S-band Dielectric Resonator Filter Design

Communication technology makes rapid progress since the end of the 20 th century.China began to build 2G network in 1995 and launched the 3G network in 2009.This process cost 14 years.In 2013,China formally began to issue 4G licenses,which means that the 4G network has been used commercially.The transition from 3G to 4G networks costs just four years.Many intelligent devices with complex functions begin to appear in terminal equipment application.To achieve these complex functions,the underlying hardware and devices are fitted for excellent performance and better indicators.Filter,as an important component in the signal processing system,whose performance plays a key role in the whole system.This paper focuses on how to improve the performance of the filter.Scholars,at home and abroad,have done a lot of research on the filter during several decades of time and made great achievements.There are many mature examples of the theoretical analysis and the physical design of the filter.Now research on the filter mainly focus on miniaturization,broadening the bandwidth and suppression of parasitic pass band.This paper mainly studies the dielectric resonator bandpass filter,which has many advantages and disadvantages.The work is focused on its strengths and weaknesses.This paper mainly includes following parts:1.This paper summarizes the basic theoretical knowledge about filters and dielectric resonators and the commonly used models of dielectric resonators,their working models and the design structure of dielectric resonant filter.The design ideas of this subject are obtained from former reviews.2.This paper designs a six-cavity band-pass filter,which uses a dielectric resonator with TE_01? as the main mode of operation.This structure can miniaturize the cavity,and its Q value is high.Researchers can use commercial dielectric resonators rather than costuming the size.This design structure can be quickly applied to commercial applications by changing the size of the filter cavity to achieve the requirements of filter.But its drawback is parasitic passband.3.A dielectric resonant band-pass filter for suppressing the parasitic passband was designed using a mixture of metal cavity and dielectric resonator.This structure not only uses the near distance from metal cavity high modulus to main mode,but also the high Q value of dielectric resonator.The farthest distance from the center frequency?2.75 GHz?of the out-of-band rejection of the filter can reach 5 GHz.