Development of SMD Chip Inductors for RF System Applications

The objective of this research was to investigate micron size, high-performance, solenoid-type RF chip inductors utilizing low-loss Al2O3 core materials. To accomplish the paper objectives, first, the high frequency characteristics of the inductance, quality factor, impedance and equivalent circuit parameters of the developed solenoid chip inductors were measured and analyzed using a E4991A RF impedance/material analyzer with E16197A test fixture. Then, the size of the RF chip inductors (1.0x0.5x0.5 mm(3)), the materials (96% Al2O3) and shape (I-type) of the core, the diameters (40 mu m for N=6 and 30 mu m for N=12) and position (middle) of the coil, and the lengths (0.35 mm for N=6 and 0.4 mm for N=12) of solenoid were determined by a Maxwell three-dimension field simulator to maximize the performance of the inductors. The developed inductors with 6 turns have inductances of 10.99 to 11.29 nH and the quality-factors of 22.33 to 65.68 over the frequency ranges of 250 MHz to 1.7 GHz. The simulated data predicted the high-frequency data of the inductance and quality-factor of the inductors developed well.