution of the fan-wire antenna via a combinatorial approach. Compared to a reference antenna with a single 240 W resistor for each fan the minimum overall efficiency - including return loss ? of the system could be increased by more than 50%.
Biography:Priv.-Doz. Dr Fickenscher is with the Chair of High-Frequency Engineering and Optoelectronics in the Department of Electrical Engineering at Helmut Schmidt University (Hamburg, Germany).
He has industry experience with Lucent Technologies (Bell Labs) and Siemens AG. He is currently a visiting Research Fellow with the Centre for Wireless Monitoring and Applications at Griffith University and is taking some classes in Advanced Communication Systems.
Type: ITEE Seminar
Contact:Aleksandar Rakic, seminar host (rakic@itee.uq.edu.au)
or Heng Tao SHEN (ITEE seminar co-ordinator)
(shenht@itee.uq.edu.au)