Dual Lumped Ports Technique and Its Applications in Modeling of Planar Schottky Diode in THz Band

Micro-coaxial probe technique (MCPT) is widely used in three-dimensional electromagnetic (3-D EM) modeling of planar Schottky barrier diodes (SBDs) for the design of terahertz multipliers and mixers. However, the inconsistency of port numbers between 3-D EM model and intrinsic model of diode has been pended for years due to the lack of alternative internal port techniques. In this paper, after investigating port techniques available for field simulation software, a novel dual lumped ports technique (DLPT) is proposed to replace the MCPT for removing its non-physical grounding requirement, which makes the defined internal ports have definite physical meaning. Moreover, the proposed DLPT possesses higher accuracy than MCPT for the elimination of epitaxial layer penetration and additional consideration of port coupling effect. Detail technical procedures for DLPT are presented for internal double ports implementation. To verify its feasibility and accuracy at terahertz band, a 110 GHz broadband tripler was designed utilizing the proposed DLPT and the measured results agree well with the simulated ones. Furthermore, a series of frequency multipliers designed by MCPT are post-analyzed with the same models derived from DLPT. Finally, a slight discrepancy is observed between MCPT and DLPT, and the latter coincides better with the measured results. All these results indicate that the proposed DLPT is validated to be effective and accurate for the design of diode frequency multipliers and mixers in terahertz region.