Lumped LTCC Coupler with Inductor and Capacitor surrounded Resonators

A high density packaged lumped is proposed for super heterodyne intermedia frequency (IF) band applications. The circuit miniaturization is achieved by the inductor and capacitor (LC) surrounded resonators (ICSRs), which install spiral inductor outside vertically-interdigital-capacitor (VIC) for circuit size reduction. The ICSR solely occupies one inductor’s size without substrate layer increasing. Using low temperature co-fired ceramic (LTCC) process with 10 layers, a small size of solely 0.004×0.004 × 0.00035 λ
g
is obtained. Furthermore, a 2
^nd
-order harmonic suppression of 35 dB is possessed as well. Discussion and comparison is done as well.