Compact LTCC Balun using L-C Embraced Structure for 128 MHz 3T MRI Applications

Abstract

A compact lumped-element balun is proposed for 128 MHz frequency 3 Tesla (T) magnetic resonance imaging (MRI) applications. The miniaturization is achieved by the inductor-capacitor (L-C) embraced structure, which places vertically-interdigital-capacitor (VIC) inside spiral inductor for higher integration. The L-C surrounded structure only takes up one element’s area without increasing the number of substrate layers. The balun is built on a 10-layer thickness low temperature co-fired ceramic (LTCC) substrate and has the smallest reported size of only 0.007×0.008 × 0.0009 λg. Moreover, the proposed balun also has a 2nd-order harmonic suppression of 32 dB. Furthermore, comparisons and discussions are also implemented.