A pattern reconfigurable antenna applied for automobile 5G communication

In this article, a radiation pattern reconfigurable antenna (RPR antenna) based on the complementary source principle is proposed for automobile communication. This antenna achieves four end-fire radiation patterns in four directions by controlling the operating states of PIN-diodes. The structure of this center-fed antenna includes a corners-shorted patch and four parasitic monopoles with eight PIN-diodes to control the states of monopole antennas. The monopole antenna works as an electric current source while the center-fed patch antenna can be equivalent to in-phase magnetic currents at its periphery due to the existence of the loaded monopole. Then the radiation mechanism of the RPR antenna can be explained as a pair of orthogonal magnetic and electric current sources. As a result, four end-fire radiation patterns can be obtained by changing OFF/ON states of PIN-diodes and this antenna can be applied for high-resolution omnidirectional coverage by switching among four modes. To verify the simulation, an example antenna is fabricated and measured. The measured result exhibits a -10-dB impedance band of 3.21-3.73 GHz with a maximum realized gain of 7.07 dBi. Results show that this antenna is suitable for automobile 5G communication.