Optimal design of precision slab-line for N type coaxial automatic tuner

This paper presents a simple precision slab-line for N type coaxial automatic tuner. The precision slab-line in N type coaxial automatic tuner is firstly calculated by conformal mapping principle. Then, the transition section between coaxial transmission line and slab-line is optimized using misalignment compensation method. The dielectric support included in the precision coaxial adapter is also designed by coplanar compensation law. Finally, these three modifications are utilized to achieve the overall improvement slab-line with very well match in the designed frequency-band. The measured VSWR results are better than 1.10 from 1GHz to 10GHz using the vector network analyzer.