In a measuring device 50, a microwave receiving unit 52 is disposed behind a microwave transmitting unit 51 with respect to a powder object 2, and the microwave transmitting unit 51 and the microwave receiving unit 52 are each enclosed by a waveguide box. A waveguide box 6 for the transmitting unit is smaller than a waveguide box 8 for the receiving unit, and is enclosed by the waveguide box 8 for the receiving unit. An opening portion 7 of the waveguide box 6 and an opening portion 9 of the waveguide box 8 are mounted on a flat window material 5, and are aligned. The window material 5 is in contact with the powder object 2. Microwaves 3 transmitted from the microwave transmitting unit 51 are reflected by the powder object 2, are received, as scattered microwaves 4, by the microwave receiving unit 52, and are measured.

The invention is directed to a gauge body for a container for pressurized gas, comprising a mounting surface for mounting the body to the container; an inner side in contact with the pressurized gas when mounted on the container; an outer side opposite to the inner side with regard to the mounting surface, the outer side being outside of the container when the body is mounted on the container; an electrical lead extending in a gas tight manner through the body from the inner side to the outer side. The electrical lead comprises a metallic rod and a bushing around the rod, the bushing being mounted a gas tight manner on the body.

A radar level gauge system, comprising a transceiver; an antenna; a feed-through connecting the transceiver and the antenna; and processing circuitry coupled to the transceiver. The feed-through comprises a first waveguide section comprising a dielectric plug sealingly arranged in a cylindrical first hollow conductor section having a diameter selected for single mode propagation; a second waveguide section arranged between the transceiver and the first waveguide section and comprising a cylindrical second hollow conductor section having a second diameter selected for single mode propagation, a third waveguide section arranged between the antenna and the first waveguide section comprising a cylindrical third hollow conductor section having a third diameter selected for single mode propagation; a first impedance matching waveguide section arranged between the first waveguide section and the second waveguide section, and a second impedance matching waveguide section arranged between the first waveguide section and the third waveguide section.

A radar level gauge system, comprising a transceiver; an antenna; a feed-through connecting the transceiver and the antenna; and processing circuitry coupled to the transceiver. The feed-through comprises a first waveguide section comprising a dielectric plug sealingly arranged in a cylindrical first hollow conductor section having a diameter selected for single mode propagation; a second waveguide section arranged between the transceiver and the first waveguide section and comprising a cylindrical second hollow conductor section having a second diameter selected for single mode propagation, a third waveguide section arranged between the antenna and the first waveguide section comprising a cylindrical third hollow conductor section having a third diameter selected for single mode propagation; a first impedance matching waveguide section arranged between the first waveguide section and the second waveguide section, and a second impedance matching waveguide section arranged between the first waveguide section and the third waveguide section.

A radar level gauge system, for determining a filling level of a product in a tank. The radar level gauge system includes a transmission line probe arranged inside the tank; a tank feed-through for mechanically attaching the transmission line probe to a tank wall of the tank through a non-conductive mechanical connection between the transmission line probe and the tank wall, and for providing a conductive electrical connection to the transmission line probe from outside the tank; and a measurement electronics unit arranged outside the tank. The measurement electronics unit includes: a transceiver; an electrical filter circuit having an input coupled to the transceiver and an output coupled to the transmission line probe via the tank feed-through, the electrical filter circuit exhibiting a series capacitance for non-conductively coupling the transceiver to the transmission line probe via the tank feed-through; and processing circuitry for determining the filling level.

A radar level gauge system, for determining a filling level of a product in a tank. The radar level gauge system includes a transmission line probe arranged inside the tank; a tank feed-through for mechanically attaching the transmission line probe to a tank wall of the tank through a non-conductive mechanical connection between the transmission line probe and the tank wall, and for providing a conductive electrical connection to the transmission line probe from outside the tank; and a measurement electronics unit arranged outside the tank. The measurement electronics unit includes: a transceiver; an electrical filter circuit having an input coupled to the transceiver and an output coupled to the transmission line probe via the tank feed-through, the electrical filter circuit exhibiting a series capacitance for non-conductively coupling the transceiver to the transmission line probe via the tank feed-through; and processing circuitry for determining the filling level.

A method of wellbore analysis using TM01 and TE01 modes of radar waveforms can include transmitting, at a first time, a radar waveform from a wellhead into a tubing disposed in a wellbore positioned in a reservoir. The radar waveform is either a TM01 mode or a TE01 mode waveform. The tubing includes a fluid, and the surface of the wellbore includes the wellhead. At a second time, a reflected waveform generated by reflecting the transmitted radar waveform on a fluid surface of the fluid is received at the wellhead. A fluid level of the fluid is determined based on the time difference between the first time and the second time, and on a transmission speed of the radar waveform from the wellhead to the fluid surface. The fluid level is a distance between the wellhead and the fluid surface of the fluid.

A method of wellbore analysis using TM01 and TE01 modes of radar waveforms can include transmitting, at a first time, a radar waveform from a wellhead into a tubing disposed in a wellbore positioned in a reservoir. The radar waveform is either a TM01 mode or a TE01 mode waveform. The tubing includes a fluid, and the surface of the wellbore includes the wellhead. At a second time, a reflected waveform generated by reflecting the transmitted radar waveform on a fluid surface of the fluid is received at the wellhead. A fluid level of the fluid is determined based on the time difference between the first time and the second time, and on a transmission speed of the radar waveform from the wellhead to the fluid surface. The fluid level is a distance between the wellhead and the fluid surface of the fluid.

An FMCW-radar based distance measuring device is characterized in that, in addition to analogue high-pass and low-pass filtering, the evaluation signal typical for FMCW additionally undergoes subsequent digital filtering. In this case, the analogue/digital conversion takes place by oversampling. As a result, according to the invention, all those frequencies in the evaluation signal that are above or below the frequency corresponding to the distance of the object are effectively suppressed. At the same time, the analogue filters can be constructed with a very low level of complexity. The space requirement and the costs of the analogue components is reduced thereby. In addition, the dependence on temperature of the distance measuring device is reduced thereby. The potentially high distance resolution is also maintained.

An FMCW-radar based distance measuring device is characterized in that, in addition to analogue high-pass and low-pass filtering, the evaluation signal typical for FMCW additionally undergoes subsequent digital filtering. In this case, the analogue/digital conversion takes place by oversampling. As a result, according to the invention, all those frequencies in the evaluation signal that are above or below the frequency corresponding to the distance of the object are effectively suppressed. At the same time, the analogue filters can be constructed with a very low level of complexity. The space requirement and the costs of the analogue components is reduced thereby. In addition, the dependence on temperature of the distance measuring device is reduced thereby. The potentially high distance resolution is also maintained.