Modeling of intermodulation in a loaded-line phase shifter based on a polynomial varactor model
Artikel i vetenskaplig tidskrift, 2024

This paper investigates if there is an optimum design of loaded-line phase shifters with respect to phase shift/loss figure of merit (FOM) and linearity. The investigation was performed by comparing six loaded-line phase shifters that were implemented in printed circuit board (PCB) technology with shunt-loaded hyperabrupt varactor-diodes. It was demonstrated that the hyperabrupt varactor's C-V characteristics must be modeled with high accuracy to predict the nonlinear behavior. A polynomial varactor model was employed and experimentally validated. To extend the range of investigated parameter values, the extracted model was scaled and evaluated further in a circuit simulator. The investigation reveals that for a given varactor-capacitance, the phase shift/loss FOM is improved if the varactor-capacitance is evenly distributed and the unit cell length is much shorter than a quarter wavelength. The study demonstrates that the phase shift/loss depends mainly on the distribution of varactorcapacitance and Q factor. The intermodulation (IM) distortion is primarily proportional to the total varactor-capacitance per unit cell. The study also revealed that an increase in the varactor's Q factor results in higher IM. Therefore, it is a trade-off between low loss and low IM.

Författare

Martin Mattsson

Chalmers, Mikroteknologi och nanovetenskap, Mikrovågselektronik

Koen Buisman

Chalmers, Mikroteknologi och nanovetenskap, Mikrovågselektronik

Dan Kuylenstierna

Chalmers, Mikroteknologi och nanovetenskap, Mikrovågselektronik

International Journal of Microwave and Wireless Technologies

1759-0787 (ISSN) 1759-0795 (eISSN)

Vol. In Press

Ämneskategorier

Annan elektroteknik och elektronik

DOI

10.1017/S175907872400076X

Mer information

Senast uppdaterat

2024-11-27