Design And Research Based On LTCC Wide Stop Band Filter

With the determination of 5G communication standards,the paving of 5G trial networks and the rapid development of the Internet of Things,people have put forward higher requirements on the performance and volume of communication equipment.The filter acts as a key component in the communication device,and the miniaturization and high-performance design of the device greatly affects the performance and volume of the overall device.The emergence and development of LTCC(Low Temperature Co-fired Ceramic)technology provides a good solution for the filter required.The multi-layer structure unique to LTCC technology facilitates the miniaturization of devices.At the same time,due to its small transmission loss and high dielectric constant,it meets the high performance design of the filter.This thesis is based on LTCC research and design of wide stop-band filter.The specific research contents and achievements are as follows:1.Using the principle of electromagnetic hybrid coupling cancellation,a wide stop-band filter is designed by using electromagnetic coupling to cancel multiple transmission zeros in the stop band.The equivalent circuit diagram is given in the paper.Through the theoretical analysis and index calculation of the equivalent circuit,the mechanism of achieving wide stop band is explored,and its rationality is verified by simulation software.Innovatively coupled to source load coupling,introducing zero points near the passband,enhancing the steepness of the transition zone and improving filter performance.The final design and processing of the filter stop band is suppressed to the fourth harmonic,and the size is 2.6 mm × 2.6 mm × 0.8 mm.2.The new resonant unit structure metal cylinder is used to load the grounding capacitor,through the design analysis of the new resonant unit and the coupling structure,two wide stopband filters with different resonant stages are designed by using different coupling structures.The back-coupled wide-band filter has a stopband that is suppressed to the fifth harmonic,and its size is 4.4mm×2mm×1.2mm.The same-coupling wide-stopband filter stopband is also suppressed to the fifth harmonic,and its model size is 6.2 mm × 2 mm × 1.2 mm.3.The lumped cascading and semi-lumped cascading are used in different cascading modes.The lumped cascade uses a resonant unit parallel capacitance to generate a transmission zero point in the stopband to design a lumped combined wide stop-band filter.The analysis of the cascade circuit and the design of the lumped component,the design of the lumped low-pass structure,and the cascading of a high-pass structure to complete the design of the lumped cascade wide-band filter,Its stop band is suppressed to the fifth harmonic,the size of which is 6.4mm × 2mm × 0.96 mm.The semi-lumped cascade uses distributed inductors and capacitors to complete the energy transfer of the resonant unit.By designing a single structure and cascading two single-half lumped structures on the basis of this,the design of the semi-lumped cascode wide stop-band filter is completed.The final stop band is suppressed to the fourth harmonic,and the size is 4.2mm × 1.3mm × 1mm.