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-(cid:12)red 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 (cid:2) 0 : 0021 (cid:2) 0 : 001 (cid:21)g 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 ◦ (cid:6) 0 : 5 ◦ and 0.75 dB, respectively. Comparisons and discussions are also implemented.