Electro-optic E-field sensors for shielding measurements up to 18 GHz

Two small intrinsically optical electric field sensors suitable for making shielding effectiveness measurements of small enclosures over the frequency ranges 50 MHz to 2 GHz and 2 to 18 GHz have been developed. Each sensor is based around a Mach-Zehnder optical modulator with a miniature antenna used as a sensing element. Fields as low as 0.1 m V m(-1) can be measured in the lower of the two frequency ranges with a dynamic range of 100 dB available for shielding measurements. Optical field sensors have been reported before, but not with the sensitivity described here, or the ability to operate up to 18 GHz. In addition, the sensors are made mainly with "off-the-shelf" components.