Differential-Fed Pattern-Reconfigurable Dielectric Patch Antenna and Array With Low Cross-Polarization

A novel differential-fed dielectric patch (DP) antenna with beam steering capability is investigated in this communication. The TE
_mn
mode in the DP resonator is theoretically analyzed to provide guidance for the subsequent antenna design. The high-order TE
₁₂
mode that can be differentially excited is selected as the operating mode to further enhance the gain. Based on this, three parallel coupling slots loaded with p-i-n diodes are used as a beam steering structure. By controlling the ON-/OFF-state of the p-i-n diodes to change the
$E$
-field distribution of the TE
₁₂
mode, the main beam can be switched to five directions. The measured gain of each state is higher than 7 dBi, and the peak value reaches 8.1 dBi. The beam steering structure and differential-fed scheme show good coordination, which effectively suppresses the deterioration of cross-polarization caused by structural asymmetry. The cross-polarization of each state is lower than −26 dB. To further verify the scalability of the proposed ideal, a 1
$\times $
4 array fed by two dual Marchand baluns is implemented, which well maintains the beam steering capability and low cross-polarization. Reasonable agreement is obtained between the simulated and measured results. The proposed DP antenna provides a suitable candidate for indoor wireless communication.