Linear Polarization Switchable Patch Array Antenna using Magic-T Bias Circuit and Orthogonal Feed

Abstract

In this paper, a linear polarization switchable patch array antenna is proposed. The orthogonal feed circuit and magic-T circuit is introduced to realize the proposed array antenna. The advantage of the magic-T circuit is the excellent isolation between the RF signal and the switching bias signal. The microwave integration technology is effectively employed to realize proposed linear polarization switchable array antenna. The proposed array antenna consists of four patch elements and 16 PIN diodes. In order to realize the ±45º polarization switching, four switching diodes are integrated with each patch elements. Using the ON/OFF condition of the diodes, the polarization axis can be easily switched to ±45º. The array antenna is realized in very simple and compact structure as all the antenna elements, feeding circuit and bias circuit are arranged on both sides of a dielectric substrate. The ability of the proposed array antenna to switch the polarization axis at ±45º at 10 GHz (X band) is confirmed by the experimental investigation.