Design And Research Of LTCC Micro - Power Splitter And Directional Coupler

Nowadays, power distribution components are widely used whether in the phased-array radar, electronic detection, and electronic warfare military system, or in mobile communications, satellite communications, wireless LAN, TV, remote control, and other civilian systems. Therefore, obviously power synthesis and distribution technology has played an irreplaceable role in the system. Among them, Wilkinson power divider and directional couplers have been attracted more and more attention recently. Furthermore, the ever increasing demand for compact, high performance microwave components in RF front-end system leads to the requirement of miniaturized high performance power divider. Therefore, this paper mainly focuses on the design of high performance miniaturized Wilkinson power divider and directional coupler. The main contribution of our work can be summarized as follows:(1)In order to solve the size problem of traditional dividers such as microstrip structure, coaxial structure, and waveguide structure, the LTCC technology is employed for the 3-D integration of the internal buried inductance and capacitor. Meanwhile, the lumped form Wilkinson power divider is utilized to achieve the high isolation and good port matching performance. By utilized both ADS and HFSS simulator, a power splitter with a passband of 1.8-2.2GHz and a volume of 3.2mm* 1.6mm*0.9mm is designed through fitting the components in the principle diagram one by one.(2)For Wilkinson power divider, the debugging law based on LTCC lumped structure and the impact caused by inductance, grounding capacitance and shunt capacitance are firstly studied. Then, according to the scanning simulation of the parameters mentioned above, the impact on performance of power dividers is summarized. Finally, based on the analysis above, we designed two good performance power dividers with passband located at L-and S-band, respectively. Specifically, L-band passband was 0.9-1.2GHz, S-band at 2.8-3.7GHz, and their volume is 3.2mm* 1.6mm*0.9mm. The measured results show that the insertion loss is less than 1.5 dB and the isolation is better than 20dB. And the measured results show a good agreement with the simulated ones within the error allowed.(3)To solve the problem of oversize and high loss in the conventional microstrip directional coupler, double stripline based on LTCC technology and serpentine line was introduced to realize the high integration performance. Meanwhile, scan optimization is used to decide the length, width, and spacing of microstrip line according to the theoretical calculation. Finally we designed a miniaturization and high-performance directional coupler with volume 4mm*7.48mm*2.2mm, insertion loss less than 0.2dB, isolation degree better than 25dB, and working in 2.65-3.55 GHz.