Patent ID: 7944404

Claim:
An apparatus operable in each of a transmission (TX) band and a receiving (RX) band, comprising: at least one helical radiation element for radiating orthogonal circular polarized waves in the TX and RX bands, wherein the helical radiation element includes a helix; a two-part circular wave guide including a first part surrounding the helix and a second part having a diameter that is increased in a predetermined ratio, the first part surrounding the helix having a constant diameter; a first feed line coupled to a first end of the helix; and a second feed line coupled to a second end of the helix, wherein the first feed line is coupled to a receiving feed point coupled to a receiving port for operation in the RX band, and the second feed line is coupled to a transmitting feed point coupled to a transmitting port for operation in the TX band, wherein the receiving port is physically separate from the transmitting port to enable simultaneous operation in both the TX band and the RX band, wherein the helix has a predetermined number of turns and a diameter of the helix is gradually increased or decreased in a predetermined ratio, depending on the number of turns.