| The contrawound toroidal helical antenna (CTHA) is a patented antenna developed at the Center for Industrial Research Applications (CIRA) of West Virginia University. In this study, a computer numerical model was built to simulate the behavior of printed circuit board versions of the CTHA. The numerical model was built upon the finite difference time domain method (FDTD). The results were compared to results from physical antennas, obtained from the CIRA anechoic chamber located in the WVU hanger, to verify the validity of the results of the numerical model. The results from both the numerical and experimental models were also used to reach an understanding of the general performance of the PCB-CTHA and its behavior under different feed configurations.; In order to understand the behavior of the antenna under different feed configurations, a feed study was conducted to check for all the possible feeds of a PCB-CTHA. These were found to be thirteen different feeds and were named feeds 1 through 13. Thorough numerical and experimental analysis was done on all thirteen feeds for both understanding the behavior of the antenna under these different feeds, and also comparing the predictions of the numerical model to the data obtained from the anechoic chamber.; It was found that the reactance curves can be predicted to an accuracy of 3% or better by the developed numerical model. The far field gains, on the other hand, are far from being reliably predicted by the model. The study also found that significant differences in the behavior of the PCB-CTHA occur when the feed configuration is changed, and three different feed configurations were recommended for future consideration, feeds 7, 12, and 13. |
