**Indirect Off-Axis Holography for Antenna Metrology**

Ana Arboleya, Jaime Laviada, Juha Ala-Laurinaho,

Yuri Álvarez, Fernando Las-Heras and Indirect Off-Axis Holography for Antenna Metrology

Antti V. Räisänen

Additional information is available at the end of the chapter Juha Ala-Laurinaho, Yuri Álvarez, Fernando Las-Heras and Antti V. Räisänen

http://dx.doi.org/10.5772/67294 Additional information is available at the end of the chapter

Ana Arboleya, Jaime Laviada,

#### Abstract

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.

Keywords: antenna measurement, antenna diagnostics, amplitude-only, interferometry, off-axis holography, indirect holography, phaseless, microwave holography, millimeterwave, submillimeter-wave

© 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.
