Research And Design Of Miniaturized Antenna Based On Low Temperature Co-fired Ceramic Technology

The dramatically development of wireless communication and the trend of handset miniaturization lead all kinds of electronic devices development to the direction of smaller package size, higher integrated and performance. Also the antenna need to be miniaturized, which there should be wider bandwidth and good gain performance simultaneously. The laminated structure based on LTCC (Low Temperature Co-fired Ceramic) technology has obvious advantages for reducing the size of electronic devices which allows the conductors layout to expand from plane to three-dimensional.In order to overcome the defects of narrow bandwidth and low radiation efficiency caused by small-sized and high dielectric constant ceramic, this dissertation employs design methods using the LTCC material with low dielectric loss and LTCC multilayer layout technology, combined with high frequency electromagnetic field simulation software. The main work and research results are as follows.Firstly, it can be deduced various performance of parameter expressions related to antenna design using the antenna basic radiation theory. The theories of meander antenna and helix antenna are described. It can be gave relation expressions of physical parameters with the resonance frequency. And its correctness is explained through the two simulation examples.Secondly, the various ways are investigated to improve bandwidth and gain performance. Taking consideration of materials, a low dielectric constant and low loss tangent of the LTCC ceramic can be used to improve the bandwidth and gain performance. The experimental results shown that the bandwidth and gain can be improved by using the lower dielectric constant materials. Consider from the antenna structure, the multi-resonance method be introduced to improve bandwidth and increase the width of the antenna radiation conductors, so that improve the gain performance of antennas by expanding the area of radiation.A GPS antenna is designed using via-holes to connect the upper and lower radiators, with size of 10mm×3mm×0.77mm, bandwidth of 125MHz and gain performance of 2.62dBi. The relationship between the upper and lower layer height with the antenna return loss are analyzed. The other antenna operating in 2.45GHz is designed by the dual-resonance technology, which size is 3.2mm×1.6mm×0.8mm, bandwidth is 281MHz. Simulated results shown that the proposed two LTCC antennas meet all the expected requirements. Finally, the equivalent lumped circuits of helix antennas are derived to analyze antennas resonance performance.