Design Of Balun And Balanced Filter Based On Slotline

With the rapid development of wireless communication,the systems have become more and more demanding for anti-interference.The balance systems have received extensive attention and research due to its superior electromagnetic compatibility and effective noise suppression characteristics.As key components in balanced circuits,baluns and balanced filters are widely used in circuits such as balanced mixers,push-pull amplifiers,and antennas.This thesis is mainly based on the slotline to study and design the broadband and high-isolation balun,high-selectivity balun filter and high-selectivity balanced filter.The main contents of the thesis are:1.Based on the slotline,two broadband baluns with high isolation are designed.One is to combine the Wilkinson power divider and the asymmetric slotline to achieve high isolation and wideband inversion characteristics,respectively.The other is to load symmetric two-segment microstrips on the slotline.The resistor connects the two microstrips to absorb the signal reflected by the output ports to achieve high isolation.2.Combining the slotline split-ring resonator and the proposed ?-type structure,a balanced filter and a balun filter with high selectivity and wide stopband are designed respectively.The slotline split-ring resonator uses a zero-degree feed structure to introduce a zero on each side of the passband,which enhances the selectivity characteristics of the passband.At the same time,the proposed ?-type network achieves ultra-wide suppression for high-frequency harmonics.3.Combining the slotline complementary split-ring resonator and the slotline loading junction,a balun filter with a high selectivity and wide stopband is realized.A slotline is used to connect the slotline complementary split-ring resonator,and an additional zero and pole are added to the first passband to enhance the passband selectivity characteristics.Moreover,the introduced slotline does not affect the independent controllability of the two passbands.The balun with wideband and high isolation,high-selectivity balance filter with wide stopband,high-selectivity balun filter with wide stopband and dual-band balun filter with high selectivity and wide stopband have good application prospects in radio frequency communication systems.