New High-performance Filter Of UWB Based On LTCC Technology

With the vigorous development of wireless mobile communication technology, the research of ultra-wideband system has important significance and great market value. Nowadays, ultra-wideband technology has been applied in many fields, not only can be used for position fixing, weapons guiding and some other military projects, but also for wireless LAN and other civilian facilities. People are putting more and more attention to the modern mobile wireless equipments which have a combination of advantages like high equality, low costs or small scale and so on. At present, the number of mobile digital devices is growing at an alarming rate. People put forward higher requirements for mobile communications equipment, so the completion of data reception and transmission of wireless devices must have a smaller size and faster transfer rates. In order to be able to achieve miniaturization and high performance, various functional modules and modular of the equipment need to be much smaller and modular to improve its working performance. UWB filter which is an important component in communication systems is also be given more requirements. The thesis adopts the new structure and the more advanced LTCC technology to achieve the UWB filter design. The main contents of this thesis are given below:In this thesis, focuses on two novel coupled resonator structure and the structure of the theoretical analysis and design, combined with LTCC technology successfully design a variety of new high-performance UWB filter. The main work is as follows:A new type ultra-wideband filter of cavity loaded has been designed by resonant rod and metal plane, which has the following characteristics:(1)the size of the resonator can be reduced by means of capacitive loading;(2)the coupling structure of decreasing the filter plane area could be found through the study of coupling between the resonators;(3) electric coupling and magnetic coupling transform could be adopted. Taking these points, a four poles filter and eight poles UWB filter designed of two topologies has been designed. To increase the sharpness of the edge band, the band-pass of the filter transmission zero is introduced. The eight poles UWB filter has been designed with center frequency4.4GHz, bandwidth of2.8GHz, relative bandwidth of63%, insertion loss of less than2dB, band rejection reaching40dB.Conventional interdigital bandpass filter using planar coupling, which plane area is large, and not beneficial to the integrated circuit device. In this thesis, the filter is designed by the vertical coupling resonant, which can reduce the plane area. A five band-pass filter can designed by the vertical coupling resonant. The input and output of the design of the five poles filter is at the same side of the filter and different heights. It has the impact on the device installated and performance. In this thesis, an ultra-wideband bandpass filter has been designed by two five vertical coupling cascading broadband filter, with a bandwidth of4GHz, less than2dB of insertion loss, input-output in the same plane. The planar area of the filter subsection, only4.1mm*4.6mm, as the increasing number of stages, the plane area could not increase, thereby it could improve the integration of the device.The UWB filter, based on LTCC3D integration technology has a band high rejection, a small plane area, low insertion loss, high reliability characteristics. Therefore, a new ultra-wideband bandpass filter design methods and tools can be used to achieve other bands and bandwidths, and have broad application prospects and reference value.