DUCAT

The Delft University Chamber for Antenna Tests (DUCAT) is a moderate size anechoic chamber which allows for far-field and near-field measurements thanks to a foldable inverted T scanner. It has recently been refurbished with new absorbers and stepping motors.


Inside of the DUCAT (near-field configuration)


Far-field mesurements configuration of the DUCAT

Chamber description

The chamber is a 6m x 3m x 3m Faraday cage providing 120 dB isolation ( at 10 GHz ) to reject external interferences. The walls, ceiling and floor are covered with RF absorbers with reflectivity performance below -40 dB from 1.2 GHz to 40 GHz. The maximum distance between the transmitting antenna and the antenna under test is 4 meters, meaning that a 10 cm aperture antenna is still in the far-field zone at 60 GHz.

Mechanical subsystem

The mechanical subsystem consists of 9 stepping motors.

The antenna under test (AUT) positioner is a roll over azimuth type, mounted on a dual axis translation stage to allow for accurate alignment of the AUT's phase centre with the rotation axis. The azimuthal resolution is better than 0.001 degrees.

The transmit antenna can be aligned in azimuth and elevation.

The foldable inverted T planar scanner has a 2m x 2m aperture. The resolution is better than 10um.

Configurations


Far-field


Planar near-field


Cylindrical near-field


Plane-polar near-field

 

RF subsystem

A 4-port vector network analyser is used as RF source and receiver for the antenna measurement set-up. The N5227A covers the frequency range from 10 MHz to 67 GHz with a dynamic range better than 120 dB thanks to the direct receiver access option which bypasses the internal directional coupler.

In addition a 24-port test-set can be used up to 20 GHz.

Dedicated phase-stable flexible RF cables are used with manufacturer specifications up to 50 GHz.


An object in scanner of the DUCAT

Near-field probes and standard gain horns

Our research group owns an array of near-field probes covering the frequencies from 1 GHz to 26 GHz. For far-field measurements standard gain horns are used which cover all bands from L to W (1 GHz to 110 GHz).

Additional Measurement Equipment

Following list of equipment is available for the MS3 group and can be used for measurements within DUCAT.

Equipment

Frequency band

Network Analysers:

Agilent HP 8753D

30 KHz - 6 GHz

Agilent E 8364B

10 MHz - 50 GHz

Agilent N5242A (4 ports)

10 MHz - 26.5 GHz

Agilent N5227A (4 ports)

10 MHz - 67 GHz

Millimeter wave extension modules:

Agilent N5260-60003

67 GHz - 110 GHz

Multiport test set

Agilent 87050A - K24 (24 ports)

10 MHz - 20 GHz

Spectrum Analysers

Agilent 8592A

50 KHz - 22 GHz

Agilent 8565E

9 KHz - 50 GHz

Arbitrary Waveform generator

Tektronix AWG 5014B

1.2 GS/s

Oscilloscopes

Tektronix 784A

1 GHz, 4 GS/s

Agilent DSO-X-91604A

16 GHz, 40/80GS/s

Geozondas SD3003NF + SU4126NF

100 MHz - 26 GHz (stroboscopic 10 MHz)

Power meters

Anritsu ML2437A

up to 50 GHz

Agilent E4418A

up to 110 GHz

 

Contact persons

prof.dr. Alexander Yarovoy

Scientific coordination

ing. Fred van der Zwan

Organization and technical coordination

ir. Pascal Aubry

Technical and research questions


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Back

Back to the MS3 group facilities

Fred arms an 'object'
DeMSIS

Agenda

PhD Defence

Albert Oude Nijhuis

Radar remote sensing of wind vector and turbulence intensity fields from raindrop backscattering

Scanning radars are promising sensors for atmospheric remote sensing, giving potential to retrieve parameters that characterize the local air dynamics during rain. For the observation of air motion, radars are relying on the backscatter of particles, which can, for example, be raindrops or insects. To measure wind vectors and turbulence intensities remotely during rain the radar is a common choice. This is mainly because the radar signals are not attenuated too much by the rain itself, which is the case for instruments operating at other frequencies, such as lidars. There is, however, a problem with measuring air dynamics from raindrops. Raindrops are not perfect tracers of the air motion. It may thus be necessary to make some corrections when air-dynamics parameters are estimated with a radar during the rain, and account for that raindrops are imperfect tracers of the air motion. This dissertation focuses on this problem. In addition, existing radar-based wind vector and turbulence intensity retrieval techniques are assessed for when they are applied during the rain, and they have been further developed.

PhD Thesis Defence

Jeroen van Gemert

Efficient computational methods in Magnetic Resonance Imaging

How to design dielectric pads that can be used to increase image quality inMagnetic Resonance Imaging, and how to accelerate image reconstruction times using a preconditioner.