Development of innovated optoelectronic E-field probes for near field scanning

This paper presents an E-field probe especially for near field RF measurements [1-6]. Its whole loop includes antenna, solar cell as the optical power supply, VCSEL (vertical cavity surface emitting laser) as an electrical-to-optical communicator and photodiode as an optical-to-electrical converter. The probe operates at frequencies 300k~3GHz. Using optical signal transmission ensures a negligible field distortion. The technique of near-field scanning is presented in this paper with its schemes and transmittance plots. Also, the characteristics of the main elements are described, which improve the probe´s performance. Moreover, because asymmetric antennas are adopted for the probe measuring, not merely aiming at dipole antenna near field investigations, it will occasion the problem that the polarized direction will no more be unidirectional. In order to do all kinds of antenna near field measurements, by changing VCSEL component to VCSEL chip can solve the problem and bring extra benefits. The alteration discards the package method of TO-Can to diminish conductive material, reduces the probe dimensions and has a brand new design.