Which duplexer sub-component accepts RF transmit power from the transmitter and directs it through the waveguide to the antenna assembly?

Which duplexer sub-component accepts RF transmit power from the transmitter and directs it through the waveguide to the antenna assembly?

• A. Antenna switch
• B. Polarizer
• C. Duplexer filter
• D. Circulator

Answer: (D)

Circulator is the device that takes RF power from the transmitter and directs it into the waveguide toward the antenna, while also providing isolation for the receiver path. It’s a three-port, non-reciprocal component arranged so that the transmit signal goes from the TX port to the antenna port, enabling the duplexer to feed the antenna with the transmit power. The receiver is kept separate from the transmitter through the circulator’s directional routing, which is essential to prevent the powerful transmit signal from leaking into the receiver. The other options don’t perform this exact routing role. An antenna switch would select between different antennas or feeds, not provide the fixed TX-to-antenna routing used in a duplexer. A polarizer alters the polarization of the wave, not the signal path. A duplexer filter helps separate TX and RX bands but doesn’t by itself route transmit power to the antenna.

Circulator is the device that takes RF power from the transmitter and directs it into the waveguide toward the antenna, while also providing isolation for the receiver path. It’s a three-port, non-reciprocal component arranged so that the transmit signal goes from the TX port to the antenna port, enabling the duplexer to feed the antenna with the transmit power. The receiver is kept separate from the transmitter through the circulator’s directional routing, which is essential to prevent the powerful transmit signal from leaking into the receiver.

The other options don’t perform this exact routing role. An antenna switch would select between different antennas or feeds, not provide the fixed TX-to-antenna routing used in a duplexer. A polarizer alters the polarization of the wave, not the signal path. A duplexer filter helps separate TX and RX bands but doesn’t by itself route transmit power to the antenna.