Electro‐optic field probe sensor incorporating a high‐k dielectric with an aperture

Abstract

AbstractAn electro‐optic field probe sensor relying on a lithium niobate sensing tip, which is integrated with a fiber collimator, was proposed and fabricated. A high‐k dielectric sheet with a circular aperture at the center was placed in front of the sensing tip to concentrate and strengthen the field near the aperture, leading to an improvement in the sensing capability. The applied electrical field/power was successfully estimated from the optical output power from the sensor, which is dependent upon the electro‐optic effect induced phase retardation between the ordinary and extraordinary waves traversing the electro‐optic sensing tip. The completed sensor functioned successfully up to a frequency of 1.2 GHz. The sensor was used to scan a microstrip test circuit to provide the field distribution. The results are in decent agreement with the theoretical results obtained through a HFSS based simulation. Finally, a high‐k sheet with a dielectric constant of up to 90 was introduced, which improved the sensitivity by ∼10 dB. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:151–153, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25658