A wideband diplexer using multilayer inductors for compact wireless LTCC modules

In this paper, we present a compact wideband diplexer based on the low temperature co-fired ceramic technology. To realize wide passbands and a compact size, a new design method uses multilayer inductors. This method can also eliminate the matching circuits between a common port and wideband bandpass filters. Its performance has been simulated and optimized by the finite element analysis. The diplexer can separate a low-frequency band (0.9–1.8 GHz) and a high-frequency band (2.4–4.5 GHz). It achieves wide passbands and a very compact size (5.0×3.0×0.552 mm³).