Ltcc Multilayer Chip Duplexer

Nowadays LTCC technology (Low Temperature Co-fired Ceramics)has become a high-quality and effective technology for passive integration, which can satisfy the requirements of miniaturization, lower cost and higher frequency applications. Diplexer passive integration including derivation of equivalent circuit model for LTCC capacitor, design and implementation of LTCC diplexer is studied in this dissertation.Based on cited reference, derivation and verification of traditionalπand T broadband equivalent circuit model of LTCC capacitor at high frequency are presented. The equivalent circuit model is established using the method of combination matrix Y,Z and physical circuit model which simplifies the process of derivation. The results of derivation are consistent with conclusions of literature. The typical MIM capacitor is used to verify high-frequencyπand T equivalent circuit model. HFSS simulation results agree with those ofπequivalent circuit model simulated by Ansoft designer up to self-resonant frequency. T equivalent circuit model includes two-order resonant frequency and results in several times larger.To design and implement complicated LTCC diplexer effectively, simple low pass filter with cut-off frequency 400 MHz is simulated by Ansoft HFSS and implemented in 0805 package size for verification about design software and experimental process. The measured results of LTCC filter agree well with the full-wave electromagnetic simulation responses, showing that design and implementing procedure are feasible. Based on this successful case, an implementation example of LTCC diplexer with low frequency passband from DC to 200MHz and high frequency passband from 1.5GHz to 1.7GHz is discussed. Insertion loss in both pass band of diplexer is about 1 dB. Finally, simulation results and measurements agree well except attenuation out of passband, which is due to imprecise implementation process according to SEM analysis.