US 2014/0111371 A1Published application

Radar level gauge system with reduced antenna reflection

AssigneeRosemount Tank Radar AB

InventorOlov Edvardsson

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Abstract

A radar level gauge system for determining a filling level in a tank. The radar level gauge system comprises a transceiver, a horn antenna having a first opening connected to the transceiver and a second opening facing a surface of the product in the tank, and processing circuitry connected to the transceiver for determining the filling level based on an electromagnetic surface reflection signal. The horn antenna is configured in such a way that an electrical distance from the first opening to the second opening, along a path defined by an intersection between a wall of the horn antenna and a half-plane starting from and extending in parallel with a cone axis of the horn antenna, is different for different orientations of the half-plane with respect to the cone axis. Hereby, disturbance from an antenna reflection signal can be reduced, which provides for improved measurement of high filling levels.

Claims30

Dependent claims

A radar level gauge system for determining a filling level of a product in a tank, said radar level gauge system comprising:

a transceiver configured to generate and transmit electromagnetic signals having a first polarization and to receive electromagnetic signals having a second polarization different from the first polarization;
a horn antenna for directing an electromagnetic transmit signal transmitted by said transceiver towards said surface of the product, and for returning back to said transceiver an electromagnetic surface reflection signal resulting from reflection of said electromagnetic transmit signal at said surface;
and
processing circuitry connected to said transceiver for determining said filling level based on said electromagnetic surface reflection signal,
wherein said horn antenna comprises:
a first opening coupled to said transceiver;
a second opening, larger than said first opening, directed towards said surface of said product in the tank;
and
a conductive horn antenna wall connecting said first opening and said second opening to form a horn structure having a central longitudinal axis,
wherein said conductive horn antenna wall exhibits:
a first electrical distance from said first opening to said second opening, along a first path defined by an intersection between said conductive horn antenna wall and a half-plane extending from said central longitudinal axis at a first rotational orientation in respect of said central longitudinal axis;
and
a second electrical distance from said first opening to said second opening, along a second path defined by an intersection between said conductive horn antenna wall and a half-plane extending from said central longitudinal axis at a second rotational orientation in respect of said central longitudinal axis, said second electrical distance being different from said first electrical distance, and
wherein a difference between said first electrical distance and said second electrical distance is such that an antenna reflection signal resulting from reflection of said electromagnetic transmit signal by said horn antenna has a polarization being different from said second polarization.

11 more elements

A radar level gauge system for determining a filling level of a product in a tank, said radar level gauge system comprising:

a transceiver configured to generate and transmit electromagnetic signals having a first polarization and to receive electromagnetic signals having a second polarization different from the first polarization;
a horn antenna for directing an electromagnetic transmit signal transmitted by said transceiver towards said surface of the product, and for returning back to said transceiver an electromagnetic surface reflection signal resulting from reflection of said electromagnetic transmit signal at said surface;
and
processing circuitry connected to said transceiver for determining said filling level based on said electromagnetic surface reflection signal,
wherein said horn antenna comprises:
a first opening coupled to said transceiver;
a second opening, larger than said first opening, directed towards said surface of said product in the tank;
and
a conductive horn antenna wall connecting said first opening and said second opening to form a horn structure having a central longitudinal axis,
wherein said conductive horn antenna wall exhibits:
a first electrical distance from said first opening to said second opening, along a first path defined by an intersection between said conductive horn antenna wall and a half-plane extending from said central longitudinal axis at a first rotational orientation in respect of said central longitudinal axis;
and
a second electrical distance from said first opening to said second opening, along a second path defined by an intersection between said conductive horn antenna wall and a half-plane extending from said central longitudinal axis at a second rotational orientation in respect of said central longitudinal axis, said second electrical distance being different from said first electrical distance, and
wherein a difference between said first electrical distance and said second electrical distance is such that an antenna reflection signal resulting from reflection of said electromagnetic transmit signal by said horn antenna has a polarization being different from said second polarization.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/659,021Filed 24 Oct 2012
Published: 24 Apr 2014
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G01F 23/284
By measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material:…
G01S 7/026
Using polarisation effects: involving the transmission of elliptically or circularly polarised waves
G01S 7/038
Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver: feedthrough nulling circuits
G01S 13/88
Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose…:…