Compact Multiport Antenna With Radiator-Sharing Approach and Its Performance Evaluation of Time Reversal in an Intra-Car Environment

A compact multiport antenna with three ports sharing one radiator is presented. The radiator is composed of two Sierpinski fractal triangles. This antenna contains two main ports and one auxiliary port. The two main ports have the same operating frequency band of 1-4 GHz. The auxiliary port with a multiband at around 2.4, 3.4, and 5.2 GHz provides an additional WLAN/WiMAX port. Since all the three ports share one radiator, the dimension of this antenna is only about 0.21λ * 0.15λ * 0.01λ, where λ is the wavelength at the lowest operation frequency. Simulation results of time reversal (TR) propagation in an intra-car environment show that all the ports of the antenna have excellent TR focusing characteristic in each operation frequency band and the enhancement of the ratio of receiving signal amplitude to transmitting signal amplitude has been obtained. The radiator-sharing approach can be used to miniaturize the multiport antenna in TR time-domain communication systems.