LTCC Inductors Research Articles

Increasing LTCC inductance density by using inverse coupling technique and multi-permeability structure

Inductor size is one of the biggest challenges to reduce the size of the portable electronic devices. Several methods are presented for reducing inductor’s size, among which LTCC has a specific significance in low power converters. Given the fact that it does not need any additional control circuits and also by considering its structure and constituent materials, the value of this inductor and its efficiency increases. This paper investigates LTCC inductor with the inverse coupling method in form of a multi-permeability structure. First, the inverse coupling inductor is considered in vertical and lateral flux patterns in the single permeability state and then, these inductors’ behaviors are considered in a multi-permeability structure by optimizing inductor’s core. Ultimately, a new structure in multi-permeability lateral flux inductor is presented which leads to increasing inductance density that is more phenomenal in low currents. Then, the behavior of the proposed inductor is investigated in a buck converter with 1.5 MHz switching frequency. It is observed that power density increases up to 735 (w/in3). Performance accuracy of mentioned inductor is confirmed by simulation in MATLAB and FEA2D FLUX.

Fine Tuning of 3D LTCC Inductor Properties Using Combination of Different Ferrite and Dielectric Tapes

Presented research offers solutions for properties alternation of 3D LTCC inductors by variation of materials implemented for their fabrication. Investigated geometry is solenoid‐shape micro‐inductor. Two types of dielectric cores are applied to achieve increase of quality factor for over 40% at GHz range. Five different stacks of ferrite material combinations are implemented when either fine inductance adjustments are needed or in cases when higher quality factor is required at MHz range frequencies. Increase of starting inductance of solid dielectric core solenoid is realized in tuning range of (35–60) %. Different ferrite core configurations can double quality factor maximum.

Comparison of Silver vs. Gold Systems in High-Q FTTF LTCC Inductors

Two different types of full tape thickness feature (FTTF) inductors designed to operate in the VHF/UHF bands were fabricated using the DuPont Green Tape 5738 Gold System and the 6141 Silver System. The first was a 50 nH inductor, with 5 turns and an 80 mil diameter. The second inductor was 20 nH with an 80 mil diameter, but with only 3 turns. High-Q measurements were taken to characterize the inductors. The measured results show that the Silver System produces inductors with Qs up to 110 whereas the Gold System only produced inductors with Qs up to 80. Depressions in the Q measurements were noticed at certain frequencies due to electromagnetic radiation losses. Methods to reduce these dips are also discussed.