A reconfigurable patch antenna with independent frequency and polarization agility

摘要

A frequency and polarization reconfigurable patch antenna is proposed in this letter. The antenna consists of a circular patch surrounded by four sector-shaped patches. Four pairs of varactor diodes are introduced to bridge the gaps between the circular patch and the sector-shaped patches; the capacitance of the varactors is controlled by two DC signals. By adjusting the reverse bias voltage of the varactors, the proposed antenna can switch between linear polarization (LP), right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP). Furthermore, the operating frequency of each polarization state can be independently tuned. A prototype has been designed and fabricated. The results indicate the proposed antenna with a continuously tunable frequency range from 1.82 to 2.28GHz in LP states, and from 1.88 to 2.25GHz in either RHCP or LHCP states. Meanwhile, stable radiation patterns with low cross-polarization and back radiation levels (-15dB) are achieved for all states.