| Nowadays, the wireless communication technology is developed rapidly. A variety of commercial and military radio network architectures adopt multi-antenna systems due to their simplicity. In particular, transmit-receive modules mounted on vehicular platforms are widely encountered in ad-hoc network configurations of HF/VHF military radio. However, when many antennas are placed on the same structure the problem of interference and coupling between the concurrent operation of individual receive-transmit modules, often gives rise to co-site interference side effects, such as desensitization, cross-modulation that eventually corrupt the overall systems performance. Further, since vehicles carry several antennas for different frequency bands the radiation patterns regarding the beam width and the side lobe level are often affected significantly by neighboring antennas and especially by the shape of the platform. How to make these devices work well in limited space is crucial for practical application. Predicting and solving the electromagnetic interference (EMI) between them is given more and more attention and it became one of the most important contents in electromagnetic compatibility (EMC) research. In this paper the characteristics of several wire antennas mounted on vehicular platform and the infection between them are analyzed. In this paper, the finite-difference time-domain (FDTD) method is used to model and analysis the operational characteristics of multi-antennas on a vehicular platform. The FDTD method is derived from the discretization of the differential form of Maxwell's equations directly in the time domain, and can give insight into the physical processes for electromagnetic field propagation. If the source is defined as a pulse, the system response can be obtained over a wide bandwidth with one FDTD calculation. As a full wave technique method, the FDTD method is very efficient at modeling problems involving multiple sources or ports. The FDTD program can be easy modified... |
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