Design Of LTCC Passive Microwave Components For Bluetooth System

The continuous development of modern wireless communication technology requires excellent microwave modules with high integration density, which leads to the necessity of the miniaturization and high-performance of microwave device. As the essential parts of microwave device, Antennas and bandpass filters should be improved accordingly. Low Temperature Co-fired Ceramic(LTCC) is very suitable to be used in miniature antenna and filter due to its high performance such as low medium loss, high Q, etc. in microwave field. LTCC technique which employs multi-layer structure design allows configurations of microwave components to expand form 2D to 3D, and that makes it an effective way to realize components'miniaturization, integration, high reliability and low cost.This dissertation focuses on novel Bluetooth antenna and filter in LTCC technology and the neural network-aided design of them. The research covers the design of the novel Bluetooth meander-line antenna with a 3D feeding system of Tilt-shaped strip line in LTCC technology, multi-layer LTCC filter using Stepped Impedance Resonator(SIR) applied in WiMAX system, a novel LC type Bluetooth filter in LTCC technology and the network-aided design of them.A novel feeding system of Tilt-shaped strip line which is very similar to three-dimensional helical structure is proposed to design LTCC Bluetooth antenna. It is proved that the combination of meander-line radiator and 3D Tilt-shaped feeding system can realize the miniaturization of the LTCC antenna very well on the premise of acceptable performance by using the available space more effectively, and the following equivalent circuit analysis confirms the accuracy and reliability of the design; The proposed filter loaded with SIR exhibits compact size and the output performance of the filter is improved. With SIR structure applied to LTCC 3D circuit design, a cascaded SIR stacked LTCC filter with capacitor load is designed in this dissertation which can be applied in WiMAX system, the SIR unit only occupies 0.117λg; Then based on the research of the lumped parameter circuit of the microwave filter, a novel LC type LTCC Bluetooth filter is presented. The filter is constructed out of buried distributed inductors and capacitors which have clearly corresponding relations with the lumped parameter circuit. This can strengthen the guidance of the classical microwave filter theory to LTCC 3D microwave circuit design.The microwave components mentioned above give good performance to meet the Bluetooth or WiMAX systems, and also with small sizes and high stability. However, the relationship between the dimensions of the complex components and the output characteristics is very complex and nonlinear. So the aided design based on the neural models of the designed LTCC Bluetooth antenna and filter are used to clearly express the nonlinear relationship between the dimension of the components and their output characteristics.