Study On Ultra Small Broad-Band Electrically Small Atenna

According to the particularity of the HFSW OHT by ship, we have done research on a special electrically small antenna, Crossed-Field-Antenna (CFA). The research on the principle of CFA is a tough task because the inventor of CFA, do not have a proper explanation about it.In order to acknowledge and understand the principle of CFA, this paper introduces the radiation and working rules of traditional antenna and CFA. Furthermore, it points out disputation about CFA.After incisive understanding of principle of CFA, this paper chooses the biggest time domain 3D electromagnetic field simulation software---CST MWS as tool to simulate and compute CFA. In order to test the usability and accuracy of this software, CSM(Charge Simulation Method) and MoM(Method of Moment) are introduced. CSM is a numeric mothed of analyzing static electric field.This paper compares the values of capacitance of different size of plate D and plate E in CSM and CST MWS. MoM is a typical numeric method of researching high-frequency electromagnetic problems. Accordingly, this paper computes input impedance of plate E and impedance matrix of traditional two element antenna array of electrically small dipoles separately in MoM and CST MWS, and then compares them detaily.Finally, this paper simulates, discusses and analyzes the performance of CFA. The optional dimention of CFA is determined through simulation in CST MWS with maximum radiation efficency(including port absorb efficiency) of antenna. For the final dimention of CFA, impedance matrix, near electromagnetic field, and directivity are got directly from the simulation. Then based on impedance matrix, input impedance and other relevant parameters of two ports are computed under different excitating conditions in programs of Matlab.