Efficient Modeling of a Circular Patch-Ring Antenna Using the Cylindrical TLM Approach

This letter addresses the ability of the TLM method with an incorporated compact wire model, both adjusted to the cylindrical grid, to accurately model a coaxially fed patch-ring antenna together with an investigation of the computational efficiency in a modeling procedure. Design of the antenna has included an optimization of the coaxial feed location to achieve a wider bandwidth. A prototype of the antenna was fabricated and measured. It has been shown that the patch-ring antenna exhibits more than three times wider bandwidth than the classic circular patch antenna. Advantages of the cylindrical-grid-based TLM approach related to a better conformity of the orthogonal polar mesh with the structure being modeled and a better efficiency associated with a number of TLM cells in the modeling procedure have been demonstrated with regards to the rectangular-grid-based TLM method. Also, a limitation of the rectangular solver related to an inadequate modeling of narrow slots that is dependent on the mesh resolution applied has been accentuated and proved.