A novel circular polarization switchable slot-ring array antenna with orthogonal feed circuit

In this paper, a novel circular polarization switchable slot-ring array antenna is proposed. The proposed antenna consists of a 2 × 2 slot-ring array antenna and a orthogonal feed circuit. The feed circuit has a SPDT switch circuit using two switching diodes and a 90-degree hybrid circuit. A “Both-Sided MIC Technology” is used to form the proposed antenna. The excellent design flexibility of the “Both-Sided MIC technology” is very effective for an arrangement. The orthogonal circular polarizations (RHCP: Right-Hand Circular Polarization, LHCP: Left-Hand Circular Polarization) are easily switched with high speed by the switching diodes loaded into SPDT switch circuit. The characteristics of the proposed antenna are investigated experimentally. The 3 dB axial ratio bandwidth of 12% is obtained. The circular polarization switching function can be achieved by the polarity of the bias voltage. Consequently, the circular polarization switchable slot-ring array antenna with the orthogonal feed circuit can be realized successfully.