PhD Defence

  Abstract:

  A suitable centered longitudinal shunt slot is proposed. It is shown that the proposed slot antenna can be an effective candidate for replacing the conventional longitudinal shunt slot. The proposed structure is realized by adding the V-shaped to the ridge of the single ridge waveguide. The wiggly ridge is placed exactly under the slot. It has been shown that the radiation characteristic of the slot can be varied by changing both slot length and V-shaped depth. In order to design a high performance array composed of the proposed slots, two methods are proposed which both are based on the well known Elliott’s design procedure. One of the methods is called semi-analytical and the other called analytical method. In the semi-analytical method, general relation connecting the backward- and forward-scattering dominant mode coefficients to the slot voltage is derived using available electromagnetic field simulator and by fitting some proper polynomials to the derived data. In analytical method, the V-shaped ridge is approximated by discrete steps. Then, the electric field at each step is found by defining a suitable scalar potential ional and solving it. Finally, the electric field in V-shaped wiggly ridge waveguide is found by considering previously obtained electric fields for each step. The general relation connecting the backward- and forward-scattering dominant mode coefficients to the slot voltage is found using reciprocity theorem and by fitting some proper polynomials to the derived data. The Elliott’s design procedure is used to design some slot antenna using analytical and semi-analytical results.

  The simulation results show that the butterfly lobe suppression of the proposed array is better than 6dB in comparison to the single ridge waveguide fed array while allowing the beam to scan to a relatively wide angle of 40 degrees.  

  THE DEFENCE TAKES PLACE:

  Monday 7 March 2011, at 15.00

  Room 303, Department of Electrical Engineering