INEXPENSIVE AND EASY FABRICATION OF MULTI-MODE TAPERED DIELECTRIC CIRCULAR PROBES AT MILLIMETER WAVE FREQUENCIES

Tapered dielectric fibers are widely used in the near
field microscopy to focus the incident beam or collect near field
signal. Single mode is always required so that the geometrical
dimension of the waveguide is smaller than the wavelength. This
paper proposes an inexpensive and easy fabrication of multimode
tapered Telfon probe which has bigger dimensions than the wavelength.
The field distribution in and outside the probe is analyzed by the
total internal reflection theorem and solid core circular dielectric
waveguide theory. Simulations are carried out in Microwave Studio
CST. Novel applications based on focal points in and outside the
probe are discussed, especially dielectric permittivity sensing of
biomolecules using a capillary tube is emphasized by the simulations
and experiments.

Publication year:2012

Keywords:multimode, tapered dielectric waveguide, dielectric permittivity sensing, capillary tube, millimeter wave