A Phase-Flip Van Atta Array Based on Dual-Polarized Edge-Fed Microstrip Antenna

This paper introduces an upgraded bipolar rectangular edge-coupled feed antenna with a slotted back, which is subsequently employed in a four-element linear Van Atta array to accomplish the phase inversion of electromagnetic reflections. The proposed design improves port isolation by coupling the feed at the patch edge. It reduces antenna size by incorporating a rectangular slot in the ground. Based on this, the proposed antenna forms a four-element linear Van Atta array, with a PIN diode added to the microstrip transmission line connecting two pairs of antenna units to realize phase reversal of electromagnetic echoes under two polarization modes. Simulation results reveal that the proposed antenna showcases a $\mathbf{- 1 0} \mathbf{~ d B}$ impedance bandwidth of $240 \mathrm{~MHz}(\mathbf{7. 6 7 \%})$, achieving a peak gain of 4.12 dBi at 3 GHz while maintaining isolation of over 25 dB between the two ports. The phase shift of each element in the Van Atta array varies by 180° during the transition between the on and off states of the diode.