Exponentially tapered dielectric loaded probe for accurate near field measurements

This paper presents an exponentially tapered dielectric loaded probe. The backlobe of the probe is significantly reduced without increase the aperture size. The VSWR is less than 1.4 in the whole X band. The E field and current distribution are presented, which indicate the principle of the novel probe. The nominal radar cross-section (RCS) is below -25 dBsm in the whole frequency range. The performance of the novel probe is carefully compared with the standard open-end rectangular waveguide (RWG).