Radar level gauge system propagating multiple individually generated transmit signals by a common antenna

A radar level gauge system, for gauging a level of a product in a tank, the radar level gauge system comprising:

• a first microwave unit including:
• a microwave transceiver;
• a transmitter patch coupled to the microwave transceiver for transmitting a first transmit signal;
• a receiver patch for receiving a first reflection signal resulting from reflection of the first transmit signal at a surface of the product in the tank;
• and
• processing circuitry coupled to the microwave transceiver for determining a first measure indicative of the level of the product based on a timing relation between the first transmit signal and the first reflection signal;
• a second microwave unit including:
• a microwave transceiver;
• a transmitter patch coupled to the microwave transceiver for transmitting a second transmit signal;
• a receiver patch for receiving a second reflection signal resulting from reflection of the second transmit signal at the surface of the product in the tank;
• and
• processing circuitry coupled to the microwave transceiver for determining a second measure indicative of the level of the product based on a timing relation between the second transmit signal and the second reflection signal;
• an antenna for radiating the first transmit signal and the second transmit signal towards the surface of the product, and for receiving the first reflection signal and the second reflection signal;
• and
• a signal coupling arrangement connecting the first microwave unit and the second microwave unit with the antenna, the signal coupling arrangement including:
• a first hollow waveguide directional coupler having a first waveguide section with a first end coupled to one of the transmitter patch and the receiver patch of the first microwave unit, and a second waveguide section with a first end coupled to the other one of the transmitter patch and the receiver patch of the first microwave unit;
• a second hollow waveguide directional coupler having a first waveguide section with a first end coupled to one of the transmitter patch and the receiver patch of the second microwave unit, and a second waveguide section with a first end coupled to the other one of the transmitter patch and the receiver patch of the second microwave unit;
• and
• a signal combiner coupled to a second end of the first waveguide section of the first hollow waveguide directional coupler, to a second end of the first waveguide section of the second hollow waveguide directional coupler, and to the antenna,
• the signal combiner being configured to provide the first transmit signal received from the first hollow waveguide directional coupler and the second transmit signal received from the second hollow waveguide directional coupler to the antenna, and to provide the first reflection signal and the second reflection signal to the first and second hollow waveguide directional couplers, respectively.