Reconfigurable Rhombus-Shaped Patch Antenna With Y-Shaped Feed for Polarization Diversity

In this letter, a reconfigurable rhombus-shaped patch antenna with a Y-shaped feedline for polarization diversity is proposed. This antenna exhibits a simple structure, which consists of a rhombus-shaped patch, two p-i-n diodes, and a Y-shaped feedline. The two p-i-n diodes are inserted in the gap between the rhombus-shaped patch and the Y-shaped feedline. In order to easily supply a dc bias voltage to the p-i-n diodes, a shorting pin is inserted in the center of the rhombus-shaped patch. The proposed antenna can be operated in two modes-the left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) modes-by electrically controlling the two p-i-n diodes. The measured 10-dB reflection coefficient and 3-dB axial-ratio bandwidths of the prototype antenna are approximately 5.62% and 2%, respectively.