||This dissertation aims to study and design a compact single-band and dual-band bandpass filter and EMI filter array for a personal portable system using low-temperature co-fired ceramic technology. First, a compact bandpass filter with wide stop-band in land grid array (LGA) is proposed. The design uses quasi-lumped LC resonator and open stub to create smaller size and better upper stopband performance. In the next, a new approach for design of a compact dual-band bandpass filter using series λ/4 resonators and an open-stub line with multiple transmission zeros is presented due to the requirement of different communication standards. The proposed device has two passband responses with low insertion losses and multiple transmission zeros (TZ) to deliver a wide stopband with high rejection level. To meet the requirements of various operating bands in different regions worldwide, reduce the number of components, and conserve space in the PCB, it is desirable to use a dual-band bandpass filter that covers all operating bands and that can be realized in a single integrated design. Therefore, a compact multilayer dual-band bandpass filter design with shunt architecture is proposed. The proposed dual-band filter has a dual passband to meet the requirement for different operating frequencies. The first (I) and second (II) passbands with small insertion losses have bandwidths near 380 MHz and 1350 MHz to cover all IEEE 802.11 bands in different regions of the world. This dual-band filter has multiple transmission zeros to supply a high rejection level as well. The filter was fabricated using low-temperature co-fired ceramic (LTCC) technology, resulting in miniaturized dimensions of only 2.5 mm (L) x 2.0 mm (W) x 0.7 mm (H). Finally, the measured results are in a good agreement with the simulated values.|
Following the developments in personal portable system which has multimode function, it could have EM interference at the interface. To solve this issue, a compact EMI filter array is proposed in the second part. This component is a full-integrated electromagnetic interference (EMI) filter array which was realized using mixed type material that is described for the first time, and this device is implemented via LTCC (low-temperature co-fired ceramic) technology . To miniaturize the size of the component and retain the high rejection and low insertion loss, a mixed powder material with a higher permittivity and lower loss tangent is used in the design and fabrication of the filter. The material system used in this study is BaNd2Ti4O12 (BNT) + Ni-Cu-Zn ferrite. The addition of Bi2O3 reduces the sintering temperature to less than 900 ℃. A compact EMI filter array architecture with a wide rejection band and sufficient isolation is introduced as well. In development of wireless communications, the spectrum for global 4G-LTE covers different frequencies of 700 – 2600 MHz. In this investigation, an EMI filter array is presented that rejects unwanted frequencies from 700–2690 MHz and covers all 4G-LTE bands. The overall dimensions of the EMI filter array are 1.6 mm (L) x 0.8 mm (W) x 0.5 mm (H), the smallest reported so far. The measured results of the developed filter are in good agreement with the results simulated by a full-wave electromagnetic simulator.