Design Of Multi-functionality Baluns Based On Slotline And Microstrip Line

With the continuous development of modern wireless communication systems in the trend of miniaturization and high-integration,the requirements for the multi-functionality performance of the radio frequency(RF)front-end module are becoming more and more stringent.As the component with balanced-unbalanced conversion ability,balun is widely used in the design of antenna feed networks,push-pull amplifiers and balanced mixers.In this context,the dissertation focuses on the research of multi-functional integrated balun components,and is mainly carried out in the following aspetcs:1.Based on the dual-mode ?-type short-circuited spiral sloltine stubs structure,a tri-band and a quad-band balun filter is designed,respectively.Compared with the conventional shortcircuited sloltine stub,the proposed dual-mode ?-type short-circuited spiral sloltine stub introduces two highly controllable transmission zeroes simultaneously with high Q factor,and also introduces transmission zeros at the high frequency spurs.The designed tri-band and quad-band balun filter are therefore demonstrate high passband selectivity and wide stopband.2.Based on the muti-ring loaded microstrip-sloltine transition structure and hybrid coplanar waveguide(CPW)-microstrip stepped impedance resonator(SIR)structure,an ultrawideband balun filter with 161% franctional bandwidth is designed.The multi-ring slotline termination can effectively improve the bandwidth of the microstrip-sloltine transition structure,and reduce the radiation loss of the transition structure simultaneously;By employing the CPW-microstrip SIR hybrid structure,the high frequency spurs can be suppressed.The designed balun filter demonstrates ultra-wideband,low instertion loss and wide stop-band characteristic simultaneously.3.Based on the switched central-loaed parallel coupled-line structure,a RF component is designed with the functionality of balun,in-phase power-divider,single/dual-band singlepole-double-throw switch and shutdown mode.By controlling the biasing voltage of the PIN diodes,the parallel coupled line can operate at different circuit status,therefore the output port demonstrates different amplitude and phase characteristic;By employing the compensation network and central-loaded short-circuited stubs,the out-of phase bandwidth and port isolation can be improved.The designed switchable component can achieve more circuit functionality with less applied PIN diodes,together with wide bandwidth.The designed tri-band/quad-band balunfilter,ultra-wideband balun filter and switchable component with balun characteristic in the dissertation is suitable for the development of compact and highly-integrated wireless communication systems.