Research On Wideband Filter And Filter Power Divider Based On LTCC Technology

The transmission of information must use the frequency spectrum,but the frequency spectrum is very limited.However,the continuous development and application of communication technology has led to the excessive use of radio spectrum.Narrowband system and planar technology can not meet the needs of practical application.People turn their attention to the wireless communication equipment with new technology.Wideband technology can provide an alternative to the spectrum scarcity.Multilayer technology has become an ideal choice for miniaturization,compact structure and solid components.Combined with the above background,this paper focuses on Wideband filter and filter power divider based on LTCC technology.This paper includes the following research results:1.The traditional fourth-order split ring cross coupled filter has been studied.Firstly,the placement position of the split ring resonators is studied,and it is found that different opening directions can cause different coupling forms.Then,based on the coupling matrix and design method of the cross coupling filter,the fourth-order split ring cross coupled filter is simulated and analyzed.Finally,it is concluded that the filter can generate a pair of zeros through cross coupling,but the bandwidth of the structure is narrow and still needs to be improved.2.A four wire interdigital coupled wideband filter has been proposed.Firstly,aiming at the problem that the bandwidth of the split ring resonant CQ filter is too narrow,a four wire coupling structure is introduced based on the two-wire coupling;Then,by studying the multi line interdigital structure based on Lange coupling structure,it is found that the parallel coupling line structure connected by gold wire bonding line between each resonant unit effectively increases the bandwidth.This structure makes the filter miniaturized,the relative bandwidth increases to 28%,and the return loss is less than-15 d B.At the same time,two attenuation poles are generated outside the band,which are located at 7 GHz and 12.5 GHz respectively.The performance of the structure is obviously improved.3.A filter power divider based on LTCC multilayer technology has been proposed.Firstly,the structure of UWB power divider is selected,and then the vertical transition structure from stripline to microstrip line in LTCC structure is studied.It is found that adding a grounding through hole in the dielectric layer can eliminate the resonance point in the parameter curve,effectively suppress the outward radiation of electromagnetic wave,and finally improve the performance of the transition structure;Finally,the two-stage power divider and the two-layer four wire interdigital structure filter structure are connected through the vertical metal through hole.Through the analysis of the through hole diameter and the through hole diameter of the grounding plate,the overall structure is optimized.HFSS simulation results show that while realizing miniaturization,the filter power divider has good performance characteristics.At the center frequency of 10.5 GHz,the relative bandwidth reaches 27%,the return loss is better than-15 d B,the insertion loss is-4.5 d B,and the isolation is better than-20 d B.