Planar Gradient-Meander Line Microwave Inductor and Designing a 10-MHz–67-GHz Stopband Inductor for Ultrawideband Applications

Abstract

This article presents a new planar gradient-meander line (PGML) inductor, analyzes its characteristics, and provides a simplified expression for its high-frequency inductance approximation. We further introduce the procedure of PGML inductance that explains the high-frequency application principle of the inductance. Inductors of different sizes on the print circuit board (PCB) and monolithic microwave integrated circuit (MMIC) substrate are fabricated with the same length as the meander line inductors control groups. The samples for broadband microwaves have an excellent inhibitory effect. Full-wave electromagnetic simulations show that the first design on PCB has a more than 18-dB suppression from 10 MHz to 10 GHz, more than 37-dB suppression from 10 to 67 GHz, and a circuit area of $26\,\,\text {mm} \times {22}$ mm (occupied by maximum inductor). The inductance is about 0.4 nH @ 400 MHz, and the maximum Q value is 175 @400 MHz. The GaAs substrate design has a more than 10-dB suppression from 36 to 67 GHz, with a circuit area of $1.5\,\,\text {mm} \times {0.7}$ mm. The inductance is 5.5 nH @ 3 GHz, and the maximum value is 8.4 @ 3 GHz.