Holographic testing of terahertz antennas

Junkin, G.; Huang, T.; Bennett, John C.

doi:10.1109/8.841902

Cited by 36 publications

(46 citation statements)

References 4 publications

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“…Conventional setup is usually implemented as shown in Figure 1 employing a radiated reference field [21,25] that is obtained from a sample of the source by means of a directional coupler. A variable attenuator (or amplifier) is usually included in the AUT or reference branches in order to balance the power between both branches and to increase the dynamic range of the hologram.…”

Section: Indirect Off-axis Holographymentioning

confidence: 99%

“…[1], the maximum spatial bandwidth 3 of a radiated field in a planar acquisition is W k ¼ k 0 . On the other hand, since the autocorrelation terms are the FT of a squared field, their bandwidth doubles the bandwidth of the original field [21,28,38] and, thus, the no overlapping condition is given by…”

Section: Overlapping Control: Off-axis Reference and Sampling Requirementioning

confidence: 99%

“…[21,38] and successively adapted for synthesized reference fields (see Section 2.3) in Refs. [27][28][29].…”

Section: Modified Hologrammentioning

confidence: 99%

“…The technique consists in the removal of the autocorrelation terms of the hologram prior to the filtering process and can be implemented by means of two different approaches. First of them requires an extra measurement to characterize the amplitude of E aut (the amplitude of E ref is a priori known) [21,23,29,30,39]. Second approach, commonly known as opposite-phase holography [28,40], introduces a hybrid-T component in the setup, which provides simultaneously the complete hologram in the sum port and the autocorrelation terms in the difference port.…”

Section: Modified Hologrammentioning

confidence: 99%

“…This kind of technique is popular because they involve minor changes in the measurement setup, nevertheless they can suffer from stagnation and their convergence is strongly related to the first guess solution. On the other hand, and belonging to noniterative techniques, most of the interferometric approaches [5,[20][21][22][23] rely on the use of a reference field, previously known in amplitude and phase, used to interfere the field of the AUT and allowing an easy and iteration-free phase retrieval by means of a filtering process in the spectral domain.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Indirect Off-Axis Holography for Antenna Metrology

Arboleya

Laviada

Ala‐Laurinaho³

et al. 2017

Holographic Materials and Optical Systems

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Phase acquisition in antenna measurement, especially at millimeter-and submillimeterwave frequencies, is an expensive and challenging task. The need of a steady phase reference demands not only a very stable source but unvarying temperature conditions and strong positioning accuracy requirements. Indirect off-axis holography is an interferometric technique that allows for characterization of an unknown field by means of a simple filtering process of the hologram or intensity interference pattern in the spectral domain, provided that the reference field, employed to interfere with the unknown field, is known in amplitude and phase. This technique can be used to avoid the effect of the errors related to the phase acquisition and to further develop new efficient and robust techniques capable of phase retrieval from amplitude-only acquisitions allowing for cost and complexity reduction of the measurement setup. A short review of the state-of-theart in antenna metrology is presented in this chapter, as well as a description of conventional indirect off-axis techniques applied to this field. Last sections are devoted to the description of novel measurement techniques developed by the authors in order to overcome the main limitations of the conventional methods.

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Section: Indirect Off-axis Holographymentioning

confidence: 99%

Section: Overlapping Control: Off-axis Reference and Sampling Requirementioning

confidence: 99%

“…[21,38] and successively adapted for synthesized reference fields (see Section 2.3) in Refs. [27][28][29].…”

Section: Modified Hologrammentioning

confidence: 99%

Section: Modified Hologrammentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Indirect Off-Axis Holography for Antenna Metrology

Arboleya

Laviada

Ala‐Laurinaho³

et al. 2017

Holographic Materials and Optical Systems

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Antenna Measurements at Millimeter and Submillimeter Wavelengths

Räisänen

Ala‐Laurinaho

Crowe

et al. 2017

Aperture Antennas for Millimeter and Sub-Millimeter Wave Applications

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Millimeter-Wave Phaseless Antenna Measurement Based on a Modified Off-Axis Holography Setup

Arboleya

Ala‐Laurinaho

Laviada

et al. 2015

J Infrared Milli Terahz Waves

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A novel scheme for planar near-field phaseless antenna measurement based on off-axis holography is presented. Separation of the image terms of the hologram is artificially increased by multiplexing the measurements of two sub-sampled holograms generated with two 180 • phase-shifted reference waves. Combination of both sub-sampled holograms produces replicas of the image terms at half a period distance of the originals in the spectral domain, while the amplitude of the original image terms is highly reduced, easing the filtering process of the desired replica. The higher separation of the image terms reduces overlapping making the method suitable also for the characterization of medium and low gain antennas in the near-field. As the separation is artificially increased, the reference antenna can be placed close to the antenna under test allowing to reduce the scan distance and the sensitivity to scan axis errors. Nevertheless, spatial multiplexing requires the retrieved data to be spatially low-pass filtered to remove the effect of the aliasing. Mirror reflection is used for illuminating the acquisition plane with the reference wave, being the phase shift achieved by means of a mechanical displacement of the mirror. The effect of the location of the reference antenna on the position and shape of the image terms and their replicas has been studied through numerical simulations for a setup in the W-band. Experimental validation of the method is presented for the characterization of three different antennas at 94 GHz.

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Holographic testing of terahertz antennas

Cited by 36 publications

References 4 publications

Indirect Off-Axis Holography for Antenna Metrology

Indirect Off-Axis Holography for Antenna Metrology

Antenna Measurements at Millimeter and Submillimeter Wavelengths

Millimeter-Wave Phaseless Antenna Measurement Based on a Modified Off-Axis Holography Setup

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