A Simple $\pm 45^{\circ}$ Polarization Reconfigurable Antenna

This paper presents a reconfigurable antenna element based on active components. An L-shaped feeding structure is employed to couple energy to the antenna, facilitating broadside radiation and covering a frequency range from 9.1 to 9.7 GHz. Four blind holes are utilized for antenna miniaturization and improved impedance matching. Two groups A and B of PIN diodes are embedded on the antenna surface. When the diodes in Group A are in the ON state and those in Group B are in the OFF state, the antenna operates at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$+45^{\circ}$</tex> polarization. On the other hand, the antenna functions at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-45^{\circ}$</tex> polarization when the states are reversed. Due to its compact size and ease of fabrication, this antenna is a potential candidate for polarization-reconfigurable phased arrays.