Design Rf Passive Components Based On LTCC Technology

The rapid development of technology has risen up the demands of wireless communication systems, particularly the requirements of more multifunctional, miniaturized, and cheaper RF-products. Microwave devices can be miniaturized using the multilayer wiring LTCC technology. High stopband suppression of bandpass filter can be achieved by adding transmission zeros in the stopband. Three different package sized bandpass filters are prepared and studied in the first part. Then the effects of key parameters on bluetooth antennas are studied theoretically and experimentally.Firstly, easy calculating formulas for theoretical design on bandpass filters are derived. The circuit model is simulated and tested by ADS software. Then, modeling on LTCC inductance and capacitance are studied, and the formulas for effective inductance and capacitance are obtained. Analysis on the principle of different ways to produce transmission zeros is focused. And appropriate methods for corresponding stopband needs are chosen. Eventually, according to the theories above, three types of widely used bandpass filters with different package sizes are designed, models of which are analyzed and studied to obtain the structure principle and effects of the key parameters. Experimental results show that the overall performance of the filters achievs the expectation, which in return confirms the theory obtained for design.In the second part, the performance parameters of antennas are briefly introduced. Relationships between each parameter are studied. And main methods to miniaturize LTCC Bluetooth antennas are summarized. 3D models of a bluetooth antenna are established. Test substrate and key parameters for the performance of antenna are explored. A simple microstrip line is chosen to feed. Optimizing simulation results indicate that 40mm×28mm×0.8mm is the best substrate size and the distance between the test board and the antenna C=5mm. Several ways to broaden the bandwidth of the antenna are obtained studying on the key parameters: Increasing the width of the conductor w and the distance 1d, Decreasing the width of the antenna xL and the hole height H. Ways to reduce the resonant frequency are as well obtained: Increasing 1d, xL and H, whilst decreasing w. Simulation results show that the center frequency of the antenna is 2.45 GHz, the bandwidth can reach up to 170MHz(relative bandwidth 6.9%), and VSWR ?1.5 in the range of 50 of ?MHz. Its highest gain is 1.61 dBi, and its overall size is 5mm×2mm×1mm.