Two-channel directional antenna and a radar level gauge with such an antenna

摘要

A two-channel directional antenna for use in a radar level gauge. The antenna comprises a partition wall dividing the antenna into a first partition for emitting an electromagnetic transmit signal, and a second partition for receiving an electromagnetic echo signal, the partition wall having an outer potion located downstream in a direction of radiation of the antenna. The partition wall comprises an electromagnetic de-coupling structure, which is arranged to reduce any leakage of electromagnetic energy from the transmit signal into the echo signal.;The electromagnetic de-coupling structure according to the present invention ensures that the leakage of transmit signal into the received signal is reduced to a satisfactory level.

主权项

1. A level gauge for determining a filling level of a product in a tank, said level gauge comprising:
a transceiver for transmitting an electromagnetic transmit signal and receiving an electromagnetic echo signal, processing circuitry connected to said transceiver and adapted to determine said filling level based on a relationship between said transmit signal and said echo signal, a two-channel, directional antenna having an antenna aperture adapted to emit electromagnetic energy in a direction of radiation, said directional antenna being connected to said transceiver and arranged to emit said transmit signal into said tank towards a surface of said product, and to receive said echo signal resulting from a reflection of said transmit signal in said product surface, a partition wall dividing said antenna into a first partition for emitting said transmit signal, and a second partition for receiving said echo signal, said partition wall having an outer portion located downstream in said direction of radiation, and an electromagnetic coupling arrangement comprising a first waveguide feeder arranged to couple said transmit signal from said transceiver into said first antenna partition, and a second waveguide feeder arranged to couple said echo signal from said second antenna partition to said transceiver, an electromagnetic de-coupling structure connected to said outer portion of said partition wall, said electromagnetic de-coupling structure arranged to reduce any leakage of electromagnetic energy from said transmit signal into said echo signal.