Highly Packaged LTCC Coupler Using Vertically Stacked LC-elements for 1 and 1.5 Tesla MRI Applications

Abstract

A highly packaged coupler using vertically placed inductors and capacitors (LC)-elements is proposed for 1 and 1.5 Tesla (T) magnetic resonance imaging (MRI) applications. The coupler is made on a 24-layer thickness low temperature co-fired ceramic (LTCC) substrate, and the full integration is reached by heaping up LC-elements in the vertical dimension. The coupler has a smallest reported size of only 0.0035 × 0.0021 × 0.001λg and a wide fractional bandwidth (FBW) of 44%. The measured in-band phase difference between the coupled and through ports and the amplitude imbalance are less than 91 • ± 0.5 • and 0.75 dB, respectively. Comparisons and discussions are also implemented.